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The back-emf from stepper motors is significant - they're good little generators. The protection diodes in the stepper drivers will rectify the back-emf and if you turn it fast enough power up the driver which is clearly bad news. I found that below a certain speed they manually turn quite easily, but when that threshold is exceeded it gets a lot harder. Clearly it will vary significantly with the size of motor.
Easily solved - just unplug the motors.
Quote:
Originally Posted by Robin Hewitt
A tiny update to X-axis screw.
- Red texts are updates.
Attachment 5516
Will take a note of that. Again really good suggestions. Thanks!Quote:
Originally Posted by Robin Hewitt
Project has been moving at a snail's pace, but that is okay, have already avoided many pitfalls.
What's the dimension I've marked with '???':
Attachment 5518
Pretty minor, but I changed the end bearing surface from 7mm to 9mm since the bearing is 10mm wide and it's best not to have the bearing resting on too much thread.
I'm confusing my milling machines, on this one I used full nuts rather than pairs of half nuts. I didn't want to stress a half nut by asking it for 500 lbf of tension.Quote:
Originally Posted by Jonathan
10mm for the bearing, 10mm for the nut, say 1mm protruding, 21mm total.
Doesn't really matter how far the thread goes inside the bearing, the big axial load from the Belleville washers overwhelms all the other loadings.
I made all the bearings an easy sliding fit, inside and out. This made it very easy to assemble but it went rock solid the moment I tensioned it.
How do you plan to mount the motors? I suggest you cobble them on somehow with plates and studding then replace everything when you have CNC. Motor mounting is important now only because it determines the length of the screw.
Things to remember when designing motor mounting plates...
Putting the motor on so it faces away from the machine is best.
Putting the motor on facing the machine saves a couple of quid on the ballscrew length but makes everything else difficult.
Leave a tadge of motor movement to adjust the belt tension.
Cut the outline for a belt cover and it's mounting bolts, assume you have CNC for making the belt cover.
Somewhere to attach a flexy conduit over the motor wires saves bodging it later on.
My point was not knowing those dimensions means the length of ballscrew directly between the bearings is unknown, which is a critical dimension.Quote:
Originally Posted by Robin Hewitt
I guess so long as the mounting surfaces are accurate, but there's no reason to have the thread far in the bearing surface.Quote:
Originally Posted by Robin Hewitt
That is a sweet picture Jonathan. Good point that 9mm.Quote:
Originally Posted by Jonathan
Final versions of X, Y, Z -axis screw are like this (changed according to Robin's / Jonathan's comments)Quote:
Originally Posted by Robin Hewitt
- X-axis:::
Attachment 5527
- Y-axis:::
Attachment 5528
- Z-axis:::
Attachment 5529
Revised shopping list is here. A couple of notes about that
1) Power supply perhaps is slightly undersize. Thought to trial and see.
2) Need two (2) of the Nema 23 -motors WITHOUT the rear shaft
- Need one (1) --------------//----------------- WITH the rear shaft (Z-axis, will attach hand wheel there)
3) Items 12, 14 -- 19 not sure where to source from, have not found yet
4) Bearing housings / fittings ---> DIY ?
