Method for generating CNC machine tool offsets without cycle time impact

Abstract

The present invention generally describes a method for machining a workpiece in a machine tool, wherein the method determines an offset of the machine tool and adjusts the offset during production operation. In one form, the method includes recording offset data of the machine tool over a period of operating time with varying thermal conditions, and comparing the recorded offset data to a thermal model, wherein the thermal model is generated based on a probing routine and a dry cycle for a plurality of test cycles on a calibration workpiece. Based on the comparison, the method estimates the offset of the machine tool and adjusts the offset of the machine tool during operation.

Description

Technical Field

[0001] The present invention relates to a method for determining deflections in a Computer Numerical Control (CNC) machine tool due to thermal growth of one or more components. Background Art

[0002] The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

[0003] Typically, a computer numerical control (CNC) machine executes a pre-programmed sequence of commands to automate various machining operations. For example, a drilling rig, a lathe, and a water jet cutting machine may be configured as a CNC machine. A CNC machine typically includes a plurality of components (e.g., a motor, a spindle, a ball screw, a rotating axis, and a column), and may be operable to orient the workpiece relative to a tool attached to the spindle prior to machining the workpiece. Each of these components has different thermal expansion properties, and may cause the CNC machine to become out of position.

[0004] In order to correctly place the tool for the workpiece, the CNC machine is calibrated by means of a machine reference point (hereinafter referred to as the "reference point") that serves as the origin of the coordinate system used by the CNC machine. The reference point can be determined using a probing routine that utilizes a precision gauge hole that can be positioned on a fixture and a touch probe attached to the spindle. During the machining process, the temperature may fluctuate due to heat caused by, for example, the motor, cutting energy, idling, and friction. The temperature fluctuation may cause thermal growth of various components (such as the spindle, ball screw, rotating axis, and column) and cause the reference point to shift. For example, in minimum quantity lubrication (MQL) machining, the thermal growth can be as high as 100 μm where the coolant flow is the smallest. In mass production, the machine tool is frequently started and stopped due to various reasons (such as machine tool blockage, material shortage, gantry problems, and movement changes), which may also cause the reference point to shift due to thermal growth.

[0005] These offset adjustment problems, along with other issues related to performance and cycle time of CNC machines, can be solved by the present invention. Summary of the invention

[0006] In one form, the present invention provides a method for compensating for thermal variations in a machine tool. The method includes sensing the machine tool with a plurality of temperature sensors, enclosing the machine tool in an environmentally controlled atmosphere, and installing a calibration workpiece into the machine tool. The method further includes immersing the machine tool in a plurality of predetermined ambient temperatures, probing the calibration workpiece at the plurality of temperatures, and generating a thermal model of the machine tool based on the probing.

[0007] In another form, the invention provides a method for machining a workpiece in a machine tool. The method includes recording offset data of the machine tool over a period of operating time with varying thermal conditions, comparing the recorded offset data with a thermal model, wherein the thermal model is generated based on a probing routine and dry cycles for a plurality of test cycles on a calibration workpiece. Based on the comparison, the method estimates the offset of the machine tool and adjusts the offset of the machine tool during operation.

[0008] In another form, the invention provides a method for machining a workpiece in a CNC machine tool. The method includes recording offset data of the CNC machine tool during a production operation during a period of time with changing environmental conditions. During the production operation, the method compares the recorded offset data with a thermal model of the CNC machine tool, estimates an offset of the CNC machine tool based on the comparison; and adjusts the offset of the machine tool during the production operation so that the CNC machine tool is adjusted without downtime.

[0009] According to the present invention, there is provided a method of compensating for thermal variations in a machine tool, the method comprising:

[0010] Use multiple temperature sensors to monitor machine tools;

[0011] Enclose the machine tool in an environmentally controlled atmosphere;

[0012] Installing the calibration workpiece into the machine tool;

[0013] immersing the machine tool in a plurality of predetermined ambient temperatures;

[0014] Probing the calibration artifact at multiple temperatures; and

[0015] Generate a thermal model of the machine tool based on probing.

[0016] According to an embodiment of the present invention, the probing comprises a probing routine and an idle cycle for at least one test cycle.

[0017] According to one embodiment of the present invention, the plurality of predetermined ambient temperatures simulate four (4) seasons, namely winter, spring, summer and autumn.

[0018] According to an embodiment of the present invention, the calibration workpiece is a material with a low coefficient of thermal expansion.

