Six sigma is understood as a technique for the continuous improvement in process quality; however, it has been rarely scientifically analysed in small- and medium-sized enterprises (SMEs). SMEs representthe vast majority of enterprises throughout economies and contribute to automotive supply chains in various tier ranks. As SMEs are known to lack resources and skills while focusing on short-term benefits rather than on long-term gradual improvements, the aim of of this paper is to analyse the perception of six sigma process capabilities in automotive supply chains assuming differences in company size, supply chain rank and six sigma duration. This was tested with Fisher’s exact test. Companies with less than 1000 employees, subsuppliers and companies with a six sigma implementation in the last 3 years struggled to meet six sigma principles, suggesting that mainly small companies inhibit a risk for the supply chain. These findings contribute to the existing theoretical body of knowledge by identifying a three-to-five-year period for six sigma implementations until six sigma maturity. Practically, the findings contribute to the research by explaining the need for a continuous supplier development over a three-to-five-year period until the company meets its performance requirements, with a supply chain risk incorporated in lower-tier ranks and with small companies.

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SMEs in Automotive Supply Chains: A Survey on Six Sigma Performance Perceptions of Czech Supply Chain Members

Two-Criterion Optimization of the Worm Drive Design for Tool Magazine

Six-Sigma, a data-driven methodology, employed to improve the process in terms of Defect reduction or process optimization. In this paper, an experimental study is presented optimizing the cutting parameters while machining of shoulder bolt in a Computer Numerical Control (CNC) turning machine to reduce the cycle time. This study identifies, the effects of cutting speed, feed rate and dwell time on Thread rolling diameter (TRD) in CNC turning machine that was experimentally investigated. The experimentation plan is designed using six sigma D-M-A-I-C methodology, and the subsequent statistical analysis has been done using Minitab-16 software. Shainin based variable search tool has been used to investigate the design parameters that contribute to the reduction of the cycle time and factorial plots are employed to determine the contribution of important parameters. Later, the optimal values for the best cutting conditions are proposed for industrial production using the formulated mathematical model. Finally, this paper documents the analysis and tasks performed that reduced cycle time which resulted in increased productivity and also in annual savings.

Biswajit Kar

Papers

Cycle Time Reduction in CNC Turning Process Using Six Sigma Methodology – A Manufacturing Case Study