I machined a load of parts on my Seig KX1 a couple of weeks ago and when I got around to assembling them last week I found that some of the parts were oversize - typically +0.35mm in 75mm on the X axis, or just under +0.5%. I've audited the CAD and GCode and all the values are correct. Unfortunately I was producing the parts as fast as I could over two or three days and I can't remember any peculiar conditions that might have existed when the oversize parts were machined. I re-machined one of the oversize parts yesterday with the same GCode files and it turned out dimensionally accurate.
I checked the motor settings in Mach3 and they seemed to be OK - Steps Per = 500; Velocity = 1000.2; Acceleration = 150; Step Pulse = 2; Dir. Pulse = 0.
I remember having the same problem about a year ago when another part turned out oversize, but I was able to re-machine it to correct dimensions using the same GCode files.
Any pointers to what might be happening? At the moment I'm going to check the motor settings before I start any machining. I never normally touch the scale settings on the MDI and always assume them to be 1, but I will keep an eye on them as well. I also checked the code from Cut2D for the possibility of any G50/51 entries, but there are none.
The mach version is 3.043.022.
Jim.