The Design And Research Of Automotive Parts’ Flexible Welding Fixture

Automotive components are assembled into parts assembly by welding process on welding station. Precise positioning and suitable clamping force are provided by the welding fixture,which can ensure the welding accuracy. Therefore, to establish accurate positioning model and determine the appropriate size of the clamping force is the key to design the welding fixture.On the other hand,the flexible welding has great practical value as automotive life cycle becoming shorter and shorter and growing number of car type.But because of the low level of flexibility, high R & D costs and low management efficiency, flexible fixture has not been widely used.Therefore,the research of flexible fixture is imminent.The door is the most complex parts of the body process, so the door’s welding fixture has a strong representation. Based on automotive welding fixture design theory, The door welding fixture development process through virtual design methods is discussed. A set of flexible welding fixture development methods and product data management method for flexible fixture are also put forward. Specific contents are as follows:(1) Positioning model and clamping force model design: Based on "N-2-1" positioningtheory and RPS reference point system, the door’s positioning model is established. Themaximum permissible clamping force of door’s anchor point is obtained by FEM ofclamping force.(2) Force analysis of spot welding and welding fixture design: Locating and clampingscheme and clamping force size are determined by finite element coupling analysis ofspot welding; Fixture design, interference checking and ergonomic optimization arecompleted in CATIA.(3) Flexible welding fixture design: flexible welding fixture is designed with the designideas of “replace the distinct" and"merger the similar".The flexibility of welding stationis implemented in the structure.Then the flexible fixture and ordinary jig are also becompared.(4) Fixture product data management: In order to make flexible fixture on the station beadjusted quickly and accurately according to the product,a product data management system for flexible fixture and fixture knowledge engineering ar established initially.