My machine is a Momus Ver.1 that I've been using for several years with Carve Pro and Mach3. I've been cutting 2 circle profiles about .100" apart. They come out not circles, but slight eclipses. The diameter is 8.00" and the ellipse minor diameter and major diameter will end up about .020" different. On the Carve pro preview, they are perfect circles, but on the machine, they are eclipses. I used a plotter pen and drew out the pattern to eliminate the cutting forces and got the same result - eclipses. The major and minor diameters are not orinented to the X & Y axis, but are tilted 45 degrees. And I have noticed that if I change from a climb cut to a conversional cut, (a clockwise vs, counter clockwise cutter path), the tilt angle of the eclipse will reverse as shown in the drawing below. The elipses are nice and smooth, with no breaks are sudden jumps. I have checked the drive sprockets, and motor mount bolts, the X & Y bearings, and anything else that might cause some looseness. Everything seems tight. The belts seem 'tight enough', but that is just my guess. I'm thinking that there might be some belt stretch happening since the error changed direction according to the path direction. I did a test by drawing a 8.00 X 8.00 box in VCarve Pro and it came out exactly 8 X 8 with the plotter pen, but only 1 stepper motor was running at a time. When doing the circles, both motors are running at the same time. That would indicate a problem with the controller or Mach3. I went throught the 'steps per' calibration on the Settings page of Mach3 and that made no difference.
Does anyone have any ideas of what may be causing this? This is not a new problem, I've just lived with it since it has not effected what I was cutting. Now with the concentric circles, it does pose a problem.
Thanks,
RichardAttachment 315274