Mobile Phone Assembly Process Quality Management Study Base On Six Sigma

With the increasingly fierce market competition, mobile phone manufacturing enterprises are facing the unprecedented challenge, and facing higher requirements on the quality of products. In order to change the downturn situation, Nokia make decision to collaborate with Microsoft, produce smart phone with windows system, and began to integrate its own resources, Beijing factory become the unique assembly factory of Nokia smart phone in global field. To improve the quality of smart phone in assembly process, has an important significance for the cost saving of Nokia smart phone manufacturing.This thesis focus on the quality management’s development and application trend firstly, and clarify the Six Sigma has become the most preferred method in enterprise quality management. Next, this thesis in-depth study the Six Sigma theory and application method. Then simply introduce the manufacturing process of Nokia smart phone, and select Nokia B products as an example, using Six Sigma DMAIC (Define, Measurement, Analyze,Improvement, Control) method to improve the back cover scratch issue in assembly process. In project define phase, firstly analysis the B product’s quality status in assembly process by Pareto chart, then define the customer requirements, quality issue, project scope, target, cost saving estimation, set up the project team and make the improvement schedule. In project measurement phase, firstly estimate the repeatability&reproducibility of measurement system, analysis the process capability, and then find out the top three scratch types of back cover scratch issue according to Pareto chart analisis, In project analyze phase, find out the possible key factors of the back cover scratch issue by cause and effect diagram analysis and FMEA analysis, then validate those key factors by hypothesis testing analysis. In project improvement phase, firstly improve the key factors one by one, then update the FMEA, analysis the process capability and calculate the cost saving after improvement. In project control phase, update the control plan, standardized related documents and monitor the production process regularly. After the quality improvement by Six Sigma DMAIC method, back cover scratch ratio of B product has been sharply reduced and effectively controlled, thereby reducing the assembly cost and make benefits to the factory. The successful implementation of this project, not only shows that Six Sigma DMAIC method is a feasibly quality improvement method, but also bring a rich experience for other products.