Research on design optimization and manufacturing of coating pipes for automobile seal based on selective laser melting

The existing flow pipes used in Volkswagen vehicles for PVC coatings are weak and would break easily, the root cause analysis is undertaken in this study to address this problem, the structure of these flow pipe made by the traditional manufacturing technology is analyzed. We have designed and proposed the manufacturing of the precise flow pipes for PVC coatings by combining metal Additive manufacturing with the traditional processes, including CNC and electric spark. The design of the flow pipe structure is optimized without compromising the quality of the PVC coating. Coating performance has been pre-evaluated using CFD simulation. The influence of the selective laser melting parameters (e.g., placement orientation of the forming surface, the wall thickness of the pipe) on the fabrication of flow pipes are investigated, and the optimized flow pipe showed better flow rate. The variation in pressure inside the pipe when compared to the pipes manufactured using traditional techniques. High-quality fabrication of the flow pipes can be achieved by setting the forming surface angle at over 45 degrees when the pipe wall thickness was 0.15 mm. After the flow pipe fabrication by SLM, the outlet was processed by the electric spark drilling to improve its surface quality and coating performance. Tests are performed to coat PVC glue on the lid of the trunk using the optimized flow pipe. The coated PVC glue has resulted in a smooth surface with an appropriate width, qualifying it as Grade A. The experiments demonstrate the capability of the combination of SLM and traditional manufacturing techniques to fabricate complexed parts with high precision.