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How to extend the service life of the mold?

Update:02-06-2022
Summary:

By using PVD coating, the problem of mold stickiness is […]

By using PVD coating, the problem of mold stickiness is solved. Originally, the mold was cleaned once every 2 hours, and once every 2 days after using the CrNC coating; after using the improved NF1 coating, the machine was shut down and cleaned once every 5 days. This not only solves the problem of difficult mold ejection, but also reduces downtime and mold saving time, and improves the quality and stability of the finished product. The service life of the mold is greatly increased, and the production efficiency is significantly improved.
PVD is physical vapor deposition method, and PVD coating is a surface coating manufactured by physical vapor deposition method. Due to the high requirements of plastic molds, the durability of plastic molds has attracted more attention. For example, there are fibers in the plastic produced, which are easy to wear the mold surface, or the performance of lubrication needs to be improved during demolding. PVD coating has unique lubricity and ultra-high hardness, which can greatly improve the above problems encountered in the production process.
Beryllium copper is characterized by fast heat dissipation, and its hardness can generally reach Rockwell hardness 40. Fast heat dissipation (3 times faster than steel) means that the injection molding production cycle can be shortened and the output can be higher. Beryllium copper is expensive, more expensive than general plastic steel, so any wear, scrap or regrind is costly. Since the hardness cannot exceed 40 on the Rockwell hardness, surface wear is a serious problem encountered. Considering the hardness and the characteristics of beryllium copper, the coating company specially designed a complete PVD coating scheme TiN-BeCu for beryllium copper molds or inserts, which improves the wear resistance of beryllium copper surface without reducing its thermal conductivity. high sexual characteristics.
In terms of material selection, PC+ABS+glass fiber materials are generally used based on the high protection performance of the shell and the high internal strength. The material is highly abrasive and corrosive to molds. In addition, plastic molds are generally tempered at low temperatures, so all PVD coatings treated at high temperatures are not suitable. In this case, CrNC is the best choice. CrNC has strong chemical corrosion resistance, and its hardness is not lower than HV2000, which is enough to meet the hardness required by plastic production, and is the best choice for plastic molds. At the same time, precision mold inserts are characterized by small errors and many deep grooves. It is not easy to achieve no deformation and balance of coatings. The production conditions of die-casting molds are the most severe. The high-temperature metal solution is injected under high pressure, and the surface of the mold is constantly thermally expanded and contracted, resulting in a very short service life of the die-casting mold. During production, it is necessary to constantly repair the mold, maintain. PVD TiAlN-F3 coating can solve the problems encountered by some die-casting molds, but the effect of prolonging its life is relatively worse than that of tools. Coating companies have developed a new technology for PVD coating pretreatment in response to this problem, and have achieved certain results in improving liquid metal mold sticking and thermal cracking.

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