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View Full Version : BUILD LOG: Sturdy and Fast all Steel CNC , my first build



Boyan Silyavski
22-08-2013, 10:45 AM
Hi there,

I am on the way of my 1rst real build. The idea is to be fast and sturdy. I am building it for a friend by order. Its a smaller variant of a sturdy machine i designed not long ago for my self which i would build after that build, which will serve also to figure some points of the process.

I have a lot of questions and will appreciate any help with this one, as i would like to make it really right.

From my part, once finished, i will provide the Sketchup plans for free here, so anybody can use them if wished so.

Some of the design points:

1. All steel soldered construction. Overbuild for stiffness, avoiding weak elements in the design.
2. Money is not an issue for the frame or the length of the supported rails, so i am not going to go cheap to save 10cm of rail or steel profile.
3.This machine is for continuous 3d jobs routing plastic or composite epoxy based materials so a desired stable routing speed of 300ipm is the goal
4. Usual job size would be 800x400x160, hence that commands the gantry clearance and z design
5. 3d continuous very detailed jobs, > 24h sometimes, made me choose a low power spindle like the 0.8kw water cooled one. Electricity cost is an issue here

So i am at the point of finishing the design, still waiting for some details on the profiles. Already started purchasing the components. I hope in 3 months it should be making dust:afro:

Here are some pictures of the design, still not finished:

9726972797289729

Profiles used 180x80x4mm
gecko 540
Nema 23 low inductance motors , CNC routerparts Pro Rack and pinion drives 1:3, mod 1 rails, Hiwin HG 20 rails with long wide bearing blocks on all axis,
All plates are 10mm thick mild steel,

The doubts:

1. Now before i finish the design and order the profiles and plates , i wonder about the gantry weight. My design is 1000mm 180x80x4 profile with soldered over it at all sides 10mm steel plates. Basically the profile weight will be around 15kg ,reinforcing it will be another 50 kg+ the side plates another 10 + 2 motors and drives + Z another 12-15kg=more or less 100 kg. I am waiting for an advice from CNC routerparts about the gantry weight. If it heavy i can hollow some holes in the reinforcing plates to bring it to the desired weight , however i would like to reinforce it more than leave bare profile.

2.Another point here is that i am not sure if i can bolt to 4mm profile directly threading it or should be 10mm plates below RP rails, Hiwin rails, as i designed it

Notes:
- the table would sit on 2 more rails same of similar size soldered. This should raise it for the cable guides and stiffen it, to avoid twisting . I am contemplating making a case there and all electronics mounted inside the base of the machine

What do you think about the design?

JAZZCNC
22-08-2013, 06:49 PM
Hi,

Well the design looks strong but you have some quite major conflicts going on here.?

First the weight of the gantry really means your on the very edge of needing Servo's not steppers.!

Next because your using R&P then efficiency is very low so larger Nema34 motors will usually be needed to deal with this and the weight of the gantry.
The G540 is limited to 3.5A and 50V which isn't nearly enough for Nema 34 motors which you'll need at least 75Vdc or higher and more amps.
Nema 23 motors (even low inductance) just will just not be able to handle the Inertia this gantry's weight will put on them. Plus combined with R&P they will also struggle to give fast acceleration with that heavy gantry which you'll need for 3D work.
Even with larger Drives and higher 70Vdc voltage nema23 motors won't work with this weight gantry and high speed requirements.

Really I wouldn't recommend R&P for a machine this size and with your requirements for accuracy and 3D work, Ball-screws are the only way to go.!!. . . .You'll seriously regret using R&P.

Regards Steppers or servo's then I'd say lighten the gantry 20-30Kg and use Nema 23 motors running on 80Vdc drives with 70Vdc power supply and connected to 10mm pitch ballscrews.

If you don't lighten gantry then I'd say choose Servos has they will handle the inertia and speed much better.
Larger Nema 34 motors will handle the inertia at slower speeds but not do so well with the combination of speed and inertia has because they spin considerably slower than Nema23 motors they will struggle with reaching higher speeds anyway and the torque will be low at high speeds so with heavy gantry will struggle to handle inertia when changing direction.

So Above 80KG gantry at speed will need servos.

With Electrics in base of machine then I wouldn't recommend it has vibrations tend to loosen wires and don't mix well with sensitive electronics.!!

The 4mm steel will be fine for threads with rails.!

Boyan Silyavski
22-08-2013, 07:25 PM
Thanks. I am starting to realize this.

Let me explain something.

This build is a rip-off of my design for my next build which is meant to ride on 34 name Rack and Pinion.

I spend quite some time asking people around when i designed it, so it seems the overall opinion was that a 150kg gantry is quite well driven by 34 nema rack and pinion, i mean the acceleration and deceleration. There were even people on CNCzone that insisted that the gantry behaves well if is loaded more than 130kg so they made it heavy on purpose.

So everything started as i would like to test the RP on a real build, The nema 34 would raise the price, so i went for Nema 23 and started slowly underrating my original idea.
Now Just received an answer from CNCrouterparts and Ahron tells me what i suspected , that the g540 is not up to the task and i should couple their low inductance motors with better drivers, due to possible g540 overheating during long runs.

So it seems i am insisting on the RP drives:hysterical: . I like to test them and could not help . I am at the point of ordering the RP drives , racks and the low inductance Nema 23 . That means i must lower the gantry weight.

Ok, gantry weight.
Lets see. I can go back to 50 kg, complete gantry with Z, still keeping some reinforcement. Only eventual twisting should be considered, z is 300mm wide so no worry there in the other directions. Another point is that normally the jobs will be done with rough cuts by 1/4 router bits and fine passes 1/8 router bits, with passes equal to the width, routing wood as i said and that easy going special cast materials which route like MDB , so this is not a factor that would play in the final design.

Jazzcnc, i highly value your opinion. Why you believe the Chinese ball screws 2010 for example could give me better finish than the RP drives? All seem to be happy running RP drives, did i miss something? I know the table is not so big to really need RP.

JAZZCNC
22-08-2013, 08:05 PM
Jazzcnc, i highly value your opinion. Why you believe the Chinese ball screws 2010 for example could give me better finish than the RP drives? All seem to be happy running RP drives, did i miss something? I know the table is not so big to really need RP.

Those people on the Zone are probably only using R&P because.!
A: They are large long machines so ball-screws are harder to use.
B: They can't afford Us made Ball-screws and the Yanks are very reluctant to Import Chinese parts.
C: The CNCRP R&P is US made so fits with above.
D: They have never used ball-screws so they don't know the difference in performance and smoothness ball-screws make.

My advise is just that "Advise" take it or leave it but I know thru experience with R&P that Nema23 motors with heavy Gantry is recipe for trouble if your wanting high feed rates.

Yes I know Nema 34 will handle heavy gantry ok and that heavy helps with cutting but Heavy and high feed rates is a completely different issue.!
Combine this with 3D work which requires Small fast direction changes and this issue becomes worse.

Now the difference between R&P and ball-screws is several.

Ball-screws are much more efficient so don't require has much power to turn, typical efficiency for Balscrew is 90%+ were R&P is 60% or lower.
Ball-screws have much lower backlash so are far more accurate and repeatable. R&P is quite high backlash and not easy or cheap to make real antiback lash using correct pinions.

R&P resolution is much lower and to get higher resolution requires at least 3:1 gearing this in turn means steppers need to spin fast and has you may or may not know torque drops off fast at higher speeds on steppers and even more so on Nema 34 motors unless running really high voltage.

R&P is noisy and needs much more maintenance and protection from chips etc.

Ball-screws give a silky smooth action where has R&P is in comparison a clunky action so this does translate back into the cutter at some level.!!. . . For general wood working then this is fine and doesn't get noticed but if your wanting high quality finish or high detail then you will see a enough difference compared to ball-screw machine.

Again just My opinion and you choose to take my advise or not.? . . . . But let me just say go try to find some one who has experience of Both and ask which they would choose for a machine this size, weight and with your requirements.?? . . . . I know the answer because I've give it you.!!

Boyan Silyavski
22-08-2013, 08:13 PM
OK,
I get it. I appreciate the help.

Then what would be your exact recommendation?

Drivers, breakout board, nema 23 motors , PSU combination in combination with which ball screws?

JAZZCNC
22-08-2013, 08:37 PM
OK,
I get it. I appreciate the help.

Then what would be your exact recommendation?

Drivers, breakout board, nema 23 motors , PSU combination in combination with which ball screws?

Ok for this size and with Gantry upto 70-80KG.

80V Digital drives and recommend Leadshine AM882
3Nm nema 23 motors like these SY60STH88-3008BF (http://www.zappautomation.co.uk/en/nema-23-stepper-motors/380-sy60sth88-3008bf-nema-24-stepper-motor.html)
70Vdc PSU preferably unregulated toroidal with correct amperage for all motors.

BOB recommendation is difficult because the one I'd recommend and think is by far the best is PMDX 126 but it's expensive. PMDX.COM - Products for CNC and motion control applications (http://www.pmdx.com/PMDX-126)
The next I'd recommend and use often so know are OK boards is this one. OPPB (http://www.diycnc.co.uk/html/oppb.html) but it's not in the same league has PMDX.

Ball-screws would be 10mm pitch and 16mm Dia for X & Y axis with 5m pitch 16mm dia. Motors would connect to them using 15mm HTD timing belts and pulleys with 1:1 ratio. This lessens resonance which helps on a steel framed machine and it's much more flexible if you ever want better resolution or higher speed has it's easy to apply a ratio with simple pulley change.
20mm Dia 10mm pitch could be used but really not required at this length and would be over kill, would also restrict performance not increase due to extra inertia of larger screw and ballnut.

All the above I've used on several steel framed machines with gantry's approaching 80Kg so know they work.!!

Boyan Silyavski
22-08-2013, 10:01 PM
80V Digital drives and recommend Leadshine AM882
I see that these get more popular here than the geckos. I read some threads here on the forum. I will go with them


3Nm nema 23 motors like these SY60STH88-3008BF (http://www.zappautomation.co.uk/en/nema-23-stepper-motors/380-sy60sth88-3008bf-nema-24-stepper-motor.html)
I had my eye on these as a substitute for the ones that i had to buy from abroad and pay duty. I will look deeper in the specs, but most probably will order them through Zappautomation.


70Vdc PSU preferably unregulated toroidal with correct amperage for all motors.
No idea for this one. I should educate my self how to calculate this amperage and from where to get the transformer.


BOB recommendation is difficult because the one I'd recommend and think is by far the best is PMDX 126 but it's expensive. PMDX.COM - Products for CNC and motion control applications (http://www.pmdx.com/PMDX-126)

I was looking into this one. For sure i need a board with 2 LPT connections as i need more ports for communicating with the VFD, turning on mist and vaccum and
On my actual small machine i have trip signals from the VFD and power detection which are very handy in real life. And a second BOb af course. So that BOB wins. Actually its not so expensive for what it offers. I spend more money on my 2 boards.


Ball-screws would be 10mm pitch and 16mm Dia for X & Y axis with 5m pitch 16mm dia. Motors would connect to them using 15mm HTD timing belts and pulleys with 1:1 ratio. This lessens resonance which helps on a steel framed machine and it's much more flexible if you ever want better resolution or higher speed has it's easy to apply a ratio with simple pulley change.
20mm Dia 10mm pitch could be used but really not required at this length and would be over kill, would also restrict performance not increase due to extra inertia of larger screw and ballnut.

All the above I've used on several steel framed machines with gantry's approaching 80Kg so know they work.!!

Sorry, i dont understand you:gorilla:

1. 1610 for long axis that moves gantry and 1605 for the gantry / that moves Z/ and 1605 for the z, correct?

2. I buy belts from Belting online. Should i use the minimum sized belt pulley or go a bit bigger for the size of belt i mean? What is the typical size? I cant seem to find the sheet i used for calculating belts. I remember the AT was stronger but a kind of harder. Obviously either way it should be pitch 5, otherwise i have to go with bigger pulleys

JAZZCNC
22-08-2013, 10:22 PM
No idea for this one. I should educate my self how to calculate this amperage and from where to get the transformer.

Will PM you about this has it's easy misunderstood and don't want others reading and not understanding properly so getting into trouble blowing stuff up and electrocuting them selfs.!!!!!




Sorry, i dont understand you:gorilla:

1. 1610 for long axis that moves gantry and 1605 for the gantry / that moves Z/ and 1605 for the z, correct?

No 1610 for Long X Axis and Gantry Y Axis (moves Z).
Then 1605 for Z axis (UP/DOWN)


2. I buy belts from Belting online. Should i use the minimum sized belt pulley or go a bit bigger for the size of belt i mean? What is the typical size? I cant seem to find the sheet i used for calculating belts. I remember the AT was stronger but a kind of harder. Obviously either way it should be pitch 5, otherwise i have to go with bigger pulleys

Don't go less than 18 teeth and I always use 20 teeth has the belt engages pulley better giving better wear.
Don't use less than 15mm wide belts and I find 15mm is perfect size. 20 or 25mm is overkill and wasted money.
HTD is the preferred belt type for it's profile but don't think it would make a big difference here anyway has the belts are only short and not under much stress or heavy loads.

Yes 5mm pitch.

Boyan Silyavski
23-08-2013, 12:54 AM
After some fast brainstorm i decided on the CNC4PC breakoutboard 23 (http://www.cnc4pc.com/Store/osc/product_info.php?cPath=33&products_id=182) coupled with solid state relay board (http://www.cnc4pc.com/Store/osc/product_info.php?cPath=24&products_id=132). This board seems more perfect for me:

1.I have my spindle control board from him and the support was great
2. All IC are mounted for easy removal without soldering / this is a big deal, i have repaired breakout boards in the past /
3. All necessary functions and really no extra ones that i dont need and would pay for choosing other boards
4. Better priced than the PMDX 126. When i started adding the spindle control/ not integrated/ ,relays, inputs, outputs, cables and so, the price jumped a lot
5. Some extra jumpers and functions i like
6. Straight out from the box 2 ports BOB with most possible inputs and outputs

Soon will start showing you packets :kiwi-fruit:

Thanks again to Dean/ JazzCNC/, now i know quite more than yesterday:monkey:

Tomorrow will redraw the design for the ball screws.

JAZZCNC
23-08-2013, 01:19 AM
Erm.!!! . . . Arturo's stuff is ok but it's no where near has good or well built has PMDX boards.!

Boyan Silyavski
23-08-2013, 01:32 AM
Erm.!!! . . . Arturo's stuff is ok but it's no where near has good or well built has PMDX boards.!

He he he, maybe not but i have been with faulty breakout board and had to wait a month for an exchange. The easily removable IC is a feature that living here in Spain is a must.
the local electronic genius has work for 3 months ahead. And i am not into electronics repair really. Sometimes simpler is better.

Boyan Silyavski
24-08-2013, 02:47 AM
Today after whole day drawing, considering, redrawing, considering... designed the ball screw assembly on Y/ the long axis that moves the gantry/.

I wanted it sturdy, compact, at the right place and most of all easy to rectify and assemble. Following step by step. Still have not figured the belt length, so a minor correction maybe tomorrow. Other challenge was how to keep the working distance at maximum and at the same time ball screw length minimal.

Designed the hard stops with threaded holes for proximity sensors. A bit overbuild but for sure there will be crashes as the guy is a new to CNC.

Some pictures. Have to finish the design this weekend in order to buy the rails, ball screws and order the laser cut pieces.

9753 9754 9755 9756

Robin Hewitt
24-08-2013, 12:39 PM
I don't really understand why the spindle motor is sitting so far below the gantry?

The maximum depth of cut is usually the longest tool that you can fit.

If this to engrave the top of a large object, to clear hold down fixings or what?

CraftyGeek
24-08-2013, 12:46 PM
Isn't it more a case of the gantry being positioned high, rather than the spindle being low?
If the bottom of the gantry was level with the top of the x-axis it wouldn't be anywhere near as bad?

Boyan Silyavski
24-08-2013, 01:36 PM
Hi,

as i mentioned before but maybe you missed it, this machine exclusively will be used for 3D jobs most of them in the 140mm-170mm height region. Not for lettering, woodworking or similar.

The guy is doing model yacht building. So shapes would be very strange
So the Z that enters the zone below the gantry should be thin, as not to touch the other parts of the model while the bit is routing deep below hollowing something.

Check my picture and will see for yourself what i mean. Its a specific 3D job machine. I don't believe that reinforced 20mm steel plate for the spindle with 10mm ribs is flimsy as you suggest.

