Sculpture Surface Machining by Automatically Indexing Tilted Tool Axis on 5-axis Machine Tools (3^rd report)

—Evaluation of tool attitude by analysis of cutting force on tilted tool axis ball end milling—

Abstract

Nowadays most of die and mold machining are manufactured by three dimensional controlled machining using ball end mill. Using this manufacturing method, we can obtain complex shapes by point contact machining between cutting tool and workpiece. To shorten set-up time and machining time, we have proposed 3+2 axis controlled machining method which the mold and dies are machined by indexing tilted tool axis on 5-axis machining center. In the proposed machining process, high speed machining is executed on each tilted tool axis. In this machining process, the list of indexing angle should be determined automatically, because the shape of the die and mold is very complex to determine the angle by an operator. Therefore, the main objective of this research is automatic determination method of the list of indexing angle for machining the die and mold. We have proposed, in the first and second reports, the calculation method of optimum indexing angle candidates for required machining surfaces using normal vectors of the surfaces and effective cutting edge shapes. And we have shown the procedure of deriving of optimum indexing angle and machinable area based on inverse offset method with state flag. However, we need the effective tilting angle range which we get the stable machining condition in tilted tool axis ball end milling. For this reason, in this research, we propose the machining experiment method using dynamic force dynamometer on 5-axis machining center to analyze the machining properties using tilted tool axis ball end cutting tool. And, we show the machining evaluation diagram from which the results of machining experiments property by tilted tool axis ball end cutting tool.