Microcellular foaming principles originated at the Massachusetts Institute of Technology (MIT) in the 1980's and 1990's and were further developed by Trexel Inc., Woburn (Massachusetts, USA) which invested approximately $US 30 million to create a robust commercially useful system and process for worldwide deployment.rnThe technology is covered by patents and patents pending in developed and marketed worldwide in a variety of industries, including automotive, office equipment, medical devices, consumer goods, electrical/electronics, structural parts for industrial and consumer applications.rnThe use of screws to fasten plastic parts is common for compact injection molded parts. This paper looks at the effects on the MuCell~® microcellular foaming process on the performance of screw fastening for a number of plastics common in the injection molding industry.rnTicona as a material supplier ran the boss testing mould from EJOT with different materials on their MuCell~® machine in the Ticona lab in Kelsterbach near Frankfurt.rnEJOT as a well known screw manufacturer made the required torque tests in their Applitec (test lab) to find out the performance of microcellular foamed bosses.rnThe results show that all of the tested materials are "screwable" with MuCell~®. The thread geometry of the screw is important for the clamp force capacity and clamp force relaxation of each connection. The same boss design can be applied for MuCell~® parts as recommended by Ticona and EJOT for solid moulded products.
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