Advantages
Overmolding combines a substrate and a second material in one component. It can add grip, cushioning or a sealing feature while reducing separate part assembly.
Overmolding
Review the base component, molded layer and intended grip, cushioning or sealing function with Aria.
Design the join around the way the part will be used
A soft layer needs to do more than look attached. Aria’s engineering review considers the selected material pair, joint geometry and the function of the finished component. For a grip, that means the surfaces a user touches; for a seal, it means the mating interface and the test you need the component to pass.
We discuss the mold and manufacturing approach with the part requirements, including exposed edges and retention features. Material names alone do not establish a suitable bond, so the selected grades and the agreed sample checks matter more than a broad promise that any two materials can be combined.
Capabilities
Multi-shot / two-shot (2K) molding
Two or more injection stages combine materials or colors in one component. Two-shot (2K) molding is a two-stage route. Material bonding, tool design and handling must be reviewed together.
Elastomer over plastic
A compatible elastomer can add a soft contact surface to a rigid plastic substrate. Select the grade for the substrate and review exposed edges where peeling could begin.
Plastic over plastic
Two plastics can combine color, feel or function within one component. Compatibility and molding temperature must suit the substrate; geometry may also provide mechanical retention.
Elastomer over metal
An elastomer layer can provide grip or cushioning around a metal component. Surface preparation and retention geometry require review for the selected metal and elastomer.
Plastic over metal
A rigid plastic can be molded around metal features to combine insulation, shape or assembly functions. Define the exposed metal areas and the method of retaining the plastic.
Planning your overmolding order
- Material combinations
Plastic over plastic, elastomer over plastic, plastic over metal and elastomer over metal; two-shot / 2K tooling. Material pairing requires review.
Advantages and considerations
Applications
Grips, cushioning and sealing features
Overmolding adds a second material to a rigid component for grip, cushioning or a sealing feature. The material pairing and the shape of the joint determine how the layers stay together.
Manufacturing process
01
Prepare the base component
Make the rigid component that will support the molded layer. Its dimensions, material and surface condition must suit the agreed material pairing.
02
Prepare the overmold tool
The tool defines the added layer and holds the base component in position. Review layer thickness, exposed edges and the surfaces that must remain uncovered.
03
Mold the added layer
Place the base component in the tool and inject the selected material around it to form the required grip, cushion or other feature.
04
Cool and release the part
Allow the molded layer to cool, then remove the combined component from the tool.
Design considerations
Adhesion and retention
Bonding depends on the exact grades and surface preparation. Review interlocks and exposed edges, then evaluate adhesion on representative samples.
Compression behavior
For compressed elastomer features, consider recovery after loading as well as initial softness. Define the working gap and the test conditions for a seal or cushion.
Flexibility in the part
Material stiffness and section geometry both influence bending. Evaluate the assembled part where the design must flex or provide a soft contact surface.
Grip and surface texture
Grip depends on the material pair and surface condition, including wet or dry use. Evaluate texture and material together for the intended handling conditions.
Hardness and feel
Hardness describes resistance to indentation. Contact geometry and layer thickness also affect how a grip feels in use.
Overmold thickness
Layer thickness affects feel, flow and cooling. Review transitions and the support offered by the substrate, especially around thin edges.
Tensile performance
Use grade-specific tensile strength and elongation data when selecting the molded layer. Validate the component under the loading and environmental conditions of the application.
Frequently asked questions
Overmolding VS Insert Molding, What is difference?+
The primary difference between them is that, in overmolding, the plastic material is injected directly onto a molded part or assembly; in insert molding, the plastic is first injected into a cavity and then the finished piece is inserted into another injection-molded part.
What is plastic overmolding?+
Overmolding is a process where two or more different materials are molded together to create a single product. In the case of plastic overmolding, one of the materials is typically a plastic. The other material can be another plastic, metal, rubber, or even glass.
Why choose overmolding for your project?+
Overmolding can reduce production costs. While standard injection molding can combine multiple parts into a single multi-cavity mold, secondary molding can produce individual parts made of different materials without assembly. Mold production is more complex, but it eliminates the repetitive cost of assembling thousands of parts. Get Your Free Quote About Overmolding parts Today. Get Overmolding Quotes Online All information and uploads are secure and confidential.
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