Plastics Technology

DEC 2018

Plastics Technology - Dedicated to improving Plastics Processing.

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proposal that envisioned the use of two six-axis robots, which would offer 360° of operational reach along with the ability to handle even the most complex part manipulations. This approach suggested that one large, centrally located, six-axis robot could do the bulk of the work, handling parts from the stamping machine through overmolding to the testing apparatus. From there, a smaller six-axis robot would remove the parts and load them into trays, which would proceed to an automatic tray-stacker and onto carts for removal. Two identical, highly compact vertical injection molding cells are among the most recent additions to the KHG Plastics GmbH plant in Velberg, Germany. The new cells, which together can produce some 40,000 over- molded electrical contacts per week for automotive lighting systems, combine a sequence of metal fabri- cation, overmolding, testing and packaging into fully automated production. And, they do so with elegance and simplicity. Originally, the company considered moving parts through these diverse functions with the help of two six-axis robots, a human operator, and additional automation. But a much simpler proposal, evolved by robot maker Sepro and kiki Ingenieurgesellschaft mbH, a local systems integrator, convinced KHG Plastics that the cells would be more compact and productive using three linear, three-axis robots, all integrated through a single control system. This solution offers a tip to other molders on how unconventional approaches can lead to success. AUTOMATING MULTIPLE FUNCTIONS After winning the chance to produce a new overmolded metal contact for an automaker's vehicle lighting systems, KHG got to work designing the production system for this part. The com- pany sought a fully automated process that would integrate a variety of production equipment: • A metal-punching and bending machine to receive metal blanks and produce left- and right-ori- ented metal contacts; • A vertical injection molding machine to rec eive and overmold the metal stampings; • A test station to short-circuit test the overmolded contacts; • A packaging station where "good" right-hand and left-hand parts are transferred to stackable trays that can be moved to further automation in-house or palletized and shipped to the customer. Since the application involved moving parts through a series of pre-and post-mold operations, the company considered an initial By Matthew H. Naitove Executive Editor QUESTIONS ABOUT ROBOTS? Visit the Robots Zone. Simplicity Conquers Complexity in Automotive Molding Cells Six-axis robots are often recommended for complex automation cells, but here's an example of how cost- effective, three-axis linear robots can be up to the task. The only human involvement in each cell's opera- tions is removal of full parts trays about every 6 hr. Two identical molding cells each include three Sepro linear robots operating together with Arburg vertical injection molding machines. 22 DECEMBER 2018 Plastics Technology PTonline.com Close -Up On Technolog y

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