Plastic molds are relatively expensive, so their durability is more concerned. In particular, plastic mold is difficult to machine because of its complex structure, so the cost is relatively high. Therefore, increasing the service life of the mold is a major issue. The mirrors and etched surfaces are particularly prone to wear, which is very upsetting. For example, if there are fibers in plastics, the hardness of which can easily wear the mold surface, or the lubrication performance need to be improved when demoulding. PVD coating can greatly improve these problems in the production process because of its unique lubricity and high hardness. But the specific methods are also based on the use and characteristics of the mold.
1. Beryllium Copper Mold or Insert
The heat-dissipation hardness of the beryllium copper is up to 40HRC, which is unmatched by ordinary copper alloys. Fast heat dissipation (3 times faster than alloy steel) means shorter production cycles and higher yields. Beryllium copper is 5 times more expensive than normal plastic steel, so the cost for any wear, scrap, or coping is very high. As the hardness of it can not exceed 40HRC, so the surface wear is a serious problem for it.
2. Precision Molds or Inserts
Today, the Trendy consumer products such as digital camera, laptops, mobile phones or PDA products have special features, but their appearance is in the direction of petite and exquisite. Therefore, the requirements for precision and material selection of such products have greatly improved. In terms of material selection, PC+ABS+ glass fiber materials are generally adopted because of the high protection performance of the shell and the high internal strength. But it is very abrasive or corrosive to the molds, which cause the quick wear of the mold. Besides, the price for maintaining the precision mold is also quite high.
3. Nylon Molds or Mass Production Molds
PET bottles are typical mass-produced products. In the case of high-speed production of molds, the requirements for the surface are particularly high, such as high surface hardness, good mold release ability, good ability to polish to the mirror and so on. In general, European and American manufacturers use PVD coating treatment to enhance the hardness of the mold surface and improve the lubricating mold release capability. PVD coating has high hardness and lubricating properties which can shorten the production cycle and increase the output. On the other hand, automobile manufacturers need to continuously reduce the total weight of vehicles without affecting safety and quality, so as to achieve the purpose of fuel economy. With high strength and light weight, the engineering plastics are good materials for auto parts.