Formal method for selecting rough datum in part machining using graphs of dimensional relationships

Abstract

We set out to determine formal conditions for selecting rough datum surfaces and rules for specifying the relationships between the surfaces of the workpiece and the part machined by metal-cutting equipment. The research was based on the geometry of non-ideal objects, which represents the geometric configuration of the part or workpiece in the form of a set of surfaces (S) arranged in strict accordance with a set of linear and angular dimensional relationships (V) in a sixdimensional geometric space. The representation of dimensional relationships in each of the six dimensions was performed using graph theory. The algorithm described in the works of V.G. Starostin and V.E. Lelyukhin was used for modeling the process of sequential surface machining. The question of selection of rough datum surfaces was considered. Here, the selection criterion is the possibility of automatic formation of machining sequence without recalculation of the dimension chains defined in the drawing. This criterion eliminates the problem of significant toughening of tolerances and additional