Evaluating the design of parts in the form of solids of revolution

Abstract

Ensuring that the design of a part is technologically convenient is an important task. Whereas objective numerical estimation of the design’s compliance with the specified function is simple, quantitative estimation of technological convenience is much more challenging. The lack of accepted methods of numerical estimation of technological convenience prevents objective resolution of unavoidable conflicts between the designer (as the supplier of design documentation) and the technologist (as its consumer). In the present work, a method of objective estimation of technological convenience is proposed. It permits the creation of a CAD subsystem determining the level of technological convenience of a component in the design process. Rather than the machine part as whole, the convenience of its components is estimated, since the cost and difficulty of the machining of individual components greatly exceed the cost and difficulty of assembly. In the present work, we consider parts in the form of bodies of revolution, which are very widely used in manufacturing. Obviously, each set of parameters of the component (including the shape and size of the surfaces, the roughness, the tolerances, the design bases, and the ease of machining of the material) corresponds to a particular technological convenience K T . It must exceed the minimum permissible value determined by the production capabilities, since the same component may be technologically convenient for a plant with modern equipment but not convenient (or not feasible) for a plant with old equipment. According to State Standard GOST 14.201‐83, the technological convenience of the component is basically determined by considerations of laboriousness, cost, and standardization. Since the labor content has a clear momentary value, it is usually included in the cost. Therefore, estimation of the technological convenience includes two basic components: the technological cost C ; and the standardization, which may be broken down to the design standardization k ds and the technological standardization k ts .