What is the best kind of bit for machining thermoplastics like polyethylene, polycarbonate and PVC?
When machining thermoplastics, there can be a significant difference between cutting cast and extruded products. Cast materials which are usually a bit harder and have a higher melting point than their extruded counterparts, machine easier, with a cleaner edge and less deposition of melt on the cutting tool. In both cases, however, you need a VERY sharp tool designed specifically for cutting thermoplastics. Our M208 PreciseBIT family of cutters has proven to work very well in these materials if you use tool diameters 0.0625″ (1.59 mm) or greater. PVC presents an additional challenge in that it is much more abrasive than most of the other members of this family. Cutting both cast and extruded products will result in accelerated bit wear with an associated deterioration in the quality of machined edges and surfaces. The key to cutting all of these materials is to insure that you select a combination of RPM and feedrate that produces high enough chip loads. For example. If you are cutting