Abstract: The coach side skin is an important part of the apparent quality display of the car body, which is very concerned by manufacturers and customers. This paper takes the improvement of flatness of coach side skin of A coach factory as the research carrier, according to the steps of Six Sigma DMAIC, using Six Sigma tools and methods such as high-level process flowchart, measurement system analysis, variable flow chart, cause-effect matrix, regression analysis to improve the main problems related to flatness in the process of making coach side skin. The flatness of coach side skin was reduced from 3.25 mm to 2.11 mm before improvement, which achieved the target. According to the results, similar problems can be effectively improved by applying Six Sigma steps and methods.

Key words: Six sigma; Coach; Flatness of coach side skin; Flatness improvement

摘要： 客车侧蒙皮是车身表观质量展示的重要部件，各生产厂家与客户都极为关注。文章以 A 客车厂客车侧蒙皮平整度改善为研究载体，按照六西格玛 DMAIC 的步骤，应用高级过程 流程图、测量系统分析、变量流程图、因果矩阵、回归分析等六西格玛工具与方法，对客车 侧蒙皮制作过程中平整度相关的主要问题进行改善，使客车侧蒙皮平整度从改善前的 3.25 mm 下降至 2.11 mm，达成设定目标。从结果来看，类似的问题应用六西格玛步骤与方法可以得 到有效改善。

关键词: 六西格玛；客车；侧蒙皮平整度；平整度提升