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

Abstract

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.

The Influence of Sample Size on Long-Term Performance of a 6σ Process

“…Analyzing the data in Table 1 and the four graphs in Figure 8, it was found that, for these reduced values of the step, relatively small different values were obtained, which means that at this level of detail the errors of the method are acceptable, and, therefore, the results obtained for the smallest step (0.01) will be used for interpretation (Figure 9). It is obvious that the results obtained are significantly different from the value of 3400 PPB, which is accepted by most authors [15,23,24,[27][28][29] or disputed by other authors [11][12][13] who do not propose another solution.…”

“…Since most works dedicated to the Six Sigma concept associate this concept with a maximum shift of 1.5σ and a long-term performance of 3.4 PPM or 3400 PPB [23,24,[27][28][29], it is obvious that this is only a short-term situation (although it is extreme-for the maximum drift), and the following question arises: For a 6σ process (which keeps its standard deviation value unchanged over time, but which naturally has a drift over time, remaining stable), what is the proportion of long-term non-conformities (long-term performance of 6σ processes)?…”

Lean, six sigma and sustainability case studies on supply chain management: a systematic literature review

“…Table 4 shows the frameworks and their application in supply chain management. The authors highlight as a limitation of the model the non-implementation in the industries due to financial limitations (Cherrafi et al, 2017b;Pfeifer, 2022). The relationship between the manufacturer and its suppliers must be observed and improved so that the benefits of this relationship are transferred to the final customer (Cherrafi et al, 2016;Chiarini & Vagnoni, 2017;Powell et al, 2017a;.…”