Rubber Molding Capabilities
Compression molding is an efficient, low waste, cost effective molding method. It is best suited for all but the closest dimensional tolerances, medium volumes, and medium to large size parts. Compression molding tools are the least expensive of all methods. Any extra cost associated from longer cycle times may be offset with additional tooling cavities. Advantages of compression molding are low tooling cost, short set-up times, and the ability to process a wide range of elastomers, including higher durometer (hard) materials.
This type of process is the original production method for molding rubber. It is the compressing of an uncured rubber preform in a mold that’s under heat and pressure causing the rubber to flow and fill a mold cavity. Under heat and pressure, the rubber gains cross link density and cures out.
This production method is a simplified version of injection molding. A rubber preform is compressed in a transfer pot through sprue holes. The rubber flows through these many sprue holes into the mold/part cavity. Transfer molding is excellent for more complicated designs, close tolerances, and small to medium part sizes. Tooling tends to be more expensive than compression molds, but significantly less expensive than injection tools. Advantages of transfer molding are less reject, shorter cycle times, maintaining tight dimensions, excellent uniformity, and low cost.