Design for Robustness of Modular Product Families for Current and Future Markets

Abstract

Abstract This paper presents a modified Taguchi methodology to improve the robustness of modular product families against changes in customer requirements. The general research questions posed in this paper are: (1) How to effectively design a product family (PF) that is robust enough to accommodate future customer requirements? (2) How far into the future should the designers look to design a robust product family? An example of a simplified vacuum product family is used to illustrate our methodology. In the example, the customer requirements are selected as signal factors; the future changes of customer requirements are selected as noise factors; an index called the quality characteristic (QC) is set to evaluate the product vacuum family; and the module instance matrix (M) is selected as the control factor. Initially a relation between the objective function (QC) and the control factor (M) is established, and then the search space is systemically explored using the simplex method to determine the optimum M and the corresponding QC values. Next, various noise levels at different time points are introduced into the system. For each noise level, the optimal values of M and QC are computed and plotted on a QC-chart. The tunable time period of the control factor (in the example, the module matrix, M) is computed using the QC-chart. The tunable time period represents the maximum time for which a given module matrix can be used to satisfy the current and future customer needs. Finally, a robustness index is used to break up the tunable time period into suitable time periods that the designers should focus on while designing product families.