The process of rubber moldings has helped shape the way that we use rubber in today’s world. Rubber molding consists of shaping rubber into the desired shape. Sometimes the rubber is mixed with other materials to make the rubber more flexible, tougher, or resistant to UV rays and cracking. In general, there are three main types of rubber moldings that help create the rubber products used today.
These processes include: compression molding, injection molding, and transfer rubber molding.
Compression Molding: Compression molding is the simplest form of rubber molding. In this process, a sheet of rubber is placed inside a mold. The two halves of the mold are pressed into the sheet, forcing the sheet of rubber to take on the shape of the mold. This is one of the oldest forms of rubber molding, and it is also the crudest form of molding. Only the simplest shapes can work with this form of molding, and it often produces rubber pieces with errors in the final shape.
Injection Molding: Injection molding is the most precise way to shape rubber. In this process, the rubber is heated until it has a toothpaste-like consistency. The rubber is then injected into a mold and allowed to harden. Rubber pieces created this way are strong, unlikely to loose their shape, and retain the exact shape of the mold with few inconsistencies.
Transfer Molding: Transfer molding is somewhat of a mix between compression and injection molding. In this process, a large slug of rubber is placed into a pot. A machine forces the slug into the mold, which causes the rubber to take on the shape of the mold. Rubber pieces made this way have higher quality than compression pieces, but less than injection pieces.