[Bigtoy302]

So everything on my table works good with the THC(mp1000) off, I can
dry run and everything runs smooth. MDI works fine.I can turn
everything on and cut just fine but after the first cut, when the Z is
supposed to raise up before it rapids to the next hole the motor
screams and goes nowhere and drags the part across the table. The
motor makes the same sound as if you were to stall it. On a dry run
the z operates normal before a rapid move. When I cut A basic part with only one cut the THC operates normal.

Ryan

[Torchhead]

the z operates normal before a rapid move. When I cut A basic part with only one cut the THC operates normal

The answer is in that single line. It happens in the first lift after a cut. Since the THC hardware is not even engaged in the motion after the torch turns off, it has nothing to do with the problem. It's obviously losing steps and it occurs with THC active in MACH because MACH does not use any accel parameters while cutting with THC. To keep the motor for losing steps under THC control and just stopping, the VELOCITY on Z is reduced by the amount of specified in the THC RATE; default is 30% (or 30% of full velocity). MACH is SUPPOSED to know that the normal Z motion, like the lift at the end of a cut, uses NON-THC motor parameters (normal accel and velocity you set for Z) but there has been a bug in some versions where it "forgot" to apply the normal accel curves to Z and it just tries to move the motor at full Z velocity with NO ACCEL applied....it will cause a stepper to grind and refuse to spin or a Servo drive to fault.

You have been advised to tune the velocity down on Z to 30% (and you can raise the THC rate to 90% to verify that the software is the problem. That then should lead you on a course to change the version of MACH3.

TOM CAUDLE
www.CandCNC.com

[Bigtoy302]

I did not have time today but I will try and mess with it tomorrow. Thanks again Tom for all your help.