General Information on Rubber Molding

Metro Industries carries a number of standard molded rubber products (O-Rings, Grommets, etc.), and supplies a wide variety of custom molded rubber components.   Almost any rubber product can be molded, but it is only the best option for certain applications, depending largely on configuration and the overall volume of the requirement.

As opposed to sheet rubber and extruding, which are both inherently limited to two-dimensional shapes, rubber molding allows truly three-dimensional configurations to be made.   Molding can also reduce the amount of waste created by external web and internal cut-outs inherent in parts fabricated from sheet rubber.

However, molds are generally costly and many molding processes are also relatively labor intensive, which often makes this an unattractive choice when die-cutting, extrusion, or other processes are viable options.   For these reasons, Metro’s staff carefully considers all options before quoting a job, and we don’t hesitate to ask questions or offer suggestions based on our 35 years experience and our regard for our customers’ success.

Metro has innovated combinations of molding and die-cutting on some products, gaining the best of both worlds.  This has allowed us to reduce overall material waste plus incorporate limited three-dimensional features in a molded “blank”, while minimizing mold costs by using inexpensive steel rule dies to complete the fabrication process.  We have also found ways to incorporate typically molded features into die-cut parts using machining, stamping, and vulcanizing techniques.

The point is that Metro leaves no stone unturned to ensure that our customers get what they need, when they need it, and at the best price.   We won’t try to sell you an expensive mold if you don’t need it, but if your requirement is genuinely best suited to rubber molding, Metro can and will take good care of you.   We can even almost always adapt and use existing molds.

Molded Rubber Compounds

Most rubber compounds can be adapted to molding processes.  Compounds Metro typically deals with include the following:

• SBR
• Neoprene
• Buna-N/NBR/Nitrile
• Silicone & Fluoro-Silicone
• FKM
• TPR (Thermo-Plastic)
• Urethane
• Natural and Gum Rubber

Related Pages:

• O-Ring Catalog Complete line of Buna-n, Silicone, Viton, EPDM, more, includes Prices, Specifications, Sizes, Tolerances
• Rubber Grommets – Online Prices, Specifications, Discounts.
• Chemical Resistance of Common Elastomers
• Stock Sheet Rubber
• Die Cutting, Waterjet, Slitting, Other Custom Fabrication Services
• Rubber Washers – Online Catalog with Prices & Specs
• Rubber Flange Gaskets – Online Catalog with Prices on 1000’s standard styles

Resources, Links, Technical Information on Elastomers (rubber)

• Silastic High Consistency Silicone Rubber – Compounds & Bases – Dow Corning
• Standard-Gasket.com Technical Information Center
• Silastic Fluorosilicone Rubber – Compounds & Bases – Oil, Fuel, and Chemical Resistant Rubber – Dow Corning
• ITDG – Technical information service – Manufacturing technical briefs
• Rubber Fabrication – Rubber Product Types – Technical Articles – Dow Corning

“Viton” is a registered trademarks of E.I. Dupont, Inc.