Choosing the best cutting tools for the machining of acrylics is vastly different from choosing the best wood carving drill bits for a woodworking project, because machinists must always consider the fact that plastic chips can easily re-weld to the material during the cutting process. There are many other factors that make the selections of plastic routers bits and drill bits different from the selection of wood carving drill bits, though. Tools with the right diameter can provide the right finish and the right configuration can provide an excellent finish without having to go back over the cut edge after the routing process.
Many cutting tools manufacturers have suggested that the best diameter to ensure a smooth finish for the acrylic routing process is 3/8 inch, although it is common to see diameters as small as 1/8 inch. Smaller plastic routers bits typically require a spiral configuration to yield the optimum edge finish, but larger diameters demand straight flutes to provide the desired finish. The best straight flute plastic routers bits for large diameters are typically low helix multi-fluted tools with some variations depending on the manufacturing method of the acrylic. The best straight flute bits for smaller diameters are typically single edged spiral O-flutes.
There are also many different custom router bits made especially for plastics, just as there are numerous custom tools for woodworking. Some of these plastic routers bits can be used to provide a radiused edge on parts, while others rout a finished edge and apply a top chamfer at the same time, while others create a smooth bottom surface during pocketing without the swirling effects of standard router bit points. Cutting tools such as these either solve problems that have been recurrent in the industry, or they allow fabricators to avoid tool changing problems.
When it comes to the machining of acrylics, one thing is certain – there is nothing more important than the selection of cutting tools.