Research On Compensation Method For BIW Manufacturing Error

Car body and cab are the major products of automobile manufacturing enterprise,and the government of the manufacturing error in body-in-white is always worked tobe done. Since the error is affected by many factors and has strong randomness, itmakes errors governance complex and difficult. On existing production models, thelevel of manufacturing error control in BIW is an important symbol of product quality;For the research and development of the new product， Whether or not themanufacturing quality of BIW up to standards often determines the speed to market ofnew models. This subject comes from actual scientific research, aims to research thegovernment of manufacturing error of the BIW in the trial stage of the car.Bysumming engineering experience, this paper summed up a method which uses weldingfixture to compensate the errors of stamping. this paper uses non-contactthree-dimensional scanner, scanning the stampings and assemblies gets the point clouddate of it; then the scan results are compared with the standard modulus, detectingerrors stamping surface and evaluating.Finite element simulation of fixture adjustmentfirstly puts the point cloud reversing NURBS surfaces, Then the paper selects the pointof welding fixture and measures errors between the surface and the standard modulusof these points; Then these errors are applied as a constraint to the stamping surfacedisplacement, and using finite element method to analysis these surface,Which is toachieve the effect of the adjustment fixture simulation; Finally, the simulation proceedsderived surface grid nodes as the standard point cloud modulus contrast, evaluatingand predicting the result of the adjustment of welding fixtures. If this article satisfieswith the results of the errors after simulation, then it can use a displacement amount ofsimulation to adjust the production site of the fixture adjustment.This paper describes a method of the error compensation, and using this methodto complete a fixture adjustment project example to verify the feasibility of thismethod. The result of the study for governing the white body manufacturing error has certain reference significance in the future.