Abstract: The assembly quality of auto body is the key element of the whole production – level of a car, because the appearance, leak- proofness, and aerodynamic characteristics of the finished product depend on the dimensional quality of the body in white (BIW). At present, large- lot production and small sample measurement exist commonly in the auto plant in China, and accurate and quick evaluation of the quality of BIW is difficult to be achieved. Based on Bayesian theory, taking full advantages of the historical measurement information from stable production conditions, and synthesizing the current sample information, an evaluation method, which can precisely estimate the dimension quality while realizing the timing and effective dynamic monitoring of the BIW’s dimensional quality is provided. An opportunity for due discovery and control of assembly dimensional variation is given. An example of calculation about the practical measured data on BIW is given. Simulation calculation and real application shows that the method presented is very effective.

Key words: Assembly, Autobody, Dimension, Small sample