Canadian Plastics

Conference Highlights Large-Part Capabilities

There's large, and then there's larger. Better yet, largest.The descriptive certainly fits the 525 lb., 8 ft. x 14 ft. entry in the design competition of this year's Structural Plastics conference hel...

May 1, 2000   Canadian Plastics



There’s large, and then there’s larger. Better yet, largest.

The descriptive certainly fits the 525 lb., 8 ft. x 14 ft. entry in the design competition of this year’s Structural Plastics conference held in March in Vancouver (see News, p. 13). The part, a structural road mat molded by Loma Co. in Carencro, Louisiana, won the competition’s Conference Award and Building and Construction Award. FGL Precision Works Ltd. (Concord, Ont.) built the aluminum tooling used to compression mold the parts from HDPE. The mats are connected and used by oil companies and others as temporary road beds over soft ground.

Tom Meisels, FGL vice-president, says each half mold of aircraft aluminum measures 14 ft. in length by 8 ft. in width, and a complete set, or two halves, weighs about 10,000 lb. FGL built 24 sets of molds for Loma, which molds the part in a stack mold configuration on a custom-built vertical compression press. Each stack contains eight sets of tools.

Loma looked internationally for a company to make tools for the road before selecting FGL, in part because few moldmakers wanted to take on the project.

“Making this mold was very technically challenging because of the inconsistent wall thickness,” Meisels reports. “Some areas have two-inch wall thickness, some have one-quarter inch thick walls. Plus, with a part this big, you have to deal with a lot of shrinkage.”

A reaction injection molded (RIM) rear engine hood for a John Deere commercial mower won the People’s Choice Award. GI Plastek of Westlake, OH manufactures the part. The hood, which replaces a metal-based assembly, is molded from high-heat grade polyurethane in one piece, without hinges. The part is slid in and out of position on an extruded ABS track system. Also, the hood is designed to seal directly to the radiator, eliminating the need for an intermediary duct to draw air into the radiator. A Class A painted surface finish is achieved by an in-mold coating process applied to a nickel-shell cavity coupled with an aluminum core. PPD Recherche Inc. of Waterville, Que. built the mold for the hood.


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