An online geometric/thermal error measurement and compensation system for computer numerically controlled (CNC) machine tools belonging to the technical field of error testing and compensation of CNC machine tools. The online CNC machine tool geometric/thermal error measurement and compensation system includes two parts: the hardware platform and the measurement and compensation software. The hardware platform includes a unidirectional acceleration sensor, a precision integrated circuit (IC) temperature sensor, a multi-channel temperature data collector, and a geometric/thermal error measurement and compensation host. The error measurement and compensation software runs in the geometric/thermal error measurement and compensation host and realizes testing and compensation of geometric and thermal errors in machine tools, which are communicated to the FANUC CNC system.

A machine tool including a first cooling unit, such as a fan, that cools at least one of a drive part that drives a component of the machine tool and an amplifier of the drive part, a second cooling unit, such as a Peltier element, that cools the at least one of the drive part and the amplifier, and a cooling control unit that controls the first cooling unit and the second cooling unit, wherein vibration caused by the second cooling unit is less than vibration caused by the first cooling unit, and the cooling control unit switches cooling of the at least one of the drive part and the amplifier, from cooling by the first cooling unit to cooling by the second cooling unit.

The invention provides a method for modeling and compensating for the spindle's radial thermal drift error in a horizontal CNC lathe, which belongs to the field of error compensation technology of CNC machine tools. Firstly, the thermal drift error of two points in the radial direction of the spindle and the corresponding temperature of the key points are tested; then the thermal inclination angle of the spindle is obtained based on the thermal tilt deformation mechanism of the spindle, and the correlation between the thermal inclination angle and the temperature difference between the left and right sides of the spindle box is analyzed. According to the positive or negative thermal drift error of the two points that have been measured and the elongation or shortening of the spindle box on the left and right sides, the thermal deformation of the spindle is then classified and the thermal drift error model under various thermal deformation attitudes is then established. Then the influence of the size of the machine tool's structure on the prediction results of the model is analyzed. In real-time compensation, the thermal deformation attitude of the spindle is automatically judged according to the temperature of the key points, and the corresponding thermal drift error model is automatically selected to apply the compensation to the spindle. The method is used to distinguish the thermal deformation attitude of the spindle in a CNC lathe, and the thermal deformation mechanism is used to predict the radial thermal drift error of the spindle.

A method for determining the preload value of the screw based on thermal error and temperature rise weighting. Firstly, thermal behavior test of the feed shaft under typical working conditions is carried out to obtain the maximum thermal error and the temperature rise at the key measuring points in each preloaded state. Then, a mathematical model of the preload value of the screw and the maximum thermal error is established; meanwhile, another mathematical model of the preload value of the screw and the temperature rise at the key measuring points is also established. Finally, the optimal preload value of the screw is obtained. The thermal error of the feed shaft and the temperature rise of the moving components are comprehensively considered, improving the processing accuracy and accuracy stability of the machine tool, and ensuring the service life of the moving components such as bearings.

A method includes four steps, (1) setting an initial tool temperature, (2) estimating a temperature of a tool or a position measurement sensor based on the initial tool temperature and a temperature of a spindle, (3) estimating an amount of thermal displacement of the tool or the position measurement sensor with a preliminarily set tool thermal displacement estimation formula based on the estimated temperature, and (4) moving a feed shaft of the machine tool based on the estimated amount of thermal displacement to perform a correction. In the second step, the temperature of the spindle is measured, then a tool-mounted portion temperature of the spindle from the measured temperature is estimated. Further, the temperature of the tool or the position measurement sensor is estimated with the tool-mounted portion temperature, the initial tool temperature of the tool or the position measurement sensor, and the preliminarily set tool temperature estimation formula.

The invention provides a method for modeling and compensating for the spindle's radial thermal drift error in a horizontal CNC lathe, which belongs to the field of error compensation technology of CNC machine tools. Firstly, the thermal drift error of two points in the radial direction of the spindle and the corresponding temperature of the key points are tested; then the thermal inclination angle of the spindle is obtained based on the thermal tilt deformation mechanism of the spindle, and the correlation between the thermal inclination angle and the temperature difference between the left and right sides of the spindle box is analyzed. According to the positive or negative thermal drift error of the two points that have been measured and the elongation or shortening of the spindle box on the left and right sides, the thermal deformation of the spindle is then classified and the thermal drift error model under various thermal deformation attitudes is then established. Then the influence of the size of the machine tool's structure on the prediction results of the model is analyzed. In real-time compensation, the thermal deformation attitude of the spindle is automatically judged according to the temperature of the key points, and the corresponding thermal drift error model is automatically selected to apply the compensation to the spindle. The method is used to distinguish the thermal deformation attitude of the spindle in a CNC lathe, and the thermal deformation mechanism is used to predict the radial thermal drift error of the spindle.

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 compensation control system for a machine tool having a milling cutter and a cutter driver includes a tool setting probe, a temperature sensor, a workpiece touch probe, and a controller. The cutter driver is connected to the milling cutter to drive the milling cutter to process the work piece based on a control signal. The tool setting probe is configured to detect a cutter length of the milling cutter. The temperature sensor is configured to sense a measured temperature of the cutter driver or the milling cutter. The workpiece touch probe is configured to measure processing errors of the processed work piece. The controller is configured to generate the control signal based on a processing instruction, a temperature compensation model, the cutter length, and the measured temperature. The controller is further configured to determine whether to modify the temperature compensation model based on the processing errors.

A machine tool for processing a workpiece having a temperature that deviates from a pre-defined processing temperature, the machine tool comprising a base to position the workpiece on, at least one processing means for processing the workpiece, one or more actuators for moving the processing means relative to the base, a control unit for controlling the actuators, the control unit comprising a data storage for storing nominal data providing nominal dimensions of the workpiece at the pre-defined processing temperature, and at least one temperature sensor that is configured to determine one or more actual temperature values of the workpiece, wherein the at least one temperature sensor is configured to generate temperature data based on the determined actual temperature values and to provide the temperature data to the control unit.

A thermal compensation control system for a machine tool having a milling cutter and a cutter driver includes a tool setting probe, a temperature sensor, a workpiece touch probe, and a controller. The cutter driver is connected to the milling cutter to drive the milling cutter to process the work piece based on a control signal. The tool setting probe is configured to detect a cutter length of the milling cutter. The temperature sensor is configured to sense a measured temperature of the cutter driver or the milling cutter. The workpiece touch probe is configured to measure processing errors of the processed work piece. The controller is configured to generate the control signal based on a processing instruction, a temperature compensation model, the cutter length, and the measured temperature. The controller is further configured to determine whether to modify the temperature compensation model based on the processing errors.