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View Full Version : BUILD LOG: 1rst build, time to do next step



Gytis
05-07-2013, 07:09 PM
First of all I want to say hello to everyone and thank you for sharing with their experience and knowledge!


After a year or so reading on CNC forums I decided that I have more knowledge about it than before and I think I'm ready to go to the next step.
But first of all I would like to hear from more experienced members than I about my CNC design and hardware, any input or criticism are more than welcome guys.

So there is a components which I decided to use in my build:

Whole machine will be from aluminum, plates (10, 20 and 25 mm thick) and profile 45x90
Ball screw for the X - RM 2005-RM 2010 ???, with fixed + fixed ends
Y - RM1605-RM1610 ???, same as X fixed ends
Z - RM1605
Hiwin profile rails, X-25mm, Y and Z 20mm
Nema 23 motors 320 oz-in 2.8 mH 3.5A, all axis
48V 12.5A power supply
Gecko G540 4 Axis stepper driver
Water-cooled spindle motor 2.2kw with a VFD

oh yes, I forgot to say that is cutting area is about 1220x845 mm

So that is all for now, Thanks again to all and good luck to everyone !:beer:

Excuse me for my bad English


Gytis


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Jonathan
05-07-2013, 09:30 PM
X isn't long enough to warrant a 20mm diameter screw, so use RM1610.

Gecko G540 is a waste of money - get something like this:
CNC Micro-Stepping 57 Stepper Motor Driver 2M542 2phase 4.2A Switch Controller | eBay (http://www.ebay.co.uk/itm/CNC-Micro-Stepping-57-Stepper-Motor-Driver-2M542-2phase-4-2A-Switch-Controller-/400509116600?pt=UK_Home_Garden_PowerTools_SM&hash=item5d403420b8)
Or better, a higher voltage driver, like DQ860MA - cheap at AliExpress.com - Online Shopping for Electronics, Fashion, Home & Garden, Toys & Sports, Automobiles from China. (http://www.aliexpress.com)

These (http://www.cnc4you.co.uk/index.php?route=product/product&product_id=65)motors are good and probably cheaper than what you specified.

25mm profile rails are completely over the top, so unless you've found some cheap ones on eBay I'd go for smaller rails - even 15mm would be fine for this size machine.

Your gantry could be made a lot stronger without using more material - flat plate is the worst cross section for the gantry since the forces are often in the direction where it is weakest. Box section would be better, or even better remove the gantry sides and have the Z-axis operating below the level of the X-rails.

Gytis
05-07-2013, 11:45 PM
Hello Jonathan, and Thank you for your reply !




X isn't long enough to warrant a 20mm diameter screw, so use RM1610


well, you are right., I was thinking same as you., but when I got my first ball screw RM1605 1m long it was bent about 5 mm in the middle, so I can just imagine what will happen with 1.6m long screw



Gecko G540 is a waste of money - get something like this
These motors are good and probably cheaper than what you specified.


I can not argue with you about the drivers and motors, probably you are right .,
but : 1. I already have one G540
2. maybe I have spent to much my time on American forum before I found you guys in the UK (so there is reason why I have chosen these drivers and motors)


25mm profile rails are completely over the top

I'm not sure about 15mm rails, it seems to me that is too weak


or even better remove the gantry sides and have the Z-axis operating below the level of the X-rails.

no, I don't like this design, I want to keep open table design and keep rails & ball screw from dust as much as I can

And finally, this machine will be built not for hobby use, she has to be strong and durable


Thanks

Gytis

JAZZCNC
06-07-2013, 03:58 PM
Hi Gytis,

First don't listen to Jonathan the G540 is a great bit of kit for a small machine. There are cheaper but it's a quality unit with great back up and warranty from Gecko and worth the money.

BUT every thing else he's correct about.


