Injection Molded Rubber

Injection molding is the process of rapidly filling rubber into a mold's forming cavity through the use of very high forcing pressures. This is facilitated by heating and shearing the rubber compound in an injection head so it will flow much more readily. This process delivers the most rapid process cycles possible as well as excellent molding precision. Robinson Rubber Products can custom formulate rubber to meet your specifications, design and build the injection mold, and supply you with your custom injection molded rubber components in volumes from prototype through production. Call 1 (763) 535-6737 to speak to one of our qualified experts or fill out our Molded Rubber Component Design Specification Checklist.

Injection Process

1. The uncured rubber material (or "compound") is fed into the injection barrel in the form of a continuous strip or ribbon.

2. The uncured rubber is worked and warmed by an auger screw in the temperature-controlled barrel.

3. As the rubber accumulates in front of the auger screw, the auger screw is forced backwards. When the auger screw has moved back to a specified shot volume, the injection press is ready to "shoot" or inject the rubber into the mold cavities.

4. With the mold closed under massive hydraulic pressure, the auger screw is pushed forward like a plunger, forcing the rubber through the feed runners and into the mold cavities.

5. While the rubber cures in the heated mold, the auger screw turns again to refill the injection barrel for the next shot.