Manufacturing method of a thermoplastic semi-finished product as reinforcement in laminate thickness direction

This work presents carbon fiber reinforced thermoplastic pins as thickness reinforcements for carbon fiber reinforced plastic (CFRP) laminates. The pins have a staple-like geometry (so called clips) and are intruded into dry fabrics during preforming. In order to ease the pin handling, the processing and to stabilize the pin during the intrusion, several pins are fixed to a thermoplastic tape. The pins and the carrier tape define a semi-finished product. The base material for the pins is a rod-shaped consolidated composite made of carbon fiber reinforced PA 6. A thermoforming process is presented, which forms the base material into the staple-like geometry and simultaneously bonds the pin onto the carrier tape. The influence of different CFRP pin widths at a constant volume content on interlaminar properties was investigated in GIC tests. The smallest investigated pin width of 1 mm increased the interlaminar toughness compared to unreinforced samples by 113%.