Machining Metal Laminate on the CNC

Advise on choosing bits and setting toolpaths to achieve clean cuts in metal laminates. March 3, 2010

We landed a job that uses some metal laminate. We currently run our laminate on the CNC to give us accurate sizes and less waste. Has anyone ever used a CNC to cut metal laminate? Can it be done and how?

Forum Responses
(CNC Forum)
From contributor G:
We have had our customers use a 3+3 compression. It doesn't give you 70+ panels prior to service, but the samples we received show a great edge.

From contributor S:
We do laminate work every day of our lives, so we use the CNC to make templates about 1/4 larger than the finished piece. We just use laminate trimmers to cut the laminate, using the solid carbide cutters. They work fine on the metal laminates also.

From contributor B:
I've used our CNC quite a bit on metal laminates. First note - there is some metal laminate that is actually a thin stainless steel. This stuff is almost impossible to do anything with on a CNC (try a variable speed hand router at lowest speed if you have to deal with this).

For aluminum based metal laminates I've found the material to machine pretty much the same as regular laminates. For small detailed pieces you may want to lay it up first on 1/4 sheet and cut into it (I have a flat bed router) with a 1/4 downshear spiral (16K rpm at 400ipm). For larger pieces if you can get a good vacuum you can just lay the sheet on the table.

I had a project where I was using chemmetal with an engraved wave pattern in it. I had to make a series of connecting nodes (looked sort of like a rope with regular big knots in it) and the wave had to run consistently through the pattern. It was a pain but I was able to position the sheets exactly so the waves would all match up where the sheets joined. It took a lot of time and looked great (it was for a long desk front). Strangely enough, the project owners decided they didn't like the overall look (not a quality issue, just a bit busy) and had us laminate over it with wood grained plam.

From contributor H:
I like to make a tool path about 1/16" of an inch from the finished cut .and then move in to cut the finished cut. This approach keeps the heat down which seems to be the cause of the metal curling along the tool path (at least for me). By doing it this way I can use a 1/4" two-fluted down sheer solid carbide bit at 18000 rpm and 475 inch per minute working speed. Even if the metal is pressed up on 3/4" core I cut the metal first and then the core. This approach is time consuming but effective.

From contributor J:
I use to cut the metal only first then cut the core. Then I tried routing the entire board at once with a 2-flute downshear carbide (or upshear depending on your good face) 18,000 - 360ipm and it cut fine. You may have to adjust.