A Reduction of Interior Peel off Defect in a Robot Spray Coating Process
The Teflon coating on the hardened aluminum surface is the process of creating a film on the smooth surface which requires three layers of coating and each layer must be cured at a certain temperature. Due to a complexity of the process, peel off defect is one of the intimidate defects in the coating process. The objective of this research is, therefore to determine optimal coating parameters in order to reduce the peel off. A robot attached with a spray gun at the end effector is used to spray Teflon onto the hardened aluminum work-piece. Typically, there are three steps coating process i.e. primer, middle, and top. In this research, only the prime coating layer is studied due to the fact that the peel off defect normally occurs from this layer. A curing temperature immediately after coating is one of the root causes besides air pressure, an angle of the spray gun and fan pattern. Therefore, the experimental design technique is used to determine the relationship among these mentioned variables and identify the optimal condition. The 2k factorial is used in the experimental design and analysis of variance is used to analyze the result. It is found that the optimal condition of curing temperature at 95 degree Celsius, air pressure at 2.5 bars, a gun angle at 60 degrees, and the fan size at 5 Volt setting at the robot controller provides a better result. The peel off defect is reduced from 2.88 to 1.60 percent.
T. Kasorn and S. Prombanpong, "A Reduction of Interior Peel off Defect in a Robot Spray Coating Process", Materials Science Forum, Vol. 911, pp. 8-12, 2018