Close Coordination of Robots & Molds Highlighted at Engel Medical Symposium

At the April event, nearly 100 visitors witnessed five machine demonstrations and half a dozen technical presentations by Engel and its technology partners. Here are a couple that caught my attention.

A recent Medical Technology Symposium at Engel Machinery in York, Pa., provided at least two examples of what can be accomplished through coordinated development of robotic automation and injection mold tooling.

• An Engel Victory 120-metric-ton, all-electric machine demonstrated LSR molding of “duckbill” valves in four cavities (photo). The innovation was the in-mold slitting system developed a few years ago by the moldmaker, M.R. Mold & Engineering Corp., Brea, Calif., a specialist in LSR molds.

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Normally, slitting is performed as a secondary operation outside the machine, but sometimes the part geometry does not permit that approach. M.R. Mold devised a method whereby the valves are molded with slits, which are then “opened” by pressing the valves against a resilient surface after the mold opens. To avoid metal-on-metal contact of the mold cores against the slit-opening surface, M.R. Mold uses a roll of thick, stiff paper or cardboard, which indexes through the mold every few cycles.

“The tricky part,” according to Geri Anderson, M.R. Mold marketing director, “was that we had to make the press close partly while the robot was in position. It takes programming on our end and software from the molding machine manufacturer.” In this case, Engel also makes the top-entry Viper robot.

• Another example, this time for thermoplastics, was presented as part of a talk by Jan Nietsch, business development manager of German automation specialist Hekuma GmbH, which has a sales office in Laguna Beach, Calif. He discussed a very tight-tolerance, multicavity application for a Gillette razor, in which the robot places spring inserts and removes molded parts.

To achieve the necessary exactitude of positioning for the robot’s end-of-arm tooling, and to avoid mold damage, the robot EOAT docks onto the mold half using bushings and pins. Nietsch said Hekuma has used this technique in a number of cases, another one being an automotive mold into which the robot places up to 126 inserts.