Rubber to Metal Bonding

After deciding on the proper elastomer material, manufacturers prepare the surface of the metal substrate. First, the surface needs to be thoroughly cleaned with a degreasing solvent and stored away from moisture. If the parts need to be handled manually, technicians should wear gloves or use a cloth so the parts are maintained in pristine condition.

Vulcanization bonding is the most common choice for creating a strong metal to rubber bond. This involves applying a specialty primer and cement bonding agent to a cleaned and prepped metal surface. We then place unvulcanized rubber onto the adhesive-covered metal surface, applying heat and pressure to chemically alter the rubber and create a strong bond.

After the adhesive application, the molding stage should take place as soon as possible.

A common molding technique is rubber compression molding, which is a closed mold process that produces low to medium volumes of rubber to metal bonded components. Compression molding involves positioning an uncured rubber preform or profile into a heated mold, which applies high clamping pressure to fill the cavities with the rubber material. The rubber takes the shape of the mold and is cured into a finished molded component. Once the part finishes curing, technicians cut off excess material and set aside the bonded parts.

After molding, the parts are tested to ensure the bond, tensile strength, and other properties meet customer specifications. Manufacturers also test the components according to the standards established in ASTM D429. Common performance modes to test include 1) the strength of the rubber and adhesive bond, 2) the strength between the primer and adhesive layer, and 3) the strength between the adhesive and the metal.

There are many variables throughout this five-step process that can impact the final results. For example, using the right glues and adhesives can ensure durable bonds in the intended application.