[Blendwood]

So I've had these KL4030 Stepper Drivers, and this C10 BOB for about 6 years. They've made the transition between a few homemade cnc routers as my needs have changed. A while back I picked up an older Mimaki me500 engraver. I gutted it of all the old electronics and stripped it down. I bought new timing pulleys all around, and put my nema23 425ozin steppers in place. The entire machine is ballscrew driven x,y, and z. I went through the normal procedure in mach3, and calibrated each axis in the settings screen. First I went through each axis with my 6" digital fowler calipers. Once I got my steps per and adjusted my accel, and velocity, I went to to the MDI screen and one axis at a time I ran single lines of code to jog each axis back and forth across a 4" span to confirm how much backlash I has as well as repeatability. All of my testing came back within .0005-.001
So repeatable within about half a thousand, to a thousandth, better than what I even need. So checked backlash by also going back and forth on each axis, and the same result. So I went through, setup my spoil board on my tslot table and created a setup for indexable workholding. Now I went to run a plaque for a customer the other day, and it has a 3d carving along with some lettering. When I was was running the 3d carving the z axis has been creeping up on me. After about 1 to 2 mins of run time, the z axis has found it self about .125" above the point it started. Now I have gone through this machine very diligently. Mechanically this machine is rock solid. So I started to do some testing, one change at a time to figure out exactly what seems to be causing it. I went through methodically and switched out the x and z axis to test my program. X axis had a little noticeable position change while the z axis had the same amount of change. Then switched them back. I switched out the y and z axis next, and there was no noticable position change in the y axis, but the z axis still performed the same, gaining height over the top of the work. So I'm at a loss here as to what is going on. If you have any suggestions or advice it would greatly appreciated. Thank you for your time!

[Blendwood]

So I've had these KL4030 Stepper Drivers, and this C10 BOB for about 6 years. They've made the transition between a few homemade cnc routers as my needs have changed. A while back I picked up an older Mimaki me500 engraver. I gutted it of all the old electronics and stripped it down. I bought new timing pulleys all around, and put my nema23 425ozin steppers in place. The entire machine is ballscrew driven x,y, and z. I went through the normal procedure in mach3, and calibrated each axis in the settings screen. First I went through each axis with my 6" digital fowler calipers. Once I got my steps per and adjusted my accel, and velocity, I went to to the MDI screen and one axis at a time I ran single lines of code to jog each axis back and forth across a 4" span to confirm how much backlash I has as well as repeatability. All of my testing came back within .0005-.001
So repeatable within about half a thousand, to a thousandth, better than what I even need. So checked backlash by also going back and forth on each axis, and the same result. So I went through, setup my spoil board on my tslot table and created a setup for indexable workholding. Now I went to run a plaque for a customer the other day, and it has a 3d carving along with some lettering. When I was was running the 3d carving the z axis has been creeping up on me. After about 1 to 2 mins of run time, the z axis has found it self about .125" above the point it started. Now I have gone through this machine very diligently. Mechanically this machine is rock solid. So I started to do some testing, one change at a time to figure out exactly what seems to be causing it. I went through methodically and switched out the x and z axis to test my program. X axis had a little noticeable position change while the z axis had the same amount of change. Then switched them back. I switched out the y and z axis next, and there was no noticable position change in the y axis, but the z axis still performed the same, gaining height over the top of the work. So I'm at a loss here as to what is going on. If you have any suggestions or advice it would greatly appreciated. Thank you for your time!

Solved, thanks for the help