Quality control of paint coatings on car bodies using individually created inspection plans

For a variety of reasons, assessing the quality of paint coatings on car bodies is increasing in importance. Narrow tolerance limits and strong demand for smooth finishes require precise measurements of the coating thickness according to clearly defined testing procedures. In addition, the measurement results should provide clues for potential process optimizations. Therefore, consistent inspection procedures – regardless of who is doing the measuring – are also essential.

Paint finishes on car bodies must fulfill a range of criteria: Not only should they provide sufficient corrosion protection (therefore requiring at least a minimum thickness) while simultaneously containing costs (minimum material waste), the color and texture must also be even and homogeneous. To check all these criteria systematically, test measurements should always be taken at the same spots, in the same way, regardless of who is currently executing the inspection.

Fig.1: Simplified surface development of a car body with defined measuring spots

Using simplified surface development drawings, precise inspection specifications can be displayed for the examiner, showing exactly where the paint coating is to be measured. However, such sequences are often very complex and therefore susceptible to operator fail