Engel Cell Automates Composite Overmolding

One of the big ongoing stories today in plastics—really manufacturing in general—is the increasing automation and cost reduction in processes to mass produce high-strength engineering composites, often using carbon fiber. The goal is to replace steel components and cut weight. Newly developed technologies often combine preformed composite sections that are heated and then placed in injection molding machines for overmolding.

In one of the interesting new developments, Lanxess subsidiary Bond-Laminates is operating a demonstration cell for processing Tepex continuous-fiber-reinforced thermoplastic composites in Germany. The composite is formed in a fully automated, “near-series” process and overmolded in a hybrid molding system.

“We plan to use the facility as a platform for transferring technology to customers. We want to familiarize our customers with the strengths of Tepex and how it is processed, as well as supporting the development of innovative components,” says Ulrich Jecmeniza, applications engineer with Bond-Laminates.

In a cell (manufactured by Engel), Tepex inserts are placed in the machine using a magazine, so that various sections can be processed in a single production run. There are two pyrometrically controlled infrared furnaces with a “drawer system” recently developed by Engel. These enable the inserts to be heated quickly in an even, material-specific way, without causing any damage to the thermoplastic matrix.

The injection molding machine in which the Tepex inserts are shaped and overmolded has a clamping force of 130 metric tons. The maximum projected size for the molded parts is 330 x 280 millimeters, which means that both structural and visible parts in these dimensions can be processed.

The first component made in the cell consists of a Tepex section with TPU matrix that is overmolded with TPU on both sides after shaping. Other near-series molds are expected to be available soon.

Plastics used as the matrix material in Tepex are polyamide, polypropylene, thermoplastic polyurethane (TPU), polycarbonate and polyphenylene sulfide. The continuous-fiber fabrics are made of glass, aramid or carbon fibers. Tepex combines high stiffness, strength, and low weight. Metal replacement is targeted in sporting goods, automotive and other applications, such as soccer boot soles, racing cycle brake levers, seat shells, and brake pedals.

In the Engel cell, inserts are heated in two furnaces and then placed in a 130-ton injection molding machine. (Lanxess)

In the Engel cell, inserts are heated in two furnaces and then placed in a 130-ton injection molding machine. (Lanxess)

About Doug Smock

Former Chief Editor at Plastics World and Senior Technical Editor Design News

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