Custom Molding


National Rubber specializes in the molding of a wide range of elastomers from organic rubber and engineered synthetic compounds to silicone using a variety of efficient manufacturing processes including compression, transfer, injection, and insert molding for custom products that conform to your design requirements.

Compression molding is the most fundamental method of molding, also very cost-effective and widely used. It involves compressing pre-heated rubber into a mold cavity and holding it until cured. Benefits of compression molding include:

  • Produces more complex parts

  • Low tooling costs

  • Good for high durometer parts

  • Rapid production

  • Fewer knit lines

Transfer molding also utilizes a press and a mold. However, the process involves forcing the material through small holes into the mold cavity. Benefits of transfer molding include:

  • Used for more detailed designs

  • High production rates

  • Short production cycle

  • Reduction in product finishing time

Injection molding is the cost-effective method and is best suited for higher volumes. The process involves feeding the material into a press, where it is cooled or heated as per material compound and injected into the mold. Benefits of injection molding include:

  • Consistency

  • Highest rate of production

  • Parts have little or no flash

We can produce:

  • Boots and Bellows

  • Bushing

  • Diaphragms

  • Grommets

  • Lip Seals

  • O-rings and Gaskets

  • Oil Seals

  • Rubber to Metal Bonded Components

  • Rubber Sheets

  • Valve Stem Seals

...and more

If you already have a design for your custom molded part, we can produce them for you. Or if you need assistance with your design, our staff can design most any part to your specifications.