Compression Molding is one of the simplest and least expensive ways to produce molded rubber parts. While it is not typically recommended for complex parts requiring tight tolerances or flawless finishes, it is very cost effective method for manufacturing lower volume items.
Typically the preheated rubber is placed into an open heated mold cavity. The mold is closed and pressure is applied forcing the material to thoroughly cover the mold cavity. Constant heat and pressure are maintained until the material cures.Transfer molding is very similar to compression molding except that the material is pushed or "transferred" into the cavity by a piston instead of being directly placed into the mold. The added control in this process allows it to produce more complex parts with tighter tolerances and more consistent surface appearance. On the downside, the tooling is typically more expensive and it tends to operate at slower speeds than compression or injection molding.
Both compression and transfer molding processes require the measuring of the material being placed in the mold. This is not the case with the dip molding and injection molding processes.
The injection molding process for rubber is nearly identical to our process described in our website with one main difference. The heat is typically higher and the curing time longer when using rubber materials.
Materials - Commonly molded rubber materials include Silicone, EPDM, Nitrile (NBR), Neoprene®, Hypalon®, SBR, Viton®, and Natural Rubber. Please refer to our materials chart or consult your sales engineer for determining the best material to use in your application.
These materials are particularly effective in the finishing industry. Two features that make rubber outstanding for the masking process are:
Equipment – Machines vary between the different rubber molding processes. For example, when comparing compression and transfer molding, the compression operations require a unit of the equipment to apply pressure whereas the transfer molding process does not. Size of the end product can be factored in to the type of machines needed. Measuring instruments also factor in to the equipment features.
Our Specialty – We produce components capable of withstanding temperatures up to 600° F (316° C).Benefits of Compression Molding