ITEM
NO.Item
QTY 1 Nema 23 stepper motor, 3Nm (425 Oz-in) Zappautomation http://www.zappautomation.co.uk/sy60...cPath=9_159_42 2 Nema 23 stepper motor, 3Nm (425 Oz-in) Zappautomation 1 2 PM752 Microstepping Driver Zappautomation http://www.zappautomation.co.uk/pm75...ml?cPath=9_3_4 3 3 Power supply / PS705 - 75V DC at 0A & 68V DC at 5A Zappautomation http://www.zappautomation.co.uk/sps705-p-587.html 1 4 X-axis R 1605 ballscrew 853 mm (not machined) Zappautomation http://www.zappautomation.co.uk/r160...crew-p-93.html 1 5 Y-axis R- 1605 ballscrew 508 mm (not machined) Zappautomation http://www.zappautomation.co.uk/r160...crew-p-93.html 1 6 Z-axis R 1605 ballscrew 259 mm (not machined) Zappautomation http://www.zappautomation.co.uk/r160...crew-p-93.html 1 7 Ball nut R1605T3-FDID Zappautomation http://www.zappautomation.co.uk/prod...roducts_id=574 3 8 Ball screws machining Jonathan
3 9 Pulleys, larger around 70mm diameter, 21T5/44-0 Zappautomation http://www.zappautomation.co.uk/sync...Path=14_72_153 3 10 Pulleys, smaller around 35mm diameter, 21T5/22-2 Zappautomation http://www.zappautomation.co.uk/sync...Path=14_72_153 3 11 Belts, 3 for the pulleys (10mm) Zappautomation Ask Gary 3 12 Angular Ball Bearings 7201B -type Local bearing shop http://www.vxb.com/page/bearings/PROD/Kit1085 6 13 Belleville washer Robin
6 14 E-stop switch TBD (to be decided)
15 Limit switches TBD
16 Connectors for stepper motors TBD
17 4-Core CY, 1.5mm^2 cable TBD
18 Sleeves for handwheels TBD
2 19 Handwheels TBD
3
Think this should be pretty good now. (until someone points out inconsistencies :smile:)
£300 on ballnuts! Are you sure you can't get the cheap RM1605 ballnuts from china to fit as they're $25 each from eBay. Surely you can at least use the cheaper ones for Z?
Pulleys - the tooth profile of HTD pulleys is much better suited to this application than T5 and similar price, so get pulleys and belts from here:
http://www.bearingstation.co.uk/prod...HTD_Pulley_5mm
Most (if not all?) the 3Nm motors have dual shafts, so unless the rear shaft is going to get in the way you can just get 3 of the motors you linked to at Zapp.
I've got lots of 4-core CY, 1.5mm^2 cable for the motors...yours for £1.20 (I think, will check) per meter.
Making the handwheels can be the second project on the machine after cutting the motor mounts! I could make the piece that attaches the handwheel to the screw (18), wont cost much.
The power supply you've linked to is probably sufficient, but more power would be better. It's cheaper to make your own using a transformer like 88-3839 from Rapid Electronics. Just -earch on google for making a power supply with a toroidal transformer. There's not much to it - you just need the transformer above, bridge rectifier and capacitors. Let me know if that's not enough information and I'll explain better.
Have you considered in the Z-axis screw mount how to temporarily disengage it from the spindle when changing tools so that the force from hammering on the draw-bolt to release the tool taper isn't transferred to the relatively delicate ballscrew/ballnut?
Cheapest e-stop switch I can find is here:
http://www.tlc-direct.co.uk/Main_Index/Distribution_and_Switchgear_Index/Emergency_Stop_Buttons/index.html
One day I'll get round to buying one...
Are these cheap chinese ballnuts doubles like the Zapp DF1605 at £44 ?
That would give about 10 microns backlash until it beds in, but with a bit of Belleville jiggery pokery you can get that down to around zero microns.
Transformers are okay until you get a mains surge and everything goes pop. Unlike back EMF from turning a motor, I have personal experience with this little snag :naughty:
Updates:
1) Placed an order with Zappautomation, via the online-store.
1.1) Replaced pulleys / belts with HTD -type, as suggested by Jonathan
1.2) Plan is, screws would be going to Jonathan for machining.
- not sure if the ballnuts could be detached from the screws. They are preloaded. Will talk to Gary at Zapp(automation).
Good point Jonathan. Thought about that, this time key criteria came to four (4) facetsQuote:
Originally Posted by Jonathan
- Overseas shipping costs - located in Finland, buying from different places will hike costs up. Shipping costs add zero value to the conversion, so minimize them.