[0019] According to an embodiment of the present invention, the detecting includes detecting a component of the machine tool and generating a thermal model of the component.

[0020] According to an embodiment of the present invention, the machine tool is a CNC machine tool.

[0021] According to an embodiment of the present invention, the detecting includes detecting at least one component of the CNC machine tool and generating a thermal model of the at least one component.

[0022] According to an embodiment of the present invention, the component is selected from the group consisting of: a spindle, a ball screw, a component table, a trunnion, a column, a bed and a fixture.

[0023] According to an embodiment of the present invention, the thermal model includes machine tool growth in a multi-axis coordinate system.

[0024] According to the present invention, there is provided a method for machining a workpiece in a machine tool, the method comprising:

[0025] recording deflection data of a machine tool over a period of operating time with varying thermal conditions;

[0026] comparing the recorded offset data to a thermal model generated based on a probing routine and a dry cycle for a plurality of test cycles on a calibration workpiece;

[0027] estimating an offset of the machine tool based on the comparison; and

[0028] Adjust machine tool offsets during operation.

[0029] According to an embodiment of the present invention, the comparison is performed using at least one of regression analysis, principal component analysis, and a lookup table.

[0030] According to an embodiment of the present invention, the machine tool is a CNC machine tool, and the recorded offset data is based on at least one component of the CNC machine tool.

[0031] According to an embodiment of the present invention, the component is selected from the group consisting of: a spindle, a ball screw, a component table, a trunnion, a column, a bed and a fixture.

[0032] According to an embodiment of the invention, wherein the machine tool comprises a temperature sensor, and the position of the temperature sensor is adjusted based on the comparison and the thermal model.

[0033] According to an embodiment of the present invention, the offset is based on a multi-axis coordinate system.

[0034] According to one embodiment of the present invention, a component manufactured according to the above method is provided.

[0035] According to the present invention, there is provided a method for machining a workpiece in a CNC machine tool, the method comprising:

[0036] Recording offset data of a CNC machine tool during production operation over a period of time with varying environmental conditions;

[0037] Compare the recorded offset data with the thermal model of the CNC machine during production operation;

[0038] estimating an offset of the CNC machine based on the comparison; and

[0039] Adjust machine offsets during production operations to allow adjustments to CNC machines without downtime.

[0040] According to one embodiment of the present invention, the recorded offset data is based on at least one component of the CNC machine tool, and the at least one component is selected from the group consisting of: spindle, ball screw, component table, trunnion, column, bed and fixture.

[0041] According to an embodiment of the present invention, the CNC machine includes a temperature sensor, and the position of the temperature sensor is adjusted based on the comparison and the thermal model.

[0042] According to one embodiment of the present invention, additional temperature sensors are positioned on the CNC machine based on the comparison and the thermal model.

[0043] Further areas of applicability will become apparent from the description provided herein.It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order that the invention may be better understood, its various forms will now be described with reference to the accompanying drawings, given as examples, in which:

[0045] Figure 1 is a schematic diagram of a CNC machine having a controller constructed in accordance with the teachings of the present invention;

[0046] Figure 2 yes Figure 1 Block diagram of the CNC machine tool controller;

[0047] Figure 3 A thermal characterization process according to the teachings of the present invention is shown;

[0048] Figure 4 is a flow chart of an example thermal characterization process according to the teachings of the present invention; and

[0049] Figure 5 is a flow chart of an example of a thermal offset calibration process in accordance with the teachings of the present invention.

[0050] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present invention in any way. It should be understood that corresponding reference numerals throughout the drawings indicate the same or corresponding parts and features. DETAILED DESCRIPTION

[0051] The following description is merely exemplary in nature and is not intended to limit the present invention, application, or uses.

[0052] In a manufacturing environment, a CNC machine tool is typically required to perform one or more machining operations on a work piece within a specified cycle time. To account for the shift in reference points, the manufacturer of the CNC machine tool may interrupt the machining operation to perform a gauge bore probing to determine thermal growth and compensate accordingly. While gauge probing can account for this shift, it can take up cycle time and is generally considered a non-value added operation in manufacturing, however, it only considers one or a limited number of cutting planes. Therefore, frequent probing increases cycle time and is disadvantageous in high volume production.

