Problem- Stepper motor speed unstable!?

[MACKAY9999]

Help! I am using a torchmate 3 gantry kit, I am getting really sad cuts for some reason but only when cutting in the Y+ direction!

For example, cutting an 18" square in 1.6mm thickness, move X+,Y-,X-,Y+ the first three sides have excellent finishing, however the motor speed on the last Y+ cut seems not constant as it moves during the cut (slow/fast/slow/fast) etc.

Disable the THC during the last Y+ cut, with the torch cutting at a fixed height the best result you can get is excess dross and a poor quality finish, with excessive opposite kerf angle.

THC to auto, in Y+ cut, and the THC is constantly compensating for the changes in speed (and resulting voltage jumps), this only adds more sadness to a miserable finish with the torch changing height constantly the cut also becomes wavy.

Apart from checking the obvious loose connections, grounding etc. is there anything else I should be looking at to get this motor working properly in "both" directions? Do I need to replace the motor?

3 directions perfect, Y+ misery!!

[Mike@Torchmate]

It sounds as though it could be the program itself changing the speed of the cut. The g-code for a square should be a total of 6 lines of code with no leadings or straight line lead-ins.

I'd recommend giving us a call and speaking with one of our techs on it if you haven't already.

[MACKAY9999]

Thanks for your help, unfortunately any cut is bad in the Y+ direction, even a single line.
I used the example of a square to show that 3 directions out of 4 cut nice, but the Y+ direction does not.
It isn't the program, cut a straight line down the middle of a plate in the Y- direction, nice. Exact same program in the Y+ direction, disaster! What else should I be looking at?

[Mike@Torchmate]

Originally Posted by MACKAY9999 Thanks for your help, unfortunately any cut is bad in the Y+ direction, even a single line. I used the example of a square to show that 3 directions out of 4 cut nice, but the Y+ direction does not. It isn't the program, cut a straight line down the middle of a plate in the Y- direction, nice. Exact same program in the Y+ direction, disaster! What else should I be looking at?

Is the speed and height remaining consistent throughout this square cut? Have you looked at your blank material after the piece has dropped out to see if one side of the torch has the problem? Have you replaced the consumables in the torch yet?