The exponentially weighted moving average (EWMA) control chart is a memory chart that is widely used in process monitoring to spot small and persistent disturbances in the process parameter(s). This chart requires normality of the quality characteristic(s) of interest and a smaller choice of smoothing parameter. Any deviations from these conditions affect its performance in terms of efficiency and robustness. For the said two concerns, this study develops a new mixed EWMA chart under progressive setup (mixed EWMA–progressive mean [MEP] chart). The proposed MEP chart combines the advantages of robustness (under nonnormal scenarios) and high sensitivity to small and persistent shifts in the process mean. The performance of the proposed MEP control chart is evaluated in terms of average run length and some other characteristics of run length distribution. The assessment of the proposed chart is made under standard normal, student's t, gamma, Laplace, logistic, exponential, contaminated normal and lognormal distributions. The performance of the proposed MEP chart is also compared with some existing competitors including the classical EWMA, the classical cumulative sum (CUSUM), the homogenously weighted moving average, the mixed EWMA–CUSUM, the mixed CUSUM–EWMA and the double EWMA charts. The analysis reveals that the proposal of this study offers a superior design structure relative to its competing counterparts. An application from substrates manufacturing process (in which flow width of the resist is the key quality characteristic) is also provided in the study.

中文翻译：

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在渐进设置下开发指数加权移动平均线图：一种有效的制造过程方法

指数加权移动平均值（EWMA）控制图是一种内存图，广泛用于过程监视中，以发现过程参数中的细微和持续性干扰。该图表需要关注的质量特性的正态性和较小的平滑参数选择。这些条件的任何偏差都会影响其性能，如效率和鲁棒性。针对上述两个问题，本研究在渐进设置下开发了一个新的混合EWMA图表（混合EWMA –渐进平均值[MEP]图表）。拟议的MEP图表结合了鲁棒性（在非正常情况下）和对过程平均值小而持续变化的高度敏感性的优点。建议的MEP控制图的性能是根据平均游程长度和游程长度分布的其他一些特征来评估的。拟议图表的评估是在标准正常，学生的t，伽马，拉普拉斯，对数，指数，受污染的正态分布和对数正态分布。拟议的MEP图表的性能也与一些现有竞争对手进行了比较，包括经典EWMA，经典累积和（CUSUM），均匀加权移动平均值，混合EWMA-CUSUM，混合CUSUM-EWMA和双EWMA图表。分析表明，相对于竞争产品，本研究的提议提供了更好的设计结构。该研究还提供了来自基板制造工艺的应用（其中抗蚀剂的流动宽度是关键的质量特性）。