[0053] The present invention is directed to a method of compensating for offsets of a CNC machine using a predetermined thermal model, and the invention does not require high-precision gauge probing that may take up valuable machining time. Specifically, the thermal offset calibration process of the present invention is stored and executed by a controller of the CNC machine to estimate the offset of the CNC machine based on the thermal model stored in the CNC machine and other data (such as temperature and stored offsets). The process can then adjust the CNC machine so that the origin of the coordinate system is aligned with the original reference point. A detailed explanation of thermal offset calibration will now be provided with reference to the accompanying drawings.

[0054] refer to Figure 1 , a CNC machine 100 according to the teachings of the present invention is shown to include a table 102 having a precision gauge hole 103, a spindle 104, a trunnion 105, a tool 106 disposed at the end of the spindle 104, a controller 108, one or more user interfaces 110 communicatively connected to the controller 108, and one or more temperature sensors 112. The spindle 104 is typically operable to move along the X, Y, and Z axes relative to a workpiece 114 disposed on the table 102. The part is typically operable to be oriented using the A and B axes to present a part surface / plane that needs to be machined. The tool 106 may be operable to rotate about the Z axis and apply force to the workpiece 114 to perform a machine tool operation (such as drilling a hole through the workpiece 114). The CNC machine 100 may be configured to have multiple tools so that the spindle 104 is operable to switch between tools between non-machining operations.

[0055] The temperature sensor 112 measures the ambient temperature and can be positioned at various locations of the CNC machine 100, such as the spindle 104, the table 102, the machine base (not shown), the ball screw (not shown), and other suitable locations, which can be determined according to the method of the present invention as described in more detail below. The temperature sensor 112 can output data to the controller 108 at fixed intervals throughout the machining and non-machining operations. Alternatively, the temperature sensor 112 can output data at fixed operating times (e.g., when a specified operation starts and stops), and / or when requested by the controller 108.

[0056] The CNC machine 100 may be operated by a user (e.g., a machine operator) through a user interface 110. In the illustrated form, the user interface 110 includes a monitor 116, which may display a graphical user interface, and a keyboard 118. The user interface 110 may include other components, such as a mouse, a touch screen display, and other suitable devices for operating the CNC machine 100.

[0057] The controller 108 controls the operation of the CNC machine 100 based on received inputs and based on a predetermined program stored and executed by the controller 108. The controller 108 can communicate with various external devices through wired and wireless communications. For example, the controller 108 can be communicatively connected to the user interface 110 and the temperature sensor 112 through a communication port and cable and / or through wireless communications via a transceiver (e.g., Bluetooth, ZigBee, and / or Wi-Fi). The controller 108 can communicate with other external devices (e.g., a server located outside the CNC machine 100, an external memory, etc.).

[0058] Reference Figure 2, the controller 108 may include a memory 202 (e.g., a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), and / or an electrically erasable programmable read-only memory (EEPROM)) storing control programs, and a processor 208 for executing the programs in the memory 202. Some programs are directed to one or more machining operations performed by the CNC machine 100, and may control the CNC machine 100 to, for example, place the workpiece 114 on the table 102, machine the workpiece, rotate the workpiece 114, and remove the workpiece 114 from the table 102. As described in detail herein, other programs may be directed to non-machining operations (such as a thermal offset calibration process) to adjust for offsets caused by thermal growth of one or more components of the CNC machine 100. In addition to the control programs, the memory 202 may also store other information, such as data input by a user through the user interface 110, temperatures detected by the temperature sensor 112, and pre-stored data (such as calibration position information and thermal models of the gauge hole 103).

[0059] As described above, components of the CNC machine 100 may experience thermal growth that causes a shift in the reference point of the machine coordinate system. To compensate for this shift, the controller 108 performs a thermal offset calibration process in which the controller 108 estimates the offset of the CNC machine 100 using a predetermined thermal model and input offset data, and then adjusts the offset so that the workpiece is aligned relative to the tool 106 based on, for example, the reference point.

[0060] The thermal model characterizes the thermal growth of the CNC machine 100 and is used to estimate the machine growth offset along one or more axes at a given temperature and machine state (e.g., warm-up time, off time, etc.). One factor in developing the thermal model includes evaluating the effect of temperature on the thermal growth of one or more components of the CNC machine 100. To this end, the CNC machine 100 may undergo one or more thermal-based experiments in which the environmental conditions of the CNC machine 100 are controlled and the thermal growth of key components is measured.

