Cutting foamcore

[jf_allie]

Hey guys,

What would be a good bit and appropriate speeds for cutting foamcore?

JF

[matt_r]

I would like to bring this back up again. I was cutting some foamcore last night for the first time ever on my bot. Just some basic circles. I tried a down spiral bit at 21K rpm. It did OK, but the bottom paper edges were terrible. Slowing down the router to 15K rpm, seemed to help a little. I switched to a shear single blade bit. The rough edges on the bottom were less, but they increased on the top edge. I believe I was cutting at 1.7 in/sec. Just curious what anybody else has done and had success with. Again, this is 1/4" thick foamcore.
Also, the spiral bit was one that had some hours on it, but the shear bit was brand new.

Thanks,

Matt