Abstract: A numerical control machine estimates a future rotational speed ahead by a delay time that is a phase difference between a rotational speed fluctuation of a main spindle and a feed rate fluctuation of a feed axis, and fluctuates the feed rate such that a constant ratio is maintained with the estimated rotational speed.

Abstract: In a linear motor used for a driving axis of a large-size machine tool having a very long driving stroke, pole position correction values at a plurality of stroke positions are stored in a memory. A pole position correction value corresponding to an actual stroke position of a slider is calculated based on the stored pole position correction value. A corrected electrical angle offset value derived based on the calculated pole position correction value is used to control the linear motor.

Abstract: In a multitasking machine tool, a first tool post including a tool spindle configured to allow a tool to be detachably attached thereto is configured to be slidable in predetermined directions, while a second tool post is configured to allow a tool to be detachably attached thereto. A tool-change part includes at least one gripper configured to hold a tool to be attached to the second tool post. An automatic tool changer is configured to detachably attach the tool-change part (as well as to change the tool installed) to the tool spindle of the first tool post positioned in a first tool-change region. Change of the tool attached to the second tool post is carried out by a motion (sliding and/or rotation of the tool spindle) of the first tool post (with the tool-change part attached to the tool spindle thereof) located in a second tool-change region.

Abstract: A machine tool includes a main axis 30 to which a touch probe 17 is attached, a motor 15 that rotationally drives the main axis 30, a rotation angle position detector 16 that detects a rotation angle position of the motor 15, and a control device 20. The control device, when a measurement mode command for performing measurement of a workpiece by the touch probe 17 is input, multiplies a d-axis current command value Idc by a d-axis current correction coefficient K that is less than 1 to reduce the d-axis current command value Idc to a d-axis current command correction value Idc?, using a d-axis current command correction section 4. Thus, in the machine tool, small rotation vibrations of the main axis, generated when rotating the main axis to which the probe is attached and performing measurements of a workpiece, can be suppressed to thereby increase the measurement accuracy.

Abstract: There is provided a speed monitoring device which can use a low resolution position sensor and provide a high speed response without false detection. The speed monitoring device stores, in a memory unit, a permitted margin PM, a comparison distance VC which is a maximum movement distance permitted for a moving element within one cycle period, and positional data P(t?nT) (n is a natural number equal to or less than M) of the moving element obtained from the present time t to M cycles ago. During speed determination, whether |P(t)?P(t?nT)|>VC*n+PM holds true is determined for every integer n from 1 to M. When the inequality holds true, it is determined that the speed exceeds the speed limit.