Development of a Fuzzy Loss-based Process Capability Index

Process capability indices are appropriate tools to measure the inherent capability of process, and it is very important for companies to evaluate and minimize their losses. Since most of process capability indices do not consider the losses, the these indices based on losses can help manufacturers to understand the real capability of their processes in order to improve them. The result of this study is a new loss-based index with more specifications such as mean-based, target- based, variation-based, bounded, and loss-based compared with other process capability indices. In order to validate the new loss-based method, the sensitivity of this index to process specifications was studied. Sensitivity analysis showed that this index is sensitive to the mean, variation, and target of data. The new index has 99.6% relationship with the loss especially asymmetric inverted normal loss function. This relationship with loss is the highest relationship compared with other process capability indices. Moreover a regression analysis showed that the new index has the most relationship with the value of loss compared with other process capability indices.