Application of fuzzy TOPSIS and harmonic mitigation measurement on Lean Six Sigma: A case study in smart factory

Abstract

Customers’ requirements for product quality are increasing and more and more manufacturing companies are improving the quality of processing conditions at each production process by applying advances in Internet Technologies, Internet of Things, Big Data, Industry 4.0, Industrial Engineering Tools, Multi-objective optimization algorithms, Digital Numerical Control (DNC) method, and Six Sigma tools to improve productivity and quality of product. Continuous improvement of the manufacturing process presents a huge opportunity for the transformation of the normal production model to smart manufacturing. Manufacturing condition data, production data, quality of product data, and power quality data are measured and collected in real-time forming big data fed into operation analysis of the development strategy of the manufacturing company. In this study, the implementation of the Hybrid DMAIC (Define-Measure-Analyze-Improve-Control) method in six sigma is presented in detail based on the statistical hypothesis testing techniques for analyzing production data applied at the measurement phase, Multi-objective decision Fuzzy TOPSIS techniques applied to choose the best improvement solution applied at the analysis phase, Multi-objective optimization technique optimizes production conditions, and the DNC method performs automatically program call by RFID system applied at improvement phase, measurement technique, real-time measurement result collection and analysis by Industry 4.0 system and the method of phase shift is used to keep Total Harmonic Distortion (THD) and Total Demand Distortion (TDD) less than 5% within the international standard limits defined by IEEE 519:2022 and IEC 61000 applied at control phase. A common data system linking all activities at a particular manufacturing process and hybrid DMAIC in Six Sigma continuous improvement model is proposed in this study. This research’s results, the rate of occurrence of smaller-than-standard outer diameter defects decreased from 31.20% to 4.5% per month, the grinding process productivity achieved 610 pcs per day while the number of operators decreased from 4 people to 2 people per day, and productivity per person per hour increased from 15 PCS to 30 PCS. The profit is achieved at 11,184 USD per year. The Hybrid DMAIC method in Six Sigma is considered a model of continuous improvement that can be applied to production processes in manufacturing companies. The Hybrid DMAIC method in Six Sigma is simple to implement, easy to deploy into the real environment at production processes, and uses commercial software such as Minitab, LABVIEW, and SPSS. Manufacturing companies apply this research model to help improve competitiveness, improve business performance, and improve customer satisfaction.