I've been working on making an aluminum part using my PM25 mill converted to CNC with an Acorn board. I am programming the tool paths in VisualCAM, and then running the Gcode in CNC12, all the latest iterations. It is a two sided part, so I ran the top side with multiple tool paths and it ran perfectly. I then inverted the part, reset zero, and started to mill the bottom when trouble started. I first sent code with contained multiple tool paths - a roughing tp, followed by a facing tp, then a profile tp, all with the same mill. I set all the G54 zeros, and started running. The roughing and facing tp's ran perfectly, but when it started the profiling tp, it was off in the +x direction by 0.098". It just offset at the start of the tp, but than ran properly for the profile. If the vise or stepper slipped, it only did once, then didn't slip again. I checked the coupler and vise clamps and all was very tight with no evidence of slipping. The VisualCAM sim was perfect, as was the Gcode sim in Cimco Edit. I came back out this AM, set zero, and reran the profile, and it worked perfectly, just ghost cutting the same profile as the previous day. I then put in a 1/4" mill to do a small pocket hole, and the X changed again like before, but this time by 0.117" - no visible slip, driver errors, missed steps, nothing. The perfectly formed pocket just wasn't where it was supposed to be, despite sim'ing perfectly as described before.
Anyone seen something like this before or have any suggestions?
Need help with random X position change
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