Alignment Quality Improvement Research Of Generator And Gear Box Based On Six Sigma At YSM Company

In June2011, In order to be more competitive in wind power market, a battle called “MUSTWIN” was introduced to YSM company. There are two big projects involved at Nacelle PBU:lean production and six sigma. One of the critical to quality point that improve the alignmentquality level of generator and gear box is implemented as six sigma project. Currently, YSMquality level of aligning generator and gear box is about two sigma and it takes a lot of time, andadjusting results is instability. Customers are not satisfied with the quality level, and sometimesYSM has to send maintenance personnel to rework it in wind turbine which stands tens of metershigh on field.YSM company decides to adopt six sigma methods to study quality improvement of thealigning generator and gearbox in response to the call of headquarter and to enhance customersatisfaction and to reduce non-conformity costs.YSM analyzes and demonstrates and researches on the subject by six sigma DMAIC mode.First, define the scope of the study, identify process related with the subject; second, clarify andmeasure the critical outputs of process, and set goals; then, use the fishbone diagram to presumethe factors causing the process failure, analyze the process base on the flowchart and select themajor input factors by tool of process potential failure mode and effects analysis; the forth,remove or reduce these major factors and run process to verify the assumption; finally, if thecorrective method is effective, revise the process documents and implement statistical processcontrol to keep the improvement achievement. During the research on the subject, we used a lotof tools and graphics and charts, such as flowcharts, fishbone diagram, cause and effect matrix,process potential failure mode and effects analysis, Minitab software etc.YSM company ultimately finds a method to improve the aligning quality level of generatorand gearbox through six sigma methodology, and reduce the time of adjust. Now the qualitylevel of aligning becomes from six sigma to four sigma. If our people work according to theoptimized process and methods, then it will greatly reduce the production cost andnon-conformity cost, improve work efficiency. In the meantime of research and practice, wegradually understand the six sigma DMAIC methodology, and familiar with the MSA, control chart, PFMEA, Minitab and other tools，the project team activities also enhance our teamcollaboration.