Am using Bobcad with the nesting program, in their program when you nest and do the profile it cuts all inside holes then cuts the outside profile. My question is how much plate warpage will there be in cutting 14ga. stainless? The parts have 8 holes 5/16"x1 1/4" and the part is 4 3/16"x10". Am going to have over 800 holes in the sheet before it wil cut the outside profile. Is this going to be an issue? Any help would be much appreciated.

Sorry I have never cut SST with plasma so I can’t say. I would not be a very happy camper if I could not change the sequence of the tool path to cut internal holes then outside profile part for part. I am able to sequence any way I want with the software I use even after I nest an entire sheet.

Greg
Home Page: http://www.ctcn.net/~3kings

“Eagles may soar but weasels don’t get sucked up in jet engines”

Sir,

In general, the cutting process should cut the holes inside a single piece part, then cut the perimeter, completing EACH piece. Then you go to the second piece and finish it. As you probably also know, the cutting is CCW inside and CW for the outside cuts.

We sold a machine to a Seattle customer who cut .090 SS; he solved the warping by just barely submerging the sheet under water. The airflow from the torch pushed the water aside in the immediate cut vicinity, but the water very effectively carried the heat away from the rest of the thin sheet.

Regards,
Jack C.

Cutting under water would be your best bet, also changing the cutting path with your nesting software would help. This would allow the plate to cool a bit.

SS warps worse than mild steel. The water trick really works. I don't think cutting each piece complete will help a lot. It just puts more heat into a smaller area in a given time. Your CAM software should let you sequence in any order you want. I clamp the edges of thin material to keep it from warping into a pretzel. Some material warps from heat and also from the changing stress relief from the cuts.

I have actually hand misted the material as the table cut to reduce the heat load and the resulting steam is impressive to the surrounding crew!!