- Need for the smaller dimensions of the FDI -type -ballnuts.(X/Y-axis tight space)
- Quality ... don't know much about ballnuts, but did rollerskating / skateboarding in my youth.. what a difference bearings can make :smile:
Perhaps biggest factor I have is "risk aversion". Still must admit, not sure if one will ever complete this thread. It is a big project for me, and if there are many set backs, project gets longer and longer, you never know. Does this thread end up in classifieds -section? Need to stick to safe choices.
Erm, would love to try that. But my skills..not very confident, have set a soft limit of "no mains" electrical appliance -jobs for me. :redface: Think one can manage stepper motor -cabling, and drivers, because they are sort of behind the power supply (not directly mains)Quote:
Originally Posted by Jonathan
Have not yet figured out how that could be best done. Some sort of a quick-release system would be cool. But not sure about design, and whether it would introduce slack to the Z-axisQuote:
Originally Posted by Jonathan
- Something like this maybe, to quick-release?
Attachment 5531
Really grateful for all comments and advice in this thread. They have been very helpful. Thanks!
You can remove them, but i would just leave them on the screw and screw the nut out of the way when doing the machining.
Quote:
Originally Posted by diy-john
It has been quiet lately, while waiting bits to arrive. Status update:
- Jonathan now has the ballscrews.
-- Screws are R 1605 -type. They are un-machined, and only roughly cut to length
--- 900 mm screw will be cut to ---> 853 mm (X-axis)
--- 600 mm screw will be cut to ---> 508 mm (Y-axis)
--- 300 mm screw will be cut to ---> 259 mm (Z-axis)
Jonathan will have a look at the screws, and lets see what can be done to them.
Motors, drivers and other bits were dispatched on Wednesday 28.03. Now they are in Germany, latest status on EXPD -site:
30/03/2012
11:43 IN TRANSIT - DEPARTURE SCAN - LANGENHAGEN, GERMANY
Meanwhile, thought time will pass more quickly, if one would do something, instead of constantly checking where the parcel is.
1) Downloaded today Ubuntu / linuxcnc from:
http://www.linuxcnc.org/docs/2.5/htm...tting_EMC.html
2) Burned on a blank CD ubuntu-10.04-linuxcnc1-i386.iso from
http://dsplabs.upt.ro/~juve/emc/
2.1) For burning used my linux laptop: (commands given on command-prompt, screen output on violet)
- though could use Windows, or whatever software you have. One just likes linux, so that it will be.
cdrecord -scanbus
scsibus1:
1,0,0 100) 'MATSHITA' 'DVD-RAM UJ890AS ' '1.00' Removable CD-ROM
1,1,0 101) *
1,2,0 102) *
1,3,0 103) *
1,4,0 104) *
1,5,0 105) *
1,6,0 106) *
1,7,0 107) *
cdrecord -v dev=1,0,0 ubuntu-10.04-linuxcnc1-i386.iso
3) Found a dusty old PC, with a parallel port, it is an 800mhz pentium processor -pc
- vacuum cleaned the inside a bit (it was really dusty)
Attachment 5596
3.1) Attached an old 160Gb maxtor -drive into it (to be used for the Ubuntu-linux installation)
- there are some DIY-cabling inside this old PC. She used to have a lot of hard-drives inside it, so the extra cabling is because of that. Not needed for this project.
Attachment 5597
3.2) Going to boot the computer with this freshly burned Ubuntu (linuxcnc) -bootable CD:
Attachment 5598
3.3) Almost ready to boot now
Attachment 5599
3.4) On bootup newly added hardware shows
Attachment 5600
3.5) Installation process begins and there are some easy-to-answer questions
Attachment 5601 Attachment 5602
3.6) Installation took perhaps 30-40 minutes. Once installation is finished, installation says to remove the CD from drive, and press enter for a reboot
3.7) On starting up the Ubuntu first time, noticed there are indeed CNC -related software there, EMC2 for example
Attachment 5603
Okay this is how far we got now. Did not try the software more. Next steps would be:
- postman brings the Nema 23-motors, drivers etc.
