We have found a bug in he V4.28 Mach3 Plugin that can sometimes cause a Motor Stall.

The plugin identifies points forming small arcs and compresses the points into equations of motion.  It is not necessary to have Circles in the GCode to have the problem occur.  The bug occurs when points in the xy plane form an arc through the wrap point of -180 to +180 degrees.  This results in a huge short duration pulse in the output trajectory.  This may result in a motor stall or miss-step.  The occurance is rare but most likely to show up in complex 2D jobs in the xy plane (roadrunner).

If you are running KMotion V4.28 and using the Mach3 Plugin.  Please copy the file below to your Mach3/Plugins directory

http://dynomotion.com/Software/Patch/V428Mach3PluginStallFix/Dynomotion.dll

Regards

TK