BurnTables THC going haywire

[Burner_96]

I just recently got my table set up, it is a used unit. 5x5. Running a Hypertherm 65. Mach 3 “burntables” software, Sheetcam to export. So far I think I have it dialed in most of the way except for the THC… I tried searching for this topic but i couldnt find much relating to my specific issue. Ive found from reading other threads that the height control isnt exactly a strong point on a BurnTables system.

Ive never had an issue with pierce height once THC is turned on. The standoff itself has always been good. BUT, for some reason, the torch will loose its zero position after running a cut cycle. Ill zero the machine out on the origin, turn THC on, and run the program dry (plasma off). Once its raised it will return to the zero position, only the zero position it goes to is about an inch off from where i originally set it… The program will read “0” on all axis.

Ive been manually setting torch height and its “okay”.. my cut quality suffers. I have some A36 to cut that has a slight bend so id like to use THC to avoid a collision.

Anyone run into this??

[acourtjester]

Have you changed the post processor recently, the G-code may not be the same and that is why your torch position could be different. Normally the torch should go to the pierce height at the start of the cut operation, not zero.

[Burner_96]

Have you changed the post processor recently, the G-code may not be the same and that is why your torch position could be different. Normally the torch should go to the pierce height at the start of the cut operation, not zero.

Sorry just getting back on now,

Re-reading my post, maybe i was a little vague.

Ill zero the torch at the origin with THC on, initiate the cycle, and it will cut with the correct height.. however, when it “returns to home” at the origin, It will be off about an inch or so from where it was zeroed. Leaving me to lose my position if I were to do a dry run first, then turn the torch on. It seems to only be on the Y axis as well..

[acourtjester]

When you do a cut does it cut the correct size, if not the correct size you may have a slippage in the drive assembly on the Y axis.
Another thing is the post processor may not be telling it to return to 0.0, look at the G-code and see it if has g1 X0.0, Y0.0 as one of the last lines.