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In deep drilling, a series of our study is going ahead with the plan for improvement of accuracy. As the result, the control system for axial deviation of holes was developed. This paper deals with a new measuring method for axial deviation of holes, which was useful not only measurements of machined parts but also in-process sensing. The deviation can be evaluated from the path length and the pulse amplitude of the ultrasonic flaw detector in this new measuring system. In comparison with the optical measuring system using laser and coner cube prism, this tool can be simply constructed, because was not in need of a measuring pipe in tool shank and a prism holder in tool head. For this result, tool head of small diameter can be produced. In conclusion, the guide for practical use was presented on the control system for axial deviation of holes.

Axial deviation of holes is a serious problem in deep drilling operation. As the results, the control system for axial deviation of holes in deep drilling was developed. The guide-pad on the new drilling tool head, the control pad, slightly moves up and down by piezo actuator in radial direction with each tool revolution. The axial deviation of the tool head is measured by in-process sensing system with laser and corner cub prism. This paper presents the development of the control method of pad using piezo actuator and the axial deviation mechanism by control pad is clarified. And it is verified various factors for deviation ability.

The effects of guide pads on burnishing action and accuracy of machined hole are investigated in deep-hole-drilling with BTA system solid boring tool using a specially designed tool experimentally. The cutting forces are balanced at the small forward regions of guide pads. The burnishing action takes place under a high contact pressure between the bore wall and those rigions. And the over-size mechanism of machined hole by the guide pads is discussed.

Non-twisted wavy type end mill, which can reduce surface error due to cutter runout is presented, for more emphasis on the creation of a highly accurate and smooth work surface in the finish process of end milling. The performance of a newly developed end mill related to cutting force and surface error is estimated through a previously developed model to predict a surface geometry and force variation with cutter runout. It is shown that the increase of cutting force on a non-twisted wavy end mill is unavoidable, for the phase shift along axial direction of the tool is restricted. However, a highly accurate work surface which is equal to a straight end mill can be derived, even if an eccentricity between a spindle axis and a tool axis exists.

Finishing end mills which can reduce dimensional inaccuracy and surface profile error in the finish process of end milling are presented. Computer simulation against chip geometry and variable distance from work surface to cutter axis are performed for the design of cutter shape with high rigidity. The performance of newly developed end mills are verified through the measurement of spiral chip diameter, cutting force variation and surface profile error in the face milling. it is shown that the magnitude of surface profile error can be reduced from 60% to 70% by the newly developed end mills, compared with the standard type. While the characteristic of surface profile error remains unchanged, for the cutter geometry with standard pitch was adopted. The cutter also possess a sufficient space to extrude chips which are produced in the finish process of end milling.