New plasma-injection molding process for hybrid components showcased at K 2016

Potential delamination and failures at the interface between plastics and metal pose serious and persistent concerns for injection molding manufacturers who produce components that combine dissimilar materials, such as for automotive lightweighting applications. To address these concerns, Plasmatreat (Steinhagen, Germany) and Akro-Plastic (Niederzissen, Germany) have developed a process that customizes the composition of an anti-corrosive plasma-polymerization layer according to the composition of the corresponding plastic compound.

The fully automated PT1200 plasma cell can be adapted to suit any conventional injection molding machine. It increases production speed and allows for a continuous production of injection molded plastic-to-metal components. The PT1200 cell includes the plasma generator, robot, control technology, plasma control unit, plasma jets, cables and consumables. Users can customize the system for their process, as required. To process parts, a six-axis robot, or, for smaller profiles, a two-axis gantry system, positions the metal inlay beneath a Plasmatreat Openair atmospheric plasma jet. The plasma jet removes contamination from the part’s surface and simultaneously activates the surface chemistry for coating. A second plasma jet applies a thin-film functional coating. The coating application is based on the patented PlasmaPlus process developed by Plasmatreat and Fraunhofer IFAM.

The plasma cleaning and coating process takes only seconds to complete, and provides a dry, environmentally friendly alternative to the slower and less-effective chemical cleaning and priming processes conventionally used in hybrid injection molding. The Plasmatreat process eliminates the need for time-consuming intermediate steps such as storage and drying, and allows components to be processed immediately after coating. Coated metal parts are transferred from the plasma cell to an injection molding cell. On entering the injection molding cell, a robot briefly maneuvers the parts under an induction heater before loading them into the mold. The PlasmaPlus coating creates a strong, covalent bond between the metal and injection molded plastic.

Supported by trade fair partners Kuka, Arburg and Krallmann, Plasmatreat and Akro-Plastic will demonstrate the entire process at booth G04 in hall 11. Visitors will receive stainless-steel sample parts that have been over-molded with PA6 GF30 plastic.

Plasmatreat GmbH is focused on improving the adhesion of inks, coatings, adhesives and sealants to plastic and improving the bond strength of molded rubber to a wide range of substrates. Plasma is frequently specified by manufacturers of automotive, medical, aerospace and electronic components, where performance is critical, reliability is important and adhesion failures are costly.