POM is available in two main types: homopolymer (POM-H) and copolymer (POM-C). The homopolymer offers slightly higher tensile strength, stiffness, and creep resistance, while the copolymer provides better chemical resistance and thermal stability. This material is highly crystalline, which gives it a distinctive combination of high strength, hardness, and excellent machinability. Unlike many plastics, POM can be easily cut, drilled, and milled with standard metalworking tools, making it a favorite for CNC machining prototypes and small-batch parts.
One of the most valuable characteristics of POM is its low coefficient of friction and self-lubricating nature. It resists wear exceptionally well, which is why it is frequently used to manufacture gears, bearings, bushings, and sliding mechanisms. By replacing metal parts with POM, engineers can reduce overall weight, eliminate the need for external lubrication, and reduce noise levels during operation.
However, processing POM requires strict attention to detail. It has a relatively high shrinkage rate (typically 1.8% to 2.5%), which means mold designers must account for this volumetric change to ensure precise tolerances. Furthermore, POM must not be overheated or exposed to strong acids during processing, as it can rapidly degrade and release formaldehyde gas. To achieve optimal results, precise control of melt temperature and mold temperature is essential.