If you have any other ideas i am open to suggestions. Point me to a better solution and i will change the design.

9759

Gytis
24-08-2013, 04:12 PM
in my opinion with so wide Z axis plates you just wasting a lot of material and travel in Y axis direction.,
with 20mm profiled rails you can do Z axis on 160mm wide plate, and extend travel in Y direction, or just save matirial in all you built.

Boyan Silyavski
24-08-2013, 05:42 PM
in my opinion with so wide Z axis plates you just wasting a lot of material and travel in Y axis direction.,
with 20mm profiled rails you can do Z axis on 160mm wide plate, and extend travel in Y direction, or just save matirial in all you built.

Hi,
you are quite right. However let me explain please. 10cm more of rail on both sides+10cm more of screw+10cm more of steel profile=no more than 60 euro, which is irrelevant in this build. If we look into KG , they are 5-6 kg more on the gantry
However an ATC is very expensive. And is quite necessary for 3D jobs. Should the need arise to upgrade, for the mere cost of 2 more short supported rails and bearings+another chinese spindle i can mount double Z axis with minor modifications and most importantly without compromising the work dimensions. One spindle will rough the other will detail and finish.
I mean, there also some other points of the design that are done with some things in mind. Its not a general hobby machine.

Boyan Silyavski
26-08-2013, 12:28 AM
After some tinkering i woke up that i am not making the CNC for myself and that i am overbuilding it too much. And overthinking it about the eventual future. Went to the local metal shop and checked the profiles. There was 140x80 profile that seemed quite good, so instead of searching for the 180x80, i sat down and redesigned everything, it was fast though taking away things. Changed the profile sizes, took away the reinforcing plates on the gantry, though i left place if i later decide there are vibrations. redesigned the Z narrower and so on. The benefit is that the profile enters the magic 6m number, as they sell it by the 6m.

So following your advice i finished with smaller and lighter gantry, like 30kg, shortened it and now everything is exactly as it should be, no over sized stuff in my opinion. 1000x400x170mm working area, as wanted by the guy.
What do you think?

97649765976697679768

JAZZCNC
26-08-2013, 10:31 AM
What do you think?

Couple of things.!! . . .The Z axis is wrong and your weakening not making stronger.? The spindle hanging down like that in conjunction with rail/bearing setup is a constant length lever at any Z extension.
It won't allow any better clearance when cutting has the Tool length mostly dictates this and your spindle support plate will still catch just like the bottom of Z axis would.
Much better option IMO would be to flip the rail and bearing setup so you have a variable length lever when extended giving much better strength and just build a sturdy spindle bracket that allows percentage of the spindle body to extend below Z axis plate.
This extension along with tool length will be give enough clearance for most 3D work. If the guy needs more clearance then better to buy longer tool and cut slower than compromise the machine in all other areas.!!

With the proximity sensors (Or limit switches) because of the small gaps required to work correctly then I wouldn't put them at the ends were they will get run into if crashed. Position them so they get passed by or over this way nothing gets crushed.

Boyan Silyavski
26-08-2013, 01:27 PM
Couple of things.!! . . .The Z axis is wrong and your weakening not making stronger.? The spindle hanging down like that in conjunction with rail/bearing setup is a constant length lever at any Z extension.
It won't allow any better clearance when cutting has the Tool length mostly dictates this and your spindle support plate will still catch just like the bottom of Z axis would.
Much better option IMO would be to flip the rail and bearing setup so you have a variable length lever when extended giving much better strength and just build a sturdy spindle bracket that allows percentage of the spindle body to extend below Z axis plate.
This extension along with tool length will be give enough clearance for most 3D work. If the guy needs more clearance then better to buy longer tool and cut slower than compromise the machine in all other areas.!!

With the proximity sensors (Or limit switches) because of the small gaps required to work correctly then I wouldn't put them at the ends were they will get run into if crashed. Position them so they get passed by or over this way nothing gets crushed.

Thanks guys for the input. I seem to have been missing the obvious.

I redesigned it following the advice. Now things seem better / to me at least :-) / . What about the result? By the way i have bought already the spindle brackets/2/ . I liked the design because can fix them on a guiding plate so if i have to move them its easy to align them.

So now the rails move and the bearing blocks stay at optimal position. If he wants to cut thin material he can fix a 10cm high MDB surfaced table made from a couple of boards glued together so there will be no need to change spindle position at all. And take it off when he likes to do deep jobs.

Can i cut the motor shaft from the back side? Is it enough place for the cables of the motor? See picture. I need to further redesign it a bit otherwise i have to solder it with the motor in place , he he he. Ok, i wouldnt do it so. Just joking.

97709771977297739774

JAZZCNC
26-08-2013, 02:34 PM
If this guy is wanting mainly to do 3D work then I'd also look to make the Front Z axis plate the narrowest and lightest you can make it.
Keep the Y axis bearing spacing wide but bring the Z rails in the most you can get away with and have light narrow front plate.

3D requires fast directional changes and high acceleration so anything to help here will speed up the job.!

Regards the motor access you have enough width and height in that plate to cut an access hole for motor and still not lose any strength, will cut weight too.! . . .Win win.!!

Boyan Silyavski
26-08-2013, 03:13 PM
If this guy is wanting mainly to do 3D work then I'd also look to make the Front Z axis plate the narrowest and lightest you can make it.
Keep the Y axis bearing spacing wide but bring the Z rails in the most you can get away with and have light narrow front plate.

3D requires fast directional changes and high acceleration so anything to help here will speed up the job.!

Regards the motor access you have enough width and height in that plate to cut an access hole for motor and still not lose any strength, will cut weight too.! . . .Win win.!!

Thanks Dean,

I finished with a 130mm wide fron z plate. It should be enough. I dont believe it can compromise anything, as in my router i have exactly this plate using only one slide with the wide flat rail+ 2 bearing blocks and is ok strong. However i would not like do it like this in this build, cause later i have to play a lot with hole placements and finding screws that could fit under the plate and then aligning it. As i did with mine.

I have another question. When laser cutting, should i do exact holes that hold the plates to the bearing blocks or i should elongate them. Cause how do i know that the rotating nut will fit exactly at that place. Otherwise i will loose some millimeters from the travel. How it is done?

97759776

Boyan Silyavski
29-08-2013, 07:49 PM
Hi there,
today worked more on the drawings, mostly lightening things where possible without compromising strength. Starts to look like a cheese. However all holes will be closed with bolted light plastic plates so at the end will be quite dustproof even if its not seen on the drawing.

Received the spindle mount brackets. And made an important decision.
Well the 2 brackets are very nice, especially for the money, but... not the same as on the sellers picture. In fact they are so robust that i will use only one. man, they are big.

The important decision is that until i don't have the ball screws and the Hiwin rails at hand Not to order and laser cut pieces and not do any soldering at all. My design heavily depends on the exact hole placement and the laser cut pieces, because i have at hand a very cheap laser service, so cheap that it would be more costly to than to draw by myself and drill the holes at home from junk steel plate with my flimsy drill. And as i don't have a mill at hand and the service here in Spain is very expensive, laser cut is the way for me. Which gives me quite a freedom in my design.

I need some help with the following because i have no idea at all:

1. Proximity sensors

Ok, i designed a plates for them, there is like 12mmm possibility for adjustment. Will solder the plates /10mm thick/ directly on their places. But..

-How far from the actual x,y,z hard stop ???? / x = moves the z , y=moves the gantry/
-any example of Z proximity switch placement? No idea still how and where to fix them. Of importance is the diode to be visible.
-Homing of the z is up, yes?

2. Drag Cable Chain
The thing still missing from the drawings.

-Judging from my current setup/2 small chains one next to another/ i need 20x50 internal drag cable chain so cooling hoses and cables can pass freely. But... i can not find anywhere what is the radius. Grrrrrrrrr. If somebody has a similar chain and point me to the radius i would be very grateful

3. Motor cables
can somebody point me to per/m good motor cable, shielded, here in EU?


It seems also for the purpose of the chain, i have to lift the machine. Another thing is that i still have not found a good case for the electronics. It has to look really good.
I am starting to thing about raising everything and boxing the electronics inside the machine. I have my small machine at home like this, so i know the all bad points and will avoid them. Believe me there are many. Like when drivers heating from inside, heats my aluminum table that heats the hot glue i use for fixing stuff and everything flows in the air some times when routing... Of course knowing them i can avoid them. By the way vibrations to the components was only once a problem and it revealed a cold weld on the BOB transformer. Nothing more...


99049905

Boyan Silyavski
02-09-2013, 06:09 PM
Waiting for the square rails and ballscrews purchace, made me play again with the design. Decided to stuff all the electronics inside the body. Due to various reasons like avoiding
10 Neutric connectors sticking out at the back, cables, enclosure and so on. mainly because i live at the seaside so connections always give me trouble and i have to glue my connections with hot glue.

Decided also to make the structure from 60x60 4mm at the important places and 3mm at the no so important. But what ever i did i couldn't figure placing diagonals so i finished with rigid square design and 100kg structure. more or less 18meters of steel. I think i overbuild it a bit.

Another decision was to make the bed deep enough so there is no need to change spindle position. Instead a wood bed would be fitted so the spindle works at normal position and only when necessary to remove the wood bed, not move the bed of the machine or anything.

Hope that structure is strong enough, cause tomorrow will order the steel.

99459946

If somebody sees something wrong, please tell me until is time, he he.

Boyan Silyavski
20-09-2013, 06:36 PM
Everything ordered including the steel for the structure. Still have not ordered the laser cut parts. Untill i have the rails and ball screws at hand.

And here comes the first major problem. The place where i found the 140x80 profile for the gantry refuses to sell me 1m even they have promised me before. :devilish: . Now i have to buy 6m , or change the design.

At the other place where i would buy the rest of the steel, i found some pieces of 100x100x4 box profile. And generally they will sell me everything cheaper and help me in their machine shop. So now i am contemplating soldering 2 pieces of 100x100 and making the gantry 100x200mm. That would change the design of the gantry widening 2cm, one at each side and making it higher by 6 cm.

What is your opinion about this change? The ball screws will be further 2 cm from the z plate. And the upper bearing slides and rail will go 6 cm higher.:stupid:

Boyan Silyavski
25-09-2013, 12:15 AM
No body says nothing, may be the thread is not so interesting as it seems to me or i am doing it right :hysterical:

Soon will make it more interesting with pictures of the process. Now everything is ordered including the steel profile. Will have to pick it tomorrow and solder it this weekend.

At the end i used only 100x100x3mm steel box for everything. The 4mm seemed very heavy and overkill for the 0.8kw spindle .
I still have doubts for the threads on the rails so most possibly will solder additional plates for the threads of the rails. Anyways they will be covered by epoxy.


Here is the final design , its lighter and stronger than the 60x60x4 and also another point is that less cutting and soldering is needed.

400x1000 x Z 170/up to 200/ working area, gantry ~35-40kg with everything mounted, profile structure and gantry with plates = ~ 100kg

10223

10221

10222

WandrinAndy
25-09-2013, 06:48 AM
No body says nothing, may be the thread is not so interesting as it seems to me or i am doing it right :hysterical:


Hi silyavski,
There may be another explanation and that is maybe something wrong with the forum...... I have been lurking recently and don't recall your post #25? Although individual posts may sometimes get lost in a rush of posts!
Cheers,
Andy

JAZZCNC
25-09-2013, 09:56 AM
No body says nothing, may be the thread is not so interesting as it seems to me or i am doing it right :hysterical

I didn't see these post's either.!

Anyway it's looking good. The 3mm wall thickness will be fine for the rails holes but don't drill them until you have epoxy on the rails. If you do it before then you'll create your self more work.

HoGo
25-09-2013, 01:58 PM
This provoked my first post here...
I'm in the middle of my own build (quite similar to yours) and I'm using 100x100x10 so I'd throw in a few words... Don't overlook the edge radius of your SHS. I got unpleasantly surprised when I was supplied with 100x100 SHS that has 35mm (or perhaps even more) diameter at edges... I was counting with 25mm diameter I found in tables of SHS somewhere but the supplied steel was cold rolled with much larger edge radius. My rails will be right at the edge of square so I added thick plate on top of SHS to support the rails. You may not have this problem with 3mm wall but I'd check at the supplier and verify the design with that in mind.
Good luck!
Adrian

JAZZCNC
25-09-2013, 04:52 PM
Don't overlook the edge radius of your SHS. I got unpleasantly surprised when I was supplied with 100x100 SHS that has 35mm (or perhaps even more) diameter at edges... I was counting with 25mm diameter I found in tables of SHS somewhere but the supplied steel was cold rolled with much larger edge radius.

That 35mm is very large Diameter and your correct it should be more like 25mm, I have some 200x100x10 here and that is only 22mm Dia. I would have took it back.!!

The Dia on 100 x 100 x 3 will be roughly 8mm, I've got some 150 x 150 x 5 here and the Dia is 12-14mm.

Boyan Silyavski
25-09-2013, 06:43 PM
Thanks for the advice. I just came from the metal shop, but they still have not cut it. However the profile seemed normal squarish, nothing unusual, so i believe that will not be a problem.

I wonder guys what are you constructing with 100x100x10 :loyal:?

JAZZCNC
25-09-2013, 07:18 PM
I wonder guys what are you constructing with 100x100x10 :loyal:?

My case It's actually 200x100x10 with front face ground for rails and it will be Fixed gantry for my new DIY-VMC .!!!

HoGo
25-09-2013, 09:36 PM
I wonder guys what are you constructing with 100x100x10 :loyal:?

This:
102311023210233
Actually the table and gantry are welded and waiting for milling for rails. So far we are at roughly 400kg, finished machine will be just hair under 600kgs. :smile:
Adrian

Boyan Silyavski
25-09-2013, 09:57 PM
This:
102311023210233
Actually the table and gantry are welded and waiting for milling for rails. So far we are at roughly 400kg, finished machine will be just hair under 600kgs. :smile:
Adrian

Hi Adrian,
i couldn't help but notice, your gantry is only supported by 1 side plates at each end? Wouldn't it need something stronger, like my design? As profile like support at the sides is stronger from even a thick plate i believe. There is a calculator Excel sheet somewhere here on the forum.

Your table structure looks great, and i have given a lot of thought how to make gantry similar to yours, it looks great also.

HoGo
25-09-2013, 10:52 PM
The gantry sits directly on the 20mm plates that will hold the rotary nuts, to which another 22mm thick plates with cars will be mounted. There's no gap there. The sides are 12mm thick steel. So there is direct contact of bottom of gantry ends to rail cars. There is no measurable side to side movement possible other than any play in the rails/cars.
I used 100x100x10 SHS for most of the construction as I had to order two 6m lengths and didn't want to throw away too much. Also one 6m length of 140x80x7 was used for gantry and for two table supports, all was used up almost without waste (supports intentionally placed along the table to create space for extra long 4th axis as we'd like to make some gunstocks in the future).
Adrian

IanS1
25-09-2013, 10:58 PM
My case It's actually 200x100x10 with front face ground for rails and it will be Fixed gantry for my new DIY-VMC .!!!

Are you taking orders for it yet? :thumsup:

Boyan Silyavski
26-09-2013, 04:47 AM
The gantry sits directly on the 20mm plates that will hold the rotary nuts, to which another 22mm thick plates with cars will be mounted. There's no gap there. The sides are 12mm thick steel. So there is direct contact of bottom of gantry ends to rail cars. There is no measurable side to side movement possible other than any play in the rails/cars.
I used 100x100x10 SHS for most of the construction as I had to order two 6m lengths and didn't want to throw away too much. Also one 6m length of 140x80x7 was used for gantry and for two table supports, all was used up almost without waste (supports intentionally placed along the table to create space for extra long 4th axis as we'd like to make some gunstocks in the future).
Adrian

Thanks Adrian! Now i get it. Its not raised. Same with me. Have to think in 6m lengths :-) .

HoGo
26-09-2013, 07:57 AM
I just realised the pics I posted were somewhat outdated. In the final version I moved the tabs holding rotating nuts/servos of X axis to the rear and turned them 180 degrees so the pulleys are just at the rear plane of gantry. This was done to make possible to add another pulleys so I can belt the two sides together with one long belt. There are schools of thought (especially on our local CNC forum) that they'd better be tied together so if one side will stall or not work properly the gantry won't damage the rails. I believe that this is not necessary as servos have quite reliable feedback and one stepper just wouldn't have enough torgue to damage rails and the other side will stall within few steps from the first side.

