just bought this app yesterday and was disappointed that there was no plastics info, moving from our manual to cnc shop with little guidance available and we, like many shops now, use as much plastic (pvc, abs, butrate, delrin, etc) as metal. Just manual milled a bunch of teflon last month it's soft and it gums up the flutes real bad. lots of clearing them and fingernails to keep buildup off of cutting edges... it will lube the cutter right over the surface. manually, i used reasonably fast speed and slightly conservative feeds. 3flutes and lots of air as the chips are not your friends. peels along edges leaving massive burrs. taps like butter and will rip threads up on way back out like butter, too.