[0061] Figure 3 shows the thermal characterization process, and Figure 4 is a flow chart of an example thermal characterization process. The thermal characterization process may be performed, for example, at the original manufacturer of the CNC machine 100 or at a manufacturing facility where the CNC machine 100 is used. In either case, the characterization is performed prior to the thermal offset calibration process. Additionally, prior to performing the thermal characterization, a high-precision gauge probe may be performed to calibrate the reference points of the CNC machine 100.

[0062] To monitor the temperature, at 402, the CNC machine 100 is equipped with various sensors, such as a plurality of temperature sensors placed at different locations around the machine 100. To effectively regulate the ambient temperature, at 404, the CNC machine 100 may be enclosed in a tent such as a canvas tent. Figure 3 300) in an environmentally controlled atmosphere.

[0063] At 406, a calibration artifact (e.g. Figure 3 The rectangular block shown in the image 302 of FIG. 304 may be installed in the CNC machine 100. The calibration workpiece has known precise dimensions and may be formed of a material having a low coefficient of thermal expansion. The workpiece may include a plurality of holes on different surfaces of the workpiece.

[0064] At 408, the CNC machine 100 and the workpiece are then immersed in one or more predetermined ambient temperatures, and the workpiece is probed at each temperature to determine the location of one or more holes. Specifically, the CNC machine 100 undergoes a workpiece test at 408, wherein the ambient temperature is adjusted to simulate different environmental conditions, such as winter, spring, summer, and fall. The workpiece test may also include probing the workpiece at different temperatures and different machine conditions to measure the hole center location and / or hole depth of one or more holes along the workpiece (e.g., Figure 3 The image 302 shows a workpiece being probed). The test may also measure other locations, such as the top and bottom sides of the workpiece.

[0065] The workpiece test may also perform a dry cycle in which the CNC machine 100 is controlled to perform one or more machining operations without the workpiece and tool. That is, the CNC machine 100 simulates a machining operation, which may include turning the spindle 104 and repositioning the workpiece by performing the required motion without the workpiece, all of which may affect the thermal growth of the component. In addition to the machining operations, the dry cycle may also include non-machining operations such as tool changes, rapid feeds, and / or A / B indications of different angular indication positions and a combination of the trunnion 105 (A axis) and the table 102 (B axis) placed on the trunnion 105. After the dry cycle, the workpiece test again probes the workpiece. Additional details regarding this temperature controlled workpiece test for characterizing thermal growth are described in U.S. Patent Application No. 14 / 463,988, which is commonly assigned with the present application and the contents of which are incorporated herein by reference in their entirety.

[0066] Workpiece testing can, for example, provide insight into thermal growth of sensitive components of the CNC machine 100, as well as provide a means for identifying ideal locations on the CNC machine 100 for accurately sensing ambient temperature. Figure 3Graph 304 in shows the expected thermal growth from a thermal study where temperature compensation for adjusting for any offset was turned off for one data set and turned on for the other data set. As shown, without any thermal compensation, the thermal growth offset is significantly different from the true measurement.

[0067] Workpiece testing can also be used to generate subsystem thermal models for sensitive components (such as spindles, trunnions, ball screws), which can provide further understanding of the thermal growth processes of these components. For example, a cutting spindle with a direct cutting load may heat up faster than other components and, as a result, grow as the temperature rises. A cutting spindle can be studied by placing one or more sensors on the spindle, exercising only the spindle, and then developing a spindle-only thermal model based on the collected data. Probes or other systems can be used to measure spindle growth. Other machine tool components not directly involved in cutting (such as component tables, fixtures, columns, and beds) can be studied by immersing other machine tool components in different ambient temperatures.

[0068] Using the data collected from the workpiece testing, a thermal model is generated at 410 and stored in the controller 108 of the CNC machine 100. The model includes thermal growth of the CNC machine 100, which is determined as growth offsets measured, for example, along a Cartesian coordinate system, based on locations measured on the workpiece during the workpiece testing (e.g., hole center and depth) and known locations of the workpiece. For example, the difference between each measured location and its respective known location is identified as the growth offset for that hole. The growth offset is related to the temperature and machine state associated with the measured location. The thermal model combines thermal growth, temperature, and time (e.g., Figure 3 The thermal model is associated with a mapping system 306 , and is used to estimate the machine growth offset at a given temperature and known machine tool states (eg, preheating, steady state, cooling phase, and disconnection time).

