Empirical Optimization of Kiss-Roll Coating for High-Speed Bicomponent Fibre Production

Abstract

Hybrid bicomponent fibres represent a novel class of intermediate materials for the high-volume production of thermoplastic composites using stamp forming. Being comprised of filaments which are individually clad with a thermoplastic, such preforms potentially exhibit very short cycle times due to full fibre wet-out while retaining the high formability of dry textiles. Therefore, bicomponent fibres overcome the drawbacks of existing hybrid intermediate materials. A proposed efficient method to manufacture bicomponent fibres is kiss-roll coating with a dilute polymer solution in-line with glass melt-spinning. This study focuses on the optimization of the coating parameters to yield fibre volume fractions appropriate for use in advanced structural composites. Experiments performed within a central composite design parameter study reveal the influence of the fibre speed, the concentration of polymer in the coating solution and the radius and the peripheral speed of the kiss-roll on the yielded fibre volume fraction. We identify an optimum parameter combination to maximize fibre speed as the concentration of the polymer is minimized and the roll radius and peripheral roll speed are maximized. Through further consideration of the robustness and sensitivity of the coating process, these findings are related to implications on the design of a high-speed coating stage in-line with glass fibre spinning.