Mold wear

Because the pressures of injection are low at approximately 25 to 50 psi (172 to 345 kPa) very fragile inserts can be molded and mold wear is at a minimum. Some formulations for LIM also may be molded at temperatures as low as 200F (93C) which permit the encapsulation of some heat-sensitive electronic components that do not lend themselves to encapsulation at conventional transfer molding temperatures of 300F (149C) or higher. 

Because of the low melt viscosity of LCPs, thin sections can he molded with highly filled (70%) LCPs. The addition of hulk lubricants reduces the melt viscosity. Injection molded parts are produced with a minimum of molded-in stress, little or no flash, and high dimensional stability. Fast cycle times, reduced mold wear, elimination of secondary operations, and other processing and performance gains of LCPs often lead to lower overall finished part costs even below those of less-expensive resins. 

Melt leakage occurs, mold wear, higher injection pressure required, poor cycle repeatability, etc. 

AvaSpire AV-750 GF40- % Glass fiber, high melt flow for injection molding wear-resistant grades... 

Mold Wear. This is a distinct problem, especially in glass-fiber-reinforced thermoplastics. Compounders often claim that their proprietary coupling agents reduce mold wear, but molders remain rather skeptical. 

Poor surface finish poor dimoisicmal accuracy molds wear rapidly relatively expensive finishing materials must be mixed and used immediately... 

Because the laminate is not in contact with the mold, the temperature loss (in comparison to the stamp forming process) worsens, which means that the cooling or cycle times increase. The service life of the mold is increased in comparison to the stamp forming process because no fiber marks occur on the mold surface due to the protection of the diaphragms so mold wear is then significantly decreased. 

The use of a 0.5 mm layer of modified tungsten disulfide in injection molding tools for polymers allows faster demolding from the molds and reduces mold wear, in some cases reducing or eliminating the need for lubricants and release agents. ... 

Transfer molding is a variation of compression molding. Here, the material is melted in a separate transfer pot, from which it is squirted into the mold. This can give faster cycle times and since no solid material is pushed around in the mold cavity itself, damage to delicate inserts (e.g., metal electrical contacts molded into a part) is minimized, mold wear is reduced, and greater ease in filling intricate molds and more uniform cures are obtained. However material cured in the transfer pot and sprue is wasted. 

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