Plastic parts processing: in order to eliminate the internal stress of plastic parts, plastic parts to improve the performance and improve the dimensional stability, injection molding of plastic parts in the mold or machine, according to the characteristics of plastic parts and use, often on the plastic after appropriate treatment, the main method is returned fire and wet processing.
  一.Annealing, annealing process is to make products in the heating liquid medium or hot air circulation oven temperature in standing for a period of time, and then slowly cooled to room temperature, thereby eliminating the internal stress of the plastic parts, improve the performance of plastic parts. The processing time depends on plastic varieties, heating medium temperature, the shape of products and molding conditions. All the plastics used in the molecular chain rigidity, the wall thickness is larger, with a metal insert, the use of a wide range of temperature, high dimension precision and high internal stress is not easy since the plastic dissipation are required for annealing treatment. However, for POM and chlorinated polyether plastic parts, although they have internal stress, but due to the molecular chain itself flexibility and low glass transition temperature, stress can slowly from the consumer, if the products are not strict requirements, without annealing treatment. The general annealing temperature should be controlled in temperature above 10-20 degrees, or lower than the plastic thermal deformation temperature of 10-20 degrees is appropriate. Annealing is: 1 the molecular chain forced freezing to relax, molecular chain solidified to random position, thus eliminating the internal stress of this part; 2 improve the crystallinity, stable crystal structure, thereby increasing the hardness and elastic modulus of crystalline plastic products, reduce elongation.
  二.The humidity treatment, conditioning treatment is the plastic parts just releasing into the water, to cut off the air, prevent oxidation of plastic parts, processing method to accelerate the speed of moisture absorption equilibrium. Its purpose is to make the plastic color, properties and size stability, prevent the use of plastic size change, product as soon as possible to reach equilibrium. Humidifying treatment is mainly used for highly hygroscopic polyamide plastics. Polyamide plastic parts in contact with air at high temperatures often discoloration. In addition, use or storage in air and easy to absorb water and expand, the need for long time to get the stable size. Therefore, if the product was stripped and placed in hot water treatment, not only can be isolated from the air to prevent oxidation annealing, also can accelerate the reach equilibrium. The amount of water can also play a similar role to the growth of polyamide plastic parts, so as to improve the flexibility and toughness, so that the impact strength and tensile strength are improved. Humidifying treatment time for polyamide plastic varieties, plastic parts shape, thickness and crystallinity.