- We buy some cable and sundries, try to connect them to the old PC.
- try to make the motors turn with the computer. (can't wait for this to happen :smile:)
Just had a look at the drawings again...
You've currently drawn the Z-ballscrew with similar end machining to the X and Y screws which will put the screw in tension. On the Z-axis putting the ballscrew in tension is surely such a large force that it will pull the quill to one side. You also can't really combine a quick release with a tensioned screw as it would take too long to setup every time.
Jonathan, here is a sketch of how I have planned Z-axis::::
Attachment 5604
So there is not going to be tension on quill at all. If you think I have mis-understood how it could work, please let me know.
Thanks!
Items arrived yesterday from Zappautomation.
Attachment 5667 Attachment 5668 Attachment 5669
In box were:
3 x SY60STH88-3008 Nema 23 stepper motor
3 x PM752 Microstepping Driver
1 x SPS705
3 x R1605T3-FDID-P1 Ballnut
1 x HTD3M-9MM Timing Belts
1 x HTD3M-9MM Timing Belts
1 x HTD3M-9MM Timing Belts
Ballscrews, ballnuts, pulleys will come later. Jonathan will have a look at them, in view of machining them. Though I appreciate they are going to be quite tough to machine. (hardened..)
Thought the summer was here, and one would have the motors running in no time. But it is winter back again and the motors will not turn at all.
What I have done, is wire one of the drivers like this:
1) High voltage side (in picture, the upper set of wiring)
- GND ---> goes to power supply "GND"
- +VDC ---> goes to power supply "V+"
Then Nema 23 motor wires go into:
A+ ---> BLUE and RED/WHITE
A- ---> BLUE/WHITE and RED
B+ ---> GREEN and BLACK/WHITE
B- ---> BLACK and GREEN/WHITE
Then the Signal wires:
PUL+ ---> into PC parallel port PIN 3
DIR+ ---> into PC parallel port PIN 2
The "PA settings" (SW1 ... SW8) are:
- first four (4) are "ON"
- last four (4) are "OFF"
Attachment 5670
Think the high voltage side wiring is correct. Signals not so sure about. Is two (2) wires enough, or does one need more connected?
I have sort of verified parallel port outputs some signals, by doing a similar test as here
http://www.youtube.com/watch?v=EtX3p4HFbtc
...by running this little C-program on linux:
http://eagerfish.eu/lpt-programming-...r-ubuntu-linux
Tried turning a single motor by running EMC2 (linuxcnc). But no luck.
Have tried googling, where to connect parallel port PINs on the stepper drivers. Have found some information, but not sure one has it right. Please can someone help?
Thanks for looking
With only one wire per input the circuit is incomplete, so no current can flow... so no go.
Connect a wire to join up PUL- and DIR-, i.e. the negative terminals, and connect those to one or more of the ground pins on the parallel port. If it's not marked pin 25 (among others) is ground.
If you still get nothing then check the voltage between PUL+ and PUL- (then DIR+/-) and it should be 4-5V ideally when active.
WOW it runs now
- connected PUL- and DIR- to pin 25 on parallel port, like you say Jonathan.
The cables are so loose one does not dare to breath near the machine.
Going to try to buy some electrical connectors or something for the parallel port, tomorrow.
- I have tried to use an old printer cable, which I cut in half. But the wires are so small it is difficult to handle them.
Thanks so much, very happy now.
Status is now that all three (3) Nema 23 -motors turn. Driving them with EMC2 (linuxcnc)
To get here, what I have done yesterday and today is:
1) Bought some sundries from a local Electrical store:
Attachment 5684 Attachment 5685 Attachment 5686 Attachment 5687
2) Parallel printer cable - test each of the small 25 different wires with a multimeter.
- try to understand which colour cable links to which PIN on the parallel port
- here is the printer cable cut, from the "printer end" of the cable
- measured with "continuity mode" in multimeter, each of these 25 small wires.
