Abstract

Composite plates and panels are increasingly used in automotive body parts. These composite structures possess excellent strength and stiffness properties. For these applications, the surface finish of exterior surface of the composite panel is of critical importance to obtain customer acceptance. Automakers pursue to attain surface finish of class A for composite panels, in which they believe class A's surface finish should be very smooth and beautiful. Due to the lack of a good objective method to describe Class A surface finish, the surface finish of Class A is often determined by visual observation. On the other hand, for low cost operation, Resin Transfer Molding (RTM) is used to manufacture composite panels. Process parameters of RTM affect the surface quality of molded panel. There is a strong desire on the part of the automakers to obtain objective means for evaluation of surface finish. This objective means may allow automated correlation between process parameters and surface finish. This facilitates process optimization. Composite plates made by the RTM process using different process parameters (i.e amount of Low Profile Additive (LPA), process temperature and time) may have variations in the surface finish. Current objective surface measurement techniques can not differentiate the qualities of these surfaces, thus can not be used easily to optimize the process parameters. Work done in this thesis has resulted in the development of a new technique that is capable of objectively differentiating the quality of the surface of one composite plate to another