Injection Molding Process Guide

Key Takeaways Injection molding is a cyclic process with four stages: melting, injection, cooling and ejection. A single cycle runs from a few seconds to about a minute, so cooling time — not injection speed — usually sets your production rate. Four parameters govern part quality: melt temperature, injection pressure, fill speed and mold temperature. Cooling consumes 50–70% of cycle time and drives most dimensional variation. Most defects trace back to mold design or resin drying rather than to machine settings alone. What Is the Injection Molding Process? Injection molding is a cyclic manufacturing process that converts thermoplastic pellets into finished parts: the resin is heated until it melts, injected under pressure into a closed steel mold, cooled until it solidifies, and ejected...