World Premiere at K 2016: New plasma-injection molding process for high-performance hybrid components

From October 19 through 26 Plasmatreat and AKRO-PLASTIC will join forces with their trade show partners KUKA, ARBURG and Krallmann at the Plasmatreat booth at the "K" in Düsseldorf to give live demonstrations of the new plasma hybrid injection molding process and the turnkey atmospheric plasma unit PT1200.

Image © Plasmatreat

The interface between plastic and metal is a risk factor which invariably proves to be a headache for injection molding manufacturers during the production of hybrid components. Over time, particularly corrosive media can cross the interface and penetrate the component, causing damage and even delamination.

System partners Plasmatreat and AKRO-PLASTIC set themselves the goal of finding an industry solution to this problem. After two years of research, the plasma specialist and the plastics compound manufacturer succeeded in creating a process which precisely matches the composition of an anti-corrosive plasma-polymerized layer generated under atmospheric pressure to the recipe for the plastic compound and the process parameters to ensure a long-time stable, media-tight bond of the injection-molded part.

In automating this innovative process, the plasma company focused on designing a multi-component pretreatment system which is compact and easy to integrate into a continuous production line. The system partners achieved their goal with the fully automatic PT1200 plasma cell, which can be adapted to suit any conventional injection molding machine. This unit makes the process faster and at the same time allows for a continuous flow production of injection molded plastic-to-metal components. The cell contains everything the process needs, from the generator, robot, control technology, PCU plasma control unit and plasma jets to cables and consumables. By selecting from a list of options, users can increase or reduce the system's scope as required for other pretreatment processes.

Preparation for the hybrid injection molding process: inside the new PT1200 cell the metal is first cleaned to a microfine level with Openair® plasma, and then functionally coated by PlasmaPlus® technology – all in a matter of seconds. (Image © Plasmatreat)

The plasma system itself has two separate plasma nozzles. A robot – or with the two smaller variants, an XY axis system – guides the metal inlay initially beneath the Openair plasma beam, which removes any contamination from its surface and simultaneously activates it. The functional coating is applied immediately afterwards from the second plasma nozzle. The coating process is based on the PlasmaPlus process developed and patented several years ago by Plasmatreat in conjunction with the Fraunhofer IFAM in Bremen, which generates functional coatings with the aid of a precursor added to the plasma.

Minimal time is required to pretreat the metal, with plasma cleaning and coating taking only a matter of seconds. The dry, environmental friendly process completely replaces the cleaning and priming processes frequently used with hybrid injection molding. It also dispenses with the need for process steps such as intermediate storage and drying, enabling components to be further processed immediately after coating. A small conveyor belt transports the metal inserts from the plasma cell to the plastic injection molding machine. At the end of the belt, a second robot picks up the component, briefly warms it under an induction heater and then places it in the injection mold. Here, the PlasmaPlus coating creates a strong, covalent bond between the metal and the plastic.

Supported by their trade fair partners KUKA, ARBURG and Krallmann, Plasmatreat and AKRO-PLASTIC will show the new plasma hybrid process together with all the machines and systems and produce a giveaway made from stainless steel overmolded with PA6 GF30.

Plasmatreat at K 2016:
Hall 11, Booth G04

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