POM, polyoxymethylene, is a thermoplastic engineering plastic with excellent properties. Its characteristics, advantages and disadvantages are as follows:

 

POM is a crystalline thermoplastic plastic with a distinct melting point, approximately between 165 and 175℃. Its properties are close to metal, so it is sometimes called plastic steel. POM materials have characteristics of ultrasonic weldability, good dimensional stability, high rigidity, high molecular weight, high strength homopolymer, impact resistance, high creep resistance, fatigue resistance, good toughness and high viscosity.

Excellent mechanical properties: POM has excellent hardness, rigidity and wear resistance, making it excellent in manufacturing various mechanical parts. At the same time, its hardness can be adjusted according to application needs.
Good heat resistance: POM has a very high heat distortion temperature, which can reach more than 140℃, allowing it to maintain stable performance in high temperature environments.
Chemical corrosion resistance: POM has good corrosion resistance to most chemicals, including acids, alkalis, alcohols, esters, etc., so it is widely used in chemical industry.
Excellent electrical insulation properties: POM is an excellent electrical insulation material that can be used to manufacture electrical equipment and electronic components.
Easy to process: POM has a low melting point and good fluidity, and can be efficiently manufactured through injection molding, extrusion molding, etc.

Limited heat distortion temperature: Although POM has good heat resistance, its heat distortion temperature is still relatively low and may not be able to withstand use in extreme high temperature environments.
Sensitive to certain chemicals: POM may corrode certain chemicals, such as chromic acid, concentrated sulfuric acid, etc., so special attention is required when used in certain environments.
Processing difficulty: POM material has high hardness, which may make cutting, drilling and other processing operations relatively difficult.
Affected by ultraviolet rays: POM materials may discolor, age or even decompose due to influence of ultraviolet rays when exposed to sun for a long time, which limits their outdoor application to a certain extent.
Higher price: Compared with other general engineering plastics, price of POM materials is relatively high, which may limit its use in some large-scale applications.
During mold design process, based on characteristics of POM materials, special attention needs to be paid to following aspects to improve mold design, product quality and production efficiency:
Mold material selection: POM plastic has a high friction coefficient and abrasion during injection molding process. Therefore, mold material should be made of materials with high wear resistance and hardness, such as carbide or specially treated steel, to extend service life of mold.
Mold temperature control: POM plastic has a high melting temperature, mold needs to have a good cooling system to ensure that plastic is quickly cooled and shaped in mold to avoid deformation or internal stress. At the same time, heating system of mold should also be reasonably designed to ensure that POM plastic is fully melted during injection molding process and improve quality of injection molding.
Runner and gate design: Due to high viscosity characteristics of POM plastic, runner of mold should be designed to be wide and smooth enough to reduce resistance of plastic in runner and increase mold filling speed. Gate design should be reasonable, not only to ensure that plastic can enter mold cavity smoothly, but also to avoid generating too much waste.
Exhaust system design: POM plastics easily produce gas during injection molding process. Therefore, mold should design a reasonable exhaust system to discharge gas in cavity in a timely manner to avoid generation of bubbles or pores.
Mold accuracy and surface treatment: POM plastics have high requirements for mold accuracy, and mold processing should ensure high precision to reduce product size deviations. At the same time, mold surface should be polished to reduce adhesion of plastic on mold surface and improve product quality.
To sum up, based on characteristics of POM plastic, mold design needs to be improved from many aspects such as material selection, temperature control, runner and gate design, exhaust system design, mold accuracy and surface treatment, etc., to improve product quality and production efficiency.