Molded Rubber Parts

Molded rubber parts offer strength, durability, cost-effectiveness, and performance. Companies use several manufacturing methods to produce molded rubber parts, each with its own strengths and limitations:   

Compression Molding: Compression molding uses compression and heat to transform uncured rubber into parts. An appropriate amount of rubber is compressed and heated in a mold cavity, where it cures. The formed part is then removed from the molding machine. Among molding methods, compression molding has the least expensive tooling costs, the most straightforward prototyping methods and the quickest lead times. The process has complexity and tolerance limitations. 

Transfer Molding: Transfer molding uses a closed-mold process where uncured rubber is pushed through sprue holes into the cavities of the closed mold. Once the rubber cures, the mold opens and the finished part emerges. Ideal for the production of complicated low-volume products, transfer molding falls between compression and injection molding methods in terms of tooling costs. Characterized by comparatively rapid processing, curing, and trim/finishing times, transfer molding is not as suitable for larger-volume products as other methods.  

Injection Molding: Injection molding, like compression molding, uses high pressure and heat to force rubber into a mold. However, it differs from transfer and compression molding by heating its charge of material until it can be injected under high pressure into the mold cavity. In the process, the rubber undergoes the vulcanization process, which infuses it with increased rigidity and durability. Known for its ability to deliver highly precise, complex moldings, its optimal use involves high production volumes given its high capital costs.  

The materials used in molded rubber parts can differ depending on the specific application requirements. For example, neoprene works well in many general applications but it is sensitive to acids and other industrial chemicals. It has good stability and will retain its flexibility under a wide range of temperatures. Silicone’s characteristics make it ideal for food processing products and other “clean” applications like medical equipment. It remains stable at both high and low temperatures. EPDM is a synthetic rubber used in many applications. Known for its superior resistance to heat, ozone, steam, and weather, it is used as an electrical insulator. Products made of FKM have superior heat and low-temperature resistance, making them ideal for aerospace applications but are susceptible to some chemicals.  

Allow Philpott’s team of material specialists and engineers help you develop the best parts based on your application. Contact us to get started.