RAPID QUALITY FEEDBACK THROUGH LEAN MANUFACTURING by Brian

This thesis presents a methodology of improving quality through the use of feedback and lean manufacturing to streamline the process of feedback. As customers' expectations and competition increase, so does pressure to improve quality and reduce manufacturing costs. This thesis examines an approach which improves quality, thereby reducing manufacturing costs. This is accomplished without negative effects on other manufacturing measurables and without large capital expenditures. An informational feedback loop is used to relay quality (and defect) information to upstream operations within a manufacturing process. A lean manufacturing tool of process mapping is then used to reduce the delay of this information through the process. This thesis also examines the implementation of this approach within a component's manufacturing and assembly process. Process mapping is used to improve operations within a retest and repair area. Waste and delays identified in the process map are reduced or eliminated to improve the rate and accuracy of defect detection. Information regarding specific defects is then fed to upstream operations to make improvements in the manufacturing process. Results of the implementation include 95% reduction in lead time through the area, 95% reduction in area inventory, and 90% reduction in total time from defect occurrence to detection. A 50% decrease in scrap cost was observed in only four weeks, and an 80% decrease has been accomplished to date. The implementation approach is directly applicable to many manufacturing systems, and the general approach is applicable to any process in which the quality of output is important. Implementation across a wide variety of industries and processes is possible. Thesis supervisors: Stanley Gershwin, Senior Research Scientist Charles H. Fine, Associate Professor