NPE2015, the triennial American plastics show, will be a coming-of-age party for physical foaming processes, particularly the MuCell technology originally developed at the Massachusetts Institute of Technology under the direction of Professor Nam P. Suh in the early 1980s.
Many insiders consider physical foaming to be one of the most important technical developments in molding in recent history, but its commercialization was initially slowed by normal industrial inertia and early requirements for royalty payments. The business model in recent years shifted to equipment sales, particularly in collaboration with machinery OEMs, and the technology has been lifting off.
Five machinery builders will show operating MuCell systems at NPE2015 in Orlando, Florida March 23 to 27 and a sixth, Wittmann Battenfeld, will show its own proprietary physical foaming system called Cellmould, which will be demonstrated on an EcoPower 240 machine, molding an ABS automotive bezel.
Engel will combine technologies in its NPE demonstration: its own “foammelt”, MuCell, and the variothermal injection molding process from Roctool (Le Bourget du Lac, France). The goal is to produce thin-walled parts with very high surface quality along with the excellent reproduction of fine structure using just a single injection molding step. The molded part will have varying wall thicknesses and surface structures. The demonstration will take place on a duo 2550/610 US injection molding machine with an integrated viper 20 robot.
The MuCell Process involves the controlled use of gas in its supercritical state to create a foamed part. The MuCell technology is targeted at engineered plastic components with maximum wall thicknesses of less than 3mm. Reported improvements include flatness, roundness, warpage, and elimination of sink marks. Relatively uniform stress patterns are created in the molded part rather than non-uniform stress characteristic of solid molding. Unlike chemical foaming agents, the MuCell process has no temperature limitation and does not leave any chemical residue in the polymer.
One interesting application for MuCell is for running shoe components developed by New Balance, which is based in Wilmington, Massachusetts. Components made with the Mucell process use less resin while also showing better rebound and durability, according to Katherine Petrecca, strategic business unit manager for New Balance.
The timing is good for both parties. New Balance is one of the few American shoe manufacturers with significant American manufacturing capabilities and, according to a recent article in the Boston Globe, is vying for significant military business that now requires domestic sourcing.
Injection molding machinery manufacturers that now offer a MuCell-ready molding machine are Arburg, Demag, Engel, Haitian, Husky, JSW, KraussMaffei (including Netstal), Milacron, Mitsubishi, Nissei, Toshiba and Toyo. Those companies will be exhibiting at NPE2015, but have not yet announced exhibit specifics.
Trexel, which owns MuCell rights, will be exhibiting at booth W1523; Engel, booth W1303; and Wittmann Battenfeld, booth W2743. “W” indicates the West Hall at the Orland Convention Center.