Using a Novel Process-Near Mechanical-Deflection-Based Spreading Test Rig for a Systematic Experimental Analysis of Carbon Fiber Rovings Spreading Process

Abstract

Unidirectional (UD) fiber-reinforced thermoplastic tapes provide excellent specific mechanical properties; thus, they are being increasingly used for the targeted local reinforcement of plastic components in lightweight construction applications. An essential step in the production of UD tapes is fiber spreading, the aim of which is to expand fiber rovings from an initial width to a defined final width. Using a test rig under realistic conditions, we systematically investigated the factors that influence fiber spreading by deflection. Carbon-fiber rovings with various numbers of filaments were guided over deflection rods, and roving width before and after spreading was recorded with cameras. A full design of experiments (DoE) plan was set up, in which (i) the number of rods, (ii) rod diameter, (iii) immersion depth of the rod, and (iv) take-off speed of the fiber roving were systematically varied. We statistically evaluated the results of the experiments and found that the main factors that influenced the response variables investigated were number of rods and rod diameter, followed by immersion depth. We also observed that a higher number of filaments in the roving led to more complexity and greater variability. Our results can be used to optimize the spreading configuration in the production of UD tapes.

Keywords

• UD tapes
• carbon fibers
• fiber spreading
• spreading by deflection
• design of experiments