Problem milling extruded polystyrene (Styrofoam) solutions requested.

Hi,

I can successfully profile cut through 120mm deep Kingspan insulation board using just a ground 8mm drill bit. By running the cnc really slowly and also keeping the spindle speed right down to 2000rpm.

I wanted to use the same process to cut through 120mm blue Floormate Styrofoam BUT it acts completely differently. I need a new approach as the drill is melting the foam and getting gummed up.Wrong speed? spindle going to fast and the drill bit running toohot?-wrong cutter?

Perhaps the Styrofoam green acts differently to the blue?

The reason i'm pursuing using the Styrofoam is to use to make masterforms for aluminium casting. I can pour the aluminium directly onto the styrene which is vapourized on contact with the alu. Kingspan hasa higher fire rating and wont dissolve in the same way.

Has anyone written an extensive list or seen a link to a list of polystyrene and foam plastics and how to router, carve into them andwith which mill ends and feeds and speeds?

Any help much appreciated