A temperature of a portion of which the temperature is difficult to directly measure is accurately estimated in a simple method.

In S1, information about a coolant discharging/stopping state is obtained. As the information about the coolant discharging/stopping state, a flag is used such that the flag represents 1 for the discharging state and the flag represents 0 for the stopping state. Next, in S2, temperature data is obtained from temperature sensors provided in components of a machine tool, a machining space, and a coolant tank. Next, in S3, lag process is performed for the coolant discharging/stopping state flag, and coefficients for measured temperatures of the coolant and the structure are calculated. Next, in S4, the measured temperatures are multiplied by the coefficients, and an estimated temperature of a portion to which the temperature sensor is not attached is calculated.

A temperature of a portion of which the temperature is difficult to directly measure is accurately estimated in a simple method.

In S1, information about a coolant discharging/stopping state is obtained. As the information about the coolant discharging/stopping state, a flag is used such that the flag represents 1 for the discharging state and the flag represents 0 for the stopping state. Next, in S2, temperature data is obtained from temperature sensors provided in components of a machine tool, a machining space, and a coolant tank. Next, in S3, lag process is performed for the coolant discharging/stopping state flag, and coefficients for measured temperatures of the coolant and the structure are calculated. Next, in S4, the measured temperatures are multiplied by the coefficients, and an estimated temperature of a portion to which the temperature sensor is not attached is calculated.

A thermal displacement state (target thermal displacement state) in which thermal displacement of a machine tool is saturated when the machine tool is operated based on a machining program is previously stored, and a warm-up operation pattern of a motor is determined so as to approach the target thermal displacement state. The motor is driven based on the warm-up operation pattern and the warm-up operation of the motor is stopped if the thermal displacement state of the machine tool is within a predetermined range.

A thermal displacement state (target thermal displacement state) in which thermal displacement of a machine tool is saturated when the machine tool is operated based on a machining program is previously stored, and a warm-up operation pattern of a motor is determined so as to approach the target thermal displacement state. The motor is driven based on the warm-up operation pattern and the warm-up operation of the motor is stopped if the thermal displacement state of the machine tool is within a predetermined range.

A machine learning apparatus learns a setting value in a machining program of a machine tool configured to machine an impeller. The machine learning apparatus includes a state observation unit configured to acquire the thermal displacement amount during a period of machining a workpiece, as a state variable, and a determination data acquisition unit configured to receive the imbalance amount in the impeller after machining as determination data. The machine learning apparatus includes a learning unit configured to learn the setting value in the machining program on the basis of output from the state observation unit and output from the determination data acquisition unit.

A machine tool of the present embodiment includes: a column that is disposed in a vertically standing manner and has a predetermined linear expansion coefficient; a spindle head that is supported by the column and supports a horizontal spindle for attaching a tool thereto; and a reference bar that is disposed separately from the column and has a linear expansion coefficient that is different from the linear expansion coefficient of the column wherein the column has a column-side measurement target zone, the reference bar has a reference bar-side measurement target zone, and a measurement means measures a distance between the column-side measurement target zone and the reference bar-side measurement target zone.

A machine tool includes a workpiece holding unit to hold a workpiece. A tool holding unit holds a tool. At least one of the workpiece holding unit and the tool holding unit is drivingly rotatable or drivingly movable in a predetermined direction to machine the workpiece with the tool. Temperature sensors are attached to members constituting the machine tool. An estimator calculates an environmental temperature system thermal displacement amount due to a heat source outside the machine tool. A correction magnification processor calculates an environmental temperature system thermal displacement correction amount. Another estimator calculates a driving system thermal displacement amount due to a heat source in the machine tool. A thermal displacement correction amount adder obtains and outputs a total thermal displacement correction amount based on which the machine tool performs thermal displacement correction control.

A machining center processes a section not to be corrected of a workpiece and a crankshaft bearing hole in a different position from the section not to be corrected and which is separated from an upper deck surface of the workpiece. The machining center supplies a coolant to the hole during processing and detects a temperature of the coolant. A control apparatus estimates the temperature of the coolant when a predetermined time elapses from a start of the processing to be a temperature of the workpiece, calculates a deformation amount of the workpiece due to thermal expansion, corrects a position of the hole with respect to the upper deck surface based on the deformation amount, and starts processing of the hole after the predetermined time. The predetermined time ends when a difference between a temperature near the hole and the temperature of the coolant falls within a predetermined range.

A machining center processes a section not to be corrected of a workpiece and a crankshaft bearing hole in a different position from the section not to be corrected and which is separated from an upper deck surface of the workpiece. The machining center supplies a coolant to the hole during processing and detects a temperature of the coolant. A control apparatus estimates the temperature of the coolant when a predetermined time elapses from a start of the processing to be a temperature of the workpiece, calculates a deformation amount of the workpiece due to thermal expansion, corrects a position of the hole with respect to the upper deck surface based on the deformation amount, and starts processing of the hole after the predetermined time. The predetermined time ends when a difference between a temperature near the hole and the temperature of the coolant falls within a predetermined range.

A machining tool thermal compensation system based on an aggregation model includes a calculating module and a processing module. The calculating module executes a first thermal compensation model and a second thermal compensation model. The first thermal compensation model is only related to motor temperature change and the second thermal compensation model is only related to environmental temperature change. The processing module executes an aggregation model based on Kalman filter. The calculating module inputs the motor temperature of a target machining tool at a time point into the first thermal compensation model to generate a first compensation value and inputs the environmental temperature of the target machining tool at this time point into the second thermal compensation model to generate a second compensation value. The processing module executes the aggregation model according to the two compensation values to generate a modified compensation value of this time point.