Customer-Focused L- and S-Type Quality Characteristics-Based Robust Design Optimization Models to Find Optimum Conditions for the Experimental Processes

Abstract

Robust design (RD) is a powerful technique to reduce the variability when the mean is at the specified target value. A large number of RD studies focus on controllable design factors for the nominal-the-best (N-type) quality characteristic (QC). On the other hand, the customer's perspective is necessary to be integrated while considering the larger-the-better (L-type) and the smaller-the-better (S-type) QCs for a number of situations. Therefore, this paper is three-fold. One, the four-stepped proposed methodology development is presented for the L- and S-type QCs where design factors are denoted as controllable and noise. Thus, the estimated fitted functions are found using the p-value concept for the mean, standard deviation, and variance to deal with the L- and S-type QCs. Two, customer-focused L- and S-type QCs-based robust design models are offered to obtain the optimum settings of design factors. In addition, comparison studies are conducted between the proposed customer-focused and traditional models. In conclusion, the L- and S-type QCs-based numerical examples are illustrated to present the performance of the four-stepped proposed methodology development.