Plastics Technology

JUL 2018

Plastics Technology - Dedicated to improving Plastics Processing.

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In 1985, when injection molding replaced laminating of the metal grinding surfaces onto plastic, DMT gained a major increase in quality and productivity. In the past year, DMT honed its injec- tion molding technology to a finer edge with the purchase of a new machine, robot and auxiliary equipment in a cell that embodies key elements of Industry 4.0. The age of "Smart Factories," or Industry 4.0, is still in its infancy. Many of the essential building blocks— standard communication interfaces between "smart machines"—are still being developed. At May's NPE2018 show, numerous equipment vendors showed North American processors the steps being taken on what will no doubt be a long path forward. DMT has taken some of those steps itself, becoming a pioneer among U.S. processors—all the more remarkable for a shop with only three injection machines— and has experienced significant benefits in uptime, efficiency, trou- bleshooting, and faster product changeovers. JOINING 'TEAM EDGE' DMT is a 40-year-old business that got a shot in the arm when it was purchased by Acme United Corp. in 2016. Based in Fairfield, Conn., Acme is a $140-million global com- pany with over 400 employees (acmeunited. com). Among its diversified businesses are several brands of knives, scissors, shears, axes, and other cutting implements. DMT, therefore, was a logical addition to Acme's "Team Edge" group of companies. Located in a 28,000-ft 2 plant in Marlborough, Mass., DMT (dmtsharp.com) employs 25 to 30 people in metal stamping, electroplating, and finishing the metal sharpening surfaces, as well as injection molding and packaging. It molds glass-filled polycarbonate for the ribbed backing of the metal sharpening plates, and black ABS for the holder of a double-sided sharpener. DMT also molds some products with talk-filled PP. As explained by Mark Bettke, senior director of operations and manufacturing, flatness of the sharpening surface is a key quality spec, which is why DMT uses glass-filled PC for its hardness and stiffness. "Our flatness spec is ±0.001 in. over the entire surface, which can be up to 40 in. 2 on a large, double-sided stone. Our sharpeners are the flattest in the world." "And to get that requires very consistent shot size, packing, and process temperatures," adds Stan Watson, technical director and a 31-year veteran at DMT. With a high glass content and thick walls (about 0.140 in.) in the ribbed backing structure, we don't make it easy for ourselves." The need for molding precision and consistency accounts for DMT's preference for all-electric molding machines, going back to its second machine purchase 18 years ago. Besides being more precise, Watson credits electric machines with lower energy consumption and discharging less heat into the plant air. After the acquisition, Acme United urged DMT to update its injection machines, which were then 16 and 31 years old. The first step was several months of research into machines and vendors by DMT personnel. "We visited four machine builders," Watson recalls. "We looked into everything, including maintenance, parts and service. We also talked to our outside vendor of plastic parts about how it felt about its equipment. "The more we researched, the more we became interested in Wittmann Battenfeld, because they could supply the whole system, with machine, robot, and auxiliary equipment." DMT was impressed particularly by Wittmann's expertise in robot end- "We immediately saw the value of having all the equipment talk to each other—how could we pass that up?" Visit the Injection Molding Zone Learn more at PTonline.com QUESTIONS ABOUT INJECTION MOLDING? DMT is the first U.S. molder to implement Wittmann 4.0 with the company's latest Unilog B8 press control as the integration hub. Here, Bob Parkhurst (r.) and Mark Bettke, DMT senior director of operations & manufacturing, stand by the B8 control on a new EcoPower 300 all-electric press. The large screen shows injection, hot-runner, TCU, and blender data. Parkhurst holds a key with an embedded chip that gives access to control functions. @plastechmag 39 Plastics Technology On-Site DMT/Acme United

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