Abstract: A control device which controls a servo motor of a machine tool in the event of power failure is provided.

Abstract: A method includes: (a) transferring a tool to where thread cutting is to start; (b) cutting threads in work with the tool; (c) performing tool deceleration along the Z-axis and acceleration along the X-axis during a predetermined acceleration/deceleration time Ta to retract the tool along the X-axis; and (d) returning the tool to a reference point. In Step (c), to shorten the incomplete thread portion, a command is issued concurrently with the start of the acceleration/deceleration time Ta to realize a pullout speed Ve along the X-axis that exceeds an allowable maximum speed Vmax to increase the acceleration along the X-axis. The speed command for moving the tool along the X-axis is maintained at the value of zero from the elapse of command time Te until the acceleration/deceleration time Ta expires to maintain the actual speed of the tool along the X-axis at or below the allowable maximum speed Vmax.

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: A position control apparatus calculates a position detection value by adding an output of a first-order delay circuit 17 that receives a difference between a driven member position detection value Pl and a motor position detection value Pm to the motor position detection value Pm, and uses the obtained position detection value as a position feedback value. An aging corrector 30 suppresses low frequency vibrations by controlling a time constant Tp of the first-order delay circuit 17 in such a way as to increase the time constant when a vibratory state of the driven member is detected.

Abstract: A machine diagnosing device includes a drive object driving force estimating unit for estimating drive object driving force based on a torque command value toward a servo motor which is acquired using a position command value, an elastic deformation error estimating unit for estimating an elastic deformation error of a ball screw with the drive object driving force, and a positional deviation calculating unit for calculating a positional deviation using a rotation position of the servo motor and the position of a table, and a machine damage diagnosing unit for diagnosing a machine damage by calculating a machine damage coefficient using the elastic deformation error and the positional deviation, comparing the obtained machine damage coefficient with a previously set threshold value, and diagnosing a damage state of the drive object.

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: A method for identifying geometric errors with respect to at least two translational axes and at least one rotational axis of a machine using a control device is disclosed. The method comprises the steps of: measuring positions of a jig in three-dimensional space using a position measurement sensor, wherein a measurement is carried out when the jig being indexed around the rotational axis by a plurality of angles is located at the positions; approximating a plurality of measured values of the positions measured in the measuring step to a circular arc; and calculating an error in regard to a center position of the rotational axis and/or a tilt error in the rotational axis, and tilt errors in the translational axes, based on the circular arc resulting from the approximating step.

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 motor magnetic pole position correction method includes preventing a movement of a movable element of a direct drive motor by mechanical brake (step S9), generating a command that designates a position spaced or separated from the present position (step S10), detecting a torque command value of the direct drive motor (step S12), determining a magnetic pole position correction value based on a comparison between the detected torque command value and a predetermined threshold value (steps S14 and S16), storing the determined magnetic pole position correction value in a memory (step S18), and performing motor control using an electrical angle offset value obtained based on the magnetic pole position correction value stored in the memory.

Abstract: In a machine tool including a supporting device and a tool rest, a workpiece is supported rotatably around a first axis by the supporting device, and a rotary tool or a boring tool for boring operations to machine an internal surface of the workpiece is coupled, rotatably around a second axis, to a rotary shaft of the tool rest. The tool rest is allowed to be turned around an axis perpendicular to the first axis, and the boring tool includes a tool holder adapted to be coupled to the rotary shaft and a bit which is angled with respect to an axis of the tool holder, whereby a boring operation is performed with the tool rest positioned at a predetermined oblique angle with respect to the first axis.

Abstract: A position control device for suppressing occurrence of stick-slip during a feed operation performed in a very low speed region is provided. Adders add an output obtained by multiplying actual speed deviation by a proportional gain, an integral component of actual speed deviation obtained by inputting actual speed deviation to an integral compensator, an output obtained by multiplying motor speed deviation by a proportional gain, and an integral component of the motor speed deviation obtained by inputting motor speed deviation to an integral compensator. The result is output as a torque feedback command. Each integral compensator has a coefficient changer capable of changing a coefficient from 0 to 1 to adjust integral gains in accordance with a speed feedforward command or a speed command. Large integral gain increases the response speed of switching from static to kinetic friction torque in a very low speed region thereby suppressing occurrence of stick-slip.

