DUSSELDORF, GERMANY — The Ergotech Elexis from Demag Ergotech GmbH and its sister company, Van Dorn Demag Corp., combines the best of electrics and hydraulics in a hybrid package, the firms said.
Initially, the Elexis will be available in clamping forces of 50-300 tons.
At K'98, Kenneth Vaughan, marketing manager at Van Dorn Demag in Strongsville, Ohio, said the Elexis is less expensive than an all-electric machine. It costs about 5 percent more than a hydraulic press but uses only about half the energy, he said.
Independent electric motors power both clamp and screw movements, such as clamp movement, ejection and screw rotation. Because each function moves independently, the machine can move very quickly. For example, the screw continues to plasticize resin even while the clamp is moving.
Hydraulic power moves the injection unit and other functions such as core pull and ejector pins.
One key: a patented clamp unit that uses a hydrostatic gear to turn rotary motion from the electric motor into linear movement of the clamp, without a significant loss of energy.
Demag Ergotech of Schwaig, Germany, which developed the Elexis, is touting its speed. The company claims that mechanical components, such as ball screws, used on standard all-electric presses only reach conservative injection speeds of about 8 inches a second. Since a central hydraulic accumulator drives injection on the Elexis, Demag officials claim their machine can reach injection speeds of about 33.5 inches a second.
At the Dusseldorf trade show, Demag Ergotech molded a polypropylene flower pot on a 200-ton Elexis on a 2.9 second cycle.
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