Alternatively, is there anyway to use wear compensation to account for dimensional issues in only one axis? If it were consistent in both x and y I could just modify the effective diameter of the tool, however, the y axis is dead nuts on
No. Cutter comp doesn't work this way. It'll add/subtract the comp amount and result in an offset move in both x and y.
If you haven't already sorted this out or bought the glass scales, I have a suggestion for mapping which may help narrow down the culprit.
What you're going to do is use your DTI and a 1-2-3 block or gauge blocks to measure actual distance and compare to the commanded distance. Forgive me in advance if you already know how to do this...
1. Set table in middle of travel with indicator on head.
2. Set a 1-2-3 (or stack of gauge blocks) on the table lengthwise and parallel to the table travel under your indicator. Set another block on edge behind it relative to the X travel direction, and lightly clamp the rear block so the two blocks don't move. You are basically creating two vertical surfaces exactly 3" apart.
3. Adjust the blocks and indicator so the tip is touching the edge of the lower block, zero the indicator and X-axis offset in your controller.
4. Jog up in Z to clear the indicator tip and jog X until the indicator is zeroed on the other block. Check the machine DRO and write down the difference between the reading and your block dimension.
5. Just repeat the process along the X axis over the whole travel every inch or so - just shift the two blocks. You can write the numbers down right on the table in sharpie.
Once you have a bunch of numbers down on the table you shoudl be able to see pretty quickly if the issue is:
1. Ballscrew lead distance varies over the length
2. Ballscrew lead is constant, but not to spec
3. Ballscrew is fine, but your steps per unit of measurement is off.
4. Some other voodoo, like a warped axis or other mechanical gremlin.
If it's #2 or #3 you can compensate in the software. If it's #1, you can average it out in software or write a macro which scales the X axis at various machine coordinate locations.
If it's #4, let us know and we'll try to find a tame priest for you.
-Ralph