Injection molding is a fast, high-volume, closed molding process that uses, most commonly, reinforced thermoplastics, such as nylon with chopped glass fiber. In the past 20 years, however, automated injection molding of BMC has taken over some markets previously held by thermoplastic and metal casting manufacturers. They include electrical and automotive components, appliance housings and motor housings, to name a few. The use of BMC must be justified by production volume because the cost of both molds and presses is relatively high. When injection molding BMC, a ram- or screw-type plunger forces a metered shot through a heated barrel and injects it (at 5,000 psi to 12,000 psi) into a heated mold, where the liquefied BMC flows easily along runner channels and into forming cavities. Heat build-up is controlled to minimize curing time. After cure and ejection, parts need only minimal finishing. Injection speeds are typically one to five seconds, and nearly 2,000 small parts can be produced per hour in a multiple-cavity mold. Long-fiber reinforced thermoplastics (LFRT) are materials with long (6.35 mm/0.25 inch or greater) fiber reinforcement and make up one of the fastest growing fabrication categories. Leading this expansion is one of the oldest forms, glass mat thermoplastic (GMT) and two of the segment’s newest: precompounded (pelletized) LFRTs (long-fiber reinforced thermoplastics), also known as LFTs, and inline compounded (ILC) or direct LFTs (D-LFTs).
Recent advancements in these reinforced thermoplastic technologies are expanding their performance, enabling new applications.
Read complete article
Surface Generation is providing digital process control for composites molding that cuts energy use, cycle time and processing pressures while breaking boundaries in thickness, complexity and embedded elements.Composites manufacturing — where the excitement lives CompositesWorld
A regular CW columnist and the chief commercialization officer for the Institute for Advanced Composites Manufacturing Innovation (IACMI, Knoxville, TN, US), Dale Brosius points out that for today's engineering students, a Ph.D in manufacturing could open the door to an exciting, alternative career path.High-definition part surface quality on injection molded parts CompositesWorld
RocTool (Le Bourget du Lac, France; Charlotte, NC, US) has introduced a new technology, called HD Plastics, that applies the company's fast, high heating and fast cooling to the improvement and optimization of thermoplastic resin systems in injection molding applications.Quadrant buys Piper Plastics CompositesWorld
The transaction is expected to close in the next weeks subject to governmental approval.Selective reinforcements boost “commodity” composite properties CompositesWorld
Strategically placed advanced reinforcements reduce weight, cost while dramatically increasing mechanical performance and dimensional stability.