Tormach mods

[capsteve]

I have been running a series 2 machine for a few months, mostly on 50-100 piece runs of small parts. single tool ops. my problem is after 20 or so runs the table will drift out of x,y center by a few thou, getting worse as time goes by.
its a pain to have to recenter the machine in the middle of a run. I'm pretty sure i'm not losing steps, as i've adjusted the gibbs and really checked things over.
i'm wondering if anyone has added glass scales to run a seperate dro to use to recenter/check on the mach3 dro, or better yet, i'd like to really get some feedback servos to report actual position to the controll software..

[capsteve]

i've tried two different pc's, turned off hyper threading, indicated each axis for repatability and backlash, hand turned each axis checking for excessive drag.
i've heard good things about the machine (why i bought one) and it does work well for short cycles, but when it plugs away for a while it'll get out of tolorance. if i center it up, it'll be balls on again for a short while.
I'm all ears for any solutions...thx steve

[zephyr9900]

Steve, that sounds to me like it could be a motor coupling problem. A little over a year ago I had a Z axis "drift" over long periods that turned out to be slippage in the solid coupling between the motor shaft and leadscrew end.

Description of the problem and my initial solution is at Z axis problem . I ended up retrofitting a nice Stafford 4-bolt split coupling that I bored to exact size and haven't had a problem since. I sometimes run 15+ hour contouring runs and the Z is still in registration at the end.

Best regards,

Randy

[keen]

Yes - I was going to say coupler slip also. I still have the basic standard couplers and it runs for many hours and stiil returns to perfect Zeros.

Have you checked they are fully tight? If the motor is a little out of alignment the problem is more likely as flex could agrivate any tendency to 'creep'.

[capsteve]

i'll check them out in the morning. it certainly could be that simple. i havent marked them yet in any way so i wouldnt know if it was occurring..
thx steve

[MichaelHenry]

Is there any chance that temperature could have a bearing on your drifting zero problem?

Mike

[HMB3000]

Just a thought but maybe your Fixturing or tool is moving. did the tool hight change ...or you could have a loose wire causing an intermitting signal issue...after centering paet re-refernce all axis and write positiob down....next time you notice the issue...refernce all...next measure tool hight
the position should be the same and the tool lenght should be the same....if one is off something happend....or maybe your not seating them the same also check part thickness to make sure it was the same

[capsteve]

i think your way off base, heavyload as i started the thread.. i still am having some repeatability problems. but i have been taken care of as well as i expected by the team at tormach. i wouldn't hesitate to buy the mill again.

there have been some great suggestions, but i think the problem actually may be coming from the mach3 software. if i pause a program, then restart the program from the beginning, i can expect x,y center to drift after a few cycles.
i've since started having mastercam send the mill to home position after each cycle to keep everything spot on....



would you care to explain how my question to the forum could be misconstrued by you to be a sleazy sales tactic.

perhaps you might actually put some thought into your posts before you hit send.........

[HMB3000]

When I first recieved my Tormach the Z would not hit the value from Mach every once in a while or it might drift down when power was on or would not retact to R-plane all the way...I fanilly tracked it down to a wire conection at the Z motor housing causing an intermitten signal...everyonce in a while it would miss a few thusands or drop a few thousands...the leads are crimp at the motors....so even if the wires are crimped you could have a bad conection....it sounds like your issue is an intermitten signal issue...I re-cripped wires and never had a issue again

[_swede]

Originally Posted by zephyr9900 that sounds to me like it could be a motor coupling problem.

This always comes up as something to look into on a troubleshooting checklist, and surely it has helped a lot of people on this forum. But I also have experienced the problem capsteve is talking about, and I don't think that the couplings are the problem for our particular machines.

It didn't occur to me until reading this thread that I may only be experiencing this after pausing a program... I'll have to keep an eye out to see if that's the case.

capsteve, did sending the machine to the home position (I assume this is the same as 'ref all' button on the Tormach interface) after each cycle help at all?

Otherwise, HMB3000 has a great suggestion of inspecting the stepper drive connections.

Thanks for the great suggestions!

p/s this minor inconvenience has not resulted in any machining errors because I was able to detect it beforehand. It has in no way effected my satisfaction with the machine and I'm still a very happy Tormach owner!!

Adapt and overcome!