I'm not sure about 15mm rails, it seems to me that is too weak

15mm profiled rails will be plenty strong enough and carry far more load than you'll put on the machine.
The only issue with smaller profiled rails is the small bearing blocks can be a pain, esp with making the Z axis has the low height often means using spacer blocks to allow clearance for ballscrew etc. I find 20mm a much better size bearing and plenty on top of the job.


no, I don't like this design, I want to keep open table design and keep rails & ball screw from dust as much as I can

And finally, this machine will be built not for hobby use, she has to be strong and durable

Your design will be substantially weaker than what Jons suggesting and if you want strong and durable then it doesn't get much better.
Has for keeping the screws protected then that's easy enough with a bit of thought regards covers etc. The high sides don't cause any issues in use for most work and actually help contain the cutting mess to the table area instead of slinging it all around the shop.
The advantages of the much increased strength and far better quality of finish on work combined with allowing higher feeds is well worth the sacrifice of bit of access when loading material. End of the day it's the quality and speed of cut that matters.

Both Jon and I have been there done/seen that route so believe me we speak from experience on this.!!

Gytis
07-07-2013, 04:56 PM
Hello JAZZ, and thanks for your input !


Your design will be substantially weaker than what Jons suggesting and if you want strong and durable then it doesn't get much better.
Has for keeping the screws protected then that's easy enough with a bit of thought regards covers etc. The high sides don't cause any issues in use for most work and actually help contain the cutting mess to the table area instead of slinging it all around the shop.
The advantages of the much increased strength and far better quality of finish on work combined with allowing higher feeds is well worth the sacrifice of bit of access when loading material. End of the day it's the quality and speed of cut that matters.

now I'm sitting and scratching my head ..,
new design?, short as possible sides?, Z-axis below the level of the X-rails?, Hiwin rails 15-20mm?


Gytis

JAZZCNC
07-07-2013, 09:42 PM
Hello JAZZ, and thanks for your input !
now I'm sitting and scratching my head ..,
new design?, short as possible sides?, Z-axis below the level of the X-rails?, Hiwin rails 15-20mm?

Don't despair thats par the course with first machine.!!. . . I had full head of hair before getting into CNC now I'm follicle challenged. . Lol

To be honest I may have jumped the gun slightly because I didn't ask what you intend to cut with this machine.?

If soft materials plastics,softwoods etc then the high sides won't be a problem. There's no disputing the high sides are weaker design than no sides design but they do work ok in soft stuff if rest of gantry is stiff enough.

That said sorry to say your gantry design is very weak and the single piece of plate for gantry is real bad idea. Also the Y axis ballscrew hanging down is just asking to get clobbered with rubbish.

Look around the forum you'll see pics of similar built high side machines with strong gantry's, I've posted pics of similar machines I've built that use profile which is strong design and can handle cutting upto light aluminium work.

Gytis
09-07-2013, 10:36 PM
If soft materials plastics,softwoods etc then the high sides won't be a problem

you wouldn't believe me, but I was almost sure that I will be able to cut hardwood and do light aluminum work (now you can laugh of me):whistle:

Ok., I think I know what you both trying to say for me..,
so now in my head I have new CNC table plan ( I hope it will cut at least hardwood ).
Version_2 will be here soon

Thanks guys for the advice!

Gytis
10-07-2013, 09:34 PM
Hello,

quick update., the Version_2 is nearly done.
now I thinking about X axis ball screw fitting,
my very first idea was to put it between the aluminum profiles, but now I'm not sure or it good idea, I think distance is to big between rails and screw approx.150mm?
what if I run it through the side plate support box?, right now there is few brackets., just one what I do not like, that the screw will be very few cm. above the table.
But maybe I can fix on each side of the box some brush or seal to wipe the dust away from screw ?

btw, what about design? Version_2 will be stronger then the first?

Thanks

njhussey
10-07-2013, 10:06 PM
There are two areas that look like they need strengthening on that design. The bed plate needs support otherwise it'll bounce and flex like nobody's business and you'll get a crap finish. Can you not just use the profile as the base and put profile laterally across under the bed plate to stiffen, seems like there's an awful lot of empty height under the bed plate?

The Y axis plate also looks like it needs a length of profile or two behind it otherwise it might also flex when cutting in the middle of it.

