Finishing Pass not lining up with roughing pass in Mach3

Post by **diskocat** » Sun Mar 11, 2007 9:27 am

Hello everyone. Wondering if any one can help me. I am running Mach3 and keep getting an offset between the roughing pass and finishing pass??? Is it my setting in Cut3D or in Mach3? I read another posting regarding "absolute or incremental arc coordinates" in Mach3?? Would this be causing the problem? Thanks for any feedback. Regards Scott

Post by **Juzwuz** » Sun Mar 11, 2007 11:29 pm

If you are using stepper motors, it might be that you are losing steps on your roughing pass. When you are finished with your roughing pass and the mill goes back to the starting position, there is an offset because the computer thinks it's in the right position based on the number of pulses it sent out to the motors, but the motors couldn't keep up. Does that make sense? I'm still pretty new at this (CNC machining). When I was cutting a lithophane for the first time, I had my feed rate and acceleration set too high for my little CNC Taig mill. I ran my roughing pass and then finishing pass and when I looked at the results, I had a bad offset (almost a shadow effect) in the lithophane. I've since turned down the feed rate and acceleration to better values and it seems to work better now. I'm not running Mach 3 but I think the principle still applies. If you are using servo motors, please disregard this message since it won't apply.

Justin