A cost-effective method for rapid manufacturing polymer rapid tools used for liquid silicone rubber injection molding

Liquid silicone rubber (LSR) parts have many excellent properties, such as good thermal stability, low toxicity, and self-lubrication. It is a cost-effective approach for the pilot run using polymer rapid tools. However, the cost of the commercially available materials for fabricating polymer rapid tools is inexpensive. In this study, a low-cost mixture comprising aluminum (Al) powder and epoxy resin for fabricating LSR injection mold inserts was developed. The tensile strength, hardness, compressive strength, impact strength, and heating rate of the test specimens fabricated by the mixture developed in this study were about 85%, 97%, 89%, 99%, and 82% of the specimens fabricated by commercially available materials. It was found that the developed materials are very practical and provide the greatest applications potential in the LSRIM industry under similarity in mechanical properties, physical property, and mold longevity with commercial materials without consideration of the labor costs. The Al powder and epoxy resin mixed weight ratio of 65:35 is the optimum mixing ratio for manufacturing LSR molding injection mold. The production costs of a LSR injection mold insert fabricated the material developed in this study was only about one-eighth compared with those fabricated from commercially available materials. After 200 molding cycles, the increases in surface roughness of an LSR injection mold fabricated by mixture developed in this study are very similar to those fabricated from commercially available materials.