Burn spots on backside of cuts

[Dfross (David Ross)]

It seems like I saw the cause of this effect somewhere, but can’t find with the search terms I’m using.

Anyway, my machine is an OMTech 55w w/Ruida controller.

I ran some test cuts on 1/4" baltic birch plywood and have regular burn “spots” on the backside of the workpiece (see attached).

Is this

• A result of reflection from the honeycomb that could be resolved with underside supports?
  or
• A software setting that can be adjusted?
  or
• Other?

Thanks folks.

[fred_dot_u (fred ungewitter)]

If your work piece is flat on a honeycomb bed, you are on the mark about the marks. Even a half dozen millimeters separation will get rid of the flash back damage.

[Dfross (David Ross)]

Thanks, confirms my guess. Thanks for the response!