The standard process for most rubber components on the market today, molding produces rubber parts by pressing a block of rubber into a metal cavity. The rubber inside of the cavity is then exposed to heat, activating a chemical reaction.
The three most common methods of molding are…
- Compression molding — The most basic form of molding, compression molding is exactly what it sounds like: pressing two sides of a mold together and forming rubber parts through it. Before compression molding begins, a “pre-form” in the basic shape of the final product are made. These pre-forms have extra rubber, ensuring that the cavity is filled entirely and there are no flaws in the end part.
- Rubber injection molding — This involves rapidly injecting an exact amount of rubber into a closed, heated mold. Pressure keeps the mold closed. There are some economic advantages to this type of molding, particularly a shorter molding cycle, lower unit cost, and little scrap or waste.
- Transfer molding — Transfer molding is a unique combination of compression and injection molding. A piece of uncured rubber is placed into a portion of the mold. Then, the mold is compressed and put under hydraulic pressure. When this happens, the rubber is forced through a small hole into the cavity. The mold is then held closed while the rubber cures.
RPM is capable of producing parts using all three methods. We can also produce low-cost prototypes, so you can test your parts before committing to a large order.