[0069] When the CNC machine 100 is in operation, the controller 108 routinely performs a thermal offset calibration process to correct the offset of the CNC machine 100. The frequency at which the controller 108 performs can depend on the environment and operating conditions that the CNC machine 100 has experienced. Specifically, the process can be performed when the CNC machine 100 has experienced various operating conditions (such as starting, stopping, continuous running time, and temperature fluctuations). Therefore, if the CNC machine 100 experiences this condition after two days of operation, the frequency can be set to weekly or monthly. The frequency can also be adjusted through the user interface and thus customized for each CNC machine.

[0070] Figure 5An example of a thermal offset calibration process performed by the controller 108 is provided and, in one form of the invention, is performed during production in a non-machining operating state (e.g., re-machining, steady state, etc.) of the CNC machine 100. That is, the CNC machine 100 is not taken offline like a high precision gauge probe and is adjusted during a non-machining operation of production.

[0071] exist Figure 5 At 502, the controller 108 determines the offset of the precision gauge hole 103 relative to a component of the CNC machine 100. For example, the controller 108 executes a probing routine to determine the position (e.g., X, Y, Z position) of the hole 103 relative to the spindle 104, and saves the position as a measured position in the memory 202. The controller 108 then determines the offset of the hole 103 relative to the spindle 104 by subtracting the measured position from the known position stored in the memory 202. Although the compensation data is based on the spindle 104, other components of the CNC machine, such as ball screws, trunnions, columns, and tables, may also be used.

[0072] The controller 108 then obtains the ambient temperature from the one or more temperature sensors 112 and the machine status of the CNC machine 100, and stores or records the offset data determined at 502 with the temperature and machine status obtained in the memory 202 as an offset record at 504. The controller 108 may continue to store the offset record even after the process is complete for future offset calibration processes. The machine status may be input by the machine operator through a user interface.

[0073] At 506, the controller 108 compares the recorded offset record with the thermal model based on the correlation analysis model. In an example embodiment, the controller 108 uses regression analysis as the correlation analysis model. Regression analysis is a known statistical process that can be used to estimate the relationship between a dependent variable and one or more independent variables. For example, here, the dependent variable can be the offset of the reference point of the CNC machine 100 along the positioning axis (e.g., X, Y, Z), and the independent variables can include temperature and machine state. The controller 108 can also use other methods to compare the recorded offset record with the thermal model. For example, in addition to or instead of regression analysis, the controller 108 can use principal component analysis, lookup tables, and other suitable data analysis methods.

[0074] At 508, the controller 108 estimates the offset of the CNC machine 100 and the adjustment of the offset during the machining operation. For example, if regression analysis is used, the controller 108 generates a regression equation for estimating the offset of the CNC machine 100 along the positioning axis (e.g., X, Y, Z). For example, equations 1 to 3 are for estimating the offset of the CNC machine 100 based on the temperature of the bed and the spindle (i.e., T床身 and T 主轴 ) Example equations for determining offsets are provided. Using the estimated offsets, the controller 108 can compensate for shifting of the reference point during normal machining operations. For example, the controller 108 calculates the offsets and applies the offsets by adjusting positions in a CNC program stored in the controller 108. It should be readily appreciated that the specific coefficients and constants provided in equations 1 through 3 depend on the measured offsets, and therefore the present invention should not be limited to the specific values ​​provided in the equations.

[0075] Equation 1... x-offset = 0.0400 - 0.00160T 床身 +0.00303T 主轴 R 2 =0.85

[0076] Equation 2...y-offset = 0.300 - 0.02357T 床身 +0.00121 T 主轴 R 2 =0.955

[0077] Equation 3... z-offset = 0.1661 - 0.00734T 床身 +0.00541T 主轴 R 2 =0.879

[0078] Based on the above, a thermal offset calibration process compensates for shifts in a CNC machine without having to perform a time-consuming, high-precision gauge probing process and significantly reduces the cycle time required to correct reference points. That is, in one form of the invention, the thermal offset calibration process is performed during a non-machining production operation such as a tool change. The temperature compensation routine described herein utilizes a predetermined thermal model for estimating the offset instead of performing a high-cost probing routine.

[0079] It should be easy to understand that Figure 4 and Figure 5 The steps described in the process shown in can be modified and should not be limited to the examples provided herein. Figure 4 , the workpiece can be placed in the CNC machine before it is enclosed in an environmentally controlled atmosphere, and Figure 5 In the embodiment of the present invention, the controller can be configured to estimate the offset and adjust the CNC machine tool after a certain number of measured offset records are first entered into the system.

