Plastic injection molding is a high-volume manufacturing process used to produce identical plastic parts by injecting molten thermoplastic material into a custom-designed mold cavity. Once cooled and solidified, the mold opens to release the finished part. This method is widely adopted for its efficiency, precision, and cost-effectiveness in mass production.
The injection molding cycle consists of four primary stages:
Clamping: The mold halves (fixed and movable) are securely closed by hydraulic or mechanical clamps.
Injection: Molten plastic (heated to 200–400°C) is injected into the mold cavity under high pressure (1,000–30,000 PSI).
Cooling/Solidification:The plastic cools and hardens, taking the shape of the mold cavity.
Ejection: The mold opens, and the finished part is ejected using ejector pins or plates.
Advantages of Injection Molding
High Efficiency: Produces thousands to millions of parts per mold with minimal downtime.
Precision and Consistency: Tolerances as tight as ±0.005 inches ensure uniformity across batches.
Material Flexibility: Supports a wide range of thermoplastics (e.g., ABS, PC, PP, nylon) and additives (e.g., glass fibers, UV stabilizers).
Complex Geometries: Enables the production of intricate designs with undercuts, threads, or living hinges.
Cost-Effective for Mass Production: Lower per-unit costs as volume increases, due to reduced labor and material waste.
