We use our shopbot machines to cut mainly 2 types of plastic, HDPE and VHMW. We have three machines, an alpha, PRT, and PRS. The alpha seems to have no problem with either material, but the other two have a lot of chatter and broken bits. Both the PRT and PRS run at 2ips and use Porter Cable Routers. The PRT has a lot of chatter and leaves a rough cut. The PRS has been having issues with bits snapping in half right at the shank.

I was just curious to what others use on plastics of this variety. I can get the part numbers of the bits we have been using. We are looking for a bit that can cut both types of plastic to eliminate switching.

Thanks for any help.