Thermoset Molding

For parts that require extreme durability, high heat resistance, and excellent dimensional stability, thermoset molding provides a robust manufacturing solution beyond the capabilities of thermoplastics.

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A high-quality part with a premium finish, representing the results of thermoset molding

Creating Strong, Irreversible Bonds

Unlike thermoplastics that can be re-melted, thermosets undergo an irreversible chemical curing process. This process creates strong cross-linked polymer chains, resulting in parts that are exceptionally strong, rigid, and thermally stable. We specialize in two primary thermoset molding processes.

Compression Molding

In compression molding, a pre-measured amount of thermoset material (called a "charge") is placed directly into a heated mold cavity. The mold is then closed, and high pressure is applied. The combination of heat and pressure forces the material to fill the cavity and initiates the curing reaction. It is a cost-effective process for large, relatively simple parts.

Transfer Molding

Transfer molding is a more advanced process. The thermoset material is placed in a separate chamber (the "pot"). A plunger then forces, or "transfers," the material from the pot through channels (sprues and runners) into the closed mold cavity. This is a more gentle process, ideal for molding parts with more complex geometries or for insert molding delicate electronic components.

Common Thermoset Materials

Liquid Silicone Rubber (LSR): Offers extreme temperature resistance and flexibility. Used for seals, gaskets, and medical parts.
Epoxies: Provide excellent mechanical strength, chemical resistance, and electrical insulation. Used for encapsulating electronics.
Phenolics (Bakelite): One of the first plastics, known for its outstanding heat resistance and electrical insulation. Used for handles, knobs, and electrical components.
Bulk Molding Compound (BMC): A composite material containing resin, fillers, and reinforcing fibers, used for making strong, rigid components.

A medical device housing, an application where thermosets are used for their durability and chemical resistance

Thermoset Molding FAQ

When should I choose thermoset molding over injection molding?

Choose thermoset molding when your application's performance requirements exceed the capabilities of even high-end thermoplastics. If you need extreme heat resistance, superior dimensional stability under load (low creep), or the specific properties of a material like silicone or epoxy, thermoset molding is the right choice.

Are the design rules for thermosets the same as for thermoplastics?

Yes, many of the core principles are the same. Maintaining uniform wall thickness, adding draft angles, and using generous radii are all still critical for successful thermoset molding to ensure proper material flow and part ejection.

What is "encapsulation"?

Encapsulation, or "potting," is a common application for thermosets, particularly epoxies. It is a process where an electronic component or assembly (like a PCB) is placed in a mold, and the liquid thermoset resin is poured or injected around it. The resin then cures, permanently sealing the electronics from moisture, shock, and vibration.