can delrin be injection molded

2025-04-16 10:49 Hejia Smart Technology

Can Polyoxymethylene (POM, Celcon, Delrin) Be Injection - Molded?

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can delrin be injection molded？

Polyoxymethylene, commonly known as Celcon, with the English trade name Delrin, is a high - performance thermoplastic engineering plastic. It can definitely be injection - molded and is widely used in numerous fields.

Polyoxymethylene has excellent comprehensive properties, which lay the foundation for its injection molding. It has relatively high strength and rigidity, with a tensile strength of 60 - 70MPa, close to that of metal materials, and can meet the requirements of many products with high structural strength. Meanwhile, polyoxymethylene has outstanding fatigue resistance and is not easily damaged under repeated stress. Its wear - resistance is good, and the friction coefficient is low, which has obvious advantages in the manufacture of some mechanical parts that require wear resistance. Moreover, polyoxymethylene also has good chemical stability and has a certain resistance to organic solvents, weak acids, and weak bases.

When performing injection molding of polyoxymethylene, there are some key points that need attention. In terms of raw materials, although the hygroscopicity of polyoxymethylene is smaller than that of materials like nylon, it still needs to be dried. Usually, a hot - air circulation dryer is used to dry at 80 - 90°C for 3 - 5 hours, and the moisture content should be controlled below 0.2%. Otherwise, moisture will cause defects such as bubbles and silver streaks in the product during the high - temperature injection - molding process, seriously affecting the appearance and performance.

The setting of injection - molding process parameters is very important. Regarding temperature, the barrel temperature is adjusted according to the type of polyoxymethylene and product requirements. Generally, the front - end temperature of the barrel is 190 - 210°C, the middle part is 200 - 220°C, the rear - end is 180 - 200°C, and the nozzle temperature is 180 - 200°C. If the temperature is too low, the fluidity of the polyoxymethylene melt is poor, making it difficult to fill the mold cavity, and short - shot phenomena are likely to occur. If the temperature is too high, polyoxymethylene may decompose, causing the product to change color and its performance to decline. The injection pressure is usually 80 - 130MPa. For products with complex shapes or thin walls, the pressure needs to be appropriately increased. The packing pressure is 40% - 60% of the injection pressure, and the packing time is 5 - 15 seconds. Reasonable packing can reduce product shrinkage and depression. The mold temperature is generally controlled at 80 - 120°C, which helps polyoxymethylene crystallize and improves the dimensional stability and surface quality of the product.

Mold design also affects the injection - molding effect of polyoxymethylene. Due to the relatively large shrinkage rate of polyoxymethylene, which is between 2% - 3.5%, the draft angle of the mold should be reasonably designed, generally 0.5° - 1.5°, to facilitate the smooth demolding of the product and prevent deformation during demolding. At the same time, the design of the gate and runner of the mold should consider the flow characteristics of the polyoxymethylene melt, minimize the flow resistance, and ensure that the melt fills the mold cavity evenly and quickly.

Polyoxymethylene is suitable for injection molding due to its own characteristics. As long as the raw - material drying, process parameters, and mold design are well - controlled during the molding process, high - quality polyoxymethylene products can be produced, which are widely used in industries such as electronics, automobiles, and machinery, such as gears in electronic devices, small parts in automobiles, and wear - resistant parts in machinery.