Hope this post doesn't sound negative, just a couple of observations :)

Gytis
10-07-2013, 10:32 PM
There are two areas that look like they need strengthening on that design. The bed plate needs support otherwise it'll bounce and flex like nobody's business and you'll get a crap finish.

Hello Neil,
I just forgot to mention that now I working on Z axis, and this table top sitting just to see what travel I need in the Z or how low bed has to be.

Sorry for confusing you

Gytis

m.marino
11-07-2013, 03:16 PM
Okay you want to build an all round Gantry router to cut up to aluminium. Lower your bed and re-enforce it as suggested though don't over do it too much (we DIY folks do tend to over build). I would strongly, strongly suggest putting the Y axis screw behind the gantry beam if at all possible. it reduces issues with swarf and makes lubricating it much, much easier.

Go looking through the build logs as I know there is some very good designs there. You don't have to use any of them but they do give a very good head start. Also I don't see allowances for cable paths; that is something you really want to think about now. later it will bite your back side and cause issues (I can think of a few members who can tell about the headaches of wiring gone wrong).

Jonathan is correct that at that length 1610 will do you well and you can always work with the pulleys to get the resolution you want.

Good luck and keep asking questions.

Jonathan, Gecko are good equipment and they stand behind their warranty as more then a few folks have proven. Yes, they are a bit costly but they are serious kit for some one wanting a business level ROI (return on Investment). Next you will be telling me my Leadshine AM882's are over kill. Horses for courses.

-Michael

PS Contrary to my long absence I have not died nor fallen off the face of the earth just been very very busy.

Gytis
16-07-2013, 11:11 PM
Good luck

this is what I really need now :smile:

Thank you Michael

Gytis
16-07-2013, 11:16 PM
Hello,

OK guys, this is my new gantry and Z axis, I hope I'm in right direction this time to have a strong gantry? I'm just worry now about the weight, now solidworks showing 70kg.,
this is not too heavy for motors 380oz(2.68Nm?)?

Thanks in advance!

JAZZCNC
17-07-2013, 12:14 AM
Presuming this is all ALU plate.?

Quite a bit of unnecessary weight on there.?
Don't need inner and outer gantry sides or spacers between them. They add very little extra strength only excess flab
Don't need the all the Motor plates etc sitting on gantry side and could just mount motor on inside above screw and thru gantry side if single gantry side.
Don't need the piece that Y axis ballscrew fastens too with small change of design.

The cross piece that rails sit on still looks like single piece of Alu with no bracing.? This is the major weak area which will flex under cutting conditions.
I've built a gantry using plate like what you seem to be wanting which is very very strong. With just a few changes it's half the weight and much stronger and lot neater. It protects the ballscrew and motor by completely encasing it. See pics of it part built and Cad model.
Actual Design was modified to Cad model and ballscrew raised and Motor brought inside gantry connected to screw with timing belt.
Pics of actual machined parts are only for visual purposes.!! IE ballscrew sat on offcuts to show rough position with quite a few pieces like bearing plates and strengthening braces missing.

There's also braces inside the Gantry which are not shown in Cad or pics. The Z axis motor mount is also different and doesn't use upstand pieces shown in Cad instead using a solid 2 piece machined spacer part which covers belt/pulley.

Hope this helps.!

Gytis
18-07-2013, 07:34 PM
Don't need inner and outer gantry sides or spacers between them. They add very little extra strength only excess flab
Don't need the all the Motor plates etc sitting on gantry side and could just mount motor on inside above screw and thru gantry side if single gantry side.
Don't need the piece that Y axis ballscrew fastens too with small change of design.

Thank you for pointing it out!

Well, now I have redesigned gantry, this time I took JAZZ ideas (hope you don't mind JAZZ?),
not yet finished but you can see general idea.

JAZZCNC
19-07-2013, 12:08 AM
this time I took JAZZ ideas (hope you don't mind JAZZ?),

Nope don't mind at all, only show what I don't mind being plagiarized.!!

