Solenoid valves quality improvement based on Six Sigma management

Purpose The purpose of this study is to present the implementation of Six Sigma in a solenoid valve manufacturing company in China. The project aims to reduce the solenoid valve defects, decrease the cost of poor quality, increase customer satisfaction and improve the long-term profitability of Company B. Design/methodology/approach This paper follows the Six Sigma methodology: DMAIC (define, measure, analyse, improve and control) principle of case study research. Hysteresis, the key characteristic of a solenoid valve, is the main chance for quality improvement. This paper emphasizes the solution to the hysteresis problem. During DMAIC phases, the critical factors that affect hysteresis performance are identified for continuous quality improvement of solenoid valve manufacturing. Findings The implementation of Six Sigma leads to a great quality improvement for the company studied in this paper. Control plans are made for good hysteresis performance. As a result, the first pass yield of solenoid valves has increased from 60% to 99.64%. The key hysteresis of the solenoid valve has shown a better performance. Originality/value This study presents a solenoid valve industrial quality improvement case that demonstrates how Six Sigma and DMAIC methodology can be applied to reduce defects and achieve quality improvement in Company B. This study can be referred to for managers and engineers to undertake quality improvement programs.