Boyan Silyavski
26-09-2013, 03:19 PM
I just realised the pics I posted were somewhat outdated. In the final version I moved the tabs holding rotating nuts/servos of X axis to the rear and turned them 180 degrees so the pulleys are just at the rear plane of gantry. This was done to make possible to add another pulleys so I can belt the two sides together with one long belt. There are schools of thought (especially on our local CNC forum) that they'd better be tied together so if one side will stall or not work properly the gantry won't damage the rails. I believe that this is not necessary as servos have quite reliable feedback and one stepper just wouldn't have enough torgue to damage rails and the other side will stall within few steps from the first side.

I believe the same. Moreover i believe this belt being so long is not a good idea if the expectation is to route aluminum, but that's me. I have a small belt driven machine and on it have the motor steps adjusted for wood and for aluminum differently, to compensate belt stretch. Dont know how that be if using big fat belt 25mm wide. Maybe will not stretch if pre loaded/pre tightened correctly.

Anyways the steppers just stall. Who knows what can happen with servos if stalled, i have no idea. Still not in that league.

Boyan Silyavski
28-09-2013, 08:33 PM
At the end i have the profile cut, had to help the guys from the metal shop otherwise it would be next week.

Time to make some sparks and test my recently acquired new toys:
-3 in one plasma cutter, pulse tig , stick 200A
-Mig 250A

I decided to go with the MIG even as it seems that i do better looking welds with the arc welder. Yes, its strange but is so. Would have Tig-ed it but still no Argon bottle. maybe the Mig welds are more difficult to me due to the fact that i use beer gas. The penetration is perfect, before some days welded 10mm pieces without any problem. I was saving quite some time for the 2 machines, the combi cost 470 euro and the MIg 330eur with shipping to Spain. Both from fleabay. Needless to say the Mig was a great deal for the money.

I was a little worried because my welding is 1h practice at home and watching a lot of videos. But it went extremely well. It seems i weld quite well, the only thing is that my head is not shaped for welding helmets, whatever i did it could not fit properly

10258

First did the gantry. Spot welded it, let it cool, then started short welds, then turn, then weld, then let it cool. I used my IR remote thermometer to monitor the temperature of the gantry to not pass 60C. So at the end i welded it quite precisely in fact, without twisting. However i was quite tempted to do a perfectly looking straight weld from one side to the other :orange:, but followed the correct procedure.

10259




Then decided to weld the left and right sides and later connect them. The guys at the metal shop told me first to weld the bead square and then the rest. However i decided what i felt was better, for the purpose of easier adjustment . I decided to weld it precisely, like i would not use epoxy. Wanted to check if i am being able to do this.

10260

Please don't laugh at my welds, at least they are really penetrating. The spatter is from the gas i believe.

10261

Ground the welds where the bed profiles go. Now the thing is that i have only 2 large clamps. I tightened slightly all from both sides on my new acquisition, the welding leg supports i acquired exchanging a vacuum pump for them. using a square and a plastic head hammer started playing around until i finished with square bed on one and the same plane.

10262


To make sure the bead is on the same plane i used Bosch alu profile as my Din 874 straight edge is still travelling

10263
10264

That the bed is square and is on one plane dos not mean that the most important part-the rail support profile is on the same plane, even if you welded properly.
10265

I would epoxy it later, but i tried to make it perfect, so i decided to spot weld only from the upper sides, cause as i said i have only 2 large clamps. later would take off the clamps and adjust the squareness and being in one plane of the rails supports. As the bed is spot welded only from the top, Using the clamps end by end i leveled the rails supports. Then soldered.

10266


Then became dark, and i -tired but happy. I know, its not a big deal, but for me-yes, cause i bought 2 welders and started a build without knowing if i can weld or not. So, now i relaxed a bit. The machine frame stays in front of my small workshop, cause now i can not lift it alone. It seems extremely rigid, much more than i expected. When i am finished, will measure the flex from 90kg on the bed /me/ . The gantry seems indestructible. I underestimated the need for hard stops. back to my first design. Monday will go and by some U profile. I thought of stopping it with bolt. No way, it should be something very strong.


10267

m_c
28-09-2013, 11:37 PM
The frame looks good.

The welds look fine considering you've not ground the mill scale of before hand. Although MIG welding will burn through the scale, it can lead to weld contamination as standard MIG welding can only burn of a limited amount of contamination.

Boyan Silyavski
12-10-2013, 12:15 AM
The frame looks good.

The welds look fine considering you've not ground the mill scale of before hand. Although MIG welding will burn through the scale, it can lead to weld contamination as standard MIG welding can only burn of a limited amount of contamination.

Thanks for the heads up. next time will not only grind 1mm the corners but as you say.

Here are 2 recent pictures. Just soldered the hardstops for the gantry from 100 UPN profile. My friend insisted on soldering 4 short legs, again from UPN100 profile. Strengthwise i would have soldered 6 legs instead of 4, or none at all and lay the machine and thin layer cement the machine on place but i was very curious of the deflection of my design.

Now just measured it so here is the result:

1. Applying 100kg static force/me/ on any one of the bead beams leads to 0.045 mm deflection in the middle
2. Applying the same 100kg to middle of the raised sides supported only at both sides by 9 cm legs from 100UPN profile leads to 0.03mm deflection on that side.

Conclusion: With gantry and bead mounted in real working conditions the overall vertical deflection of the machine will be unmeasurable or less than 0.01mm which is irrelevant especially with 0.8kw spindle. So first impressions are perfect.

Anyways, i will most possibly insert pads in the middle of the machine when placing it on its place, so it will stay rigid and quiet

PS. In fact using the excel file for calculating deflection on gantry and gantry side, i guess the real final value of deflection in all directions of this particular design of the finished machine will be 0.0035mm. Which i believe is great.

1041410415

kingcreaky
13-10-2013, 12:29 PM
it looks really warm there... ive just returned from holiday in turkey, to miserable cold england. :(

top work... keep the photos coming...

Jonathan
13-10-2013, 12:37 PM
Conclusion: With gantry and bead mounted in real working conditions the overall vertical deflection of the machine will be unmeasurable or less than 0.01mm which is irrelevant especially with 0.8kw spindle. So first impressions are perfect.

Your test shows that the deflection due to the frame will be very small (<0.01mm), but remember the linear guides and Z-axis especially will all lower the stiffness, so overall your deflection will be greater. Still, your gantry design looks reasonably strong so I expect it will be fine.

Boyan Silyavski
14-10-2013, 01:07 AM
Your test shows that the deflection due to the frame will be very small (<0.01mm), but remember the linear guides and Z-axis especially will all lower the stiffness, so overall your deflection will be greater. Still, your gantry design looks reasonably strong so I expect it will be fine.

Thanks. I am aware of that. For me this build is a preliminary build to my real machine. A kind of experiment. Something like how far i could go at every step.

As the machine we all know is a sum of its components.I constantly meditate on "the machine is strong as its weakest part". The Hiwin blocks are with A preload, the deflection calculator tells me the gantry sides deflection cutting aluminum will be lower than 0.01mm, so i guess the weakest part will be the Chinese spindle bearings and the bit. I will be extremely happy if i succeed in making a precise machine, just for the sake of it.

Boyan Silyavski
14-10-2013, 10:14 PM
I need some help here with the Leadshine AM882 drivers and the SY60STH86-3008BF motors from Zappautomation.

-As far as i understand the auto finding of the parameters using the dip switch would be enough?

-However i wonder what step/micro-stepping should i use with the 1605/z/ and the 1610/x,y/ ballscrews? having in mind the way i build the machine.

-Also about the Switch 8 at the drive.
the manual says:
Pulse signal: In single pulse (pulse/direction) mode, this input represents pulse
signal, each rising or falling edge active (DIP switch configurable); 4-5V when
PUL-HIGH, 0-0.5V when PUL-LOW

So i asume rising is Pul High and falling edge is Pul Low. I wonder which one will work with my C23 board from CNC4PC

Jonathan
14-10-2013, 10:25 PM
The microstepping setting is generally first limited by the output frequency of your parallel port. Using higher microstepping can help with reducing resonance problems, although those drivers have more advanced ways to deal with that so it's hard to say. Generally people don't use finer than 1/8th microstepping as going further can reduce performance, but if you can even use that will depend on the maximum frequency your parallel port will output and the feedrate you require.

For example, suppose you want a feedrate of 8m/min (sensible for cutting wood) with the 10mm pitch screw driven via a 1:1 ratio with a parallel port that can only output up to 25kHz (a lot will do more, but not all):
Screw angular speed: 8000/10=800rpm
Base frequency: 800/60*200=2667Hz
25000/2667Hz=9.4 ... so nearest is 1/8th microstepping with the above conditions.

EddyCurrent
14-10-2013, 10:28 PM
http://www.mycncuk.com/forums/machine-control-software/4677-help-please-motor-tuning-mach-3-a.html

From what I've read 1/8 is a good starting point

RE. switch 8 I guess if it won't work one way then try the other

JAZZCNC
14-10-2013, 10:40 PM
However i wonder what step/micro-stepping should i use with the 1605/z/ and the 1610/x,y/ ballscrews? having in mind the way i build the machine.

Well depends a lot on your PC and how good the parallel port is and what speeds your looking to achieve. PP and PC speed to some degree will determine the Kernal speed in Mach3 and how many pulses you can put out which in turn will determine the speed you'll get from the machine. Higher micro steps require more pulses to achieve same speed has lower MS but they give smoother running motors and to a lesser extent some resolution.
Personally I don't go higher than 10x or 2000ms and this is my preferred choice if PC can handle it. Higher MS also helps with resonance but these drives are great with handling resonance so it won't be a problem and if it is you can change tune it out using the software.


So i asume rising is Pul High and falling edge is Pul Low. I wonder which one will work with my C23 board from CNC4PC

I would agree but check with Arturo and I'm think it may even be possible to change a jumper on the board has well to suit but either way your covered because the drives allow it.
If you can't find out then you'll have to make some witness marks run some G-code and then check if it's lost position. If the pulse is on the wrong side it will drop a step on every direction change so won't take long to find.

JAZZCNC
14-10-2013, 10:45 PM
Bloody heel all that typing and Jonathan had already said it all . . Lol



RE. switch 8 I guess if it won't work one way then try the other

Not that simple Eddy it will work in either mode but if pulse is on wrong side then it will drop a step on direction changes.!

Boyan Silyavski
14-10-2013, 10:54 PM
Thanks a lot guys!

Yes 300ipm / 8mpm/ is the speed i aim considering the tooling/price and the spindle speeds.

8 microsteping was what i had in mind. I have tested the PC upto 100Mhz as far as i remeber and it was Ok. With other BOB, but i assume will run with this also.

Anyways i will make to files for Mach3, one for 100ipm and one for 300ipm, as the guy is new to this, so at first untill he is aware what he is doing...


On my small commercial machine the z steps in mach3 was set to 10000? this is quite high micro stepping, thats why i wondered, on the other axis is 8 microstepping. reverse calculating it the microstepping in z is 256, i am not quite sure now for the 10000 but it was ridiculously high.

JAZZCNC
14-10-2013, 11:22 PM
8 microsteping was what i had in mind. I have tested the PC upto 100Mhz as far as i remeber and it was Ok. With other BOB, but i assume will run with this also.

Don't run that high thou otherwise high chance of troubles. Only set the Kernal speed high has needed and no more. 25Khz is the best and every increase above increases chances of trouble. Wouldn't go above 60khz no matter what driver test says or PC thinks it can do.!!
If you need that high pulse rate then buy motion control card, in fact I'd buy one anyway if you want the best performance from machine.!

Boyan Silyavski
06-11-2013, 04:58 PM
Hi guys,
thanks to all for the valuable inputs.

For now i have to wait until they cut with laser the pieces, so i can proceed further.

Meanwhile as a thanks to all for the help :encouragement:, here is the Sketchup file (http://silyavski.com/storage/cnc/cnc%20100x100x3%20profile%20x400y1000z200.rar)/its in winrar format for easier transfer/. So anyone who wants can use it as it is, use parts of it or just use the components or table drawings. Before ordering the laser cut parts i revised it piece by piece and against the ballscrews, housings, etc. So all small errors are fixed. It cost me a whole day to rework it precisely. The empty spaces are for epoxy, there are some clearances where necessary. The machine has work area of 400x1000x200 . Any questions are welcome if you have something that is not clear. The main point being here is that the machine is completely scaleable up to the limit of the ballscrews or with minor adjustments even up to 4x8 , this without changing the type or thickness of the profile. Other main point is that the drawing is final drawing, no need for correction before real assembly, however there are some steps to be followed, but easy to figure when playing and simulating the actual assembly. If by channce there is a small error i will fix it right away in the future.

10608

So enjoy it and thanks again. Will update when i have more to show.

cncJim
07-11-2013, 02:54 PM
Hi Silyavski,

Thank you very much for putting your sketchup files up for everyone. I am in the process of designing a new machine and learning sketchup so your files will be a big help! :)

What sort of rough price does the laser cutting cost?

Looking forward to seeing your machine come to life!

ba99297
07-11-2013, 10:48 PM
I dont understand something
The cncrouter will have legs down to ground or the cnc on the left of your scetchup will be put on the white table

Boyan Silyavski
08-11-2013, 08:49 AM
Hi there,
The table on the right is if sb wants to upscale it to 1000x1500 or similar,with small adjustments, using the gantry from the left. On the left is the complete machine 400x1000 which i am building now.

Furthermore have in mind the gantry can be simplified removing the raise sides if intended mainly for aluminum.

Boyan Silyavski
01-12-2013, 10:13 PM
...
What sort of rough price does the laser cutting cost?
....

I ordered them in my country/ Bulgaria/ and they cost there 250 euro. + 50 for a guy to bring them when he is coming back from there in 2 weeks.

Here in Spain, the price would have been outrageous.

Anyways, its a lot of metal. I don't have the means here, that's why i preferred laser cut. But in fact if you can cut and drill and have spare time, they are quite simple to produce at home.

Now i am designing my next build and definitely will try to lower the number of parts.

ba99297
09-12-2013, 09:31 AM
Let me ask something
I am planning my cnc 1500X1000 and i am very close to these plans
Is it better to weld everything together or make seperately the base and then the cnc machine that will "sit" on the table. I am asking because if i weld evertything together my construction will be very heavy ( difficult moved even by 3 or 4 people )
What is better
Solution 1
one unique construction ( both table and cnc together ) or

Solution 2
two seperate constructions( the cnc and the table). Will this second solution have stiffnees issues ?

Thanks for your time

ba99297
09-12-2013, 09:31 AM
By mistake i upload the same reply two times. Sorry

Boyan Silyavski
10-12-2013, 09:31 AM
Let me ask something
I am planning my cnc 1500X1000 and i am very close to these plans
Is it better to weld everything together or make seperately the base and then the cnc machine that will "sit" on the table. I am asking because if i weld evertything together my construction will be very heavy ( difficult moved even by 3 or 4 people )
What is better
Solution 1
one unique construction ( both table and cnc together ) or

Solution 2
two seperate constructions( the cnc and the table). Will this second solution have stiffnees issues ?

Thanks for your time

Hi,

I personally chose solution 1, welded together. I prefer playing with additional fixtures, instead raising, lowering the bed.

Other people here on the forum however choose solution 2 . There will not be stiffness issues.

At the end is up to you. Now i am building another 1250x2500 and i also have the same doubts as it will weight considerably. Its worth noting that if not welded together, possibly you will have to use some more beams and at the end it will weight even more. For my 1250x2500 i am contemplating making a hybrid, half of the bed welded, half removable.

ba99297
10-12-2013, 10:15 AM
It is possible i didnt make my self clear beacause of my english
Syliavski i will use your photo to explain
When i say cnc i mean the element A of your picture
and when i say table i mean the element B of your picture and not the cutting table
So the question is
Will i have any stiffness issues if make two different construction A and B and then let A rest on B
Or i must make one construction both A and B together in order to have more stiffness.
The problem is that if i make one unique construction it will be too heavy

Thanks for your time

10954

ba99297
10-12-2013, 10:15 AM
Thanks for your time

Boyan Silyavski
10-12-2013, 10:31 AM
Hi,

the element A is a benchtop cnc 400x1000x200. The element B is not a table. It is another CNC, 1000x1500x200. It is the same, just scale the gantry.

