Injected into the mold, the gas expands to form highly uniform, closed cells of 50 to 5 microns diam. Conventional foam molding yields non-uniform cells and voids of at least 250 microns. The tiny cell structure of the MuCell foam reportedly impart higher mechanical properties at lower densities than are seen with conventional foaming. It may even be possible to hike certain properties while reducing part weight, say Trexel sources. The MuCell process can foam large, flat parts with thin sections, or small, complex pieces.
Advocates say it reduces warpage, sinks, and molded-in stresses.
Lower clamp force means lower energy costs and enables larger parts to be molded on smaller presses. It could also allow greater cavitation, as well as use of aluminum molds. Some molders are turning to MuCell for the processing benefits, even when lightweighting is not a goal, Bernstein says. MuCell foaming can also be a solution to molding problems such as shrinkage or warpage. One example of MuCell's capability was demonstrated at the NPE 2000 show in Chicago this past June.