Research Of Quality Improvement On Automotive Interior Part For Company Q

The whole business chain of automotive industry is promoted and facilitated by the rapid development itself in recent years.The competition in automotive industry has becoming more intense with more enterprises and capitals participating,there is no additional capacity of automotive industry basically due to this impact.The enterprise business has becoming more challenging as supply demand changing and customer increasing quality requirement.The same challenges also happen to company Q,which is a supplier of automotive interior parts.The research adopts the DMAIC method,which is a general method in Six Sigma management,to analyze the quality problems from automotive interior parts of company Q systematically,to improve the product quality performance.The thesis introduces the background and the significance of the topic as well as the research objectives and contents firstly,following with a brief description for the origin and development of Six Sigma management and the literature review.For the quality problems existing in company Q,milling edge damage is determined as the main quality problem to be solved according to the improvement space and classification.Making sure the overall defect rate below 0.5% is set as project target based on the actual performance.For clarifying the quality performance before improvement,data collection is done with a one-month trial production in measurement phase firstly,and also the defect scope is narrowed by the classification for the defect products.Secondly the machine capability index is measured and calculated for making sure the equipment is stable enough.All the potential causes of defect are listed during analysis phase by Ishikawa and brain storming,and non-significant factors are eliminated one by one with quality tools such as single-ratio test,double-ratio test,measurement system analysis and process capability analysis,which leads to the conclusion that milling feeding speed is the main factor of milling edge damage.The relation between milling feeding speed and milling edge damage is clarified by logistic regression,the balance point of quality improvement and capacity losing is also found.Annually 200,000 RMB can be gained by reducing product defect rate.The defect rate of milling process can be controlled below 0.5% which means the project target achieved.With the standardization for the improvement action in control phase,the effectiveness of improvement implementation can be ensured from system procedure,with the supporting of control chart as a method for long time monitoring,the stable product status and effective measures showed the project target achieved.Starting with main quality problems of company Q,the thesis improves the quality performance with DMAIC application.And also the thesis could be the reference for quality improvement of the same type of automotive interior trim company as well as the quality improvement of milling process for wooden interior trim parts.