For over 35 years, RD Rubber Technology Corporation has been a trusted provider of precision-molded rubber parts. Our service offerings include rubber overmolding to create high-quality components for critical-to-function applications.
What Is Rubber Overmolding?
Also called metal insert molding, rubber overmolding is a process by which rubber is bonded and molded over a metal substrate. Overmolding rubber to metal involves a mechanical or chemical bonding technique or a combination of both techniques. The finished parts offer enhanced rigidity and a range of other benefits.
Rubber Overmolding Process
The specifics of the rubber overmolding process differ depending on the metal and elastomer used and the end product’s performance goals. However, there are three basic stages to the production process:
- Material preparation: The first stage in the metal insert overmolding process is to select the overmolding materials and prepare them for the bonding process. The metal substrate is thoroughly cleaned using a degreasing agent and then kept away from moisture.
- Substrate surface treatment: Next, a chemical bonding solution is applied to the metal’s surface at a controlled thickness. This can be either a one-step adhesive coating or a two-step primer and adhesive coating. RD Rubber’s chemical bonding solutions comply with ASTM D429 standards. The coating will then dry in a low-humidity, contamination-free environment.
- Overmolding production: After applying the adhesive, the rubber overmolding process can begin. The metal insert and an uncured rubber preform are positioned inside a heated mold that is clamped tightly to fill the cavities with rubber. The rubber bonds to the metal and is then cured into a finished overmolded component.
After the rubber has cured, technicians remove any excess material and then test the parts per the customer’s testing requirements.
Benefits of Rubber Overmolding
The rubber overmolding process delivers many benefits, including:
- Tight seals, including waterproof seals
- Decreased number of components needed for an assembly
- Maintains seal and assembly alignment
- Produces an extremely strong elastomer bond with the metal substrate, at times stronger than the rubber’s physical properties
- Improved durability that can extend a product’s lifespan
- Ideal for seals, gaskets, poppets, latches, and other components that experience force and movement
Applications of Rubber Overmolding
Bonding rubber to metal creates durable, high-performance components for demanding industries, including aerospace, defense, military, medical, food processing, and more. Some of the most common applications for rubber insert molding include:
- Overmolded gaskets
- Overmolded diaphragms
- Overmolded poppets
- Overmolded seals
- Overmolded latches
- Overmolded valves
Considerations for Rubber Overmolding
For any application, there are several factors that should be taken into account to ensure the finished components adhere to all performance requirements:
- Prototype, first article, and production quantities required to select the optimal production method.
- Material selection in consideration of the product’s application, environment, and performance requirements.
- Part design and its influence on how to effectively design the mold and manufacture the part.
Quality control and customized testing is performed to ensure all requirements are met.
Rubber Overmolding from RD Rubber Technology Corporation
At RD Rubber Technology Corp., we create custom-engineered, rubber products to meet our customer’s critical to function application requirements. If you have any questions, contact our team, or request a quote to get your project started.