Schröbel spoke with MPW in March at the annual "Plastics in automotive engineering" event in Mannheim, Germany, organized by the country’s engineers’ trade group, the VDI. During the 2007 trade show, KraussMaffei molded an electroluminescent PMMA-based display on a KM 80-180 CX molding machine, applying a liquid acrylic-based reaction mix for a one-step clear coat molding for a scratchproof part. The coating, from Evonik, was applied in the mold under cleanroom conditions immediately following injection molding. A purpose-built, small-volume unit metered the liquid acrylic reaction system into the mold cavity. This was followed by compression molding to spread the coating evenly over the PMMA surface.
The material’s low viscosity allowed long flow paths and spread a very thin layer, less than 50 µm, over the component. The coating cured in two stages: partially in the mold so that parts can be demolded without causing damage to them, and then curing was completed under UV light in a post-mold process.
Schröbel told MPW that his company plans this summer to open a customer center at its Darmstadt facility to allow for customer testing of the process. —[email protected]