Impact of Weld Fixture Clamp Force Variation on Dimensional Integrity in Low Volume Body-in-White Build

Body in White (BIW) is an assembly of multiple sheet metal components. BIW is a major contributor to the dimensional and structural integrity of an automobile. The accuracy and precision of the BIW is influenced by multiple factors involved in the manufacturing lifecycle of the BIW, of which component development and assembly strategy are the most significant contributors. Weld fixtures are the tools used for accurately locating and holding, sheet metal components for joining. The primary motive of the locating and holding strategy is to arrest all degrees of freedom of a component. Geometric repeatability of the components is also of high importance. Component location is typically achieved by standardized locator pins that maintain the Principal Location Points (PLP). Mylars provided at Master Control Patches (MCP) ensure the resting and clamping of the component. Low volume BIW builds employ non-automated clamping methodologies, either with manual clamps or toggle clamps. This paper studied the dimensional variation of sheet metal assemblies with variation in clamping forces in both non-automated clamping strategies. Impact of the clamping strategies on the dimensional integrity of the assemblies were evaluated using both strategies. The appropriate clamping strategy is recommended based on the results of the study.