Elastomer manufacturing moulding processesHow is it manufactured? A question we get asked in the seal design process, but perhaps not considered often enough. How a rubber seal is produced can affect a number of things; the cost, the material choice...even how a part should be designed. All of these can have a significant impact on the performance of the seal in application. Let's take a look at the three main manufacturing methods for moulding elastomer seals. Compression Moulding This is the most simple method of converting a piece of rubber into a finished seal product. First, the rubber compound is mixed and prepared. The material has a stiff and non-elastic consistency (like thick dough). From this dough we produce a rubber blank (also known as a pre-form) by either cutting, punching or extruding cord. These blanks are normally a little bigger than the finished part (normally based on weight) will be placed into a metal moulding tool. The tool (in its simple form) is in two halves with the final product shape cut into the metal. This is known as the mould cavity. Injection Moulding This manufacturing process is often used to produce plastic components, but for rubbers, the temperatures are switched. A warmed rubber is injected into a hot tool, as the force required to inject uncured rubber is much greater than what’s required to push molten plastic into a chilled mould. Otherwise the equipment and principles remain similar. Transfer Moulding This is a variation on compression moulding. It uses the same hydraulic compression presses, but this tooling is a little more sophisticated (and consequently a little more expensive). Comparing the three most common methods of producing an elastomer seal, it's clear that evaluating how the part is going to be made, is key to ensuring the technical and commercial success of the seal in the application. Read more about our engineering, design and innovation service HERE