Steam type high fineness and no-weldlines injection moulding process for complex precise plastic product

Abstract

The invention discloses a steam type high fineness and no-weldlines injection moulding process for a complex precise plastic product. The process comprises the following steps: (1) material selection; (2) backheating treatment; (4) mold preheating; (5) die assembly and quick heating; (6) speed-regulating and pressure-regulating injection in stages; (7) quick cooling; and (8) mold opening to take piece. According to the process disclosed by the invention, corresponding backheating treatment is performed on a material body, so that the internal stress problem of the material body is solved; then, an injection mold is of a design of a hot runner and a cold runner multipoint feeding subsurface gate, and meanwhile, the travel times of the corresponding hot runner and cold runner are added for a key portion of a product, so that the problems that a plastic melt is slow to flow at a far end to generate sink marks and the internal stress exists and the like are solved, and therefore, the appearance quality and the forming percent of pass of the product are extremely improved, the process cost and the like are reduced, and the actual using demand is met.

Description

technical field [0001] The invention relates to a steam-type high-gloss traceless injection molding process for complex precision plastic products, and belongs to the technical field of plastic injection molding and processing technology. Background technique [0002] With the continuous development of science and technology and the continuous improvement of people's material living standards, the quality requirements of injection molded parts with complex shapes are getting higher and higher in the communication, automobile, medical device and other home appliance industries, such as the smoothness and precision of products. In order to improve the surface quality of injection molded products, a spraying process is usually used in the prior art. Spraying is the most basic, broadest and most effective method used in surface protection. Spraying can ensure that the surface of the TV casing has anti-corrosion function and bright appearance. The quality of spraying is directly...

AI Technical Summary

Problems solved by technology

However, while providing beautiful and durable products, the spraying process uses a large amount of volatile solvents, additives, paints and other dangerous chemicals, which pollute the environment. These chemicals are flammable and explosive. potential safety hazards, and these chemicals are likely to cause occupational diseases to operators, such as acute and chronic benzene poisoning

[0003] At present, the high-gloss traceless injection molding process has become a new focus of people. The high-gloss traceless injection molding is mainly realized by rapid cooling and rapid heating of the mold during the plastic injection molding process. The heating and cooling of the injection molding mold is achieved by It is carried out by setting hot and cold medium channels in the mold; for some products with simple structures in the past, their appearance quality requirements and performance requirements can be met, but for products with complex structures and high precision, it is difficult to obtain high-gloss seamless injection molding technology. Satisfactory quality effect

The reason is that the heating and cooling of the mold relies on water channels to rapidly heat and cool the cavity and core of the entire mold. For complex and precise products, the punching distance of the plastic in the mold is long, and the rate of cooling and solidification is not consistent. The speed is slow at the place where the wall has ribs, and the speed is fast at the thin wall. The uneven heating and cooling of each point of the plastic product in the mold cavity will cause internal stress of the plastic product and seriously affect the appearance quality of the product. These will cause the product Lower production efficiency, low molding pass rate, high process cost, affecting market delivery time and other adverse consequences

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