Abstract
Clamping is the technological stage where the orientation and positioning scheme is conserved during machining, by applying a force system. The optimal clamping scheme is determined from a multitude of technical possible clamping schemes. There is an double process of selection, first a technical selection is made and second and economical selection, based on solution cost. More technical-possible clamping/ tightening schemes can be generated due to the following: various surfaces of the part can be used to apply one or more clamping forces, on various directions, sense, and point of application, if multiple clamping forces are applied, they may be parallel, convergent or divergent; the clamping forces can be applied in various successions. The informatics system proposed, in this paper, allows the generation, systematically and scientifically, of technical-possible clamping/ tightening schemes in machining fixtures. It starts from the optimal orientation-positioning scheme, which essentially indicates the orientation-positioning surfaces and the degrees of freedom to be removed. Next, an identification of the types of surfaces that delimitate the workpiece is made. On each type of surface, the program offers several solutions for the location of the main clamping forces and, eventually, of the pre-clamping or initial clamping forces. Finally, the various clamping possibilities are combined for each surface, thus, resulting several clamping schemes for the entire workpiece. The informatics system allows ranking of the generated clamping schemes, based on the number of clamping forces. Based on the study, the task of setup planning and fixture design was structured into a setup planning and fixture design plan. The plan was implemented as a system that automatically plans the setup sequence and designs fixture configurations from the toleranced solid model of the finished component. |