EZ-Trak DxII Cutting D's Instead Of O's

[Zombiestomp]

AKK! lol,Replaced the Y axis drive motor several weeks ago and today We ran, need to runn some varying diameter circles and my operater came to me in tears wondering what she had done wrong :} I checked the tooling size versus the hole diameter ,Because this has caused the problem in the pass if the cutter was more than 2/3 larger than the hole diameter this doesnt seem to be the case. I feel maybe the motor needs tunning or the backlash is now incorrect for the new motor maybe? can anyone help?

[NC Cams]

YOu're on the right track re; motor tune.

Assuming you're encoders are proper count, you may have a motor that has a different response curve than machine was initially programmed for.

Also, you need to have the motor tach's checked. IF it is an SEM, the tach's can go flakey after a while. Clarkson near Chicago can take care of them (factory service center).

Brian at BPT Machine in carol Stream ILL tuned my "trak and did a superb job (630-784-9942). Fixed a bunch or other "issues" that I was living with in the process. I have no affiliationn with BPT and paid the bill like anyone else would have to.

Backlash and lead comp are issues he took care of as part of the tune-up as well as gibb adjustment check....

[machintek]

I wonder if the encoder count is correct since you said that the motor was replaced. You could swap the motors (X and Y) to see if it indeed follows the motor.

If the replacement motor is the same make, it should cut real close. If it is a new CRC motor in place of a SEM motor (example) it may need significant tuning.

Yes, if you use the approach move, and the Math is wrong (size of pocket, size of endmill, and size of approach move), you will not have a round hole.

George

[wizard]

Before going spending to much time on the motors I'd verify that the leadscrew assembly is good. By that I mean that you have no excessive backlash in the leadscrew and that the thrust bearings are in good shape. I'd especially look for issues with lock nuts.

I almost always go through a mechanical checkout of an axis even if I'm certain the motor and/or encoder is/are the bad components. It is one of those things that has bit me a number of times.

The Y Axis drive very likely needs tuning if it wasn't done when it was replaced awhile back. This has to be done but I'm not convinced that it is your issue. Backlash compensation may also have to be changed but agian not convinced that is the whole isssue either. I do wonder why the drive was replaced originally.

Thanks
Dave

[Zombiestomp]

Thnx Fellas Lotsa good tips. And George yes it is a CRC and the old motor was an SEM. Guess my next question should be ......Is there an Auto tune for this? Or do i adjust using the pots on the axis cards?

[NC Cams]

The tuning can all be done by adjusting values in the config files used by TRAK software without touching the servo amps (including encoder count values) or even opening the control cabinet.

As far as I know, autotune didn't exist when 'Trak DX was concieved.

As the values in confiig are in "Bridgeport speak", you'd better let somebody who knows what to do deal with it....

Servo tuning, like brain surgery, is not a DIY project as far as I"m concerned. Strongly suggest contacting someone who knows the system (see prior post for suggestion if you live even within a reasonable drive of Chicago).

[machintek]

A GOOD service tech can tune these drives using PFM (in DOS) which is a piece of software that shows the DAC command, position error, etc.
No atutotune. Sorry.

George

[Zombiestomp]

Thnx for all your help guys I know just the man too call :} ,,,,,,,,,,,,,,,,,,,GEORGE!!!!!!!!!!!!!!!!! lol THnx again !