On designing an efficient control chart to monitor fraction nonconforming |
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Authors: | Zameer Abbas Hafiz Zafar Nazir Noureen Akhtar Muhammad Abid Muhammad Riaz |
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Affiliation: | 1. Department of Statistics, Govt. Ambala Muslim College Sargodha, Sargodha, Pakistan;2. Department of Statistics, University of Sargodha, Sargodha, Pakistan;3. Department of Statistics, Government College University Faisalabad, Faisalabad, Pakistan;4. Department of Mathematics and Statistics, King Fahad University of Petroleum and Minerals, Dhahran, Saudi Arabia |
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Abstract: | Process control measures are mostly applied in production and manufacturing industries. The most important tool used in these disciplines is control chart. In manufacturing and production processes, when the quality characteristic of interest cannot be directly measured, it becomes essential to apply attribute control charts. To monitor fraction nonconforming of the output, quality practitioners mostly prefer p-chart. In this article, a new progressive mean (PM) control chart is being proposed for monitoring drift in proportion of nonconforming products. The design evaluations of the proposed chart are made and compared through different properties of run length distribution, such as average run length (ARL), standard deviation of run length (SDRL), and some percentile points. The performance of the proposed chart is assessed under zero-state and steady-state scenarios. The proposed PM chart is compared with p-chart, moving average (MA) chart, optimal CUSUM chart, modified exponentially weighted moving average (EWMA) chart, and runs rules p-charts for monitoring fraction nonconforming. The proposed chart spots efficiently sustained disturbances in the process as compared with their existing counterparts. Two illustrative examples are also provided; one from real-life application of nonconforming bearing and seal assemblies data and the other from simulated data for the implementation of PM chart. |
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Keywords: | attribute average run length control charts fraction nonconforming p-chart process progressive mean |
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