Abstract
Rubber moulds used in the injection moulding process in Thai rubber product industry are usually manufactured by the mould makers who often use skilled and experienced workers with trial-and-error method including conventional tools/ machines in mould design and manufacturing processes. As a result, various defects of the rubber products such as excessive flash and air trap are occurred. This leads to several mould try-outs and loss of raw material used in the process. Therefore, this research aims to apply the Computer Aided Design/ Engineering (CAD/CAE) techniques for optimized injection conditions. The significant input variables include material properties of the natural rubber (NR40) like heat conductivity, viscosity and shear rate, curing time and operating conditions like mould temperature, injection pressure, injection time including the gating and runner positions. The numerical results are also correlated well with the empirical data using the rubber injection machine. This research provides rubber researchers the tools to seek the best operating conditions in rubber injection moulding.
