New Foaming Technology for Thin-Wall Parts

New technology for physical foam molding is being unveiled at NPE by Trexel, which has new dosing equipment that reportedly allows thin-wall molders to lightweight products to a level never before possible. The new MuCell P-Series delivers nitrogen under pressure as a supercritical fluid; what’s more, it is able to do so at ultra-fast cycle times not previously possible with Trexel’s T-Series dosing equipment.

Now, thin-wall packaging molders will be able to achieve 6 percent lightweighting, 7 percent faster cycles, 30 percent lower clamp tonnage, and 12 percent lower injection pressure, according to Trexel. Other benefits are increased L/T capability and ability to “break the rules” by filling from thin to thick to produce a stiffer rim for sealing.

Trexel is demonstrating the P-Series in molding with what it calls a “groundbreaking” 6-oz (200-ml) yogurt cup with IML. Using StackTeck TRIM technology, it will have ultra-thin-wall panels of only 0.008 in. (0.2 mm).

Trexel has also announced what it calls “the first-ever design service dedicated to foamed components.” 2Limit is a joint venture of Trexel and GK Concept of Dresden, Germany, a specialist in product development, FEM calculations, filling simulation, prototyping, tool design, and mold trials. This venture is intended to fill a gap in the marketplace, making it easier to find design engineers skilled in the art of foamed part design—who know how to “break the rules” of conventional design for injection molding.

MuCell microcellular foaming can be seen at several more booths besides Trexel’s: Engel uses MuCell together with its DecoJect IMD process to provide uniform low-pressure packing to reduce stress on the thin TPO decorative film and avoid sink marks and read-through of mold features. MuCell also allows molding a thinner, lighter part.

Milacron is using MuCell to produce an SUV door panel with map pocket on a two-platen Maxima Performance 600-ton, wide-platen press using Milacron’s “Core Back/Reverse Coining” technique, whereby the mold is closed and then opened to a predefined position to allow foam expansion.

And Yizumi-HPM uses MuCell to mold a protective briefcase in an aluminum mold on its DP-N two-platen press. Yizumi FoamPro technology combines MuCell with rapid-heat/cool mold technology. This produces a range of surface textures, from leather-grain to high gloss, on the MuCell part, with the aid of a hot/cold mold-temperature-control unit from Single.

Milacron achieves a Class-A surface on its MuCell foamed part using Roctool “Heat & Cool” technology with rapid induction heating.