Metal and plastic are said to bond together better in a newly developed turnkey, automated treatment process that will debut at Plasmatreat’s booth at K2016 in Düsseldorf, Germany, Oct. 19-26.
Plasmatreat says it launched the research project with AKRO-Plastic two years ago because the interface between plastic and metal is a risk factor. “Over time, particularly corrosive media can cross the interface and penetrate the component, causing damage and even delamination.”
In the new approach, the metal insert is treated with an anti-corrosive plasma-polymerized layer generated under atmospheric pressure. AKRO developed a plastic compound that molds to the layer to ensure a long-time stable, media-tight bond, according to the partners.
The automated PT1200 plasma cell comprises a molding machine, generator, robot, and plasma jets. A robot guides the metal inlay initially beneath the plasma beam to remove contamination from its surface. A functional coating is applied immediately afterwards from a second plasma nozzle. The coating process is based on a process developed and patented several years ago by Plasmatreat in conjunction with the Fraunhofer IFAM in Bremen, Germany.
A conveyor belt transports metal inserts from the plasma cell to the 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 covalent bond between the metal and the plastic.
AKRO-Plastics, which is building the molding tool and doing all tests, formed an exclusive partnership in the field of nylon and polyketone to develop the technology.
Other partners in the K2016 exhibit are KUKA, Arburg and Krallmann. In the demonstration, stainless steel is overmolded with a specially developed polyamide 6 compound loaded with 30 percent glass.