Evaluation of Warpage for Composite Automotive Components
Abstract
Thermoplastic composite parts are manufactured using compression molding for the purposes of assembly in a car seat sub-assembly. Concerns about the dimensional accuracy of the parts prompted an investigation into the part warpage. The warpage of the parts needs to be evaluated for the purposes of determining processing conditions which are linked to part warpage, in order to reduce part warpage.
Laser line probes (LLP) are becoming a more attractive tool for the purposes of part inspection. LLPs quickly acquire point cloud data from complex surfaces and are a non-contact method of measurement; these qualities make LLPs the best tool for the inspection of warped composite parts. Currently there are no guidelines for inspecting this class of parts which require special scanning conditions (no rigid fixtures). There exists no evaluation of the repeatability or accuracy of LLP scans under these specific scanning conditions. To address this knowledge gap, research was conducted comparing several methods of scanning to outline a scanning procedure which would provide reliable results.
Similarly there are no guidelines for warpage measurement in general. The method of measuring warpage is typically informed by part geometry and warpage behavior, and thus can be different for each case. To address this issue several warpage metrics are proposed and applied to discover the effectiveness of each method. Finally the investigation of processing parameters can be accomplished. In this thesis several experiments are conducted to understand the impacts of mold temperature, charge placement, material, and geometry on the final part warpage.