[jdr21]

I have a tree 425 mill with a PC 2100 control. I have had it for quite a while , but have never done any precision machining with it. The other day I tried to machine some bores and found that it was cutting out of round. It does well on rectangles and straight cuts. At one point in the past I had to replace a servo motor. Would anyone know if the motor would have to be tuned when replacing it?

[Jim Dawson]

Tuning is a good idea on a motor replacement, all motors are not exactly the same.

Define ''out of round'' my mill consistently interpolates holes that are out 0.001 across the 10:00 - 4:00 measurement while rectangles are fine, this seems to be due to known Y backlash. If I need an accurate hole, I bore it.

[underthetire]

Yes it does. Those machines use DC motors usually Baldor in the later ones. All DC drive machines need to be tuned on occasion. I don't remember how to get to the servo error/axis lag page on that control any longer, I did way more Dynapath ones. It's not hard to adjust them.

[jdr21]

Yes , mine is at 10 and 4 but it was .040" on a 3" hole. If I check for backlash with an indicator it checks pretty good. I will see if I can find the parameters for adjusting it. Thanks

[underthetire]

The lag or servo error is just to display a value. Actual adjustment is done with a jewelers screwdriver adjusting pots on the axis drive card. Usually tach or sig gets them right in. Basically, you want to move all the axis at ~15ipm individually and adjust the pots so each axis lag is identical. Jim, sounds like yours is off as well, backlash shows up always at 12-6 or 9-3. When i used the ballbar to calibrate these machines, i could usually get them to .0002 on 12".

[Jim Dawson]

The lag or servo error is just to display a value. Actual adjustment is done with a jewelers screwdriver adjusting pots on the axis drive card. Usually tach or sig gets them right in. Basically, you want to move all the axis at ~15ipm individually and adjust the pots so each axis lag is identical. Jim, sounds like yours is off as well, backlash shows up always at 12-6 or 9-3. When i used the ballbar to calibrate these machines, i could usually get them to .0002 on 12".

Good information, thank you. :cheers:

[machinehop5]

I think the Tree 425 had DC Westamp Axis Drives ...this manual might help confuse you more.or help others walk you thru Tuning
https://www.ormec.com/Portals/ormec/...stamp/A711.pdf

[zpsbob]

Sorry, late to the party.
No westamp drives were ever put on J425 machines.

Balance the lag on the 2100 machines:
Press DISPLAY
Select SERVO SETUP, Press the green check mark
Select a linear axis (x,y, or z) from the pull down menu on upper right.
Press the scale/balace icon thing mid page on right.Wait 2-3 seconds. Press scale again. Do 3 times per axis.
Perform balance for all linear axes (X,Y,Z).