[FoxCNC1]

Hi guys, I have NEVER surfaced my spoil board. I used to cut MDF for the most part and some very thin acrylic,
Recently I started experimenting with HDPE / Starboard with some thickness to it. On profile cuts that I use to separate the part I seem to be getting some tool marks and "poor" finishes.

I noticed my spoil board is 0.04 or so higher towards the front than the back. This is consisten wit the markings. They are more preeminent when cutting left to right or parallel to the front edge.
My question is, will such slight variation in height / slope can cause markings?

here is a photo or some parts cut.

Thank you.

[Routerfiend]

Hi
Yes it is possible that an uneven spoil board could be the cause but looking at the pieces you have cut it looks like chatter to me. Plus possibly cutting deep can show up spindle deviation. I.E. not being perpendicular to the table/job. Are you getting rid of the chips effectively ? Chopping chips can ( if it doesn`t melt ) cause cutter deflection and chatter especially if you also have alot of cutter stick out.
Then there is work holding. If the stock material moves then that can also cause the effect you are seeing.