Gardner Business Media

Hot Runner Technology OCT 2017

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F E AT U R E 16 Hot Runner Technology Switch to Hot Runners Pays Off for Pulley Molder Retlaw has cut scrap, improved part quality and slashed cycles since adopting hot runner technology. Osco's Multi-Gate Nozzle specified by Retlaw offers balanced feed to each gate and minimal residence time within the hot runner. Change never comes easily in manufacturing, and injection molding is no different. Retlaw Industries got along fine without hot runners in its 40-year history, so why would the company bother changing? After all, if it's not broken, why fix it? Retlaw Industries is based in Hartland, Wisconsin. Retlaw started in 1977 as a tool shop making molds. Then it added a press to sample molds. "By 1982, we were asking our customers, 'Why don't we just mold your products too?'" says Mark Eberhardt, CEO and sole owner of the family-owned group. Today, moldmaking is a small part of the company's business. Retlaw operates out of a 50,000 square- foot plant, employs about 40 people and runs 20 injection molding machines ranging in size from 50-720 tons clamping force. Its business is split evenly between custom jobs and a proprietary product line of 33 percent glass-filled nylon pulleys that it sells directly to original equipment manufacturers (OEMs) of lawn and garden equipment, conveyors, fitness equipment and manufacturers in a range of other industries. Until this past spring, Retlaw could not justify utilizing hot runners on its pulley line. Eberhardt says, "Initially the volume wasn't there. The sales weren't there, so it didn't make sense for us to invest in a hot-runner system. But as that changed, so did our philosophy on manufactur- ing the part and the best way to mold the part." Retlaw started to look more seriously at hot runner technology about two years ago. The company started working with Osco Inc. of Rochester Hills, Michigan. Retlaw engineers and Peter Rebholz, Osco's vice president of sales, noticed something troubling on a three- plate, four-cavity mold running small-diameter pulleys. It was eye-opening. "The runner was a pretty substantial percentage of the over- all shot weight," Rebholz says. He meant that this application was ideal for going runnerless. Eberhardt says, "The parts were getting smaller, the volumes were getting higher and we were generating a higher percentage of regrind than By Jim Callari Images courtesy Retlaw Industries.

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