NEED HELP!!! Table goes nuts when cutting full 4x4 sheets

[CNCFlavor]

When cutting a part here or there the table cuts okay. But when we do a full sheet of cutting,
It skips holes and loses its location on the sheet. I'm using a Hyperthern 85 amp plasma cutter on
a Wright CNC 4x8 size table.

Any help will be much appreciated.

THX

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[LeeWay]

What CAM software are you using?
Likewise CAD?
I use Turbocad and Sheetcam on our plasma. When you have fully nested parts with multiple operations, it pays to check over everything twice. For each step. It's critical that the drawing be flawless coming out of CAD and has each process under a different layer name for us. Holes, scribe lines, profiles etc. Goof that up and it will not cut like you want it to.
Same thing in CAM.
Also not all of our parts have holes in them. We group a few that do have holes in them and then immediately following the holes for that group, it cuts out those profiles. That way there is very little machine travel doing those parts and the holes are more accurately placed.

If you let the CAM do it alone, then it will kind of jump all over in order to help eliminate any sheet warpage. That can induce small errors in positioning if the table isn't perfectly accurate. Ours is pretty good, but not perfect. Rack and pinion.

[CNCFlavor]

Im using Sheetcam. I figured that the issue wasn't in the cam or gcode because it happened in different locations
when I tried it a second and third time.
I did double and triple check the gcode and all sheetcam settings.
Everything was fine there.

I think the table electronics may not be capable of pulling it off.


Just looked into it and realized that its the cheap chinese stuff.

I managed to get enough parts cut out but it ruined 4 sheets to get 1 full sheet of parts.

[LeeWay]

Yeah. That probably makes a difference. I am using some of CandCNC stuff. Maybe 4 years or so old. That and a Hypertherm PM45. The old style Cnc Router Parts belt drives on skate bearings.
It has glitches every now and then, but they are recoverable. I just back the program up to where the trouble was. Set Next Line and have a do over.

[awerby]

See if it does the same thing when the torch is off. If it behaves a lot better, then it's probably radio-frequency interference, and you need to do more shielding and grounding.

[CNCFlavor]

I hope this isn't too stupid of a question. But, how do I turn of the "touch-off"? lol

[LeeWay]

No stupid questions on this forum. At least not that one.
What is running the table. Mach 3?


Oh and he said Torch, not touch.
My torch has a floating head, so it does touch off.

Just do not turn the plasma cutter on and run the code.

[CNCFlavor]

Ahhh I see. I will try that.

[Torchhead]

The cheap Chinese drivers are more susceptible to noise and are notorious for overheating on longer runs. You can turn off touch offs by either editing them out of the G-code or using a POST that does nto have touch offs, but then you won't be able to cut anything but thicker, flat metal.