Injection molding melts polymer and injects it into a cooled mold, then packs, cools, and ejects the part. Using PP, ABS, PC, PA and filled grades, precision tooling (cores, slides, hot runners, conformal cooling) enables high‑volume parts for automotive, medical, and electronics.
Injection molding is a cyclic process that produces complex thermoplastic or thermoset parts with high repeatability. Polymer pellets are dried (as needed) and plasticized in a heated barrel; a rotating screw melts and homogenizes the material, then injects it at controlled velocity and pressure into a closed mold via a sprue/runner/gate system. The cavity is packed to compensate shrinkage, held under pressure, then cooled (or cured for thermosets) before ejection. Critical parameters include melt and mold temperatures, screw speed, injection/packing pressure, switchover point, holding time, and cooling time; these govern dimensional stability, surface quality, and warpage. Commonly processed materials are PP, PE, ABS, PC, PA, PBT, POM, TPU, and glass‑ or mineral‑filled compounds; for thermosets, phenolics and epoxy systems. Tooling comprises hardened or hardened and tempered steel or corrosion resistant steel, copper alloys or aluminum molds with parting lines, cores/cavities, side actions, hot‑runner or cold‑runner systems, venting, conformal or conventional cooling, and surface textures/coatings. Applications span automotive interior/exterior parts, medical disposables, housings and connectors in electronics, packaging closures, appliances, and precision gears or optics.