Warco VMC Turret Mill - CNC Conversion

[antsals]

I've been in the process of converting a Warco VMC Turret mill for quite a while. I have recently up'ed the stepper motors to slightly more powerful but I have a niggle on the machine.

The Warco major build log is a good starting point as I can see a few items like the gib strip screws have been modified.

I'm using eazicnc system and g-code generated from featurecam. The main problem I'm having is that as I am machining for example a circle every so often the machine just goes off on a striaght line? The g-code is perfect it seems to be the machine. What I think it is is the x axis is jamming up and overloading the steppers so that the motors arn't turning therefore the circling motion goes out of sync.

My first question is has anyone out and about tried converting this type of machine and what have you done to mount the x - y axis ballscrews?

At the moment I have a temp x-axis mount so I could test the machine but keep encountering this problem. I'm really not sure what to do next looking for some guidence I'm even thinking the ballscreaw could be bent between the two fixed bearing mounts?

I have been cutting aluminium only 1mm cuts with 16mm endmill at 400mm/min? Whats your thoughts should I be able to run faster? Deeper cuts?

Any thoughts I would appreciate.
Cheers
Ant

[antsals]

Also have a link to video of the machine cutting:-

http://www.youtube.com/watch?v=A5z_nX987b8 (http://www.youtube.com/watch?v=A5z_nX987b8)

[M250cnc]

I'm using eazicnc system and g-code generated from featurecam

Do you mean the POS made by CDE

Phil

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[antsals]

Yep the software from CDE

[M250cnc]

Yep the software from CDE

I take it the hardware is made by CDE also, if so that i suspect is the problem (Hardware).

To test i would remove the motors from the machine run the code and see if any motor stops when it shouldn't. That will eliminate any machine binding issues.

I would also check the power supply voltage they have some pretty low output votages, i just cut my losses and sold the system.

Phil

[Robin Hewitt]

I have been cutting aluminium only 1mm cuts with 16mm endmill at 400mm/min? Whats your thoughts should I be able to run faster? Deeper cuts?

Hi Ant

Suds! You want a suds pump if you are cutting aluminium.

I am no stickler for mathematising speeds and feeds and all that malarky, I go for what works for me.

Looking at it... If your holdfasts can take the strain, for a good start setting I'd probably try half the revs, half the feed, four times as deep and a good flow of suds :naughty:

best

Robin

[antsals]

I take it the hardware is made by CDE also, if so that i suspect is the problem (Hardware).

To test i would remove the motors from the machine run the code and see if any motor stops when it shouldn't. That will eliminate any machine binding issues.

I would also check the power supply voltage they have some pretty low output votages, i just cut my losses and sold the system.

Phil

Phil,
What have you done then? Sold the system and made your own?

Ant

[M250cnc]

Ant

I an sorry to say I sold it on ebay, this was about 3 years ago.

I use Mach3 as the controller I bought new drivers and power supplies.

It is ten times better than it was before.

Phil

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[antsals]

It what way is it better? What stepper drive units are you using? I was looking at the 240v versions from Zapp automation?

[M250cnc]

It what way is it better? What stepper drive units are you using? I was looking at the 240v versions from Zapp automation?

Night & day difference.

You need the highest voltage that your motors will tolerate which gives the highest speed. Then the amps give you power/torque.

Personally I would stay away from all in one boards.

Zapp, Arceurotrade, Motion Controlled Products are good places to buy

Phil


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[antsals]

I've been building a plasma cutting bed so I could just use the CDE kit for that and put together a new controller for the mill.

[M250cnc]

That's a good idea, the mill will need the more powerful setup.

But it will work so much better I bet you bin the CDE kit.

Phil

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[Robin Hewitt]

It what way is it better? What stepper drive units are you using? I was looking at the 240v versions from Zapp automation?

I used them and no regrets, not cheap but you save a bundle on power supplies. Minimum current is 3.18A RMS 4.5 peak. I wired the coils in series because Gary said it would keep the heat down, even so. Any suds splash that lands on the motors boils off but the heat doesn't seem to be a problem. OTOH, do try and dump the heat in to the mill rather than on to the lead screws.

[antsals]

Hi Ant

Suds! You want a suds pump if you are cutting aluminium.

I am no stickler for mathematising speeds and feeds and all that malarky, I go for what works for me.

Looking at it... If your holdfasts can take the strain, for a good start setting I'd probably try half the revs, half the feed, four times as deep and a good flow of suds :naughty:

best

Robin


Robin,
I'm thinking of getting some of the stepper drive units you hve on your machine from Zapp Automation.

What size stepper motors have you got on your machine? The Warco machine you have is very similar build to mine. Did you hve to machine any of the bed below the table to fit your ball nut in? Did you have ny problems re-fitting the gib strips?

What types of speed and feed do you get from the machine cutting aluminium and steel? What size cutting an d depth of cut do you acheive?

Thanks,
Ant

[Robin Hewitt]

3.5Nm NEMA34's.

Had to open the ends of the bed out a bit to clear the nuts but only for ease of taking apart/putting together. Had to grind some metal away below the bed to get the full X travel.

The Gibb strip adjusters were horribly loose and prone to adjusting themselves. I added a fine adjustment with pinch bolts to lock them in place.

I haven't tried it in avengeance yet, been pussy footing about with sub 8mm tooling. When I think about ripping off the excess with fat cutters at high rates I start to worry about overloading the ER32 chuck vertically. If the tool slips down the job is scrap. Even if it doesn't slip the column will bend deepening the cut and forcing a seperate finishing pass if the tolerances require it. Makes me cautious.