Couple of pointers to avoid pit falls which can easily get ya.?

Slot will probably need lifting (or lowering).? Reason being chances are you won't find a timing belt short enough to keep slot in middle and still fit motor in.! The pics don't show it but the slot is offset towards top, the Ball-screw actually mounts above the slot. The ballnut fastens on top side of plate that fastens to backside of Z axis rear plate.

Would use BK/BF not FF/FK blocks mounted straight onto rear of front plate then you can get rid of those plates. Will also make assembly much easier.

With rear covers Instead of 3 flats I'd consider having a nice Arc so single piece of plate bends and follows it's shape instead of 3 separate plates.
On my design I've done it slightly different with the top/bottom rail plates shaped then single 2mm plate bends and follows shape when fastened. This way less work in making the braces and less needed has you don't need any near gantry sides to old the shape.

I'd also beef up the braces just removing enough material so Ballnut passes thru.

Gytis
20-07-2013, 12:14 AM
Nope don't mind at all, only show what I don't mind being plagiarized.!!


Come on JAZZ!, show your secret projects:link:


Slot will probably need lifting (or lowering).? Reason being chances are you won't find a timing belt short enough to keep slot in middle and still fit motor in.

I left slot in the same position, just lifted ball screw up as you suggest, I think now there is enough space (in the model now fitted T5-20 tooth pulleys)


Would use BK/BF not FF/FK blocks mounted straight onto rear of front plate then you can get rid of those plates. Will also make assembly much easier.

I did it, now both sides BK fitted. It really makes difference in assembly, and less machining in the parts.


With rear covers Instead of 3 flats I'd consider having a nice Arc so single piece of plate bends and follows it's shape instead of 3 separate plates.

well, arch is nice but I followed the angle of side plate, that's why I made braces like this shape, 3 plates is just in the model, in real life it will be in 1 piece (I hope).


Thanks for the useful tips JAZZ !:beer:

__________________________________________________ __________________________________________________ ________________________________________


And finally, one question:

timing belts width 15mm or enough 10mm ?, pulleys T5 or different?

Thanks to all !

JAZZCNC
20-07-2013, 12:47 AM
Come on JAZZ!, show your secret projects:link:

Could but then I'd have to kill you ALL.!! . . . And I actually do like some of you so I'm doing it to protect the innocent. . .:hysterical:



And finally, one question:

timing belts width 15mm or enough 10mm ?, pulleys T5 or different?

15mm and T5 . . . Don't go less than 18T on the pulleys and I find 20T the best for belt life and fitting etc.

Gytis
20-07-2013, 01:21 AM
Could but then I'd have to kill you ALL.!! . . . And I actually do like some of you so I'm doing it to protect the innocent. . .:hysterical:

I do not want to know any more your secrets, I'll better stay in safe side:peaceful:


15mm and T5 . . . Don't go less than 18T on the pulleys and I find 20T the best for belt life and fitting etc.

I was almost right in this direction

Thanks JAZZ

irving2008
20-07-2013, 01:39 AM
Don't need BK both ends, just at drive end. BF is fine for other end.

irving2008
20-07-2013, 01:42 AM
Could but then I'd have to kill you ALL.!! . . . And I actually do like some of you so I'm doing it to protect the innocent. . ..oh, which of us do you like then Jazz? :D

Gytis
20-07-2013, 02:31 AM
Don't need BK both ends, just at drive end. BF is fine for other end.
Hi Irving,

I almost sure that you are right, but it will be my first built CNC (so I'm trying to do my best as I can)
what I know about screw and ends?

only one,
fixed + fixed ends its much bater than fixed + floated
(it will eliminates wipping and increas the speed ?)