- for all of you these are probably really elementary steps. But for me it was a bit of a surprise, that one would have
to get into this level of detail.
-- Had relied on some charts I had found from internet, on colour schemes of the parallel cable wires. But they did not seem to match my cable, so had to manually check each of the wires,
to which PIN they connect in parallel port.
- Found these "alligator jaws" handy
Attachment 5679 Attachment 5680
3) Here are the parallel port PIN's, cable colours, and where I have connected them on the Leadshine M752 drivers.
Attachment 5681
4) A picture of how they are on the table now
- had bought 30 LED's for troubleshooting.
- found them helpful, though 30 is too many. I ended up using just one single
Attachment 5682 Attachment 5683
5) Now, what do you think?
- Could one now solder cables neatly in place?
- Have been thinking of using this kind of 9 PIN -cables for each stepper-driver
Attachment 5688
-- So that the cables could be quickly attached / detached.
-- Would use these for the low-voltage, parallel cable wires.
--- Parallel cable (25 wires) ---> divide to 3 smaller cables (9 PIN) ---> each stepper driver
Motors seem to work okay, though they don't "home" itself on the EMC2. Not sure why that is. Haven't got a stop-switch, limit switches yet.
Please comment on whether one can now solder things, or should one wait until have limit switches and emergency stop-button?
- actually, any and all comments welcome
Thanks!
Most people buy a breakout board and connect the drivers to that which simplifies things as the pins are labelled. Breakout boards also add isolation, but since the drivers you are using are already optically isolated there's no point having additional isolation on the breakout board, so connecting it directly is fine. However if you connect the switches directly (with just one pullup resistor on each) clearly there is no opto-isolation, unless you DIY.Quote:
Originally Posted by diy-john
Just a brief update;
- decided not to solder cabling yet, as one might still want to make changes
- today have been thinking what kind of functionalities one might want from the mill, in terms of
-- homing
-- limit switches
-- zeroing
Fiddled with EMC2 (linuxcnc), added a similar function, as here
http://www.youtube.com/watch?v=DOBxt9MIbFo
...to auto measure workpiece surface level.
Of course haven't got the mill converted yet. Just simulated the real thing, with Z-axis motor running on table, and two wires in my hands (one cable attached to parallel port PIN 13, the other ground, think it was PIN 21).
Hello!
Well, it has been some 6 months since this project has been on hold.
Not much has happened since. Got screws machined - thanks to Jonathan. Then got tied up with work, had to put all hobbies aside, and let's leave it at that. Really quite embarrassed and sorry for being away for this long.
1) Plan now is to pick up the pieces, try to remember which planet we are on, and get the mill running. Not pretty. Not good, but get it running.
1.1) For that need some bearing mounts made. A local machining workshop will make some simple mounts, hope to get them in a couple of weeks
1.2) Need attach the ballscrews
1.3) Need attach the ballnuts
For 1.2) attaching the ballscrew on Z-axis, I have today started removing the Z-axis existing pinion / spring.
- For reference, discussed this Z-axis matter earlier here: http://www.mycncuk.com/forums/diy-ma...onversion.html
What I have done today is:
A) Started removing these levers
Attachment 7155
B) So far quite easy, just use a HEX -key to open screws
Attachment 7156
C) After about 5-minutes, got already most things away from right-hand-side of the mill
Attachment 7157
D) Spring mechanism was on the left-hand-side
Attachment 7158
E) Now the spring-mechanism was easy to remove, but this is as far as we got today
Attachment 7159
F) On the other (right) hand side it looks now like this:
Attachment 7160
Now, would appreciate some tips:
- please should one remove the rest of the gears?
-- Reason I would like to remove the gears,is that I am hoping to use the hole(s) for attaching a rigid structure, on either side of the quill, to mount Z-axis bearings + motor
-- Or do you think one would be happier having the hand-lever to lower the quill?
- If gear should be removed, how does it come out? Attached is a technical drawing of the mill components, if someone would take a care to give an opinion (on how to remove the stuck gear/shaft)?
