Hybrid injection technique achieves aesthetic, resilient product surfaces

Hennecke Inc. (Bridgeville, Pa., U.S.) is showcasing the clearmelt process, a technique that combines polycarbonate injection molding with polyurethane flood injection. It coats thermoplastic substrates with transparent or colored polyurethane, yielding scratch-resistant, resilient and functional surfaces for consumer goods and automotive exteriors. This achievement stems from a collaboration with machine manufacturer Engel (York, Pa., U.S. and Schwertberg, Austria), where clearmelt technology was incorporated to safeguard the iconic kidney-shaped front module of the all-electric BMW iX.

Originally a radiator grille, the BMW kidney grille now shields the electronic assistance systems’ cameras and sensors, enabling semi-autonomous driving. To accommodate these enhanced features, the front module’s structure and its production process underwent significant alterations. Since 2009, Hennecke and Engel have been partnering to pioneer new solutions, leveraging Hennecke’s expertise in polyurethane applications, and Engel as the prime contractor. 

Following an inquiry in 2018, Hennecke and Engel, with input from suppliers, toolmakers and cleanroom experts, developed a tailored solution for BMW’s Landshut plant in Germany. In a cleanroom setting, a heated functional film is backmolded with polycarbonate, flood injected with polyurethane and promptly prepared for further processing. This eliminates the need for additional finishing, thanks to the dual-function polyurethane coating that provides aesthetics and protection. Its self-healing properties counter minor damages, ensuring the car’s flawless appearance over time.

Polyurethane flood injection offers benefits beyond scratch resistance, including transparency for sensor visibility and a glossy, depth-enhancing surface. This technique permits diverse surface structures and thicknesses within a single piece, showcasing BMW’s commitment to sustainability by minimizing waste.

Besides clearmelt, Hennecke provides additional high-quality, functional surface solutions for the automotive sector.