Formulation and selection of HSG (high specific gravity) materials for mechanical properties processing, plateability, and performance criteria

The purpose of this study was to determine the suitability of high specific gravity (HSG) composites for metal replacement applications. The study investigated a number of different filled thermoplastics to determine which materials had properties most similar to that of a current die cast product. The polymers were required to have similar weight, strength, and impact properties as the metal being replaced and also had to be plateable. The materials were processed in traditional valve gated injection molds using standard molding conditions. Experimental results showed that a nylon 6 with tungsten fillers had mechanical properties similar to a zinc baseline and was also easily plated with good mechanical strength and durability. Tungsten-filled nylon 6 was found to be an acceptable replacement to the die cast zinc product used in this study. However, it would have been better to develop a product from the start with the unique properties of HSG materials in mind rather than a replacement material for an existing product.