injectionmoulded

Injection moulding is a manufacturing process used to produce parts by injecting molten material into a closed mold. The material, typically a thermoplastic polymer, is heated to a fluid state and forced under pressure into a mould cavity. After cooling, the part is ejected. The process is favored for high-volume production due to its speed, repeatability, and ability to create complex shapes with tight tolerances.

Most commonly used with thermoplastics, injection moulding can also process thermosets, elastomers, and, in related variants, metal powders. Common polymers include polystyrene, polypropylene, polyethylene, polyvinyl chloride, acrylonitrile butadiene styrene, polycarbonate, and nylon. Molds are usually made of tool steel and must withstand high pressures and repeated cycling. Modern systems may employ hot runners, multi-cavity molds, or insert molding to enhance efficiency.

Process steps typically include clamping the mold, injecting molten material through a nozzle and into the cavity, a packing and dwell phase to ensure density, cooling to solidify, and ejection of the finished part. Cycle times vary from seconds to minutes depending on part size, geometry, and material. Complex parts may require multi-cavity molds or automation.

Design considerations involve controlling wall thickness, draft angles, ribbing, gate placement, and parting lines. Common defects include short shots, sink marks, warping, and weld lines. Design tools and simulations help optimize mould performance and part quality.

Applications span automotive components, consumer electronics housings, packaging, medical devices, and toys. Advantages include high production rates, good surface finishes, and the ability to produce intricate parts; limitations include high initial tooling costs, mold wear, and material waste that may require recycling or reclamation.