CINCINNATI - An Iowa molder won the SPI Composites Institute consumer products award for a bicycle frame molded - on a standard injection press - from polyurethane highly filled with long carbon fibers. Mid-Central Plastics Inc. molds the mountain bike frame in two halves. The West Des Moines company also molds four smaller support members. The parts are shipped to Ross Bicycles USA Ltd. of Farmingdale, N.Y.
The assembled, unpainted, thermoplastic frame weighs just 31/2 pounds and is stiffer, tougher and cheaper to make than standard thermoset composite frames, the firm said.
Mid-Central Plastics had to make a few adjustments to the 1,000-ton Cincinnati Milacron press used to mold the halves, said Jack McWilliams, vice president of sales and engineering. It adjusted wall sections of the hollow frame and tinkered with the sprue and runner system to get even filling with no knit lines.
The material is PUC40-01-4 from Polymer Composites Inc. of Winona, Minn.