Tow Steering of Stretchable TuFF Thermoplastic Tape with Laser Tape Placement

Abstract

Steering of fiber tows using the Automated Fiber Placement process has been shown to increase the versatility of composites design for highly tailored Variable Angle Tow (VAT) laminate structures. Manufacturability is limited to the minimum steering radius which can be placed without defects. A recently developed, highly aligned, short fiber material called Tailored universal Feedstock for Forming (TuFF) allows forming of complex geometries due to its 40 % elongation capability. This paper investigates the steerability of TuFF material made out of 3 mm-long carbon fiber and Polyetherketoneketone (PEKK). An industrial advanced fiber placement system (AFP) by Mikrosam is used to steer a 6.35 mm (0.25 in) tape at different radii in the range of 25 mm to 200 mm. An offset strain is applied to counteract the buckling of the fibers using a differential speed of the feeding and compaction roller. The steering experiments showed that TuFF can be stretch steered to a minimal steering radius (MSR) of 50 mm which is over an order of magnitude smaller than the MSR of conventional continuous fiber tapes.