Manufacturing of all‐thermoplastic sandwich systems by a one‐step forming technique

Abstract Thermoplastic sandwich composite systems offer great potential for future automotive applications. High specific bending stiffness, good insulation properties, high specific energy absorption and impact resistance can be achieved by the use of fabric reinforced sheets as sandwich faces and thermoplastic foam as core material. Recycling is possible by chopping and injection molding. Fabric‐reinforced thermoplastic sheets consisting of 10 layers glass fabric were impregnated continuously with a polyamide‐12 matrix using isobaric double belt press technique to 2‐mm‐thick faces with a fiber content of 50 vol%. Sandwich angles and hemispheres were manufactured by heating the faces and the 13‐mm‐thick foam core above the melting temperature and high‐speed stamp forming with matched metal tools. Cycle times for forming and cooling were below 40 s/part. Different heating methods were matter of investigation. Best results could be achieved by conductive heating. This new material system and its processing technology are promising methods to reduce structural car weight and enhance passenger safety.