Overmolding and Insert Molding
At MJM Industries, we provide overmolding and insert molding services to produce durable, consistent, and reliable molded components. Our in-house engineering team will work closely with you to design and build insert molded and overmolded parts for cable assemblies, connectors, and other critical applications. With U.S.-based production and responsive support, we help you move from concept to production with clarity and confidence.
Insert Molding vs Overmolding: Understanding the Differences
Both insert molding and overmolding create durable multi-material parts, but each process serves a different purpose. Understanding the differences between these two molding processes can help you determine which approach best meets your application’s performance, material, and design requirements.
Insert Molding
Insert molding uses a single shot of molten plastic that flows around a pre-placed insert made from materials such as steel, copper, or brass. Common inserts include pins, blades, threaded inserts, sleeves, bushings, and contact elements within a connector or housing. As the material cools, the insert and plastic form a strong, unified part that maintains consistent quality and eliminates many secondary assembly steps. Insert molding is particularly useful for applications that require secure integration of metal components within plastic housings or connectors.
Overmolding
Overmolding is a two-stage process. A rigid substrate is molded first, then a second material is applied over or around it to add protection, flexibility or visual features. The overmolding process supports parts that require strain relief, shock absorption, ingress protection, improved grip or added color and branding. For cable assemblies and connectors, overmolding can provide additional protection at critical connection points, helping improve durability and long-term performance.
Comparison Table
While both processes provide component functionality and reliability, the appropriate method depends on the materials, design requirements, and intended application.
| Insert Molding | Overmolding | |
|---|---|---|
| Process | Single shot of plastic that flows around insert | Two-shot process with a substrate and outer layer |
| Speed | Faster | Longer due to two-shot process |
| Cost | More cost-effective for prototypes and small runs | Higher cost due to two tools and two-step cycle |
| When to Use | Encapsulating inserts, creating rigid structures, and eliminating secondary assembly | Adding soft outer layers, strain relief, shock absorption, color, or grip features |
Overmolding and Insert Molding Applications
Our overmolding and insert molding services support a wide range of applications requiring durable, reliable molded components, including:
- Connector housings and custom backshells
- Molded strain reliefs for cable assemblies
- Grommets and cable exits
- Sensor housings
- Insert-molded pins and contact structures
- Sealed electronics, PCB modules, and small devices
- Multi-material parts that need both structure and protection
Our insert molding and overmolding services help ensure long-term reliability in industrial automation, transportation, medical equipment, and other challenging environments.
Why Choose MJM Industries for Overmolding and Insert Molding?
With U.S.-based molding and manufacturing, we act as an extension of your team, supporting every stage of your project. Our integrated manufacturing capabilities allow us to support custom overmolding and insert molding projects from initial design through production.
You can count on us for:
- Responsive engineering collaboration
- Flexible support for prototype and production volumes
- Consistent, repeatable quality and testing
- Integrated capabilities that combine molding with cable assembly,
potting, electromechanical assembly, and more
By combining molding expertise with our broader manufacturing capabilities, we help simplify production and deliver components designed to meet your application’s requirements.
Get Started With Our Overmolding and Insert Molding Services
MJM Industries is here to fulfill your insert molding or overmolding requirements. Whether you need custom molded components, connector housings, or overmolded cable assemblies, our engineering team can help you develop a solution tailored to your application.
Contact us to begin collaborating with our engineering team on your next custom overmolded cable assemblies. overmolding and insert molding project.