So A is strong enough even if you put it on a simple table/strong enough/ . There will be no compromise of stiffness. Same with B.

In other words just follow B design if you like it. It would weight 130kg if following the design. Look at this thread also: http://www.mycncuk.com/forums/router-build-logs/5302-tiddy-cnc-2.html to see it in real life

ba99297
10-12-2013, 01:43 PM
Silyavski i know that element b is not only a table.
I just use it as an example of table in order to give you understand what i mean
So you tell me that if i make a benchtop cnc 1000X1500 and bolt it on a table ( whatever strong table that can handle such weight ) i wont have any problems right?

Boyan Silyavski
10-12-2013, 04:41 PM
Silyavski i know that element b is not only a table.
I just use it as an example of table in order to give you understand what i mean
So you tell me that if i make a benchtop cnc 1000X1500 and bolt it on a table ( whatever strong table that can handle such weight ) i wont have any problems right?

Ok, I get it. If you use the same design and make a simple rectangular frame with the legs and diagonals on the legs, it would be rigid enough. If you use profile smaller than 80x80 you should use other design.

EddyCurrent
16-12-2013, 05:09 PM
Talking about the frame or any other frame for that matter,
If it's to be painted, which would be a good idea, do the rails sit on top of the paint ?
If epoxy is to be used under the rails or part of the associated support structure is the epoxy under the paint or on top of the paint ?

I'm asking because paint has thickness and is not rigid.

Boyan Silyavski
16-12-2013, 06:22 PM
Talking about the frame or any other frame for that matter,
If it's to be painted, which would be a good idea, do the rails sit on top of the paint ?
If epoxy is to be used under the rails or part of the associated support structure is the epoxy under the paint or on top of the paint ?

I'm asking because paint has thickness and is not rigid.

I am still waiting for a friend to bring me around new year the laser cut parts. Will solder, epoxy, mount rails and paint. In that order.

Let me explain. This machine exactly i am making for a friend who is pro model maker / yachts/ . First i suggested him to spray with gun Henkel machine paint/ anti oxide and paint directly on metal/, which i use and is very good. But the guy is a maniac, and honestly i felt ashamed when i saw his perfect yacht models which any watch maker will envy. So lazy me, i pretended i don't know how to paint a car :-) and he will come to help me with the painting. It would be painted the way the cars are painted- perfectly with glossy double component car paint and all the stuff that comes before that. Will document with pictures the process.

At the end i thought that it is good that somebody raise my bar, when perfection is expected. I will do so with the other machine i am building. Yes, 2 days job but imagine the hours i will be happy looking at it.

Basically the plan is to base paint the metal, polish, thin base, polish, 3-4 hands, laquer 2-5 hands and polish after a week or so when dry. I will use Standox car paint or Duracoat. At the end, looking at all the time and money that will go there, why not make it beautifull.

Boyan Silyavski
16-12-2013, 06:52 PM
Forgot to say that the epoxy can be colored black for example, a smallish bottle of like 20ml will color 1l. I doubt it will affect its viscosity, the small bottle i have at home looks quite liquid, like water. Its special epoxy color though, not general type. That would be great if its difficult or not possible to paint it later, or the frame is painted beforehand.

Boyan Silyavski
25-01-2014, 07:03 PM
Well, the laser cut parts came. So, i finished soldering the parts to the frame. That includes the ball screw mounts. What i did was mount the ballscrews to the supports/in the middle so there is place left for adjustmennt/ and that greatly helped the correct placing. Carefully made some tacks with the Mig and waited all to cool, so checked again if the screws move smoothly. Have to note that the machine was welded with precision <1mm greatly helped.

11369

11370



Now its epoxy time. Several mistakes here. Just to fulfill my worries.

I used some aluminum angles, hot glue from outside, instant glue below, silicone at the angle inside.

the mistakes:

-the channels connecting both sides should be wider, say at least 3cm, not like mine-8mm :-). Epoxy has difficulty to flow in so narrow channels
-i am epoxy greedy, calculated the just amount. had to mix second time to fill the channels
-scratched the base below the epoxy, with the idea of better contact. Now i can see the scratches. nevertheless i would paint the machine, but is good to know that the epoxy is quite transparent yellowish color

The clever stuff:
-the epoxy sides will be 40mm wide, works great for leveling.
-it seems the way i fixed the channels holds pretty well , cust came from the garage, no pour for now, one hour later we will see.
-used bolts on the legs to level the machine perfectly
-as i wanted 5mm epoxy thickness, i found some magnets which together made 4.5mm and put then at the corners. This was extremely clever as right from the beginning i could see how much epoxy and where to pour. In fact i believe i poured it perfectly and did not need the channels, as there was a moment when the epoxy just covered the magnets.
-used small torch to help leveling and take away the bubbles.

11371

11372

11373


Other clever stuff was that i welded 2 wheels at the back and fixed 2 handles at the front. That helps me greatly maneuver the 100kg around.

GEOFFREY
26-01-2014, 01:03 AM
Very neat. Keep the piccies coming. G.

cncJim
26-01-2014, 08:05 PM
Good job! Thanks for taking photos, sometimes I find it hard to visualise what people have done. The epoxy looks very neat, I would love to see some pictures of it when it's cured. How do you pour it? Just on one side and let it flow down the channel to the other, or fill both sides at the same time?

Did you weld the frame yourself? Looks very good.

Jim

Boyan Silyavski
26-01-2014, 08:21 PM
Thanks!

I filled both sides at the same time. The magnets at the corners helped as they were 4.25mm thick, as i could clearly see how much i should pour to achieve 5mm thickness.
As the channels that connect the sides were very thin and i have not mixed enough epoxy, had to mix second time and pour in the channels.

if i was to turn back time, i would have used the same aluminum angle profiles, fix them with scotch only from outside and use cheap epoxy with a brush to make a kind of base, which would close the distance from the channel to the profile against spill. When dry and so secured, pour over the expensive epoxy :-)

Yes, i welded the frame , the process is described at post #43 (http://www.mycncuk.com/forums/gantry-router-build-logs/6457-sturdy-fast-all-steel-cnc-my-first-build-4.html#post49973). My second welding job in fact. Good that i was careful there, now things are much more easier that could have been with not so careful welding. used a cheap 250A Mig which i obtained from ebay+C02, hence the not so smooth welds.

cncJim
26-01-2014, 08:48 PM
Yes the magnets seem a good idea. If I was doing the epoxy I think I would have also used the thin channels, so I am sorry it didn't work out as well as you intended but I am pleased you shared the results so others (me!) can learn from it.

Sorry i thought I had seen all of the posts but I guess I have missed a lot!

EddyCurrent
26-01-2014, 09:00 PM
As Jim says, the epoxy looks very good and there's no way that frame is going to move.

Jonathan
27-01-2014, 01:20 AM
How do you pour it? Just on one side and let it flow down the channel to the other, or fill both sides at the same time?

If using the self-leveling epoxy method, then the only way worth pursuing is to have a channel between the two rails (sides) and ensure sufficient depth of epoxy to flow between them. If they were poured separately, then the sides would end up at different heights, potentially resulting in significant stress on the bearings when the gantry is attached, unless shims are placed under the gantry on one side.

Clive S
27-01-2014, 03:52 PM
I know that I have posted these before but this is the way I have done it. The epoxy is the Wests system Very slow cure. ..Clive

Boyan Silyavski
28-01-2014, 12:55 AM
Now something very important. I will not move the frame at all. After a week has passed will solder the gantry and sides. Then will turn upside down the gantry and lay the upper side on the level surface of the epoxy. Then will pour epoxy on the gantry side plates that step on the Hiwin bearing blocks, connecting them together. Also pour epoxy on the lower side of the gantry beam. When dry, will turn the nagtry to normal position , rest the leveled side plates / epoxy on epoxy/ and pour the final epoxy at the top side of the gantry beam.
So with these steps i will achieve all hiwin rails lay on epoxy surfaces that are paralel to each other. The only thing left will be to ensure squareness of Z. I hope to achieve a quite precise machine.

Neale
28-01-2014, 09:24 AM
Well, that's an obvious way to set up the epoxy on the gantry. You know, the kind of "obvious" that's only obvious when someone else says it!

I've been kicking ideas around in my head for the last week or two about how to align the Y rails for "constant spacing" if I put them on the top and bottom of the gantry bars for my new design. Easy enough to lay the gantry on its back and use epoxy to level the Y rails on the front face, but I couldn't work out how to do it where the fixing faces for the rails were not in the same plane. Easy enough if you have an accurate level surface to put the gantry on and do one rail at the time but how do you generate that initial level surface in a home workshop? So use one of the level surfaces you created when you used epoxy to set up the X rails! As I say, it's obvious once someone else has pointed it out...

In practice, any idea of how much out of true a typical length of, say, 50x50 or 80x80 steel tube would be? Are we talking about a mm or two, or significantly less than that? How much does the epoxy thickness vary, in other words?

njhussey
28-01-2014, 09:38 AM
In practice, any idea of how much out of true a typical length of, say, 50x50 or 80x80 steel tube would be? Are we talking about a mm or two, or significantly less than that? How much does the epoxy thickness vary, in other words?

This should help http://www.parkersteel.co.uk/media/pdf/standards/JPSBS0010.pdf I was looking for it yesterday when I wanted to look at how "true" my beam might have been. Don't forget you're also at the mercy of the stockholder and transport to keep the steel flat and not to induce any additional bending/torsion etc...

CharlesJenkinson
06-02-2014, 08:56 PM
Very interesting build, and good research for me. A weld bead causes shrinkage where it is deposited, so weld induced distortion is not so much due to the 'heat' that goes into the part, but is due to the fact that a weld, when solidifying, pulls on the adjacent parent metal. Apart from looking nice, I'm not convinced these types of bed frames, with massive members, need to be fully welded at the joints, from a stress point of view anyway - stitch welding would be perfectly adequate - having said that, the effect of inducing bending due to weld shrinkage is possibly only noticeable on smaller dimension square hollow section, less than 70mm say. The effect of weld shrinkage induced distortion may be mitigated where possible by welding to the perpendicular plane of the material, if that plane isn't as critical for flatness, and the design configuration suits it - I don't think it applies in this particular build case though.

Sorry to theorize in your build thread - being a noob, I guess I'm eager and this seemed an appropriate, and reasonable relevant place.

JAZZCNC
06-02-2014, 09:35 PM
Apart from looking nice, I'm not convinced these types of bed frames, with massive members, need to be fully welded at the joints, from a stress point of view anyway - stitch welding would be perfectly adequate - having said that, the effect of inducing bending due to weld shrinkage is possibly only noticeable on smaller dimension square hollow section, less than 70mm say.

Charles Very true regards Stitch welding being plenty strong enough if done correctly but even larger dimension SHS will distort if the heat put into it is too great. Spreading the welds around and keeping the bead length down to a minimum is very much needed with any size material if distortion is to be kept to minimum.

I've just got my self a New 250A AC/DC Tig welder with pulse and I love it for just this reason as the heat is kept very isolated to small area. Fact I can weld thick Aluminium plate as well as thin Aliminium plate is lovely as well.

Neale
07-02-2014, 09:50 AM
Any chance of some advice on best welding strategy for welding novices like me? Starting with the assumption that we are welding box section (I'm probably talking 50x50x3 in my case), what's the best way to get an accurate frame that's not going to distort as you add bits on? I'm starting to hear things like tack welds to hold it all together, then add more tacks/spots for strength, but continuous welds at the joints are not needed.
Specific example - you are welding two pieces of box section that meet as a Tee. Couple of spots on the "internal" corners so that you don't pull the pieces out of plane, then tack the sides, then add a few more spots for strength?
I'm guessing that all this is blindingly obvious to an experienced welder but I get the feeling that a lot of people cut their welding teeth for the first time building a router!

CharlesJenkinson
07-02-2014, 10:35 AM
Erm, I don't have vast practical welding experience, but I'd say two decent 30mm long 3 or 4 mm leg fillet, i.e. one in the middle of each of the 2 flush butting sides of that joint should hold it good, for strength - just weld through (over the top of) any tack you've put down. I don't see any point welding round the corners or trying to fill the whole void in where the square cut end doesn't meet the radius edges of the mating member - doing this is just adding loads of extra heat and metal that isn't doing anything. The important point about tacking together is to set and maintain the WHOLE assembly geometry before laying heavier deposits down, so if you have any gussets orbraces supporting the ends of your T assembly, IMO they should be tacked in after the T is tacked together but before putting the structural welds down.

njhussey
07-02-2014, 10:37 AM
I'm no expert (I seem to weld every 4 years or so) but what I did was cut the pieces to length, dry assemble the uprights and the main frame outer pieces then put either one tack or a couple of tacks on each piece.

11529

Then I got a square and spirit level and made sure all was as good as I could get. I then tacked in the bed braces..

11530

I then checked all was square again before starting to add the angle braces...

11531

I then checked that the uprights were still square and all was good and then started welding the uprights. Now here I confess I didn't do it in small short runs spread out round the frame like I probably should have. I just did it in one or two runs per weld (50mm long welds as using 50x50x4 box)

11532

I then checked to see if all was still square (otherwise the angle grinder would have to come out!) and then proceeded to weld up the rest of the welds. I didn't do it in any particular order (it was pretty random) and then after finishing the frame (but without the X axis rails welded on) I checked all the frame was still level and the uprights were still 90 to the bed.

11533

I then offered one X axis rail up, clamped it with F clamps roughly level and then referencing off the frame rails and tacked it as parallel (using a digital bevel box) as I could. I then put lots of tacks on it, checking in between that it hadn't moved, and then once cool I welded over the tacks in one go.

11534

I then did the same for the second rail checking for parallellness (is that a word?) in both directions with the first rail as a reference but also checking the second rail against the frame to make sure it wasn't out. I then did the same weld procedure for the second rail and it turned out pretty square and parallel....probably more from good luck than skill!

11535

Neale
07-02-2014, 02:45 PM
All pretty obvious, then - the kind of "obvious" you only see when someone's pointed it out!

Thanks for the idiots' guide (and I'm the welding idiot, just to make it clear!).

njhussey
07-02-2014, 03:08 PM
All pretty obvious, then - the kind of "obvious" you only see when someone's pointed it out!

Thanks for the idiots' guide (and I'm the welding idiot, just to make it clear!).

I knew what you meant......I also class myself in the category of welding idiots. I just put it together and once I was happy it was square I wacked the welds on regardless of putting too much heat (see told you I was a welding idiot!!) in to the frame. I seem to have got away with it.....so far!!

JAZZCNC
07-02-2014, 06:17 PM
To be honest it's not rocket science but the Welder your using does make a difference to some degree.

Arc or MMA welders put a lot more heat into the steel than Mig or Tig so it's a good idea when using Stick to keep runs shorter and spread them around but keep balanced. By balanced I mean if you weld Left side of material for 1 " then weld right side 1" at same time before moving to another spot.

For general steel work then Mig is best has it's relatively quick and easy to learn but it's not has cheap has stick to buy equipment.

Tig is best for controlled heat but it's slow and more specialised and expensive so I wouldn't use it for steel frame work. (unless using MMA option)

Just for building a one off frame and keeping costs down then MMA(Stick) is best has it's cheap to get setup and not too difficult to learn.

Just remember bird shit can be scrubbed away so tis is true with welding and grinder is your best friend. . Lol

Welding and Epoxy leveling make steel frames very easy and cheap to achieve.

Neale
07-02-2014, 06:52 PM
Welding and Epoxy leveling make steel frames very easy and cheap to achieve.

That's what I'm hoping!

Boyan Silyavski
09-02-2014, 11:39 PM
Hi there,

I would like to point again that the further i go building the machine, the more discover how important and later time saving was to weld the whole machine with under 1mm, even possibly under 0.5mm precision.

I would like also to remind you that i welded the machine fully, but it took like more than a half of day, due to waiting things to cool and the having in my left hand the IR remote thermometer, controlling that the overall temperature of the frame and gantry stays under 60C. So any change of dimensiones was successfully avoided.
So if you don't have thermometer at hand, just wait untill cool to the touch. And no more than 2 inch at once, always mirroring.

Here is some more progress in details.