Attachment 7161
Thanks for reading
Have you tried tightening the two nuts in picture C against each other, so that they lock on to the thread, then use the inside one to unscrew the threaded rod? If it's in a tapped hole that should get it out.
I wouldn't worry too much about the hand lever. I tend to remove the hand levers on my mill when I'm using it with CNC since they have a tendency to hit stuff (or me) if I don't!
A small update:
- the pinion gear eventually came out by punching the bearing out, slowly and carefully, from the opposite side
Attachment 7180
- here is the gear/bearing that came out - this is all obsolete now
Attachment 7181
- now the Z-axis looks mean and lean (LEFT: BEFORE, RIGHT AFTER)
Attachment 7183Attachment 7182
- Now, I have bought a pile of these sort of building materials, and plenty of short 5mm bolts/nuts
-- They are made from galvanized iron, (or the more expensive ones, are stainless steel, very rigid)
-- Aim to attach bearing mounts to structures made from these building materials
-- This is cheap, but thought would make a running mock up with them.
-- Hope that way one could run the machine a bit, check dimensions again, check where to improve --> then make rigid, nice looking parts from aluminium.
Maybe this ugly duckling will turn to a beautiful swan some day.
Attachment 7184 Attachment 7185 Attachment 7186 Attachment 7187
The sensitive drill part is really useful when you come to hammer a collet out of the taper, it gives you something to hammer against.
Best if you can release the Z axis screw before you hammer so you aren't bashing against expensive ball nuts and bearings.
Good point Robin. Thanks!
Alternatively, perhaps one could use the lever on the left hand side of the quill, to lock it (during hammering)
- Not sure though is it strong enough / meant for that purpose.
Hoping to receive some bearing mounts, before weekend, so would have something to play with..
Status -update:
[x] received six (6) bearing mounts for the ballscrew -bearings
- a small local workshop made them for me.
- these are temporary bearing mounts, but very good at such.
Attachment 7222
- Holes for bearing are 32mm in diameter. Used heat to expand the mounts, so that bearings would go in easier. Holes are quite tight and precise, think it is impossible to remove the bearings in one piece.
Attachment 7223 Attachment 7224
[x] continued with a temporary, crude build
- in particular Z-axis
- Z-axis now looks like this Attachment 7230 Attachment 7225
- Z-axis lower bearing mount. Used an electric drill to fabricate some supports
Attachment 7226 Attachment 7227
Attachment 7228 Attachment 7229
- Purpose is to make a mock-up of the build, write down anything that needs changed, and then hopefully make it a nice looking mill.
[x] an un-necessary side-step was when I dropped balls from a ballnut. Thought first oh well, that was 100 quid down drain. But to one's surprise, managed to find all balls and with instructions found from internet, put it back together. For record, took out the remaining balls, and used a plastic straw from a WD40-bottle to put them back in, one by one. Used bearing grease (like Vaseline) to make the balls stick to the plastic straw / and also stick onto the inside-walls of the ballnut.
Latest is:
1) At garage, have a crude build ready to plug motors in
2) At home, have a pc with with LinuxCNC + motors running on table ( this has in fact been ready already for months)
Next steps are
- put 1) and 2) together... by Christmas time will take pc, monitor, motors, drivers, to garage and plug them in.
-- before that, need to study calibrating LinuxCNC X, Y, Z -axis
Lessons learned recently:
- making crude build takes more time than expected. Probably spent 4 days x 8 hrs = 32 hrs to make it, over a few week period.
-- need to buy small sundries here and there
-- compressed air die grinder similar to this is helpful. I find it safe to use (no sparks + quite difficult to cut yourself accidentally), and cuts material quite quickly, but not too fast. Makes a nice sound, too. Of course not a CNC -machinist / milling machine operator approach, but hey, one haven't got a mill running now.
Attachment 7646
- have already noticed a few design errors by making a crude build, so it has been worth it.
