Abstract: A control method of superimposition processing in an NC machine tool comprises providing at least one tool rest that performs machine processing to workpieces respectively held on a plurality of spindles, providing respective processing programs for performing respective machine processing to the workpieces held on the respective spindles, and inserting superimposition control program for performing superimposition processing during one of the respective processing programs is running. The superimposition processing is performed so that, during an operation of performing machine processing to a workpiece held on one of the plurality of spindles by one of the plurality of tools, the other operation of performing machine processing to a workpiece held on another one of the plurality of spindles by another one of the plurality of tools is superimposed.

Abstract: A machine tool having a function of automatically correcting a machining program in tool replacement includes: a signal output unit that outputs a signal when a tool is replaced; a machining unit that temporarily machines a workpiece to a predetermined target dimension using the replaced tool; a measurement unit that measures an actual dimension of the temporarily machined workpiece; a detection unit that detects a dimensional difference between the measured actual dimension and the target dimension; and an automatic correction unit that automatically corrects the machining program based on the dimensional difference, wherein the machining unit actually machines the workpiece based on the automatically corrected machining program.

Abstract: A machine tool having a function of automatically correcting a machining program in tool replacement includes: a signal output unit that outputs a signal when a tool is replaced; a machining unit that temporarily machines a workpiece to a predetermined target dimension using the replaced tool; a measurement unit that measures an actual dimension of the temporarily machined workpiece; a detection unit that detects a dimensional difference between the measured actual dimension and the target dimension; and an automatic correction unit that automatically corrects the machining program based on the dimensional difference, wherein the machining unit actually machines the workpiece based on the automatically corrected machining program.

Abstract: A collision stress releasing device reversely rotates a feed motor by a return amount set in a return amount setter based on a contact position of a movement unit or a collision detection position regarded as a contact position. Generally, a large error does not occur even when the collision detection position is regarded as the contact position, but when the movement unit or the colliding member has low rigidity, a control of setting a return amount in response to the speed of the movement unit or a control of estimating an actual contact position from a rise curve of a load after a collision is more desirable.

Abstract: A first speed and a second speed slower than the first speed are set as a contact speed when a work w and a detection jig t attached to a tool post are brought into contact with each other to detect a position or a posture of the work w, the work and the detection jig are brought into contact with each other at the first speed, the detection jig and the work contacting each other are separated from each other by a predetermined distance, the work and the detection jig which are separated from each other are brought into contact with each other at the same position at the second speed, and a correction value ? is obtained based on a tool post position or a spindle angle during the second contact.

Abstract: A first speed and a second speed slower than the first speed are set as a contact speed when a work w and a detection jig t attached to a tool post are brought into contact with each other to detect a position or a posture of the work w, the work and the detection jig are brought into contact with each other at the first speed, the detection jig and the work contacting each other are separated from each other by a predetermined distance, the work and the detection jig which are separated from each other are brought into contact with each other at the same position at the second speed, and a correction value ? is obtained based on a tool post position or a spindle angle during the second contact.

Abstract: A collision stress releasing device reversely rotates a feed motor by a return amount set in a return amount setter based on a contact position of a movement unit or a collision detection position regarded as a contact position. Generally, a large error does not occur even when the collision detection position is regarded as the contact position, but when the movement unit or the colliding member has low rigidity, a control of setting a return amount in response to the speed of the movement unit or a control of estimating an actual contact position from a rise curve of a load after a collision is more desirable.