German groups are making headway in developing processes to injection mold plastics with glass.

Kunststoff Institut Lüdenscheid (KIMW) is progressing in its KuGlas (Kunststoff-Glas) project, which it first discussed at its September 2010 innovative surfaces conference.

KIMW sees great potential for avoiding separate joining techniques when producing instrument panel displays for premium cars.

In August 2011, KIMW reported having investigated more than 40 adhesion promoters within the KuGlas project. These resulted in some giving high strength bonding between the glass and the plastics tested: ABS, nylon, polycarbonate, PC/ABS and acrylic. Further work showed glass breakage can be reduced to zero by foam overmolding.

At Fakuma 2011 in Friedrichshafen, KIMW managing director Stefan Schmidt showed European Plastics News overmolded and molded-on KuGlas samples, saying the next stage would be backmolding over entire glass surfaces. This was achieved and at Euromold 2011 KIMW presented the process, stating it had applied for a patent.

Dresden, Germany-based Pentacon came to Fakuma 2011 stating that it has a new patented process for overmolding glass.

It points to challenges of glass brittleness and ±0.2mm tolerance for a 2mm thick pane. Formation of flash due to the glass thickness tolerance can only be avoided with special elastomer elements.