Abstract: Upon a research in the enterprise, an understanding is reached that the auto parts company produced by the intake manifold did not come up to the six sigma standard. Combining the company's current situation with the current management model, it is decided to import the DMAIC(define-measure-analyze-improve-control) method of six sigma during the company's intake manifold production quality improvement process. The product currently below the six sigma standard should be defined, measured and analyzed. And then programs of quality improvement are put forward, and through hot-charging experiments the effectiveness of the programs is verified. Finally the control method of assembly quality is put forward. In this process the seven QC practices, foolproof design, statistical questionnaire, FMEA and some other quality management methods are used in problem assumptions, analysis and verification.

Key words: DMAIC method, assembly process, intake manifold, heat plug, quality improvement