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.

Abstract: In a rotary joint for a rotary shaft device, ring-shaped inner seals and outer seals are projectingly arranged, and concentric with faces of a front joint disk and a rear joint disk opposing with each other respectively. A ring-shaped inner space communicates with forward communication holes, and a ring-shaped outer space communicates with backward communication holes. The inner and outer space are adjacently arranged concentrically between the inner seals and the outer seals. The forward communication holes and the backward communication holes in the reciprocating flow passages and the front joint disk are arranged at an equal distance in the peripheral direction of the opposing faces.

Abstract: When a rotation speed is fluctuated, a fluctuation diagram showing the relationship between a fluctuation amplitude and a fluctuation period of the rotation speed is displayed on a monitor. In addition to a current setting value, a settable range of the fluctuation amplitude and the fluctuation period is displayed on the fluctuation diagram. At least one of an optimal fluctuation period PO based on Equation (1) below and an optimal range P1 of the fluctuation period based on Equation (2) below is also displayed on the fluctuation diagram, wherein T is a rotation period of a rotary shaft, and a, amin, amax are preset coefficients.

Abstract: In a housing 13, an air discharge hole 41 and a suction pipe 51 are arranged vertically in parallel and are located outward with respect to a bearing 12 that supports a vertical main spindle 11. A communication hole 43 connects between a space formed below the bearing 12 and an intermediate portion of the air discharge hole 41 in a height direction. A bottom end of the air discharge hole 41 and that of the suction pipe 51 communicate with an oil reservoir 45. Lubricant in the oil reservoir 45 is sucked through the suction pipe 51 and is recovered at a position outside the housing 13.

Abstract: A tool path generation device that calculates a tool path to be used by a machine tool device, and that provides a high machining efficiency with suppressed occurrence of chatter vibration by calculating machining conditions in consideration of a chatter vibration increase and decrease affecting value that affects increase and decrease in chatter vibration.

Abstract: A numerical control apparatus provides for manual shift operation involving feed shafts of a machine tool in terms of a work coordinate system easily and readily understood by an operator. The numerical control apparatus includes a manual shift amount input unit for receiving an amount of manual shift involving linear feed shafts as operator-input data in terms of a work coordinate system defined on the work revolved or rotated by a rotary feed shaft. The numerical control apparatus further includes a manual shift amount cumulative storage for cumulatively storing the received amount of manual shift in terms of a work coordinate system. Also included is a cumulative shift amount coordinate converter for converting the cumulative amount of shift from the work coordinate system data to data in terms of machine coordinate system defined on the machine tool.

Abstract: A vibration suppressing method and a vibration suppressing device are disclosed. After a tool is attached to a main spindle, a modal parameter of the tool or a workpiece is computed. Thereafter, a relation between chatter frequency and phase difference is calculated as an approximation formula based on the obtained modal parameter and machining conditions. If chatter vibration occurs after initiation of the machining, a chatter frequency corresponding to a target phase difference is obtained using the approximation formula, and based on the obtained chatter frequency, the number of tool flutes and the main spindle rotation speed, the optimum rotation speed is calculated. The rotation speed of the main spindle is then changed in accordance with the obtained optimum rotation speed.

Abstract: A cutting method capable of efficiently removing cutting chips around a cutting point with a little electric power, and cutting a work with high accuracy with a ball end mill. The ball end mill has a slit shaped-opening part at a portion adjacent to a rake face of a cutting edge in internal communication with a suction passage, and a work in which a cutting liquid is previously coated on an inclined face of the work is cut while the cutting liquid is sucked in the area around the cutting edge from the opening part through the suction passage. As a result of this, the cutting liquid in the area around the cutting edge is sucked from the opening part and a cutting power decreasing rate is higher than in a case where the suction is not carried out.