Machine shops are relying on mechanical plastics more than ever, so cutting tools manufacturers have found it necessary to create more specialized lines of products to accommodate these materials. Plastic router bits and plastic drill bits have become more important than ever as more industrial companies realize the excellent performance they provide for gears, bearings, material-handling parts, and other machine components. Plastics have become the material of choice because of their low cost and reduction in vibration.
Companies that manufacture specialized cutting tools have had to become familiar with the most common plastics, which include Acetal, Delrin, Hydex, UHMW, nylon, polycarbonate, polyurethane, and polyethylene terephtalate. When it comes to plastic machining applications, these can all be described as soft plastics. The best plastic router bits for soft plastics are the O flute variety, which has the tendency to curl the chips that result from during the machine operation. O flutes come at the soft plastic materials with a high rake and low clearance geometry to actually carve the material with a refined finish.
The O flute cutting tools for soft plastics from Onsrud Cutter, which is the leading name in this industry, are made from micro grain solid carbide. They come in straight or spiral varieties, with the upcut, or right hand spiral, being the most common. This is due to the fact that these plastic router bits eliminate the chips upward, which is preferable for flat sheet and block plastic production. This avoids re-welding in the plastic machining process, where the chips being removed are welded back to the material at hand rather than being evacuated to another location. These cutting tools are available in either single or double edge cutting diameters; although the single edged tool is most common in the machine shops of today, save for the very large scale applications which require the single edged variety.
With machine shops relying so heavily on plastics these days, it is necessary for them to have the best tools to do the job.