Motor Vehicle Manufacturing Technology (September 1995)
Wet Paint Thickness Measurement System
Develop a non-contact method for measuring the thickness of wet coatings as they are being applied to enable higher-quality, less polluting, and more cost-effective painting processes for the automotive industry.
Sponsor: Perceptron, Inc. (formerly Autospect Inc., A Division of Perceptron, Inc.)4750 Venture Drive
Ann Arbor, MI 48108
Painting is the most costly process in automotive manufacturing. It takes more than a dozen discrete steps to coat a bare metal auto body with a high-quality finish, and many things can go wrong at each step. Rapid, reliable, and accurate measurement of the amount of material being applied to surfaces is the primary way to detect and correct problems. Unfortunately, with current feedback technology, at least 100 more units will have been coated before adjustments can be made to correct a detected problem. Autospect, Inc., proposes to develop measurement techniques, known together as a Wet Film Measurement System (WFMS), that will allow automobile painters to determine the thickness of surfaces while they are still wet and being applied. This will allow more precise control over the painting process as well as faster and less costly responses to problems when they do arise. Moreover, a real time on-line analytical ability of this sort should result in less use of paint, fewer expensive repairs, less waste, fewer emissions, and a consistently higher quality appearance. Various non-contact measurement techniques will be investigated for their suitability in a WFMS. Then, experimental sensors will be designed and constructed so that they can be integrated with robotic and computer control systems. Another crucial task involves determining the conditions under which the WFMS can work in a realistic automotive painting venue. It is projected that a successful WFMS could shave $50 from the typical $345 that it costs to paint a car, translating into an annual manufacturing savings of $360 million for the Big-3. By cutting in half the current 15 percent of all vehicles with coating defects requiring a "high bake repair," a WFMS could save automakers an additional $325 million per year.