Foaming has long been a tried and true route to reducing part weight, particularly in the vehicle manufacturing industry. The MuCell foaming process, developed and patented by Trexel, offers particular advantages in this respect. A physical process for foaming thermoplastics that uses nitrogen or carbon dioxide as blowing agents, this process has gained popularity due to, among other things, the shorter cycle times and, importantly, minimal sink marks caused by expansion of the blowing agent.
During the process, the gas is transformed into a supercritical fluid, or SCF, fed into the plastic melt toward the front of the barrel and mixed with the melt. The SCF expands during the injection process to produce a part with a mainly microcellular foam structure (<100 µm).
In combination with special mold concepts and in cooperation with partners, KraussMaffei has now succeeded in creating additional high-gloss surfaces for the components foamed using this process.