POM (Polyacetal) is a thermoplastic with high crystallinity. Both homopolymers and copolymers versions are available for this engineering plastic. Homopolymers have higher impact strength at room temperature, higher stiffness and tensile strength. However, Copolymers perform better in terms of dimensional stability and resistance to chemicals.
Celanese, RTP Compay, and Sabic are the suppliers offering the broader portfolio.
Reasons to Use Polyacetals:
You will generally select this plastic when you have a need for high strength, hardness, excellent wear resistance, opacity and good chemical, fuel, heat and environmental resistance.
This plastic has however poor resistance to acids/alkalies, limited processing temperature range, poor resistance to UV radiation and is difficult to bond…
Typical POM applications:
POM is used in parts that require precision. Typical applications include automotive (fuel-system and seat-belt components…), consumer items (yoyos, electronic cigarettes, watch bracelets, zippers, insulin pens…), industrial (pump impellers, conveyor plates, gears…), plumbing (sprinklers, water meters, and pumps…), etc.
Polyacetals parts can be produced via injection molding, extrusion, compression molding, rotational casting or blow molding.
Acetal has found some in-roads into 3D printing in some applications like fan blade, impeller… Its high lubricity surface (with 3-5% on average and as high as 7-10%) makes it interesting for 3D printing specially for difficult to release parts. Also, acetal polymers have high strength which assures dimensional stability up to a maximum continuous service temperature of 80°C (180°F).
Other Names for POM:
Polyoxymethylene, Acetal, Polyformaldehyde, Polymethylene glycol, Polyoxymethylene glycol
Talking about commercial products, you may come across the following brand names: Celcon, Delrin, Duracon…