Development of epoxy matrix composites for rapid tooling applications

Due to global competition and product mass customization, the manufacturing industry is now under more pressure than ever to look for and take advantage of processes that can provide flexibility and cost savings to cope with small batches and rapid product changes. Rapid prototyping technology has gained very good acceptance for the quick fabrication of prototypes with low cost irrespective of the complexity of the shape. However, it is cost prohibitive to make more than a handful of models and part materials are also limited. In an attempt to develop a rapid and economical method for making tools with low volume production, some particulate reinforced epoxy composites were investigated in this study. Metal, ceramic or mineral salt powders were used as the particle, respectively and epoxy for the matrix. The mechanical and thermal properties of the above composites in different ratios of fillers were tested to verify the suitability for injection molds and the improvement of material characteristics. By analysis and comparison, a suitable composite, 20% alumina powder filled epoxy composite, was found to work best. A benchmark was designed and built for checking the dimensional accuracy of the tool making process. Also a set of injection mold insert with core and cavity was fabricated using the developed composite material to demonstrate the injecting of thermoplastic parts.