The Hiwin are wide 20mm, i made the epoxy 40mm wide, hence-10mm each side. Thats should be the proper way. The meniscus took like 3mm at least.
So how i dealt with the meniscus? I decided i would not waste time on it, so i glued sand paper to a stick and started sanding it off. Not completely. I decided i will mount the rails and then continuing with epoxy leveling the gantry rails and side supports.
In other words dealing completely with the meniscus is a waste of time. The process took me 20 minutes, the epoxy sanded like a snow flakes. 20 min more for the end of the epoxy, where the end of the rails would be. here i checked with straight edge and scraped a bit the last cm.
It is a very good idea to stuck a tape over the middle of the epoxy, where the rails would be, as not to scratch it!

11542


Well, it seems it worked as supposed. The epoxy i mean
11543


Buying the precise 1m straight edge and precise square was a very good idea. In a matter of minutes i placed and aligned the rails. I would say that its crucial .
Both cost around 100 euro and a week research , see here: http://www.mycncuk.com/forums/tool-tooling-technology/6546-help-needed-understanding-accuracy-measuring-tools-i-want-go-straight.html


11544

Once in place and squared i rechecked them using a long steel ruler made from 2 rules and magnets, which i fitted inbetween and checked at both ends. Tight fit as expected. I supported it with alu beam so it would not bend/ like in the picture, while i was making the shot/


11547

11548



Just a side note here. Forum is ok, but read the frigging manuals. Hiwin rails have direction, also the carriages/ its not seen on the pic, but the letters should be at the side where the arrow points to/ . have that in mind, is buried somewhere in the long manual.

11545


I was tired and working after work. But i wanted and started to feel a kind of satisfaction not being in a hurry and doing things right. So instead of drilling through the clamped hiwin rails, i used a hole transfer tool lightly using the hammer. And a torch, to see better.

11546


And as i started to feel that satisfaction, i decided to continue accordingly the process, drilling first 3mm holes, using the very handy tool to keep them vertical.
The torch helped again to see things , illuminating the epoxy from below.

11549

Some holes and here is what happened. I had to go for a new drill, as it seems if the drill is not perfect, it adds heat and the epoxy lifts around the hole. Not a big deal, will scrape it with a small straight edge. The epoxy scrapes nicely, as i said-like snow flakes

11550

Now i am waiting for a new brand M5 tap and the bolts for the Hiwin to arrive. I wouldn't risque with the cheap tap i have. I bought them from internet as it seems that screws are quite expensive locally.

Thats all for now.

GEOFFREY
10-02-2014, 09:01 AM
Coming on nicely nicely now, looking very good, but I wouldn't expect any thing else having read your build log and your obvious attention to every detail. Great stuff. G.

EddyCurrent
10-02-2014, 12:12 PM
Obviously section 1.10 of the Hiwin manual is the 'correct' method but if you don't have the gear . . .
To mount rails similar to yours, I first clamped a straight edge along the top with the edge parallel to the beam and for the Hiwin rail to be in the centre.
Then I clamped the Hiwin rail to the beam making sure it was tight up against the straight edge. The holes in the rail are about 5.5mm diameter so I used a 5.5mm drill in every mounting hole to make a dimple in the epoxy similar to using a centre punch. This allowed my 4.2mm tapping drill to go right through the epoxy and beam, all central to the Hiwin mounting holes. The other rail was mounted in a similar way but using a DTI gauge to keep them parallel.

AndyGuid
07-04-2014, 04:09 AM
Now something very important. I will not move the frame at all. After a week has passed will solder the gantry and sides. Then will turn upside down the gantry and lay the upper side on the level surface of the epoxy. Then will pour epoxy on the gantry side plates that step on the Hiwin bearing blocks, connecting them together. Also pour epoxy on the lower side of the gantry beam. When dry, will turn the nagtry to normal position , rest the leveled side plates / epoxy on epoxy/ and pour the final epoxy at the top side of the gantry beam.
So with these steps i will achieve all hiwin rails lay on epoxy surfaces that are paralel to each other. The only thing left will be to ensure squareness of Z. I hope to achieve a quite precise machine.

Hi Silyavski,

Guess you have been pulled away onto other things for a while, but I really hope you will be coming back to continue with this great build thread. . . . .

I am particularly interested in whether your intended technique worked in getting the gantry rails parallel?

Cheers, Andy

Boyan Silyavski
12-05-2014, 01:46 PM
Hi Silyavski,

Guess you have been pulled away onto other things for a while, but I really hope you will be coming back to continue with this great build thread. . . . .

I am particularly interested in whether your intended technique worked in getting the gantry rails parallel?

Cheers, Andy

Hi,
yes its been a while. I am not the fastest builder around it seems :redface:.


Basically what happened is that apart from other jobs and orders on my small machine, i had to change house , and it was 3 weeks madness. Now i am happyly suited in a new house with a proper garage/workshop/ so from 2 weeks i am continuing the build.

Here is what happened in short / only problems :chuncky:/:

1. Mistake one
I bumped the frame a couple of times when i was trying to reach the washing machine. So it moved a bit. As i wanted perfection in leveling...Only if i had hot glued the legs to the floor :anonymous:, this mistake will be not repeated again. So here is the solution. Again pouring epoxy, this time on my soldering jig. Waiting , fixing, pouring again, turning around, pouring. It took some time. A week.

12395 12396 12394


2. Next mistakes
Then when the epoxy on all necessary surfaces on the gantry was dry enough, i decided to open the holes necessary for the bolts to hold the gantry to the bearing blocks.
WOW, another mistake. The epoxy chipped and the drill bit unglued the first of 4 epoxy plate from the gantry. Now i was worried. So i marked it and cut the corners as seen in the photo. I marked all others with numbers and crossed lines and using Dremel filed the corners. And...everything unglued. The good thing was that all was marked so i knew which is which and where it has been exactly. So i finished them, cleaned everything and using instant glue and pressure/clamps fit then where they have been.

Perfect fit, the glue squeezed equally , checked with the straight edge, well it was perfect. Hell, i was worried, and the epoxy was starting to finish :greedy_dollars:

12397 12398


3. Painting problems

I actually bought a car paint. But as it was quite expensive i decided to base coat with anti-oxide yellow paint meant to be painted directly over the metal.

I found the following things:
-successfully painting small things doesn't mean you can paint a big thing well at home :toot:
-having pro HVLP gun doesn't help if your compressor is small and you want to paint big things. Not enough air.
-having smaller airbrush type gun doesn't help either
-not having dry filtering, i mean real dry filter on the air line , means bad things happen...
-painting yellow is a mean thing, really mean. 3 liters of paint. Well i sued a roller at the end, as otherwise i had to paint it a whole week.

in short-painting is not my strength :-)

12399 12400


4. Bolting the gantry to the frame and aligning the gantry rails.

Needless to say - a lot of problems.

a/ First to say i have dry bolted the gantry before painting all. It was ok. So what was my surprise when everything was painted, the machine fixed on the welding jigs for comfort and the gantry will not fit. So i called a friend that helped me and 3 times i had to lift the gantry and lower it, mean while widening the holes. The reason. This is crazy- the machine is outside, the sun heats the frame and it widens. cause i made the machine in the winter...
So basically now i cover all the time it so it could not heat . My garage is small i mean to work inside.

So at the end i squared perfectly the gantry and bolted it


b/ Now next unsuspected problem. How do i fit the rails on the gantry to be perfectly square with the long rails on the frame? I knew i could do it somehow but in reality it was a big challenge.
I know how to do it if say i make 10 same machines, a fixture and no problem. But how to do it on the cheap. Cause this machine really ate a lot of money spend on little things.
After a lot of thought i fixed the straight edge perpendicular to the base rails and decided to start with the upper rail first.
Once the upper rail was square, there came the problem with the lower rail. A friend of mine says we have all necessary stuff always at hand. So i was in no rush, thought it a whole weekend and just have done it.
Another difficulty was that i do all alone at home with no help, so first i more or less squared it using clamps and then drilled and tapped 2 holes only. Then aligned and bolted until happy. Then drilled the rest of the holes directly on place and bolted. Photos speak better than words how all of this was done.

Of course i managed to chip the paint here and there so it seems when everything is working i have to retouch it at the end. No big deal.


2 equal pieces of aluminum square bar were used to fix more or less the correct distance to the upper rail.

12401


Both were precisely squared to the straight edge which was squared to the base rails. 2 pieces of rail were used to support them, a kind of parallels . Not seen on the pictures at the end only one was used at both sides so to make sure the fit is perfect and is really squared.

12402


Holes were marked, 6mm drill used to clean the epoxy so it will not unglue or raise during drilling the beam, then 4.2mm drill to make the holes and then tapped. With the help of the nice little block i have.

12403


On all drilling and tapping the gantry was clamped so it will not move around. here is the fixture which helped me align the lower gantry rail. Dont laugh at my square, had to clamp a rule to make it longer. I said we have all we need at home, just some imagination is needed.
Used thickness gauge though to align it perfectly /yes i love that word/.

Note should be taken here that when i bolted the 2 plates from the Z i pushed them from behind till they touched the screws, so i know they are alligned to the bearing blockes, as the holes are laser cut. I mean because of this i am sure that their edges are parallel with the corresponding rails. Later i will have some additional opportunity to align them on one plane/the z face plate/ as i can move one of them a bit back.


5. The result till now
I am very late with this machine. Good that my friend still suffers me :-)
Thats all for now, problems or no i am quite happy with the result. I can not say what the precision till now is, though i can say imprecision is not obvious or visible in any way. means i use precision squares and they fit well everywhere where measured. No obvious gaps or workarounds. Lets say that for sure i am still under 0.1 mm accumulated squareness. Though it took a lot of time to achieve this.


What do you think? I hope it clears some problems one could encounter on a DIY build.

EddyCurrent
12-05-2014, 08:37 PM
After your problems it's looking nice, I like the colour.

Neale
12-05-2014, 09:10 PM
What did you use to build the dams to hold the epoxy? I can't quite make out the detail in the photos.

Lee Roberts
12-05-2014, 09:16 PM
After your problems it's looking nice, I like the colour.

+1 :thumsup:

ba99297
13-05-2014, 09:30 PM
Syliavski nice work. Congladulations!!!!
How thick steel plate did you finally use and what is the weight of the gantry ( so far without Z axis)?

AndyGuid
14-05-2014, 01:25 AM
It's looking great and STURDY!
many thanks for the update Silyavski.
Your build has given me plenty of food for thought!!!

Boyan Silyavski
14-05-2014, 04:52 PM
After your problems it's looking nice, I like the colour.

Thanks! I like to discuss here in detail the so called "problems" , not cause they are real problems, especially for a metalworker with the proper tools, machine and workshop.

I would rather say difficulties for the DIYer on the cheap where solutions have to be with what you have at hand and at the same time aiming precision.


What did you use to build the dams to hold the epoxy? I can't quite make out the detail in the photos.

Some post back you can see it on the photos. Alu angle profile, 10x10x1mm x 1m, very cheap. Instant glued to the frame and then hot glued from outside.

Its seems the epoxy is ok, as far as common sense is used, the profile is clean and 10mm margin is left from the bearing rail, as it/the epoxy/ tends to rise 5mm from the contact point with the margin, whatever the material.

PS:
-When lifting the angles or whatever you use to form the dams , it is wiser to clamp here and there the epoxy and always take care not to lift it ,break it or chip it.
-when drilling for the rails which for example are screwed with M5 screw, first mark the holes, drill with 6mm drill then center 4.2mm drill, drill and the tap M5. So the epoxy around the holes will not bother you, lift or chip, or heat and lift.
-with time , especially temperature changes can make the epoxy very easy to unglue. Clamping it is necessary in this case.


+1 :thumsup:

Thanks! Great forum :-) and a lot of help.


Syliavski nice work. Conglatulations!!!!
How thick steel plate did you finally use and what is the weight of the gantry ( so far without Z axis)?

10mm steel plates, laser cut. Laser cutting the holes saves a lot of fiddling but care should be taken cause some long and thin section parts are not perfectly straight on their surface plain, so should be checked against straight edge where necessary and plastic mallet used to straighten them.

Now looking back at the drawings, instead of 0.5mm and 1mm bigger than the respective M screw size, i would advise at least 2mm bigger diameter. The paint eats it, the straightness eats it, adjustment eats it, so i constantly had to mount, check, unmount and open more the holes. Say if you have M6 screw, the hole from the beginning should have been 8mm diameter

Lee Roberts
14-05-2014, 07:23 PM
Thanks! Great forum :-) and a lot of help.

Hi,

Your welcome Silyavski, from your build log came great discussion and realisation for others.

So, thank YOU for sharing your adventures and returning help to others, the results are a great forum and community.

In unity everyone can be successful, this is my original goal.

.Me

HipoPapi
18-06-2014, 02:19 AM
Hi,

Thanks for shearing your design and experiences is looking really good so far. I am planning to build a similar cnc router with a working area of 1100mm by 600mm and 250 on the Z. I still have to figure out how to solve the z axes as the longest bit that I need to use is 250mm by 22mm dia and has to be able to travel on top of the 250mm material block.
I have noticed earlier that you had some issues with temperature changes which has me a bit worried as I need to build the machine at normal temperature but it will have to work at -5 degrees Celsius. Common sense tells me that since it will be in there all the time everything will shrink at the same time so hopefully I should not have problems.
Could you please tell me how much this project cost you so far everything included.

Thanks again for shearing.

Boyan Silyavski
24-06-2014, 05:54 PM
Hi,

Thanks for shearing your design and experiences is looking really good so far. I am planning to build a similar cnc router with a working area of 1100mm by 600mm and 250 on the Z. I still have to figure out how to solve the z axes as the longest bit that I need to use is 250mm by 22mm dia and has to be able to travel on top of the 250mm material block.
I have noticed earlier that you had some issues with temperature changes which has me a bit worried as I need to build the machine at normal temperature but it will have to work at -5 degrees Celsius. Common sense tells me that since it will be in there all the time everything will shrink at the same time so hopefully I should not have problems.
Could you please tell me how much this project cost you so far everything included.

Thanks again for shearing.


Sorry have been busy. I have all mounted and finishing electronics and cables.

-So it seems there will be no problem following the design and making 250-300mm Z. Most wisely it seems is to make the sides of the construction deeper, by making the stairs like profiles a bit longer and the Z, keeping everything else same.

-2700-3200eur in materials, depends on how you deal with customs. using quality cables and so.



Now i before i update with pictures and details i have a question. Please sb. help cause my ignorance here is astonishing! I thought all was simple and obvious, but...

I have a toroidal transformer 2x50VAC and Power Regulator Board PSU. So one side of the board says AC1 AC2 AC3 AC4. Here i connect AC1, AC2 to the 50VAC1 and AC3,AC4 to the 50VAC 2.
At the other side it says VDC+ VDC+ Ground Ground Ground VDC- VDC-, so as i need 70VDC i connected Both VDC+ together for the + and both VDC- together for the -, but now i gave 140VDC measured between + and -. What i am missing??? i remember the time at school when + was + and -was-, something changed these years or what?:redface::redface::redface:

1262612641



PS: PSU problem resolved, Neale helped me here http://www.mycncuk.com/threads/7659-PSU-wiring-help-needed?p=59481#post59481

HipoPapi
27-06-2014, 04:35 PM
Thanks Silyavski for your reply and I am glad you sorted out the psu problem.
Have you managed to assemble the Z axes and could we have some pictures please.

Boyan Silyavski
27-06-2014, 10:17 PM
Hi,

just finished almost everything from the machine part and cables. The box its almost ready.

First of all-Thanks for the interest you are taking in my build!!! And the help of course.

Here are some photos:
/sorry they can be big on small monitor but seems they can not be parsed from G+ so had to copy paste them./


1. The Z axis. 2x6mm plates bolted together. At the back side/not seen/ 2x 20x16mm solid steel bars, on top of them at the back are mounted the rais. 16mm is the distance needed to bolt exactly the ball nut housing.