[0080] The description of the present invention is merely exemplary in nature and thus, variations that do not depart from the gist of the present invention are intended to be within the scope of the present invention. Such variations are not to be regarded as a departure from the spirit and scope of the present invention.

Claims

1. A method for machining a workpiece in a machine tool, comprising: recording deflection data of the machine tool over a period of operating time with varying thermal conditions; comparing the recorded offset data to a thermal model generated based on a probing routine and dry cycles for a plurality of test cycles on a calibration workpiece, further comprising: probing the machine tool with a plurality of temperature sensors; Enclosing the machine tool in an environmentally controlled atmosphere to effectively regulate the ambient temperature; installing the calibration workpiece into the machine tool; immersing the machine tool in a plurality of predetermined ambient temperatures; probing the calibration workpiece at the plurality of temperatures; and generating the thermal model of the machine tool based on the detecting; estimating an offset of the machine tool based on the comparison; and The offset of the machine tool is adjusted during operation.

2. The method according to claim 1, wherein the plurality of predetermined ambient temperatures simulate four seasons: winter, spring, summer and autumn. 3 . The method of claim 1 , wherein the sensing comprises sensing a component of the machine tool with a plurality of sensors and generating a thermal model of the component based on data from the sensors.

4. The method of claim 1, wherein the machine tool is a CNC machine tool, and the sensing comprises sensing at least one component of the CNC machine tool with one or more sensors, and generating a thermal model of the at least one component based on data from the sensors.

5. The method of claim 4, wherein the component is selected from the group consisting of: a spindle, a ball screw, a component table, a trunnion, a column, a bed, and a fixture. The method of claim 1 , wherein the calibration workpiece is a material having a low coefficient of thermal expansion.

7. The method of claim 1, wherein the thermal model includes a machine tool growth of the machine tool in a multi-axis coordinate system.

8. The method of claim 1, wherein the machine tool is a CNC machine tool, and the recorded offset data is based on at least one component of the CNC machine tool.

9. The method of claim 8, wherein the component is selected from the group consisting of: a spindle, a ball screw, a component table, a trunnion, a column, a bed, and a fixture.

10. The method of claim 1, wherein the machine tool includes a temperature sensor, and a position of the temperature sensor is adjusted based on the comparison and the thermal model.

11. The method according to any one of claims 1-10, wherein the comparison is performed using at least one of regression analysis, principal component analysis, and a lookup table.

12. The method of any one of claims 1-10, wherein the thermal model relates thermal growth of the machine tool at different temperatures.

13. The method according to any one of claims 1 to 10, further comprising: performing a probing routine to determine the location of the hole relative to a component of the machine tool; and An offset is determined based on the determined position and a pre-stored known position of the hole relative to the component, wherein the offset is recorded as offset data for the machine tool.

14. The method of claim 13, wherein the machine tool comprises one or more temperature sensors, and the method further comprises acquiring one or more temperatures from the one or more temperature sensors and acquiring a machine tool status of the machine tool during the probing routine, wherein the one or more temperatures and the machine tool status are stored in association with the offset and recorded as the offset data.

15. A component manufactured according to the method of claim 1.

16. A method for compensating for thermal variations in a machine tool, comprising: Using a plurality of temperature sensors to detect the machine tool; Enclosing the machine tool in an environmentally controlled atmosphere to effectively regulate the ambient temperature; installing a calibration workpiece into the machine tool; immersing the machine tool in a plurality of predetermined ambient temperatures; probing the calibration workpiece at the plurality of temperatures; as well as A thermal model of the machine tool is generated based on the detection.

17. A method for machining a workpiece in a CNC machine tool, comprising: recording deflection data of the CNC machine tool during production operation over a period of time with varying environmental conditions; comparing the recorded offset data to a thermal model of the CNC machine during the production operation; The thermal model is generated based on a probing routine and a dry cycle for a plurality of test cycles on a calibration workpiece, further comprising: probing the machine tool with a plurality of temperature sensors; Enclosing the machine tool in an environmentally controlled atmosphere to effectively regulate the ambient temperature; installing the calibration workpiece into the machine tool; immersing the machine tool in a plurality of predetermined ambient temperatures; probing the calibration workpiece at the plurality of temperatures; and generating the thermal model of the machine tool based on the detecting; estimating an offset of the CNC machine based on the comparison; and The machine offset is adjusted during the production operation to allow adjustments to the CNC machine without downtime.

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