Approach to Achieve Weight Reduction for Sprayable Vinyl Plastisol Sealer, on Automotive Underbody

Vehicles subjected to Indian duty cycles have to undergo extreme environments & road terrains, stone chipping. Underbody wear from this is one of the most significant forms of deleterious corrosion. Automobile companies deal with this by going for exotic & expensive underbody coating, which compositionally are "Polyvinyl Plastisol also popularly known as Poly Vinyl Chloride (PVC)". Across automotive industry, the stone chipping is prevented via applying PVC-coating to the extent of 800-1000 microns. The application of PVC-material throughout the vehicle underbody will add approximately 8-12 Kgs of weight. Our objective was to reduce the weight of applied PVC-material. This paper deals with our objective to reduce the weight by following two different approaches: a) Application area optimization & b) Application thickness optimization. a) Application area optimization: The region vulnerability was established via undertaking curated vehicle-level duty cycles and Computational Fluid Dynamics (CFD) simulations. Physical and digital validations revealed critical areas having maximum stone impact. So PVC-application was optimized for these critical zones. b) Application thickness optimization: For establishing the optimum thickness requirement, extensive characterization via Nut Fall Test & Stone Chipping Test was undertaken. The threshold was determined with multiple design of experiments. Thus the minimum thickness was derived to meet the critical performance requirement in this zone. The results obtained with this approach indicated a weight optimization potential of 20%.