Rule of thumb for DOC is tool radius but I won't go >4 or 5 mm, OTOH you won't get the column flex I do. I think you have to find what the mill likes, it should purr through the metal like it wasn't there, hammering or screechy noises are a sign that you've got it wrong :naughty:

[antsals]

Robin,
That could be one of the problems I'm having if the adjusting bolts a moving then I could be jamming up the bed. Maybe I could mark the bolts and see if they move. Maybe I should start on the screws! You are right they are really sloppy. I have a feeling I'll have to get the inside of the bed machined away to get some space for the nut. What size ball screw did you use?

Thanks,
Ant

[Robin Hewitt]

I used 15mm x 5mm pitch screws with a 5:4 belt reduction. Originally 5:2 before I upgraded the drivers.

If the Gibbs aren't held firmly in position the slides are tight in one direction, loose in the other. You just can't get the adjustment right.

I made some studs that screwed in where the Warco adjustors used to screw in. That gave me a very fine pitch 8mm male thread and a flanged adjuster nut rather than a bolt. I threaded the stud internally 5mm to hold a cap that pinches on the end of the Gibb. Can't turn, can't slop.

[antsals]

Robin,
Did the OD of the flange of the ball nut clear the underside of the bed? I'm thinking of buying a smaller ball nut so I can ensure I have something to bolt too. I had to grind the edge of the flange away so it would no longer clash with the underside of the bed. You can see this in the pictures at the top of the post.

Regards,
Ant

[M250cnc]

If the tool slips down the job is scrap. Even if it doesn't slip the column will bend deepening the cut and forcing a separate finishing pass if the tolerances require it. Makes me cautious.



The column is made from cast iron, and cast iron does not bend. When you say deepening in what axis is it deepening the cut.

Phil

[Robin Hewitt]

Did the OD of the flange of the ball nut clear the underside of the bed?

No trouble at all, only had to open it out a bit at one end.

[Robin Hewitt]

The column is made from cast iron, and cast iron does not bend. When you say deepening in what axis is it deepening the cut.

Anything can bend, but you don't necessarily notice until you start chasing those last few elusive microns :smile:

[M250cnc]

Anything can bend, but you don't necessarily notice until you start chasing those last few elusive microns :smile:

Very true but IF say you had a sloppy quill on your machine then the bending would come from that rather than very hard to bend cast iron.:naughty:

Phil

[Robin Hewitt]

Very true but IF say you had a sloppy quill on your machine then the bending would come from that rather than very hard to bend cast iron.:naughty:

Indubitably :beer:

[antsals]

Robin,
Have you any pictures of the mod you did to the gib strips?

Thanks
Ant

[Robin Hewitt]

Have you any pictures of the mod you did to the gib strips?

Try my Warco Major build log, reply #61

[antsals]

Try my Warco Major build log, reply #61

Just had a look at the pictures. Very interesting. Did you notch the gibbs or did it come already notched? Mine you just push on the end. How does yours maintain rigidity? You have the screw into the casting then the stud in the top how does the adjustment work? Can't tell from photos.

[Robin Hewitt]

The Major and Minor have the notch and a bolt with a very wide head on it. The bolt head fits in the notch and moves the Gibb. If don't have the notch you must have a different system and my modification won't help.

[M250cnc]

Ant take out your jib and post a photo here to be sure.

But you may have a screw at each end of the jib.

If that is the case and your jibs are loose then to tighten you backoff the screw at the small end of the jib and tighten the screw at the large end of the jib. To be working correctly both screws will be tight locking the jib in the correct position.

Phil

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[antsals]

Will do. They are two screw type. But I will get some photos.

[antsals]

I replaced the ball screw in the machine now. I had Zapp Automation machine a "custom" ball screw for me which was a great job. Fitted like a dream.

I posted a video of my test on the machine.

http://www.youtube.com/watch?v=aQblxA38q5w

Now I have a problem which I'm not to sure how to sort out. Positional accuracy is pretty good. I machined a test part but I'm a little out. I'm guessing the backlash compensation will sort it out but I'm not sure how to ensure I get it right. What procedure should I use to see how much backlash I should compensate for?

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[antsals]

Just thought I'd put my model with a few dimensions just to show how far out the machine is.

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[M250cnc]

Hi Anstals,

As you are using ballscrews you should have negligible backlash so i don't think that is you're problem.

Looking at the finish on the part I'd say you have play in the jibs X &/or Y or the Z column could have excessive play in the housing.

Have you checked the amount of backlash you have "Do you know how" ?

Phil

[antsals]

Phil,
Thanks for the reply......no I need some guidence on how to check for backlash. Thats a good call on the jibs, I need to check them all I'm guessing they are tight enough when there is no movement?

Cheers
Ant

[M250cnc]

Hi Ant,

To adjust the jibs It's best to take the motors off so you can turn the ball screws by hand you can then FEEL for any binding so get them as snug as you can but no binding. The best place to do this is at the extremes of travel as this will be the tightest area.

To test for backlash you need to have a DTI in a chuck or collet

You gently come up to a smooth face zero the DTI and zero the DRO

YOU CONTINUE TO WIND THE DTI ONTO THE FACE A SMALL AMOUNT 0.2mm say

Then you gently back off the face until the DTI reads zero

Your Backlash will be what the DRO reads

Wind the Z down about 75mm put a dowel in a collet chuck have the dowel sticking out 30mm put the DTI on the dowel at It's end push and pull on the collet chuck to measure play in the quill/housing.

Phil