Thanks for input !:beer:

irving2008
20-07-2013, 07:43 AM
Yes it does but:
A. its much harder to set up right

B. the speed increase factor isn't needed here - very roughly 2600rpm to 3900 rpm for a 16mm screw. Even with a 1605 screw the lower end is >10m/min, far more than you'll achieve in reality

C. It needs more complex machining of the ballscrew end

D. It costs more

By your own admission this is your first build so KISS IMHO :D

JAZZCNC
20-07-2013, 12:26 PM
oh, which of us do you like then Jazz? :D

Could tell you Irving but then I'd have to kill you all to protect my self. . :loyal:


Hi Irving,

I almost sure that you are right, but it will be my first built CNC (so I'm trying to do my best as I can)
what I know about screw and ends?

only one,
fixed + fixed ends its much bater than fixed + floated
(it will eliminates wipping and increas the speed ?)

Thanks for input !:beer:

Completely agree with Irving. Fine for industrial machines using servo's with high feed rates 25m/min+ and heavy loads but here the only difference you'll see is less cash in your wallet.!!
With DIY building you'll gain more performance by concentrating on build quality and careful alignment of screws/motors and linear rails than using Industry standards.

One thing wanted to point out which catches new builders out is to think carefully about bolt hole location and fastening of brackets etc.?
Often the obvious place to fasten something is completely the wrong place which makes assembly a right pain in the arse.

IE: You have the Y axis ball-nut bracket (thru slot) fastening from the front side of Z axis rear plate. Doing this means you have to remove front plate from Z axis to access those bolts or drill access holes in it.
You need this bracket to have some adjustment to make alignment with Y axis ball-nut easy and doing this from front and thru a hole will be a pain so would be much easier if it bolted from the rear into tapped holes in the Z axis rear plate.
It's simple things like this that make building and setup just that bit less painful.! . . . Unfortunately finding these things out often comes from building the first machine and at worst case scraping a few parts learning on first build.

Gytis
20-07-2013, 03:54 PM
Could tell you Irving but then I'd have to kill you all to protect my self. . :loyal:
:hysterical:


Fine for industrial machines using servo's with high feed rates 25m/min+ and heavy loads

This will be my second CNC with these feed rates:joker:


You need this bracket to have some adjustment to make alignment with Y axis ball-nut easy and doing this from front and thru a hole will be a pain so would be much easier if it bolted from the rear into tapped holes in the Z axis rear plate.

You mean like this (see pics) , just drill a bigger hole in the bracket for adjustment ?


Unfortunately finding these things out often comes from building the first machine and at worst case scraping a few parts learning on first build


I understand this and I'm ready for this (to scrap few parts, especially with my tools)!

Thank you guys

Gytis
26-07-2013, 07:54 PM
HI,

this is my almost finished CNC machine model,
bed is from the aluminum extrusions (heavy) 90 x 45 and 45 x 45, it will cost me about 800 eu + delivery?, only for the extrusions!:dejection:
overall dimensions (bed) is 1590 x 1250 x 590 mm.

JAZZCNC
26-07-2013, 09:48 PM
Wow your really making that harder and more expensive than it needs to be.? Also has a flaw.?
First I'd use Steel for the frame and save 600eu.!! . . but that's not what I mean here.?

Orientate the side profiles on there edges and you'll gain strength and be able to do away with those aluminium braces and the 2 long middle profile, then Extend the 3 uprights to meet top rail.
Put the ball screws on the outside and make drop brackets part of gantry sides, sides will be shorter than drop bracket, less material,weight,money. Easier to setup and adjust screws/motors has they are more accessible. Then you can line the inside walls doing away with the slot and stop crap hitting the screws completely.!! . . . . Your way has a BIG flaw in that it will allow chips into the sides, still hitting screw and eventually filling up the sealed cavity.:thumbdown:
You'll be constantly cleaning it out and believe me it won't take long to fill the void between middle profile and slot. Chips spray in a linear direction off the cutting tool and that Gap is in direct firing line so you'll be surprised just how much disappear thru it.!. . . . Kid you not Bet I could fill that gap with alu chips within 3weeks and that's allowing for sizeable percentage not hitting slot gap.!!!!

One other thing.?. . . If those bed supports are 45x45 then I think you'll find there not strong enough at that length and allow bed to potentially bow in centre when cutting or plunging. My suggestion is to put 2 or 3 45x90 on there edge for main supports and make rest up with 4x45.

