The paper presents an approach upon some strategies for improving the effectiveness and efficiency of engineering design activities, respectively of CAD activities, discussions being made in relation with their expected effects upon the sustainability of product development process. Concepts and principles of collaborative design, axiomatic design, integration of design applications with manufacturing planning and technical data management aspects, design reuse etc. are discussed within the presented approach. Complex assembly modeling management issues are also discussed as case study.

Abstract. The theoretical approach and the related case study presented in the paper are part of a larger research regarding the optimization of assembled products and assembly processes by enhancing the effectiveness and efficiency of design activities, including by embedment of DfX/DFMA principles. First of all, a conceptual model for the theoretical approach is proposed and discussed. The case study refers to the engineering design of an indexing mounting table for automated assembly of an electrical plug inlet. Some advanced principles and theories are discussed in relation to the technical solution design. Advanced engineering design capabilities provided by Solid Edge have been used for solving the 3D modelling task and for the other detailed design activities. Finally, some related conclusions are included, together with some directions of further researches.

Complex surfaces such as helical ones are commonly used in machinery. Such surfaces can be obtained by various machining processes, one of these processes being thread whirling. The influence of machining conditions needs to be better understood to develop a more precise prediction of the specific resulting errors involved in thread whirling. This paper firstly presents the theoretical conditions which generate micro-deviations on whirled surfaces. A theoretical model which considers the geometrical parameters describing the whirling head and cutters and the process’s whole kinematics was developed. The threaded surface was described as a complex compound surface resulting from intersecting successive ruled helical surfaces corresponding to the cutting edges of the set of cutters from the whirling head. Numerical simulation results were exemplified and validation experiments were both designed and performed. Empirical mathematical models were established to highlight the influence of the input factors such as thread pitch and external diameter, the ratio between the diameter of cutters’ top edge disposal and the thread’s external diameter, the rotary speed of the whirling head, and the rotary speed of the workpiece on some accuracy elements and roughness parameters of the threaded surface.

One of the machining methods able to ensure a high material removal rate in the case of obtaining threaded surfaces is the whirling machining. In order to obtain a high accuracy of the machined surface and low values of the surface irregularities, an adequate selection of the machining parameters is necessary. A geometrical analysis of generating the surfaces in case of applying the whirl threading was developed. Geometrical and kinematical conditions were considered and software was used in order to modelling the process and to highlight the influence exerted by some process input factors on the machining errors and height of the surface irregularities.

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