Development of fuzzy individual x and moving range control chart

Control charts are very effective tools which are used for detecting the assignable cause of variation. This paper investigated fuzzy individual x and moving range (IX‐MR) control chart in the case of uncertainty for process parameters and data. In this paper, fuzzy mode method was employed to design fuzzy IX‐MR control chart for triangular and trapezoidal fuzzy number fuzzy numbers coded by MATLAB software. Then unnatural patterns were studied in a fuzzy environment. To validate the model, an industrial example was utilised and then the results were verified. Results showed that the fuzzy one was more sensitive than the classic cases and more consistent with the actual situation. Also, fuzzy mode method was more sensitive for trapezoidal than triangular fuzzy numbers.