Papers by Keyword: Tolerance Design

Abstract: Design of experiment (DOE) is the focal collective of quality technique and is widely used in Research and Development (R&D) organization to optimize product design parameters. There are three main DOE approaches that commonly adopted by R&D companies, which are the classical Fisher’s DOE, Taguchi DOE and Shainin DOE. This paper explores how these three main DOE approaches could be integrated to optimize product design parameters in a Research and Development company. The paper starts with enlightenment of the common DOE steps, follows by discussion of issues faced by the Research and Development company during the implementation of the three DOE approaches in product design. The paper subsequently illustrates how the three DOE approaches could be integrated as a new methodology for optimization of product design parameters. The integrated DOE methodology presented in this paper offers an alternative and effective way to conduct DOE in a dynamic product design and development environment.

Abstract: The design optimization of tolerance is researched to improve the robustness of plane dimension chain. The nonlinear functional relationship between the closed loop and the component loops of a dimension chain is formulated. The tolerances of component loops are regarded as design variables. The total manufacturing costs of the component loops and the success rate of assembly of the closed loop are treated as constraint conditions. Then, a robust design optimization model is established to minimize the variance of the closed loop and to make the mean value of the closed loop approach to target value. The evidence theory is used to deal with the constraint condition on the success rate of assembly. The dimension chain of a gear box is taken as an example to illustrate the proposed method and the example shows that the proposed method is effective.

Abstract: Tolerance allocation have significant influence on the manufacturing cost and quality loss cost. In order to obtain optimal tolerance, Lagrange multiplier method is used to minimize the summation of manufacturing cost and quality loss cost subject to constraints on product functional requirement. The reciprocal power cost-tolerance model with different functional constraints is considered, and closed-form optimal tolerances are obtained. Using the model proposed in this paper, the optimal tolerance can be obtained quickly and accurately. One example is used to illustrate the method proposed in this paper.

Abstract: Setting of tolerances to meet a required specification of quality characteristic and keep low manufacturing cost is one of common problems in the process quality control. But generally traditional tolerance design only focus on cost of manufacturing, few consider product Life Cycle Cost. In these situations, to obtain a satisfactory six sigma quality level as well as keep lower life cycle total cost should be considered. This paper expands tolerance optimization based on the manufacturing cost to the product life cycle cost, which can improve product quality to the six sigma level and keep lower LCC simultaneously.

Abstract: This paper proposes a non-cooperative game framework for concurrent tolerance design. The optimization issues in concurrent tolerance design for manufacture and assembly are discussed, and the mechanism of non-cooperative game for concurrent tolerance design is investigated. Finally, the algorithm is proposed to achieve concurrent tolerance design with non-cooperative game.

Abstract: This paper presents a method for tolerance design of four-bar function generating mechanisms with joint clearances using Taguchi method. Based on previous studies made by other researchers, we propose a model to quantify the effects of uncertain factors on the accuracy of four-bar function generating mechanisms. Taguchi’s approach is applied to select the optimal tolerance ranges for the design parameters of function generation mechanisms. Sensitivity maps are plotted to provide an insight to the effects of parameter errors on the performance variances of four-bar function generating mechanisms. To illustrate the efficiency of the proposed methodology, the tolerance design of a four-bar function generator with joint clearances is discussed.

Abstract: This paper presents a solution of the Optimal Tolerance Design Problems for the production of power transformers. Based on statistical and probabilistic methods, it establishes a multi-objective and multi-constraint mathematical model. We then present a solution that maximizes the effective utilization rate of sheet material, for producing core columns of power transformers, and the passing rate of quality controls of matching coils and cores. It also minimizes the Tolerance cost of the product. The solution uses Particle Swarm Optimization (PSO), which is very effective as shown by simulation results.