Generally speaking is good before the build starts to buy 1000 allen bolts with cylindrical head M5x40, for example + say 100 M6x60. Hundreds go for mounting the rails, the others i cut and fit where possible. I mean buying every time 10 screws from the shop is expensive. All bolts together on the machine could easily cost 150euro or more. At local shop the 1000 M5 bolts sell for 60 euro. I found them for 15 euro after extensive online search. The magic word is Din 912

-The M6 bolts are for fixing the screw mounts, ball screw bearings at both ends, linear bearing carriages/hiwin 20/. Where needed i cut them to size. hell i cut a lot of screws these weeks.:hysterical:

- The spindle mount brackets are cast, means not perfect. So i had to fix them on place , mark them, measure, then drill .

https://lh3.googleusercontent.com/-Ln67_S8rh3Q/U6sj2f47NaI/AAAAAAAADfQ/VpnSZtCgsSw/w1358-h766-no/upload_100000FE4DF079_2014.06.25%252C19%253A05%253 A57%252C685_5A116CD0


2.View from side . My dog is again bored from my craziness.

https://lh5.googleusercontent.com/-ijAh8fEQo70/U6sj2Sd_EFI/AAAAAAAADqY/rLShPw3lEeQ/w1358-h766-no/upload_100000FE4DF079_2014.06.25%252C19%253A07%253 A11%252C518_3DD90D07



I am still not convinced how i have to wire the proximity switches. I mean as Limits or Limit + Home. The cables i use is 8 pin. I am still not convinced at that squaring the gantry thing.

Lets see- the machine is perfectly square. And when i say perfectly look at this - moving one of the long ball screws that move the gantry, the gantry moves with ease and the other ball screw rotates by itself :-), all along the distance i mean. I tried moving them in opposite directions but there is no play so actually i can not make it not square, at least by hand i mean.

For the moment i will go as so far that connect the gantry switches only from the left side and make all limits. It will save me some thinking how to pass the cable from the right side. Will do some tests and see if its worth connecting them Limits and Home. For the purpose will make a small connection box at the back of the Z. cause the design is so, that all cables meet there.

https://lh3.googleusercontent.com/-XHUq4Da3-Eg/U6sj2U-rylI/AAAAAAAADqM/AYcdzrETVqU/w1358-h766-no/upload_100000FE4DF079_2014.06.25%252C19%253A06%253 A22%252C118_0E17F85A



3.The box


Now this is where i wasted a lot of time. My friend just dropped me a plastic box and said -fit all here. Well, i fit it. After a lot of thinking, but was a good exercise. I made all from scratch. Next time will by a fancy box like fellow forum members do. For a reason obviously. But again, it was fun.

https://lh3.googleusercontent.com/-JnsjznsjqNM/U6sj2efrg4I/AAAAAAAADqo/ELMdpvPYTfA/w1358-h766-no/upload_100000FE4DF079_2014.06.25%252C19%253A10%253 A54%252C35_58B761B6




Let me tell you something. I wasted a whole f***ng day trying to solder with a chinese tin and flux. I even doubted for a moment that i can solder at all. So ugly and weak...
So very frustrated, i went to the shop and spend 20eur on ???g silver solder and 10 euro on flux they use for copper soldering, liquid with a brush. After a lot of thinking , yeah, i did not want to spend 30 euros more that day.

Well, what a perfect buy. A must. The flux works for everything except aluminum. The solders are Perfect. I was born again from hell. NEVER USE CHINESE SOLDER AND FLUX. Thanks to the guy on Youtube that compared the sh*t with the real thing, so i opened my eyes.

https://lh5.googleusercontent.com/-LTv1PzYm3Ec/U6sfBbuJ-xI/AAAAAAAADe0/25-GAmCAnyM/w1358-h766-no/upload_100000FE4DF079_2014.06.25%252C19%253A11%253 A42%252C64_CA3245CF




The BIG toroidal transformer /650w/ fits nicely into old PC power supply enclosure. Yes, everything is interference isolated in the box. And ventilated :-)

https://lh6.googleusercontent.com/-e7-RdiglM0o/U6sj2bO6jKI/AAAAAAAADfQ/otylEeokx7I/w1358-h766-no/upload_100000FE4DF079_2014.06.25%252C19%253A10%253 A00%252C887_DC663491



This is the side of the box. All connections go here. All connections realized using 4 pin and 8 pin chinese "aviation plug" . That makes me laugh. I certainly don't want to be in that plane :hysterical:

On my machine/next build/ i will use 4 pole Neutrik Speakon plugs only

The air comes from this side, passes through i filter/hate dust in boxes/ , cools the drives and goes out propelled by a 220v/24w ventilator at the other side.

Behind the alu plate is 4mm thick frame which gives place to fit filter. the filter is 0.7euro sheet used in kitchen filters. The box is drilled with a lot of big holes for the air to pass. Say holes total surface is 1.5x the hole of the ventilator.

The most useful instrument in making the box was STEP DRILL. I did not know what it serves for, before hand i mean , so i learned there something.


https://lh5.googleusercontent.com/-3xbQ-80FjYk/U6sj2RPHBpI/AAAAAAAADfQ/ZN15u46_1ag/w1358-h766-no/upload_100000FE4DF079_2014.06.25%252C19%253A10%253 A29%252C331_5ECCAC32

TonyD
27-06-2014, 11:52 PM
Hi. The poor Dog :) Love the machine. One comment I would make is that my gantry is aluminium plate (effectively 15mm plate in box configuration) with 20mm alu side plates and I couldnt find any play from one side (X) to the other (from a racking perspective). Once the screws were connected and the motors turned, the machine was well able to rack itself. I'm actually looking forward to the independant homing of the X axis proximity switches, as Jazz noted to me before, the bullet type allow adjustment; I'm banking on this to help me get the gantry square as its being set up. Even though your machine is steel, I suspect it can rack and be adjusted.. just a little.

GEOFFREY
28-06-2014, 09:32 AM
Hi, love the photos. that does look like a very substantial, purposeful piece of kit. Well done. G.

FatFreddie
28-06-2014, 02:18 PM
Even though your machine is steel, I suspect it can rack and be adjusted.. just a little.

Would it be possible to lock one lead screw and put a dial gauge on the other side and measure how much (little) it can be moved?

As Geoffrey said, a purposeful looking piece of kit - very nice :-)

ba99297
29-06-2014, 01:06 PM
silyavski (http://www.mycncuk.com/members/10304-silyavski) very good work and very helpfull thread.
I am planing a machine a little bit bigger than yours (X:1500mm Y:750mm Z:130mm real travel).
I have been inspired by your plans for my machine frame.
I have some questions about what i see.
1. How did your succed to have Z axis rails in the same plane? Did you use epoxy, or did you mill the 6mm plates?
2. Why you use 2x6mm plates instead of one plate 12mm?
3. What clamping system are you going to use?
4. What is the clearance from the lower part of z axis to the cutting surface. Also what is the real traver for your z axis.
5. Finally what is the horizontal distance ( from left to right ) for y,z axis carriages and the vertical distance ( from bottom to top) for y and z axis carriages ( outer side of carriages)?
Thanks for you time

Vagelis

Boyan Silyavski
29-06-2014, 10:57 PM
Would it be possible to lock one lead screw and put a dial gauge on the other side and measure how much (little) it can be moved?

As Geoffrey said, a purposeful looking piece of kit - very nice :-)

Interesting. I will do that tomorrow and report back. The gantry will not deflect for sure :-).



silyavski (http://www.mycncuk.com/members/10304-silyavski) very good work and very helpfull thread.
I am planing a machine a little bit bigger than yours (X:1500mm Y:750mm Z:130mm real travel).
I have been inspired by your plans for my machine frame.
I have some questions about what i see.

1. How did your succeed to have Z axis rails in the same plane? Did you use epoxy, or did you mill the 6mm plates?

The Z axis rails are in the same plane for 2 reasons:
1. When i mounted the bearing blocks first, i checked the plate with straight edge. luckily it was almost straight. Some hits with big rubber mallet made it perfect.
2. Now having achieved to mount them on a plane surface, using precision square i squared 1 raw of them and tightened them. The rails were in the bearing blocks but not attached to anything else. cause when you measure long things, its easier to detect any error.Then using digital caliper i measured 150mm, tightened the bolt on the caliper and from both sides made sure the distance is the same . Tightened a bit, then with the digital caliper made sure its parallel to 0.01mm. Little bumps with small plastic hammer helped. Then tightened it finally.



2. Why you use 2x6mm plates instead of one plate 12mm?


I did not want to wast more time. That's what they had at hand at the metal shop. Luckily, cause they were not perfectly flat, so it took a lot of hammering to flatten them against straight edge.



3. What clamping system are you going to use?


Its up to my friend. On my small machine i have cast aluminum grind flat plate. With a lot of tapped holes. On top of it i mount 10mm hard plastic sheet using bolts at the corners and very very thin double sided glue sheet, the ones they use in photography printing to mount photos to lexan support. I Hot melt glue all jobs. When finished, i use alcohol to un glue the detail.

But with a strong and fast machine that will not always be possible. I know your doubt. I have it for my next machine and still not decided. My best bet will be to use plastic bed. I have to make some visits to the junkyard or an recycling center. And on top of it 5mm expanded PVC . However i plan to invest some money and maybe use steel channel , like a mill, but not on all the bed, just at the nearest side, so to say for fine jobs.

So that's my suggestion. Make 2 areas/ or 3 areas as i will do but my machine will be 3m long and 1.5 wide/ . One with a proper aluminum or steel bed and the other plastic.

Cause MDF will constantly need surfacing, i believe investment here will pay very fast in the future.

Vacuum i am not planning to use. The strength of vacuum is if you have production which is repeatable, or you work with sheets only. However in the future if needed you can make some removable vacuum fixtures.



4. What is the clearance from the lower part of z axis to the cutting surface. Also what is the real traver for your z axis.



260mm and real travel of 215mm

Now, careful cause this is still unconfirmed info and just a point of view. Its just what months of mind games told me. As i said it many times in the forum, cause that's my view for a DIY really multitask machine, i seem to find that the Z to bed/ frame without anything else/ 250-260mm is perfect. With the trade off that when alu sheet is routed it had to be risen another 100mm at least, using MDF, wooden or so, ribbed or solid, removable bed or fixture.

Below is how my z plate ended. As you see the solid bars combined with the rails reinforce the plate and is very doubtful it will bend, think of bending a solid steel bar ~50mm thick and at least 50mm wide, 500mm long. Another pint here is that i use 2 spindle mounts separated at spindle both ends. So the mounts and the spindle further reinforce the thing. No it will not bend in any way.

12684




5. Finally what is the horizontal distance ( from left to right ) for y,z axis carriages and the vertical distance ( from bottom to top) for y and z axis carriages ( outer side of carriages)?
Thanks for you time
Vagelis

What i believe is the absolute minimum for a good strong machine- 240mm for the Z Spacing left right

12685

The vertical is my minimum for such a long Z plate. The width of 150mm is the minial as i see it , again having in mind the length

12686 12687


Hope that helps.




Vagelis, something else.

I have been following your build with great interest, please let me tell you something. This also to the other people that aspire to build a machine. You will need to spend at least 100eur on the following things if you don't have them, to be able to accomplish the precision mounting successfully. They are a MUST. I don't see how it can be done without them and especially by one person.
Believe me on this. Not to mention the satisfaction you will feel when all is mounted precisely.


-1m straight edge or longer.Stainless better

The Must here is to be at least long enough that it can lay on both parallel mounted rails that the gantry slides on. In other words wide as your machine. Without this you will run at the moment of mounting and later at countless problems. The best will be if it has length of the diagonal of the bed or at least of the rail.

Many will disagree but Rectangular section is better than knifed edge, especially if you work alone. Much more cheaper also.

Here is my initial experience with links from where to buy. http://www.mycncuk.com/threads/6546-Help-needed-with-understanding-accuracy-in-measuring-tools-I-want-to-go-straight-%29
To summarize it DIN 874 is the magic word. Whatever accuracy. Or Din 866 rule, especially if you go bigger machine build. Like my next one. You guessed right, i will buy at least 2 meter one.

-2x 30cm precision squares . Din 875 is the word here. these will help solder , square the gantry, the gantry to the bed, etc. Yes, 2 of them because many times you will clamp them together in clever ways.


-1x <10cm precision square , Din 875 is the word here. Stainless betterfor the tight fits, squaring the spindle, etc.

-2x cheap chinese squares

Once you have bought a really cool reference square, you go with it to the shop and buy cheap squares to use for soldering and damaging jobs. Once you reference them against the good one.

EddyCurrent
30-06-2014, 02:16 PM
Nice looking machine but the eye is drawn to those brackets from the gantry to the X ball nuts. I know from your posts that you will have made sure these are correct but I have to say they look flimsy in comparion to the rest of the machine.
You made a good job with the control box considering what you had to work with, it's been informative and a pleasure to follow your build.

Boyan Silyavski
14-07-2014, 05:32 PM
Nice looking machine but the eye is drawn to those brackets from the gantry to the X ball nuts. I know from your posts that you will have made sure these are correct but I have to say they look flimsy in comparison to the rest of the machine.

On the photos maybe so, but in real life they look normal. Furthermore the actual distance where they are not attached to something is very very short, so they are reinforced by the ball screw nut and the gantry.


Now i want to say it:
The machine is ready and running:yahoo:

:applouse: Thanks to all who helped :applouse: and all who watched the progress.


I would like to write soon a more detailed final conclusions, as these days again learned many things.

But for now i would say that i am extremely happy with the result.


Now about the final accuracy i achieved. Today i run it for first time cutting. My typical starting test is 25mm OD circle in 50mm square

Pictures speak better than words but lets say that all the careful fiddling payed itself and the final/accumulated/ accuracy of the machine without any compensation on mach 3 motor tuning and so is :victorious:0.01-0.02mm :victorious: or less , having in mind that the digital caliper measuring may be not perfect. As you can see perfect super clean circle cut. No mismatch or whatsoever.
PS.The bed is 5cm thick so the Z at the test was extended at its lowest point.

12773 12774 12776 12777

All motors are tuned at 8m/min but i believe it can do much much more. I will test it further when on the floor, cause its quite dangerous now to move very fast, the supports flex like crazy.

After 1h of continuing run/ i am surfacing the 10mm plastic bed i fitted over 50mm wood and composite board/ the motor temperature at Y and A/the gantry motors/ is 55C and the X and Z motors is 35C . Its 24C outside.

Soon will post video and some further notes .

Thanks again!

TonyD
14-07-2014, 07:22 PM
Well done. :)

JAZZCNC
14-07-2014, 08:14 PM
Hi Boyan,

Just seen your Pm. Sorry not been watching your thread so much as I tend to not to drop in much on those who are experienced or getting along good.

Well you certainly have progressed buddy and done an absolutely cracking job my friend. Looks excellent withTank like strength.:applause: . . . . Health and safety will like that colour scheme certainly won't miss it . . Lol

Look forward to seeing video..!! . . . . . WELL DONE.

Wal
14-07-2014, 08:21 PM
Excellent. Really nice build. Well done..!

Wal.

kingcreaky
15-07-2014, 07:37 AM
Excellant Machine buddy, a real credit to you.

I am very jealous.

keep us posted with all the things you make on it!.

njhussey
15-07-2014, 07:42 AM
Cracking build thread, really solid well built machine and an inspiration...

mekanik
15-07-2014, 10:37 AM
Hi Buddy
Excellent build and well worth the time and patience you put into its construction.
Mike

EddyCurrent
15-07-2014, 10:38 AM
On the photos maybe so, but in real life they look normal. Furthermore the actual distance where they are not attached to something is very very short, so they are reinforced by the ball screw nut and the gantry.

I knew you would have got them right, excellent machine and accurate too, just as you intended, spot on.

Boyan Silyavski
11-08-2014, 06:53 AM
Just installed it at its new home. The precision continues to surprise me. Instead of accumulating, all small imprecision neutralized each other, may be pure luck but still under 0.01 -0.03mm, it seems i can not measure it properly without introducing error. No need though, i am happy.

Surfacing aluminum resulted in glass like surface, small marks are not seen by naked eye and scratch test with fingernail leave impression of trying to scratch glass.

The C23 Bob works like a charm. But the integrated spindle control is erratic. I supply it with 12v stable voltage and it plays the output to spindle with 0.2v witch translates +-200rpm, which makes the spindle sound annoying. Will contact the maker. As i see it i will change the small pot with a big one external, in the hope to cure this problem. All PSUs i use are overrated at least by 100% and brand ones, so may be its the pot.

Next machine - no Flimsy: 8 wire alarm cables, connectors to box, 1 component paint.

The 0.8kw spindle seems now/ as i knew from the beginning/ way underrated. This baby deserves 3kw one and will be called - The Reaper :-). I am boasting :-)
But for its purpose is ideal.

Here is a video of it working. Unfortunately i forgot to make video when it was slicing aluminum and took it when we were testing some 3D jobs. I am surprised from RhinoCam, quite capable and i was able to figure in a minute how to program the 3d job.

