A New Evaluation Method for Surface Finish of Composite Automotive Panels Using Waveform Analysis.

The surface finish of composite plates made using Resin Transfer Molding of glass/polyester is studied. A surface profilometer is used to measure the surface profile and to record raw data. The objective is to develop an objective method (rather than using human judgment) to differentiate the quality of one surface from another. Initially commonly used current techniques are utilized to assess the quality of the surface finish. These include subjective evaluation through a survey of observations from a group of people; the use of the average amplitude of the signals, frequency analysis, and filtering. For surfaces that have approximate quality, human visual observation can differentiate the quality between the surfaces, but the objective methods (average amplitude, frequency spectrum, and filtering) cannot. A new objective technique is found to be able to distinguish surfaces of approximate quality. This uses the comparison between the parameters of a reference good surface to those of the surface under consideration. A comparative index can be obtained to indicate the degree of similarity between the surface under study and the reference (good) surface. [ABSTRACT FROM AUTHOR]