- Longer term plan:
-- Once machine is running, make revised intermediate parts. Use possibly less thick Aluminium than one would have in final build. Cheaper. One expects there will be errors as I am a newbie in all this.
--- want these parts to be relatively rigid, so that it is possible to make good quality "final parts" later.
- Hope to submit more photos next weekend + a compulsory video
Attachment 7647Attachment 7648
Well she runs now, albeit slow and ugly, though to my eyes it is pretty
http://www.youtube.com/watch?v=segC-xqdTxE
Is this it? CNC -virginity lost?
My smallest milling bit is a 10mm wide end mill, so the letters are fat beyond recognition.
Attachment 7807
Machining marks are quite visible, and think all the axis give way when pushed hard.
- Think the cut aluminium chips are around 0.2mm thick.
- Have to check what sort of feed rates I used actually, and how fast the mill bit was turning. With my zero experience I just set them to something that didn't seem overly fast.
Happy New Year to all!
Things have been moving slowly, due to work etc. commitments.
I have now officially begun an intermediate -build of the CNC -conversion.
- Focus is making now parts more rigid, and more like the final, beautiful build.
-- One is using less thick (cheaper) materials here, than in what will be the final build.
Today I have been using the mill as a manual machine, with LinuxCNC, using DRO's and Power feeds.
- Trying to get used to G-code, use simple commands like G0 somewhere, G1 elsewhere... while cutting aluminium.
- Measuring with a digital vernier, cutting a tenth here and there.
Perhaps one had thought I am going to make a fancy drawing and export it into G-code. Send chips flying and ta-da, bolt everything in place, and have a ready CNC conversion.
But it has not been like in dreams. Need to take one step at a time. It was fun cutting aluminium today. :)
Attachment 8137
Small update:
- have been getting more familiar with G-code, LinuxCNC, QCAD, dxf2gcode.
-- Also have Heekscad / HeeksCNC + Blender installed (http://www.mycncuk.com/forums/cad-ca...hat-i-did.html).
--- However so far,I have not transferred anything useful to work-piece from Heekscad/Blender.
- This weekend I started to make X-axis parts.
-- use QCAD to make DXF.
-- use dxf2gcode to make G-code.
--- each task I do in several smaller tasks.
---- I could not get dxf2gcode make one long piece of G-code, with climb-milling.
---- So instead, I have chosen to create individual smaller G-code -scripts, that I run in series.
----- Let mill return to home between each G-code script.
-- Getting used to mounting a work-piece.
--- Working with coordinates
--- Zeroing coordinates. Touchoff. In short: mount a work-piece, and practice how one can get cuttings exactly where one wants them.
-- On Friday bought a new 4mm and 6mm carbide end-mill. Smallest I had before this, was a 10mm end-mill.
It is slow progress, however rewarding. Would just love to go back to garage and start cutting again. At this stage, the machine is crude but it does what it is told to do.
Attachment 8197
It's looking good John! ...Thanks for a great thread.
This weekend have
- been milling parts for X-axis
- managed to snap first endmill (4mm carbide)
Next week:
- hope to receive new material for the build, 125 kg of 15mm thick plate 6082 -Alloy :biggrin:
- hope to send chips flying
Up until now I have had very little aluminium to work with, just a couple of used bits of 5mm plate (seen in photo)
Attachment 8270
Today is an eve of first Anniversary of this build thread.
- Removed all crude -build structures from X-axis.
- Installed "intermediate build" components on X-axis
BEFORE:
Attachment 8322 Attachment 8323
AFTER:
Attachment 8324 Attachment 8325 Attachment 8326
Some other pictures taken today:
- These are for motor mount. 5mm thick aluminium, what I have had lying around. These are mock -pieces.
-- Will use 15mm thick aluminium soon.
Attachment 8327
- Once removed all the crude structures, had a chance to clean table.