A little noisy video, but i wanted to be heard what sound it makes. If i dont forget in a week or 2 will be making some aluminum parts there, so will make another one.


https://www.youtube.com/watch?v=C9hTLN1CydU

ba99297
11-08-2014, 07:25 AM
I have no words
Excellent job
And one more time i want to say that Deans help , your ideas (about frame),Jonathans calculator, and Eddys suggestions drive me along this long trip that called cnc building. Thanks again.
One question
Are you using servos or steppers?

Thanks
Vagelis

Boyan Silyavski
11-08-2014, 08:13 AM
3 NM steppers from Zappautomation coupled with AM882 drivers , driven by 650w Toroidal Psu at 70VDC / 250v rectified by power regulator board with 4 big capacitors that gives 70VDC at the output/.
Old Dell PC 2.8Ghz with 512 Ram, stripped reworked and hacked to be extremely light and fast + stable version of Windows Server 2003, 25khz Mach3, 1/8 microstepping, 4.2A motor selected by jumpers on AM882.
Deflection at any part of the machine at any direction less than 0.00mm under 100kg load/me/
20t HTD 5M Pulleys, 270mm belts 15mm wide. 1610 screws on all axis, 1605 on Z, 1:1,
Velocity 10m per minute,acceleration 800 at the motor tuning in Mach 3.
Temperature of motors at X and A 55 Celsius, at Y and Z 35 Celsius, when here 30 Celsius.

Boyan Silyavski
11-08-2014, 08:23 AM
Yes, Dean and Johnathan are the guilty ones that all went that good. Not only them but all who criticized the initial design and followed the build which inspired me when I was tired. Great Forum. I bow to all the wisdom here.

GEOFFREY
11-08-2014, 08:27 AM
Once again, brilliant. Not one of the advisors, but an enthusiastic onlooker!!! G.

mitchejc
11-08-2014, 06:58 PM
Wow congrats Silyavksi that's a great looking machine!
If I may ask: Was it very difficult to align the top and bottom rails to get them parallel in the Z direction? Did you just epoxy cast the top and then bottom from the same level surface and the two rails were aligned or did you have to perform other magic tricks as well?

Boyan Silyavski
11-08-2014, 10:23 PM
Wow congrats Silyavksi that's a great looking machine!
If I may ask: Was it very difficult to align the top and bottom rails to get them parallel in the Z direction? Did you just epoxy cast the top and then bottom from the same level surface and the two rails were aligned or did you have to perform other magic tricks as well?


Thanks!
read please post #93 (http://www.mycncuk.com/threads/6457-Sturdy-and-Fast-all-Steel-CNC-my-first-build?p=58239#post58239) , point 1 to 4, especially 4

It was a lot of thinking but once i figured the correct steps how to do it, it was easy. You will need a straight edge though, long enough that can lay on both long axis rails perpendicular. + Big enough square. Without that its not possible to align the machine correctly. Both can be obtained for around 100euro and this is money well spend. the links are somewhere in the thread.

GTJim
12-08-2014, 07:47 AM
silyavski, this is a very impressive build. Thanks for sharing.

HipoPapi
12-08-2014, 09:10 PM
Beautiful build, and a lot of great info. Congrats on the final outcome. Must have been hard to part with it :).
Thanks again for sharing.

HipoPapi
20-09-2014, 04:40 PM
Hi Silyavski,

I see you have used HTD pulleys and belts on your machine. Did you get those from Zapp?
Also I see they do key cutting which makes it easy to mount the pulley to the servo but how did you mount the pulleys on to the ballscrew. I know its a newbie question but that is what I am. I am thinking to use 3 to 1 reduction and trying to figure it out. Also do you need any special machining for the ballscrews when using pulleys? HTD belts are a good option for me as they are rated to -25 Celsius.

Thanks,
Vass

Boyan Silyavski
20-09-2014, 06:13 PM
Hi,
All pulleys and belts are from beltingonline.com
Nothing special, ball screws machined normally. 2 grub screws on pulley. A drop of instant glue on the shaft. If I was doing it for myself i would file or drill the shaft where the grub screws are. Now it's more forgiving for mistakes

On the big machine I am building now for myself I use only aluminum pulleys as it would be geared 20:30 t and the rotating nut is heavy so I don't want to have too high inertia. These I bought from China as here prices are prohibitive. Aliexpress.

Normally you don't need any special machining given that the motor plate is not thicker than 10mm.
On the Z however is good idea not to make it too strong especially if geared for some reason. Cause hitting the bed can do some damage especially with strong motor.

HipoPapi
20-09-2014, 06:45 PM
Hi,

Thanks for the info. I am thinking 3 to 1 on X and Y and 2 to 1 on Z as my Spindle will be large about 15 kg. I see they offer grub screw and key cutting service as well so will have key cutting on the servo side and grub screws on the ballscrew.
I understand from your info given ( 20:30) that you calculate the gearing ratio by the tooth count?

I see you are using on your new machine the west systems 105+209 wich I know is ideal for this application the only problem beeing that here in the uk the weather isn't ideal :) Do you think I will be ok with the 105+207 or 206?

Thanks again,
Vass

Boyan Silyavski
21-09-2014, 12:24 AM
Hi,

I understand from your info given ( 20:30) that you calculate the gearing ratio by the tooth count?
Vass

Yes, cause 1:2 , 1:3 or whatever seems not to reflect reality , misleads the mind. The reality is that 16t is the smallest one and geared 1:3 means 48t for the second one which is in fact 75.25mm in diameter and at 100mm separated center from center they have only 6t in mesh. So imagine the inertia if from steel. Even from aluminum.

I assume you will be using servos. So the encoder count + ballscrew pitch will dictate your gearing, as it will determine resolution, max speed of the machine.





I see you are using on your new machine the west systems 105+209 which I know is ideal for this application the only problem being that here in the uk the weather isn't ideal :) Do you think I will be ok with the 105+207 or 206?

Thanks again,



No, it will be a problem. Its not only the time, the faster it cures the more heat generates, the more it distorts. Whats the problem with the weather in UK? humidity is not a problem if its not raining directly on it. And where i live its much more humid.

HipoPapi
21-09-2014, 02:13 PM
Hi,

I am planning to use 2x 750w servos on the X, 1x 750w servo on the Y and a 400w servo on Z.
The shaft on the 750w servo is 19mm dia and 31mm long so in fact that is what determines my smallest pulley.
I am planning to use 25mm HTD belts as my gantry will be close to 200 kg plus the belts are rated for -25 degrees Celsius.
http://www.mycncuk.com/attachment.php?attachmentid=13398&stc=1
In the Case of a 5 pitch pulley for 25 mm belts F= 30.5 which means that that is my whole 31mm shaft. So if I would want to use the whole L which is 38 I would have 7mm of the pulley hanging of the servo shaft. If I want to use grub screw I would be limited by Dm and an even larger Dm if I want to use key. So I have decided to cut of F from L and use just F and key cutting therefore I can use a smaller pulley and I am limited only by (De) and have nothing hanging of the shaft.
So basically 24 t pulley on the servo where Dp=38.20 and 72 t pulley on ballscrew where Dp = 114.59 giving me
a ballscrew rpm of 1000.09 on the ballscrew with 3000 rpm on the servo side so essentially 3:1.
With a 2010 ballscrew my critical speed is 1128 so would be able to get 10m/m rapids or I can go with 2020 ballscrew and get 20m/m.

With the resin my worry is that here in the uk we are getting around 21-25 degrees Celsius during day time and it goes down to 15 during the night. But I did not look into it so deeply yet and maybe that isn't a problem with the 105+209. If By any chance you already know it please let me know.

Thanks,
Vass

JAZZCNC
21-09-2014, 03:08 PM
Vass you cannot just rely on the Key you will need Grub screws as well to stop the pulleys coming off the shaft. You can buy pulleys with larger Boss so can get more screws in but also not uncommon to put the screws thru the teeth and provided they are below the teeth and deburred correctly it's not a problem.

Regards the servo's the rated Continous speed will probably be 3000rpm which is the Max speed they will provide continous rated torque but in practice they often will reach higher speeds at lower torque 4 or 5K is not uncommon.
Really thou you don't want to go past the rated speed/torque esp with a heavy gantry so your calcs are correct but with 3:1 ratio and 750W servos's you'll have much more torque than you need so won't be a problem within reason.
To be honest you could go lower on the ratio and increase the speed and lower inertia slightly at same time. Like I said in emails the critical speed isn't critical and you can run above it without any issues so 2010 run at 2:1 would give 1500rpm and 15mtr/min rapids which is more than enough. You won't be running above critical speed all the time and infact rarely will be for more than 2-3s at a time so it never becomes an issue. My own machine as been running 2005 screws with 1:2 ratio so double speed and well above the critical speed for 6-7yrs without any issues.
I would only use 2020 screws if the screw length was long and needed to lower screw speed to resist whip. In this case I'd go with 3:1 ratio to increase torque and make up for lower mechanical advantage from larger pitch.

HipoPapi
21-09-2014, 06:13 PM
Hi Dean,

I was thinking of the grub screw through the teeth option but wasn't sure thanks for confirming that.
What do you mean by the larger Boss?

Thanks,
Vass

JAZZCNC
21-09-2014, 08:16 PM
What do you mean by the larger Boss?

Boss is the bit grub screw would normally go thru or the difference between F and L

toomast
07-02-2015, 07:12 PM
Hello Sir! Amazing work! :thumsup:
How did you adjust Y axis bearing blocks against the Y rails? Did you weld the hole assembly of 10mm lasercut steel?

Boyan Silyavski
08-02-2015, 03:31 AM
Hello Sir! Amazing work! :thumsup:
How did you adjust Y axis bearing blocks against the Y rails? Did you weld the hole assembly of 10mm lasercut steel?

Thanks!
Yes, i welded the whole assembly, in fact all on the machine is fully welded except the Z assembly, which is spot welded almost fully-spot by spot each next to the other.


You mean how i squared the gantry? Y is my 2 long rails. After the epoxy they were on 1 plane. Then using straight edge and precision square i squared them. Then mounted the bearing blocks. Then mounted the gantry on top of the bearing blocks with bolts loose. Then using again straight edge touching the bearing blocks i squared the bearing blocks both sides. Then tightened the bolts that hold the gantry over the bearing blocks. So the gantry was now square.
Now have in mind all was was welded <1mm at least. Also the rails on the gantry were not drilled yet. Later i squared the rails on the gantry, fixed them with clamps and then drilled on place. Look at post #93 (http://www.mycncuk.com/threads/6457-Sturdy-and-Fast-all-Steel-CNC-my-first-build?p=58239#post58239)

toomast
08-02-2015, 07:46 AM
Actually I meant X-axis then.
I understand that you ensure with epoxy that the rails are parallel. But how did you adjust HIWIN bearing blocks to match the rails?
Surely you did not weld the laser-cut parts so precisely?
http://www.mycncuk.com/attachment.php?attachmentid=14634&stc=1

Boyan Silyavski
08-02-2015, 01:12 PM
Actually I meant X-axis then.
I understand that you ensure with epoxy that the rails are parallel. But how did you adjust HIWIN bearing blocks to match the rails?
Surely you did not weld the laser-cut parts so precisely?
http://www.mycncuk.com/attachment.php?attachmentid=14634&stc=1





The machine when long rails epoxy is poured must be glued to the floor so you will not bump it later. Then long rails mounted. Then first i poured epoxy on the gantry top , the gantry in normal position as near as it would be in final setup. Then flipped the gantry 180 degrees and the leveled top epoxy now down resting on the already leveled long Y rails. Then i poured epoxy on the low gantry rail and on the legs. So now we had everuthing parallel, gantry legs, low rail and upper rail.

Then i squared the gantry top rail as described bellow. In short i squared a straight edge on the long rails. Then using 2 equal sized aluminum bars and checking them square against the straight edge i squared the top rail. Then additionally using only one piece at both sides i carefully finished the job feeling the scratching . Drilled and mounted the same way. See first picture
Now i had 1 top rail ready and square.

The bottom gantry rail.
I mounted the plates on both rails. The plates that screw to the bearing blocks. The Z was still only pieces, not soldered. Then via 2 clamps i mounted the lower rail more or less. But clamps not tightened very much. Then using the front Z plate that will be later soldered to the both plates that screw to the bearing blocks i checked and aligned perpendicularity to the squared straight edge resting on the long rails , picture below.

Note should be taken here that when i bolted the 2 plates from the Z i pushed them from behind till they touched the screws, so i know they are alligned to the bearing blockes, as the holes are laser cut. I mean because of this i am sure that their edges are parallel with the corresponding rails. Later i will have some additional opportunity to align them on one plane/the z face plate/ as i can move one of them a bit back


So i mounted the lower rail. Z was carefully spot weld fixed while all was bolted on its place. No paint anywhere on the machine where bearing blocks contact with frame, metal only.








4. Bolting the gantry to the frame and aligning the gantry rails.

Needless to say - a lot of problems.

a/ First to say i have dry bolted the gantry before painting all. It was ok. So what was my surprise when everything was painted, the machine fixed on the welding jigs for comfort and the gantry will not fit. So i called a friend that helped me and 3 times i had to lift the gantry and lower it, mean while widening the holes. The reason. This is crazy- the machine is outside, the sun heats the frame and it widens. cause i made the machine in the winter...
So basically now i cover all the time it so it could not heat . My garage is small i mean to work inside.

So at the end i squared perfectly the gantry and bolted it


b/ Now next unsuspected problem. How do i fit the rails on the gantry to be perfectly square with the long rails on the frame? I knew i could do it somehow but in reality it was a big challenge.
I know how to do it if say i make 10 same machines, a fixture and no problem. But how to do it on the cheap. Cause this machine really ate a lot of money spend on little things.
After a lot of thought i fixed the straight edge perpendicular to the base rails and decided to start with the upper rail first.
Once the upper rail was square, there came the problem with the lower rail. A friend of mine says we have all necessary stuff always at hand. So i was in no rush, thought it a whole weekend and just have done it.
Another difficulty was that i do all alone at home with no help, so first i more or less squared it using clamps and then drilled and tapped 2 holes only. Then aligned and bolted until happy. Then drilled the rest of the holes directly on place and bolted. Photos speak better than words how all of this was done.

Of course i managed to chip the paint here and there so it seems when everything is working i have to retouch it at the end. No big deal.


2 equal pieces of aluminum square bar were used to fix more or less the correct distance to the upper rail.

http://www.mycncuk.com/attachment.php?attachmentid=12401&stc=1


Both were precisely squared to the straight edge which was squared to the base rails. 2 pieces of rail were used to support them, a kind of parallels . Not seen on the pictures at the end only one was used at both sides so to make sure the fit is perfect and is really squared.

http://www.mycncuk.com/attachment.php?attachmentid=12402&stc=1


Holes were marked, 6mm drill used to clean the epoxy so it will not unglue or raise during drilling the beam, then 4.2mm drill to make the holes and then tapped. With the help of the nice little block i have.

http://www.mycncuk.com/attachment.php?attachmentid=12403&stc=1


On all drilling and tapping the gantry was clamped so it will not move around. here is the fixture which helped me align the lower gantry rail. Dont laugh at my square, had to clamp a rule to make it longer. I said we have all we need at home, just some imagination is needed.
Used thickness gauge though to align it perfectly /yes i love that word/.

Note should be taken here that when i bolted the 2 plates from the Z i pushed them from behind till they touched the screws, so i know they are alligned to the bearing blockes, as the holes are laser cut. I mean because of this i am sure that their edges are parallel with the corresponding rails. Later i will have some additional opportunity to align them on one plane/the z face plate/ as i can move one of them a bit back.

toomast
08-02-2015, 02:58 PM
I swear I read this section many times before! But could not understand...
I guess my brain refused to believe that it is possible to fix the bearing blocks and then weld the parts together and end up with perfect alignment...
Even hammering some 10mm steel plate to perfect plane seems unbelievable. Guess it depends who is holding the hammer or welding torch :)
Sorry you had to copy hole page from your thread!

All the best,
Toomas

Boyan Silyavski
08-02-2015, 03:52 PM
The key there is to leave possibility for alignment.

I mounted the plates so all bolts touched the holes from one side, and as they were laser drilled they were more or less straight. But later i drilled the holes 1-1.5mm wider. So at the moment of mounting i had not only the margin of the hole itself , but of the widened hole. So its easy to adjust cause there is space that allows it.

