Feasibility study on the pultrusion of V-shaped profiles using CCF/PEEK prepreg tape

Abstract

The pultrusion process enables the continuous and efficient production of high-strength, lightweight composite materials, making it a key technology for the manufacturing of lightweight, high-performance structural components. This paper studies the effects of pultrusion temperature and velocity on the structural properties of pultruded continuous carbon fiber reinforced Poly-Ether-Ether-Ketone (CCF/PEEK) V-shaped profiles. Using CCF/PEEK prepreg tape as the raw material, the pultrusion was conducted at eight different temperatures ranging from 230 °C to 370 °C and at five velocities from 10 cm/min to 30 cm/min. V-shaped profiles with a thickness of 0.3 mm, a single-side width of 15 mm, and an angle of 60° were produced. Forming angle, surface roughness and cross-section morphology of the pultruded profiles were examined. Additionally, the bending load capacity of the pultruded V-shaped profiles was tested using a set of self-designed testing fixtures. Results show that below the melting temperature, i.e. 343 °C, as the pultrusion temperature increases from 230 to 330 °C, the formed profile angle gradually approach the target angle, i.e. 60° and the bending load capacity increased to 99.4 N. However, above the melting temperature, significant damage occurs with the apparent rough and irregular surface of the pultruded profiles, where the surface roughness increased to 20.3 μm at 370 °C, due to the extreme flow of the melted PEEK thermoplastic matrix and the friction between the exposed fibers with the die. The pultrusion velocity has a minor impact on performance. More importantly, an evaluation method, is proposed based on the penalty function, to add industrial selection of the optimum processing parameters for achieving a designed performance. With minor consideration of the surface roughness, the optimum process parameters are suggested as 330 °C with the designed velocity range from 10–30 cm/min. While the surface roughness is considered a dominant parameter, the pultrusion temperature is suggested to be reduced. Such study is expected to provide scientific guidance for future production of the beam structures using high performance CCF/PEEK prepreg tape and are expected to be applied as lightweight truss structures in aerospace applications.