- BEFORE:
Attachment 8328
- AFTER cleaning with denatured alcohol
Attachment 8329
It is still a crude build, but it is starting to make parts. Everything is coming more quickly now, that have taken first steps with G-code and CNC.
Got a smile on my face, when made mounting plate for motor. Keyd in coordinates, make mounting holes 47.14mm apart, as it says in technical data sheet. Guess what? The motor is a perfect fit for the plate :smile: CNC is amazing.
The best bit of this is where you said "intermediate build", this means a lot as you understand the pitfalls but not afraid to plough on. You learn a hell of a lot this way and it was the route i took when first started out. I worked out was bad by building bad, but i understood that. Training would cost you an absolute fortune. Well done!:wink:
Yes, learning by doing. One year from start of thread now, and we are here.
Please how would you see a 'final X-axis build' like this?
1) Make sort of table-top, out of 15mm aluminium (or possibly 2 x 15mm = 30mm, even 3x15mm=45 mm possible?)
1.1) The top is level with current table top
1.2) Size of original table is 500mm x 130 mm
1.3) Size of new table top is extends current table top quite substantially (60mm at the mill-side of table, more at front)
- will not reduce travel, though.
Attachment 8339
Reasons why I would want a larger table top:
- keep chips away from ball screw
- perhaps aid attaching a larger item on table (would drill + tap holes. Threaded holes covered with plastic plugs, except when in use)
- add rigidity to X-axis
- add rigidity to motor mount
2) On either side of table, would have 15mm thick aluminium plates, like in photo (except photo has 5mm thick aluminium)
3) The "boxed sections" at either end of table, would add 15mm thick aluminium blocks between original table end, and bearing mounts.
- purpose: add rigidity both longitudal and horizontal
Attachment 8340
3.1) Motor mount: 2x15mm thick aluminium
- secure motor to larger 15mm thick table top (from above)
4) Bearing mounts on either end of table: 2 x 15mm thick aluminium
I see difficulties with the build in many ways. I am sure one would have been happier with a little bigger machine to start with. But this is what I have, and it will be a nice machine.
But do you see issues with this structure? Would one regret the larger table top?
Would appreciate comments :D
Thanks!
John personally i would stay as you are for now and complete what you started. I will almost guarantee that by the time you do complete this your thoughts will be completely somewhere else....A new build!
In most cases the size of the parts you think you may want to make in the future end up being smaller. After i finish my mill build i shall be making my router smaller. The reason for this is because i am just not using the whole thing and it is space i could do with back in my workshop.
The bigger the part you want to make lends itself more to being done manually i always find. If you happen to come across a larger table for a few quid then just buy it. It will save a lot of heartache in the end.
Good point about larger items and most appropriate methods, and manual work. I will make this machine as good as I can. There will never be other one like it.
This week I have started to make the X-axis "final build". This is a slight revision of plan. I have realized time it takes to make the final build is going to be very long anyway, so not going to make Y and Z -axis any "intermediate build"... but next items are final.
On milling table there is a 708mm x 50mm new piece for X-axis. Had bought 15mm thick aluminium from Ebay for this purpose.
Attachment 8595
Dialled in G-code to cut a through-pocket (15mm depth), but to one's surprise, end-mill did not penetrate all the way through. Have measured thickness with a digital vernier, and plate seems to be 16mm ( 16.2 mm ). Had to rewise drawings.
Attachment 8596
I have cut the 708mm x 50mm parts with a cheap circular saw, bought for this purpose + blade made for aluminium. If you try this at home, please use a good respirator (aluminium dust) + eye protection. I did this part of work outdoors, due to mess it creates. Used piece of wood + clamps as a guide rail.
Attachment 8597
Resulting parts are quite straight, no curvature or windings to mention. There may be a 0.5mm difference to the 50mm I wanted, but I will not try to machine them any further. Will make holes and fittings as needed for this build. This part will attach to the "front of the X-axis -table". The 16mm thick part will replace current 5mm parts.
Attachment 8598
Nice one John good to see your back at it.