Hello all.
I have a Cncest 3040T, using Autocad to DXF, SheetCam for GCode and Mach3 for Machining.
There is a thread on here where kev2960 has a similar problem, but it's not solved.
when cutting a circle within a circle in 9mm MDF, at 1mm plunges, the first pass is perfect, then with each plunge it shaves a bit extra off the south side of the piece and steps the north side of the piece, by approx 0.3mm, giving an eliptical shape when finished, and when returning to the home position, its not where it started, it's north east of its original point by some 6mm or so. The DRO reads 0,000 on all axis.
the settings ive tried in mach3 motor tuning are:
steps per velocity acceleration notes
400 2000 300 all as per set up manual, awful results
410 2000 300 same rusults
405 2000 300 a tiny bit better
405 1500 200 same as before
405 1000 100 awful and really really slow
410 1000 200 same as the rest but landed no where near its home position

any advice or settings much appreciated