Main features of high gloss and no trace die:
First, the mold forming temperature is higher. At higher mold temperature, injection molding can eliminate weld mark, flow mark, internal stress and other defects. Therefore, the mold needs to be heated when it is working. In order to prevent heat loss, the resin heat shield is usually added on the fixed mold side;
Second, the cavity surface is extremely bright (generally mirror 2 or higher). The products produced by high gloss mold can be directly used to assemble the whole machine without any surface treatment, so this process has high requirements for mold steel and plastic materials;
Thirdly, there are many hot nozzles in hot runner system (generally 6-8 nozzles, sometimes more). Each nozzle must be equipped with a sealing needle and an independent air passage, which can be controlled separately by solenoid valve and timing controller to realize time-sharing glue feeding, so as to achieve control and even eliminate weld marks.
High gloss traceless injection molding technology has some basic requirements for molds
The inner surface of the mould requires very high finish to ensure the surface quality of the products. The setting of pipes inside the mould must be reasonable to ensure rapid heating and cooling. The pipe inside the mold should have good thermal conductivity. Due to the need to keep heating and cooling in the production process, the mold needs to choose high-quality steel. In the process of use, we should pay special attention to the maintenance of the mold to ensure that it is dry and dust-free.
In addition, the performance and service life of high gloss traceless mold are directly related to the steel used in the mold. Due to different working conditions of plastic mold parts, the external influence is also different. Therefore, in addition to the basic requirements, the steel should also be emphasized. For example, large high gloss plastic mold cavity steel, in addition to the requirements of good cutting, EDM and welding performance, also need to have excellent throwing rotation and high hardness and other characteristics. This can not only form a bright and beautiful product, but also reduce the wear of plastic on the cavity surface, which not only extends the service life of the mold, but also reduces the injection pressure and protects the injection molding machine. At present, the high-performance and high gloss non marking die steels used in different processing conditions of flat-panel TV include polmax, lkm838h, lkm818h, s-star (a), NAK80, Stavax S136, Stavax s136h, Optimax, x13t6w (236), x13t6w (236h), etc.
Application in the field of home appliances
In recent years, the traditional CRT TV in the TV industry has been gradually eliminated, and replaced by the flat-panel TV with novel appearance, thin volume and high-grade visual sense. The surface quality of the front shell directly affects the grade of the flat-panel TV. However, the TV front shell produced by the traditional mold is difficult to eliminate the defects such as the surface weld mark and the surface finish is not enough, which can not achieve the beautiful effect. Therefore, it also needs to go through the secondary processing such as surface coating, which brings the problems such as the lengthening of the TV manufacturing cycle and the rising of the manufacturing cost.
High gloss traceless mold can solve the above problems of traditional mold. High gloss traceless mold technology has been rapidly applied in the home appliance industry since it was officially announced in the 2004 German rubber and plastic Exhibition: in 2005, Samsung of South Korea began to use high gloss mold technology to produce LCD TV shell, Chinese TV manufacturers also began to carry out the application research of this technology in 2006, and began to widely use it in the production of flat panel TV shell in 2008.
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