moldedplastic

Molded plastic is plastic that has been shaped by forcing molten or pliable polymer into a mold where it cools and hardens to form a finished part. The term covers a range of molding processes, including injection molding, blow molding, rotational molding, thermoforming, and compression molding. These processes are used to produce items with complex geometry, consistent quality, and high production rates.

Materials used in molded plastics are primarily thermoplastics and thermosets. Thermoplastics can be melted and reformed, enabling recycling and post-mold processing. Thermosets cure and form a rigid, crosslinked network during molding and cannot be remelted. Common polymers include polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile butadiene styrene, polycarbonate, nylon, and PET, among others.

Injection molding is the most widely used method for mass-produced parts, offering high accuracy and repeatability, with cycle times from seconds to minutes. Other methods vary: blow molding creates hollow containers; rotational molding coats large, hollow items; thermoforming shapes thin-walled parts from sheets. Design considerations include wall thickness, draft angles, undercuts, gate placement, and mold cooling rates, all of which affect strength, finish, and cost.

Applications span consumer electronics housings, automotive components, packaging, medical devices, appliances, and household goods. Molded plastic parts can range from small intricate components to large, lightweight structures. The choice of polymer, filler materials, and surface finishes influences performance, appearance, and cost.

Environmental considerations include the recyclability of thermoplastics, energy use in molding, and waste from runners and sprues. Advances in materials and design aim to reduce material usage, enable easier recycling, and extend part life. Lifecycle assessment and end-of-life options vary by polymer and product.