Cutting plywood on CNC

When using the wood CNC to cut through plywood with a finished side and unfinished side should the finished side be facing down, up, or does it really matter?


There are multiple answers to this question.
Straight or down spiral bits you should leave the face up, but a down spiral bit may have a more difficult time with chip clearance.
with an up spiral bit you may have blow out when the bit penetrates the bottom of the wood. This can be handled in two ways. One, have a very clean spoil board and your workpiece dead flat to it, or use lead in cuts which can be a programming challenge.
Chances are you’ll get decent cuts with a sharp bit and the appropriate spindle and travel speeds.
If it’s a crucial cut on one side I’d go with whichever spiral bit and method feels most comfortable to you, or I would do test cuts… and SHARP bits!!!
Best of luck


Thanks for the advice and quick response.

My pleasure. Hope that wasn’t too much to wade though!