Machining

Machining plastic parts is different from machining metal parts in several ways. Plastic parts are more prone to deformation, melting, and cracking due to the heat and stress generated by the cutting tools. Therefore, some design considerations are necessary to ensure the quality and accuracy of the machined plastic parts.

Design considerations for machining plastic parts:

• Choosing the right type of plastic material for the desired properties and machinability. Some plastics are easier to machine than others, such as acetal, nylon, and polycarbonate. Other plastics, such as polyethylene, polypropylene, and PVC, are more difficult to machine due to their low melting point and high ductility.
• Selecting the appropriate cutting tools for the plastic material and the geometry of the part. The cutting tools should have sharp edges, high rake angles, and large relief angles to reduce friction and heat. The cutting speed, feed rate, and depth of cut should also be optimized to avoid excessive heat and stress on the plastic part.
• Providing adequate cooling and lubrication during the machining process. Cooling and lubrication can help reduce the heat and friction generated by the cutting tools, prevent melting and deformation of the plastic part, and improve the surface finish and dimensional accuracy. Water-based coolants or compressed air are commonly used for cooling and lubrication of plastic parts.
• Designing the part with sufficient wall thickness, corner radius, and tolerance to avoid cracking, chipping, or warping of the plastic part. Thin walls, sharp corners, and tight tolerances can increase the stress and strain on the plastic part during machining, leading to defects and failures. A minimum wall thickness of 0.5 mm, a corner radius of 0.25 mm, and a tolerance of 0.1 mm are recommended for machined plastic parts.