Concurrent tolerance allocation has been the focus of extensive research, yet very few researchers have considered how to concurrently allocate design and process tolerances for mechanical assemblies with interrelated dimension chains. To address this question, this paper presents a new tolerance allocation method that applies the concept of concurrent engineering. The proposed method allocates the required functional assembly tolerances to the design and process tolerances by formulating the tolerance allocation problem into a comprehensive model and solving the model using a non-linear programming software package. A multivariate quality loss function of interrelated critical dimensions is first derived, each component design tolerance is formulated as the function of its related process tolerances according to the given process planning, both manufacturing cost and quality loss are further expressed as functions of process tolerances. And then, the objective function of the model, which is to minimize the sum of manufacturing cost and expected quality loss, is established and the constraints are formulated based on the assembly requirements and process constraints. The purpose of the model is to balance manufacturing cost and quality loss so that concurrent optimal allocation of design and process tolerances is realized and quality improvement and product cost reduction is achieved. The proposed method is tested on a practical example.

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Compliance uncertainty is one of the most important elements in the next-generation geometrical product specifications and verification (GPS). It consists of specification uncertainty, method uncertainty and implementation uncertainty, which are three of the four fundamental uncertainties in the next-generation GPS. This paper analyzes the key factors that influence compliance uncertainty and then proposes a procedure to manage the compliance uncertainty. A general model on evaluation of compliance uncertainty has been devised and a specific formula for diameter characteristic has been derived based on this general model. The case study was conducted and it revealed that the completeness of currently dominant diameter characteristic specification needs to be improved.

Abstract-An exchange-coupled double-layered (ECDL) films used as enhancement of Kerr effect has been reported. It was found that the Kerr hysteresis loop of the ECDL films has shown different shapes of hysteresis loops as compared with that of single layered films. In general, "stages" was appeared in the Kerr hysteresis loop of ECDL films. The enhancement of Kerr effect was considered to be the result of exchange-coupled action between the boundaries of two layers, which was relative with the boundary domain walls. A model for magneto-optic (MO) Kerr hysteresis of ECDL films was established. Theoretical calculation for coercivity and Kerr angles of couple-bilayered films were well agreed with the experimental results.