Is Compression Molding Faster Than Injection Molding?

When choosing how to manufacture plastic parts, speed often matters. Compression molding and injection molding are two common processes, but which one is faster? Let’s compare their cycle times, setup, and production speeds.

What Is Compression Molding?

Compression molding places a measured amount of raw material into a heated mold cavity, then closes the mold and applies pressure. This shapes and cures the material. It’s often used for thermoset plastics and composites, ideal for medium to large parts.

What Is Injection Molding?

Injection molding melts plastic pellets and injects the molten material under high pressure into a mold cavity. It is highly automated and excellent for producing large volumes of complex thermoplastic parts.

Speed Comparison

• Cycle Time: Injection molding parts typically take between 10 and 60 seconds each. Compression molding cycles are longer—usually several minutes—because thermoset materials need time to cure under heat and pressure.
• Setup and Tooling: Injection molding molds are more complex and costly, but enable faster production once ready. Compression molding uses simpler, cheaper molds but with slower cycles.
• Production Volume and Automation: Injection molding suits high-volume runs with automation for rapid output. Compression molding fits medium volumes or thicker, stronger parts but produces more slowly.

Why Is Injection Molding Faster?

Injection molding quickly melts and fills molds, solidifying parts rapidly due to thin wall designs. Compression molding with thermoset materials requires longer curing times, extending cycle lengths.

When to Choose Compression Molding?

Despite being slower, compression molding offers lower tooling costs, the ability to make thick, durable parts, and works well with composites—applications where injection molding struggles.

Conclusion

Injection molding is generally faster and better suited for high-volume, thin-walled plastic parts. Compression molding, while slower, remains valuable for thicker, tougher parts and when tooling budgets are limited. Understanding these differences helps you pick the right process balancing speed, cost, and material needs.