Relations of precedence between machining process planning operations
University of Girona. AV. Lluís Santaló s/n - 17003 Girona-
972 41 84 79 marta.alberti@udg.es
01/12/20021. Introduction
For this reason, it has believed desirable to establish relations of precedence between operations, so that, given a piece to make, and applying such relationships, the sequence of the machining operations to be made can be obtained.
The problem is on the own operations of the milling, the drill, lathe and grinding, for being the most common in the majority of workshops of machining these machine tools.
2 Experimental
3. Results and discussion
(a) operations which consist of lowering a surface must be made before the drills on it.
(b) the operations which consist in making a "detail" machining on a surface (e.g. a slotted, a profiling or a drill) should be carried out after the recess of the surface.
(c) the finishing operations of a drill (for example the excavation, the screw or the countersunk) should be made after the operation that allows to make the drill (drilling, turning inland, etc.). Likewise, operations requiring, for execution, a hole that serve as them a guide, must be made after the operation that serves to make the hole.
(d) Finally, the grinding must be made after the rest of operations on a particular piece.
The application of these relationships allow sorting operations into four groups, so that the operations of the Group 1 must be made always before the Group 2, and so forth. Table I shows these groups of precedence.
