Rubber overmolding is a proven manufacturing method used to create durable, high-performance components by bonding rubber over a rigid insert or substrate. This technique allows manufacturers to combine the unique properties of rubber—such as sealing, thermal and shock absorption—with the strength of a metal or plastic core or substrate.
At RD Rubber, we provide custom rubber overmolding manufacturing solutions for critical-to-function applications. Our process involves molding thermoset elastomers over metal or thermoplastic substrates, supported by responsive communication and a commitment to engineering excellence. We are ISO 9001:2015, AS 9100:2016 certified, and Department of Defense (DOD) Joint Program certified, ITAR registered, and NIST 800-171 compliant, ensuring every part meets strict quality and regulatory standards.
Rubber Overmolding Process
Our rubber overmolding process is designed to deliver a strong, consistent bond between the rubber and its substrate. It typically follows three key stages:
- Material Preparation. We start by selecting the proper elastomer and preparing the substrate by thoroughly cleaning and drying it to eliminate any contaminants or moisture that might affect adhesion.
- Surface Treatment. A chemical bonding agent is applied to the cleaned substrate. This may involve a one-step adhesive or a two-step primer and adhesive system. All bonding agents meet ASTM D429 standards and are applied and dried in a controlled, contamination-free environment.
- Overmolding and Curing. The substrate and an uncured rubber preform are placed into a heated mold. As the mold closes, the rubber flows and bonds to the treated substrate. After curing, excess material is trimmed, and each part is inspected to ensure it meets all customer requirements.
Materials Used in Rubber Overmolding
We work with a wide range of thermoset elastomers selected for their performance and compatibility with your application’s demands. High-performance synthetic materials include:
- EPDM
- Nitrile
- Silicone
- Fluorosilicone
- Viton®
- Fluoroelastomer (FKM)
Each material offers unique benefits in terms of temperature resistance, chemical compatibility, durometer, compression set, and sealing performance.
RD Rubber manufactures rubber overmolded seals, gaskets, poppets, latches, and other critical components used in aerospace, defense, space, medical, and other critical to function industrial applications.
Rubber Overmolding Benefits
The rubber overmolding process offers advantages over alternative manufacturing and assembly methods:
- Watertight and chemical-resistant sealing
- Strong, reliable elastomer-to-substrate bonds
- Ability to create complex geometries
- Vibration damping and shock resistance
- Fewer assembly components
- Maintains seal and assembly alignment
These advantages help engineers simplify designs, reduce part failure, and meet demanding application requirements with confidence.
Rubber Overmolding Capabilities Offered by RD Rubber
RD Rubber offers comprehensive overmolding capabilities backed by decades of experience and a robust quality management system. Our services include:
- Process Engineering. We work with customers early in the design phase to ensure manufacturability and quality.
- Material Selection. We provide material qualification support, custom rubber compounding, and material testing and qualification.
- Full-Scale Production. We support every stage of production, from initial development and first articles to full production manufacturing.
Custom Rubber Overmolding Solutions at RD Rubber
Every project has its own set of requirements, which is why we offer tailored rubber overmolding solutions. From initial design through production, our team collaborates closely with customers to ensure critical specifications and performance goals are met. We offer full material lot traceability.
- Material qualification support
- Material compounding per customer design requirements
- Material testing adhesion and bonding
- Internal material testing capabilities to ASTM standards
- Hardness, tear, elongation, tensile strength, rheometer and compression set
- Customized application-specific testing
Contact RD Rubber Today for Your Next Rubber Overmolding Project
With deep expertise, engineered quality processes, and a customer-focused approach, we deliver innovative solutions for demanding applications.
Whether you’re developing a new part, refining an existing design, or scaling production, our team has the experience and capabilities to support your goals. Contact us or request a quote today to get started.
