Abstract: A method of and apparatus for searching for a fiducial point of machining in relation to the C-axis in a lathe capable of carrying out machining by C-axis control based on the C-axis origin. In a machining work applied to a workpiece having a C-axis-value-prescribed configuration whose C-axis value in relation to the fiducial point of machining is prescribed by a first angle, and second and third angles between the C-axis origin and each point of measurement located on the opposite sides of the C-axis-value-prescribed configuration facing the C-axis are measured, the angle between the fiducial point of machining and the C-axis origin is obtained on the basis of the second and third angles measured and the first angle prescribed between the C-axis-value-prescribed configuration and the fiducial point of machining, thus detecting the fiducial point of machining with respect to the workpiece having the C-axis-value-prescribed configuration.

Abstract: A method of judging and controlling simultaneous machining in a quadriaxial numerical control lathe having two tool rests. A machining pattern pair memory stores a pair table showing possibility of simultaneous execution of different machining patterns. A judgement is made as to whether a simultaneous execution of two machining processes in accordance with input machining informations is possible, through a retrieval of the table in the machining pattern pair memory, and machining programs for two tool rests are formed through an automatic judging concerning the possibility of simultaneous machining to relieve the programmer from the work for making such a decision.

Abstract: Disclosed herein is a method of controlling a numerically controlled machine tool comprising the steps of classifying cutting tools and machining order for the respective machining patterns determined in response to the final machining contour of a workpiece machined by a numerically controlled machine tool like a machining center, for example in case of the final machining contour with a counter bore and a tap, the cutting tools and machining order of centering--drilling--end milling for a counter bore and centering--drilling--tapping for a tap, by the unit of machining patterns; storing the classification in the numerically controlled machine tool; reading, during machining of the workpiece, a unit of machining patterns corresponding to the machining contour of the workpiece on a display unit; machining the workpiece with numerical information as to each machining patterns entered in the numerically controlled machine tool; and displaying the machining process conditions on the display unit.