YIELD INDEX BASED ON CONCEPT OF SIX- SIGMA SSCPK FOR ASSESSMENT PROCESS PERFORMANCE IN INDUSTRIES

Process quality is a key factor in facilitating product sales, (PCIs), which determine the relationship between the manufacturing specifications and the actual process performance by quantifying process potential. Although Cp, Cpk indices are the most popular and important criteria used in manufacturing industries to measure process performance reported extensively in the literature, in the literature, the majority of previous studies neglected the idea of Six Sigma (SS). However, existing PCIs based on SS presented only a range of quality levels rather than a specific quality level value. The purpose of this study is to measure and enhance the precision of performance evaluation for processes industrial, through the use of (PCIs) and (SS) concept. In light of this, this study introduces new performance index based on the idea SS which are SSCpk by extending the indices Cp, Cpk and calculating the sigma process level directly to measure yield process based on idea SS. To demonstrate the effectiveness applicability of the SSCpk index, this study presents an industrial case study to assess the process performance of Aden oil refinery in Yemen. Toward this end, the data for essential quality characteristic of petroleum products namely octane number was collected randomly from Aden refinery. The findings of this study indicated that the proposed index SSCpk outperformed on the existing indices Cpk as the shows at the results and discussion. Finally, the proposed process yield index based on SS concept is a promising approach and thus can be utilized by other industries and practitioners to assess process performance in the aspect of precision and quality control.