Cutting plastics and PVC

When cutting plastics such as styrene and acrylic you must consider the effects of having a bit or a laser penetrating the material and marring surfaces. Cutting plastics requires some aspects that don’t apply to metals or wood. Many plastics including acrylic and plexiglass are brittle and will crack under stress. Therefore, clamping the stock material so that it cannot move will be important especially as loads are applied during cutting. Also important is the use of lower spindle speeds. High RPMs will heat up the surrounding material and cause the plastic to deform, which can add stress to it and ultimately result in cracks and breaks when least expected.

Cutting thicker stock material is much easier than thin. Thicker stock will hold its shape better and is less likely to get damaged by the bit. When I am cutting thin plastics (2 mm thick or less), I usually resort to the laser. By the same token, cutting softer plastics presents similar issues...