LPIM - Low Pressure Injection Molding

Milacron has set the standards, driven innovation and led the industry in Multi-Nozzle Low Pressure Injection Molding Technologies for more than four decades.  These machines can be used for Structural Foam, Structural Web, Gas Assist, Solid Molding, or combinations of these technologies depending on the application.

Ideal for injection molding large, lightweight, durable structural plastic parts, the Milacron LPIM – Structural Foam Technology creates a cellular foamed core surrounded by integral skins, forming a total integral and rigid structure.  In this process a foaming agent N2 is mixed with the polymer melt and short-shot through a modular multiple nozzle system into a mold (or multiple molds) in a volume less than is required to fill a solid part. Both the injection pressure and expanding gas/polymer cellular mixture act to fill the mold. The mold cavity pressures are 10 – 20 times lower than conventional injection molding which permits the use of lower cost aluminum molds with no hot runner, since the hot runner manifold & nozzle system is integral to the machine.  Many molds and large parts of different sizes can be molded at the same time.

The Milacron LPIM-Structural Web Technology is a proprietary multi-point gas assist process, with gas introduced through gas pins in the multiple nozzles feeding the plastic to the part that has similar light weighting advantages of Structural Foam for large parts.  The parts are solid without foam, but are packed out by low pressure internal gas pressure that produces hollow channels and hollow thick sections.  The LPIM Structural Web Process has the added benefits of an improved smooth solid molded in color surface for good cosmetics and hygienic products and faster cycles for parts that have very thick wall sections.

Milacron is also integrating other technologies into the LPIM machines such as Gas Assist Controllers, Cavity Pressure Controls Systems, Hot Runner Controls Systems, and Quick Mold Change Systems.

Milacron LPIM machinery is recommended for injection molding large structural plastic products such as material handling bulk bins, pallets, tool boxes, building products, pool panels and ladders, fencing, retail display racks, tote bins, storage sheds, shelving, cargo systems, in ground enclosures, recreational slides and toys, outdoor furniture, water storage tanks and drainage systems, burial vaults, garden lattice, dog houses, dock systems, janitorial and restaurant products, and industrial carts to name a few.