The other key is to have 2 precision squares and 1 straight edge. So at all times you can check and assure perfect fit. You can not measure how perfect, but if you insist and try that no visible gap is left at any place, you will finish with very precise machine. And not be lazy, cause you need sometimes to check a simple thing 10 times untill you are definitely sure its straight.

And when i say check, i mean check with strong led torch

toomast
20-03-2015, 10:27 AM
Silyavski, do you think 10mm steel is minimum for Z axis?
I hink that I will at least try to build my Z axis from steel. If I dont succeed that I will go for aluminium :)

Boyan Silyavski
20-03-2015, 12:39 PM
Steel is cheaper, faster and easier if you don't have a mill or other cnc. 10mm steel and that having in mind the way i did it, where the rails and the rectangular bars that the rails lay on, play the role of ribs that strengthen all. You will be surprised how flexible is 10mm of steel if not strengthened by bracing plates that provide strength in contrary direction.

I managed to mill with that Z/180mm fully extended/an aluminum plate- 1.5mm deep pass, and lack of cooling and proper bed fixture was the problem to go deeper per pass.

masinecc
13-04-2015, 11:49 AM
Hi dear friends, do u thing its good ide to use ballscrews RM2505-L=2600mm on both sides of my y-axis. Could it be too long and cause vibrations ? Or should i use R and G instead?

Clive S
13-04-2015, 12:50 PM
Hi dear friends, do u thing its good ide to use ballscrews RM2505-L=2600mm on both sides of my y-axis. Could it be too long and cause vibrations ? Or should i use R and G instead?
Welcome to the forum. It would be better if you started a new thread with this.

You could use rotating ball nuts so that the screws remained static. ..Clive

masinecc
13-04-2015, 02:07 PM
Thanks for ur reply, would u like to post a picture from that rotating ball nut? Just to see how does it look like. Thanks !

njhussey
13-04-2015, 02:49 PM
Thanks for ur reply, would u like to post a picture from that rotating ball nut? Just to see how does it look like. Thanks !
If you do a search on the forum you'll see that Jonathan uses them and so does Silyavski, they have pictures in their threads...

Skipsoaring
28-05-2015, 03:31 PM
Great thread! plenty of useful information!
Cheers
Clayt

rehoward
30-12-2015, 05:03 AM
Great thread! plenty of useful information!
Cheers
Clayt

Great thread indeed!
I was wondering if there is a way to print this thread in its entirety? It is so long to read on the PC that I would like to print and highlight key info. Or maybe it can be saved as a file and imported into MS Word? Or maybe one of you has distilled it down to the basics already? I am open to ideas on this.

Randy

Wal
06-01-2016, 02:22 PM
Just looking at this quickly - go to the top of this page - you'll see 'Thread Tools' which has a 'Printable' option that you can select. From the printable version you can print to a .pdf. You'll still need to do this for every page, though...

Clive S
06-01-2016, 02:34 PM
Just looking at this quickly - go to the top of this page - you'll see 'Thread Tools' which has a 'Printable' option that you can select. From the printable version you can print to a .pdf. You'll still need to do this for every page, though...Nice to see you on again Wal. Also there is an option on the printable version to show 40 posts on one page (at the top right hand side)

Wal
06-01-2016, 02:49 PM
Good call on the '40 posts' Clive. Yeah, I've been lurking a bit... I'm around one of the weekends in Feb (8th?) I'll give you a shout and maybe drop in for a cuppa!

Wal.

f1sy
08-02-2016, 01:42 PM
Hi,

I'm new to the forum but want to build something similar to this (very similar) I have read the thread a few times and am in the process of re-drawing the design in NX as I am not familiar enough with Sketchup to be confident releasing parts from it for manufacture. Also I think if I redraw it I will have a better idea of exactly how it all works and whether it will still be suitable for my requirements.

Could you please provide exact part numbers for the ball screws and linear rails you have used in this design. I have got the Hiwin catalogues but am unsure of the exact components that have been used. Once I know exactly what is used I can then start modelling these also.

Really enjoy reading the thread and have learned a lot already.

Thanks in advance for any help you can be.

Thanks,
Sy

Robin Hewitt
08-02-2016, 02:07 PM
Could you please provide exact part numbers

You forgot to ask what he would do different if he was starting again :single_eye:

JoeHarris
08-02-2016, 03:11 PM
You forgot to ask what he would do different if he was starting again :single_eye:

You can see that for yourself by looking at the next one!! Boyan's going to have built 6 or 8 machines by the time I've done one I recon!

Boyan Silyavski
08-02-2016, 03:55 PM
The main difference is that i would have done all from aluminum plate, cause i spend too much time cleaning, , aligning, welding, painting, etc. When you draw the line is not that much cheaper and aluminum is more beautiful to look at.

Speaking especially about a machine made for sale , not for one for my self.

samsagaz
28-07-2016, 09:39 PM
Querido Silyavski, have you some detailed info, or some thread that point me to the right way about how to level with epoxy top and bottom of Y Gantry? i think that wil be a little hard to get it perfectly leveled :/

Boyan Silyavski
28-07-2016, 10:58 PM
Querido Silyavski, have you some detailed info, or some thread that point me to the right way about how to level with epoxy top and bottom of Y Gantry? i think that wil be a little hard to get it perfectly leveled :/


Read from here if you want to see all the troubles and experiments #84 (http://www.mycncuk.com/threads/6619-Quite-an-Unusual-one?p=62464#post62464). Or jump directly to #121 (http://www.mycncuk.com/threads/6619-Quite-an-Unusual-one?p=62580#post62580) to #126 (http://www.mycncuk.com/threads/6619-Quite-an-Unusual-one?p=63914#post63914) to see how to be done properly on any size machine. There is no escaping buying the West System epoxy with the slow hardener. If you read all you will see i tried other epoxies with poor result.

samsagaz
28-07-2016, 11:10 PM
Read from here if you want to see all the troubles and experiments #84 (http://www.mycncuk.com/threads/6619-Quite-an-Unusual-one?p=62464#post62464). Or jump directly to #121 (http://www.mycncuk.com/threads/6619-Quite-an-Unusual-one?p=62580#post62580) to #126 (http://www.mycncuk.com/threads/6619-Quite-an-Unusual-one?p=63914#post63914) to see how to be done properly on any size machine. There is no escaping buying the West System epoxy with the slow hardener. If you read all you will see i tried other epoxies with poor result.

impossible to get that brand in Argentina :/ btw, reading your posts now, thanks for the link!

looks like some of your pics dont work anymore :( http://www.mycncuk.com/threads/6619-Quite-an-Unusual-one?p=67113#post67113

Boyan Silyavski
28-07-2016, 11:30 PM
impossible to get that brand in Argentina :/ btw, reading your posts now, thanks for the link!

looks like some of your pics dont work anymore :( http://www.mycncuk.com/threads/6619-Quite-an-Unusual-one?p=67113#post67113

Then you have to download the technical sheet of West System 105 resin and 209 hardener, understand all details and search for similar stuff there. Or buy from USA. I bought from UK, in Spain it was veeery expensive

ImanGH
11-08-2016, 09:32 AM
Waiting for the square rails and ballscrews purchace, made me play again with the design. Decided to stuff all the electronics inside the body. Due to various reasons like avoiding
10 Neutric connectors sticking out at the back, cables, enclosure and so on. mainly because i live at the seaside so connections always give me trouble and i have to glue my connections with hot glue.

Decided also to make the structure from 60x60 4mm at the important places and 3mm at the no so important. But what ever i did i couldn't figure placing diagonals so i finished with rigid square design and 100kg structure. more or less 18meters of steel. I think i overbuild it a bit.

Another decision was to make the bed deep enough so there is no need to change spindle position. Instead a wood bed would be fitted so the spindle works at normal position and only when necessary to remove the wood bed, not move the bed of the machine or anything.

Hope that structure is strong enough, cause tomorrow will order the steel.

99459946

If somebody sees something wrong, please tell me until is time, he he.
Hi Boyan
My name is Iman and I want to design a gantry CNC. but i dont have enough data. is it possible to send me your cad design? and introduse some reference about design cnc gantry?
Thanks

Boyan Silyavski
11-08-2016, 12:23 PM
Hi Boyan
My name is Iman and I want to design a gantry CNC. but i dont have enough data. is it possible to send me your cad design? and introduse some reference about design cnc gantry?
Thanks

the design is free in the open source section of forum

http://www.mycncuk.com/threads/6979-A-Sturdy-Steel-Framed-Machine-Design


About reference? Start your own build log thread, ask there questions, people will help you. Without knowing what you need, seeing your particular design drawing, working area, materials to be used, what is the main purpose of machine, knowing how much money you are going to spend, nobody could give you a good advice

JAZZCNC
11-08-2016, 02:05 PM
Hi Boyan
My name is Iman and I want to design a gantry CNC. but i dont have enough data. is it possible to send me your cad design? and introduse some reference about design cnc gantry?
Thanks

Oh Boyan while your at it could you also tell him all your parts suppliers and phone numbers also how many meters of Mig wire and how much Gas you used.

Infact why not sit down and make full inventory of every small detail and give detailed pictures.?? . . . . Oh silly me you have.!! . . It's Here in this thread I just can't be arsed to bloody read.

Iman stop being Lazy and expecting everything handed on plate. Do some reading like all the others with successful builds have done.:thumbdown:

routercnc
11-08-2016, 08:25 PM
Hi Iman,

Welcome to the forum. If you are just starting out then have a look here - it shows some of the finished machines built by forum members:

http://www.mycncuk.com/threads/10066-Finished-builds-picture-menu

ImanGH
28-08-2016, 05:49 PM
Hi Boyan.
I have a question about rotating bull nut. when we use this method how fix and install the screw in table?
thank's

Boyan Silyavski
30-08-2016, 10:07 PM
Hi Boyan.
I have a question about rotating bull nut. when we use this method how fix and install the screw in table?
thank's

On first picture bellow you see the support, welded from 10mm steel. This is same both sides. Pink part is M20x1 thread for locknuts at the end of the ball screw. The mount hole is wider so when gantry moved by hand to each end by 2 people rotating the nuts
the screw could center itself. Then tighten. 2 locknuts each end. 8 in total.
19109


these pictures below i send before time to sb, they are for better illustration of all assembly

191071910819110

ImanGH
01-09-2016, 05:08 PM
Hi dear
I want to design and then building a industrial CNC. the aim of design is milling Aluminum and moving axis must have
2500mm X axis - 2000mm Y axis and 600mm Z axis.
for this condition i start to design a cnc machine. this is a initial design and i have must better my design.
19116

I have some question. please answer me.
1- because X and Y axis is long I used rotary bull nut. for this condition I design a rotary bull nut mechanism. is it important to use Super-precision angular contact ball bearings: High-speed for example 7015 or typical angular contact in good for this mechanism. It's notice that MY cnc machine is used for milling AL and i want to build it.
2-if the rotary speed of Spindle motor is 6000 rpm how design my cnc that vibration of this is minimum. how simulation I do in software? for example Harmonic response? and what the condition of analysis?
3- because i want to build this what's the important notice in design and assembly of the part?
Thank's

routercnc
01-09-2016, 11:09 PM
Hi Iman,

Best to start a new build thread for your design questions.

Have you built a cnc machine before, or have other building experience? 2500x2000x600 is a very large machine, especially for machining aluminium. Machining aluminium requires a stiff machine and having 600mm Z travel makes that very difficult, especially with a single gantry and large overhang.

1- I've not used rotating ballnut design but the stiffness of the axis is dependent on the AC bearing stiffness/quality so it will be a factor.

2- The simplest analysis to perform is to work out the stiffness at the collet in the X Y Z directions. The axes have to be locked in some way to stop them sliding when you do the analysis. 10-20 N/um (Newtons per micrometer) would be considered a very stiff / commercial machine. You need to apply 1N at the collet and get the software to work out the displacement. I don't think what you have drawn will come anywhere near that value.

3- Design and assembly. Make sure it can be built in a particular order so you can access the bolts as you build it. It is easy to design a set of parts which can't be put together especially if bearing blocks are near each other for Y and Z axes. Also, make sure you have slotted holes and adjustment in multiple planes. Assume the stock you buy will not be flat or straight or free from twist (although aluminium ecocast / tooling plate should be pretty good).

To give you some idea of commercial machines, here is the Mori Seki. Look through the pdf file and note the travel (way less than your dimensions), and note the weight.
19120

19121

pdf:
19122


Also have a look at this thread :
http://www.mycncuk.com/threads/9809-Aluminium-FEA-optimalized-CNC-router

Boyan Silyavski
02-09-2016, 07:27 AM
Hi dear
I want to design and then building a industrial CNC. the aim of design is milling Aluminum and moving axis must have
2500mm X axis - 2000mm Y axis and 600mm Z axis.
for this condition i start to design a cnc machine. this is a initial design and i have must better my design.
19116

I have some question. please answer me.
1- because X and Y axis is long I used rotary bull nut. for this condition I design a rotary bull nut mechanism. is it important to use Super-precision angular contact ball bearings: High-speed for example 7015 or typical angular contact in good for this mechanism. It's notice that MY cnc machine is used for milling AL and i want to build it.
2-if the rotary speed of Spindle motor is 6000 rpm how design my cnc that vibration of this is minimum. how simulation I do in software? for example Harmonic response? and what the condition of analysis?
3- because i want to build this what's the important notice in design and assembly of the part?
Thank's


i will not lie to you. If you have mechanical questions how to make 600mm Z axis strong and this is your first build, better contract me or sb from forum to design you the machine. You will make mistakes, that's reality. It takes much more planning to make a perfect machine, and to tell you the truth common sense is much more better than simulation software

So either make your own build log where people help you for free, or contract sb to design you the machine, at the end it would be much cheaper, as every mistake there is very costly.

CharlesJenkinson
02-09-2016, 08:27 AM
It's a dead giveaway - that email was meant for his wife, ..."Hi dear". But it was sent here by mistake.

Honestly, my wife would just say, build it with whatever x axis you want Love, you know best 😉

jono5axe
13-02-2017, 06:25 AM
Awesome thread, thanks, and thanks again.

Regarding the epoxy self leveling mounts for the linear rail, I would be very interested to learn about how the epoxy mounts stood up over time in respect to hardness?

I am a bit worried that it may not be hard enough to put up with the loads over an extended time (in a production shop router), as the bearing area under the linear rails is not huge. So my question is really hoping that you can tell me that it is all still good after the machine has been in service for a good while?

I am thinking about this in terms of (on my own coming build) whether to add additives to the epoxy to increase hardness, or alternatively, I may just use the epoxy for producing a level datum surface but then install a machined flat (i.e. 100mm x 10mm milled m/steel) on top of the hardened epoxy. I should mention that my build is planned as a production shop router at 2.5m x 2.5m bed, 30mm rails, 5kw spindle, gantry assembly approx 120kg.

Any feedback on the epoxy hardness issue would be very much appreciated.

Regards, Jono

Boyan Silyavski
19-02-2017, 10:03 AM
Awesome thread, thanks, and thanks again.

Regarding the epoxy self leveling mounts for the linear rail, I would be very interested to learn about how the epoxy mounts stood up over time in respect to hardness?

I am a bit worried that it may not be hard enough to put up with the loads over an extended time (in a production shop router), as the bearing area under the linear rails is not huge. So my question is really hoping that you can tell me that it is all still good after the machine has been in service for a good while?

I am thinking about this in terms of (on my own coming build) whether to add additives to the epoxy to increase hardness, or alternatively, I may just use the epoxy for producing a level datum surface but then install a machined flat (i.e. 100mm x 10mm milled m/steel) on top of the hardened epoxy. I should mention that my build is planned as a production shop router at 2.5m x 2.5m bed, 30mm rails, 5kw spindle, gantry assembly approx 120kg.

Any feedback on the epoxy hardness issue would be very much appreciated.

Regards, Jono

No problem at all with the epoxy for the moment. Its hard enough. Similar machine but 2600x1300/ look my signature/ is working nicely in my garage at 50C in the summer.

But if you are to do ~1meter machine, better use aluminum bolted to the frame and pay a machine shop to surface it. you will avoid experiments and mess.

If i was to do it again i would have ordered cast aluminum plate say 20mm thick to 40mm wide from my aluminum supplier/ they cut to any size/ . Then using a straight edge and epoxy putty i would have fitted and shimmed it there. Then drill and bolt it to frame. Then fit Hiwin on top.

hence the straight edge is most important instrument for precise build.