Sorry to keep pulling at your designs but with experience these things just jump out at you and I'd feel shit if didn't mention them, then at later date you came back and said wished I'd done this or that which I'd spotted.!!

Gytis
15-08-2013, 10:21 PM
Hello,

OK..., this is me second attempt to make a strong frame, but this time not so expensive.
Frame from the steel box 60x40x4mm all round, steel will cost me about 180 (6 x 7.5m), it's a big savings compared to aluminum.
just a little bit worried for the welding work, but I'll try and we'll see what happens:cool:

Wish me good luck:beer:

frame size 1600x1180x600 (x,y,z)

Jonathan
15-08-2013, 10:27 PM
The way you've mounted the bed looks a little weak to me. The bed box section could rotate about the fixing 'rails', so the end fixity is poor, which means the bed itself will sag more when a weight is placed upon it. You could instead bolt the bed frame directly to the machine frame.

JAZZCNC
15-08-2013, 10:45 PM
Hi Gytis,

Looking good just couple of things which will help, you may have seen me post it on other threads has I seem to be repeating my self quite a it now more folks are taking to steel.!!

Make the top rail bolt onto plates, much easier for setting rails parallel and on same plane.

The connection of bed to frame looks a little weak and could flex. I'd just bolt straight to frame with angle brackets. It will also be very heavy so I'd consider having some way to help assist with the lifting, IE Acme lead screw or Large pitch Threaded rod.

Would make the sides separate bolt on sides and have the green frames separate structures, would also make the triangle braces on green ends longer so they support frame further down.
Having separate sides will make assembly easier with flexibility to adjust any error out like getting square and vertical. Also will come apart for moving or if you sell it.

Secret to good DIY is lots of adjustability.!!

Gytis
15-08-2013, 11:05 PM
The way you've mounted the bed looks a little weak to me. The bed box section could rotate about the fixing 'rails', so the end fixity is poor, which means the bed itself will sag more when a weight is placed upon it. You could instead bolt the bed frame directly to the machine frame.

I was thinking about that, bolt bed directly to the frame
but then I have to make the bed a very accurate, This means that zero play between the bed and frame
I chose the easy way, the bed pulls out like a drawer and can have a few mm error

JAZZCNC
15-08-2013, 11:14 PM
the bed pulls out like a drawer and can have a few mm error

No BAD idea it will resonate and will show in the quality of cut.

You don't need to make the bed tight fit just have few mm gap and put the angle brackets so they fasten to the insides of steel uprights. Make the side guards out of flexible rubber or plastic like Damp course fasten to bed sides and at top rail so it travels with bed and the brackets will be underneath out of way and accessible from out side.

Then you just surface the sacrificial board on the bed to bring parallel to machine.

Gytis
03-09-2013, 11:44 PM
Hi,

quick update,

received yesterday parts for the Z axis from JAZZ CNC
well.., what I can say.., he is a real man !
I'm impressed with the quality and accuracy of the parts! Thank you Dean!

My next step will be steel frame construction , I waiting for the chop saw speed regulator (I want to drop RPM of my saw) and welding mask .
I hope to see you soon?!

JAZZCNC
04-09-2013, 12:07 AM
Your Welcome Gytis pleased they got there ok and more pleased those holes are in correct place.!! . . . Always worrying when you haven't got rails in your hands and working to someone else drawings. . .Lol . . .You did good too my friend.!

GEOFFREY
04-09-2013, 12:15 AM
Starting to look good - much better than those flowers!!! Better get rid of that remote - no time for TV now. G.

Gytis
25-01-2015, 08:54 PM
Hello CNC folk!

Just want to wish to everyone Happy and Healthy New Year!!!:beer: (little bit too late, but better late than never )
and also want to say that this built log not dead. I know I was not active since my last post, but that is different story...( it was really hard time for me )
Anyway I hope I'll be back on the track sooner or later !

Hope I'll see you soon with some built progress !:thumsup:

Good luck to all !
______________
Gytis