Six Sigma application for quality improvement of the pin insertion process

Abstract

Six Sigma is a systematic and organized, client-oriented approach that aims to improve the performance and quality of processes, products and services using statistical techniques. This paper presents a case study performed in an automotive company that intends to reduce the defective units produced by an automatic process, the process of single pin insertion, using the DMAIC (Define, Measure, Analyze, Improve, Control) method that is a structured way to carried out Six Sigma projects. In this process, excessive pin insertion force on Printed Circuit Boards (PCBs) entailed high rejection costs and line stop times that affected the supply of the final assembly lines. Therefore, the application of Six Sigma had the purpose to increase the quantity of products produced well at the first time and to reduce the quality costs associated to the process. To this end, the problem was defined, measured and analyzed starting from the machine and the two products with the highest number of rejections. An exhaustive analysis to determine the root cause allowed concluding that the excessive force is generated by the interaction of three factors: the PCBs physical characteristics, the pins contact zone and the wear of the machine components. A set of improvements focused on these factors raised the quality levels of the process, making it more stable and with less variability, by reducing the insertion forces to values closer to the nominal value. Methods for keeping the process under control were also defined and implemented. The use of some quality tools and the Six Sigma methodology proved to be extremely positive since this has led to significant improvements in the quality of the pin insertion process.