Rapid Injection Molding

Rapid Injection Molding

Rapid injection molding, also referred to as short-run injection molding, is primarily used in prototyping and the low-volume production of plastic parts since the production time is drastically shorter than conventional molding process. A major advantage of rapid injection molding is that it allows the manufacturer to bridge the gap between the concept or design and the full production by providing them with a quick, low-volume order that allows them to show working models of the parts as soon as possible, which is typically 3-15 days. In addition, rapid injection molding is much more accurate and less labor intensive than conventional molding processes, reducing both tooling costs and lead time by two-thirds. Since rapid injection molding is ideal for parts made from straight-pull molds without side-actions such as undercuts, it is becoming widely used in industries such as medical, aerospace, electronics, appliances and automotive. With applications such as bolts, hubs, gears, knobs and electronic enclosures, common thermoplastic materials that are rapid injection molded include nylon, ABS, polycarbonate, polypropylene and polyethylene.

Rapid injection molding is a fully automated process that begins with a 3D CAD part model that is programmed into CNC machining equipment. The tooling techniques used are very different from conventional injection molding and result in many part limitations. However, despite their differences, the rapid conventional molding process is very much like the typical injection molding process. First, heated thermoplastic material is injected into the cavity of a split die chamber/mold, which is then clamped shut. Then plastic resin cools as water or other fluids circulate through the cooling system of the mold, extracting the heat. The molded plastic part is held in the mold under high pressure until the part solidifies. The metal mold is typically made from aluminum and is also CNC-machined in order to create an extremely accurate model of the intended part shape. Unlike rapid prototyping, rapid injection molding produces fully functional injection molded parts, which is extremely beneficial in testing the functionality of the part. Surprisingly cost-efficient, rapid injection molding is able to produce volumes of 25 to 1000 parts per production run.