Two new fuzzy process capability indices for asymmetric tolerance interval

Process capability indices are used to evaluate the performance of the manufacturing process. When the specification limits and the target value are not precise, we cannot use the traditional methods for assessing the capability of the process. For the processes with asymmetric tolerance intervals, some fuzzy process capability indices have been introduced such as C and C . In some cases, these indices may fail to account the process performance. So, in this paper we proposed two new fuzzy indices when the specification limits and the target value are fuzzy while the data are crisp to overcome the problem with these indices. To demonstrate the effectiveness and performance of the proposed indices, we presented an application example.

Keywords:

Normal distribution , Process capability index , Asymmetric tolerance interval , Fuzzy logic