Development of Table-on-Table-Type Five-Axis Machining Center: New Structure and Basic Characteristics

The demand for five-axis machining centers has been increasing rapidly, as companies seek “intensive processes” and “high accuracy.” However, it is generally more difficult for five-axis machining centers to achieve the same or higher accuracy than three-axis machining centers since it is necessary to have two more rotary feed axes besides the three linear feed ones. Many kinds of five-axis machining centers with various structures have been developed to date; an analysis of the advantages and disadvantages of major five-axis machining center structures was done first. As a result of this analysis, this paper focuses on the “table-on-table type” five-axis machining center. It is capable of accuracy because of its wide range of rotation for the rotary axis and its advantages in the adjustment process of the axis. and this paper proposes a five-axis machining center which has this construction. Furthermore, a new high-speed, highaccuracy, “table-on-table type” of five-axis machining center which uses a direct-drive motor for the rotary axis and a driven center of gravity for the linear axis has been developed based on this concept, and its accuracy has been verified.