Canadian Plastics

On the road to lighter, tougher foamed auto parts

It would be safe to say that the average plastic processor and the average driver have at least one thing in common: a well-founded fear of high oil and gas prices.

November 1, 2007   By Umair Abdul, assistant editor

It would be safe to say that the average plastic processor and the average driver have at least one thing in common: a well-founded fear of high oil and gas prices.

For the plastics industry, rising oil prices lead to an inevitable rise in feedstock prices. And the millions of people lining up at gas stations have come to dread the constant fluctuations in gasoline prices.

A new structural foam technology developed by University of Toronto Professor and Canada Research Chair Tier I in Advanced Polymer Processing Technologies Dr. Chul Park can help manufacturers produce lighter and stronger automotive plastic parts — allowing for fuel-efficient lightweighting — and use less material in the process.

Traditional microcellular foam molding technology involves the introduction of an inert gas in a thermoplastic. According to Dr. Park, the bubbles created in the plastic using the structural foaming process address issues with sink marks, warpage and residual stress in conventional injection molded parts.


However, Dr. Park identified what he calls a “fatal flaw” in the structural foaming process. “They did not know how to control the cell size because of the technical limitation,” he explained.

“The big bubbles are uncontrollably developed, here and there,” he continued. “As a result, mechanical properties are weakened, and you don’t have a good outward appearance.”

Dr. Park’s advanced structural foam molding technology makes uniformly distributed cell structures, creating parts with excellent strength and a class-A finish. In addition to improving the impact and stiffness properties, the even distribution also enhances the part’s sound and energy absorption abilities.

More importantly, this new technology offers significant cost savings for the processor. According to Dr. Park, these foamed parts use less raw material and require lower press tonnage when compared to non-foamed injection molded parts.

“Any injection molded part can be made out of this technology, and you can decrease the weight by 10 to 30 per cent,” he said. “By introducing our technology, they can decrease their manufacturing cost by up to 20 per cent.”

The new innovation is currently being transferred to automotive part manufacturers such as Mississauga, Ont.-based Mastercore System, Woodbridge, Ont.-based The Woodbridge Group, Oshawa, Ont.-based Delphi, and Georgetown, Ont.-based Cooper-Standard. Dr. Park noted that he needs to do some more development on a larger scale to be able to apply the technology to each application area, but he is very optimistic about the technology’s future.

“In 10 years, the majority of injection molded parts will be produced this way,” he said.

Dr. Chul Park (Toronto); 416-978-3053

AUTO21 Network of Centres of Excellence (Windsor, Ont.);; 519-253-3000 ext. 4130

Canada Foundation for Innovation (Ottawa, Ont.);; 613-947-6496

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