A device and method for evaluating on-machine measurement accuracy of multi-axis CNC machine tools

Abstract

This invention relates to the field of in-machine measurement technology, specifically to an in-machine measurement accuracy evaluation device and method for multi-axis CNC machine tools. The evaluation device includes a base and at least five standard spheres; wherein the centers of the first, second, third, and fourth standard spheres and their respective projection points on the base are located at the eight vertices of the same cube; the projection point of the fifth standard sphere on the base coincides with the center point of the cube's projection plane on the base, and its height is half the height of the cube; the centers of the remaining standard spheres are all located on the diagonals of the cube. The purpose of this in-machine measurement accuracy evaluation device and method for multi-axis CNC machine tools is to solve the problem of low utilization rate of machine tool probes in both in-process and post-process key feature detection of workpieces.

Description

Technical Field

[0001] This invention relates to the field of in-machine measurement technology, and specifically to an in-machine measurement accuracy evaluation device and method for multi-axis CNC machine tools. Background Technology

[0002] To assist machining and improve processing efficiency and intelligence, multi-axis CNC machine tools are typically equipped with machine tool probes. These probes can be used for in-machine workpiece measurement, enabling workpiece alignment, establishment of the workpiece machining coordinate system, and detection of key features during and after machining processes. Currently, the utilization rate of machine tool probes for in-process and post-process key feature detection is generally low. This is because the precision of key features during and after machining is high, while multi-axis CNC machine tools lack effective evaluation devices and methods for in-machine measurement accuracy. Consequently, in-process and post-process key feature detection often relies on offline coordinate measuring machines, resulting in secondary workpiece clamping and workpiece transfer waiting times, thus reducing machining efficiency.

[0003] Therefore, the inventors provide a device and method for evaluating the in-machine measurement accuracy of multi-axis CNC machine tools. Summary of the Invention

[0004] (1) Technical problems to be solved

[0005] This invention provides an in-machine measurement accuracy evaluation device and method for multi-axis CNC machine tools, which solves the technical problem of low utilization rate of machine tool probes in the detection of key features of workpieces during and after the process.

[0006] (2) Technical solution

[0007] A first aspect of the present invention provides an in-machine measurement accuracy evaluation device for a multi-axis CNC machine tool, comprising a base and at least five standard spheres; wherein the centers of the first, second, third, and fourth standard spheres and their respective projection points on the base are located at the eight vertices of the same cube; the projection point of the fifth standard sphere on the base coincides with the center point of the projection surface of the cube on the base and its height is half the height of the cube; the centers of the remaining standard spheres are all located on the diagonals of the cube.

[0008] Furthermore, the number of standard balls is 4n+1, where n is a positive integer.

[0009] Furthermore, the in-machine measurement accuracy evaluation device for multi-axis CNC machine tools also includes multiple standard ball bars, one end of each standard ball bar being fixed to the base, and the other end being used to fix the corresponding standard ball.

[0010] Furthermore, the base has a square cross-section.

[0011] A second aspect of the present invention provides an evaluation method using the above-described multi-axis CNC machine tool in-machine measurement accuracy evaluation device. When the number of standard balls is five, the method includes the following steps:

[0012] The in-machine measurement accuracy evaluation device is fixedly placed on the worktable of a multi-axis CNC machine tool, and a dial indicator is used to straighten it so that the X-axis of the machine tool is parallel to the base edge in the direction corresponding to the first standard ball and the second standard ball;

[0013] Remove the probe from the machine tool and use it to measure the centers of the first and second standard spheres parallel to the X-axis. Calculate the distance between the two centers and repeat the measurement at least three times. Determine the X-axis measurement accuracy and repeatability based on the measurement results.

[0014] Use a probe to measure the centers of the first and second standard balls parallel to the Y-axis of the machine tool, calculate the distance between the two centers, repeat the measurement at least three times, and determine the Y-axis measurement accuracy and Y-axis measurement repeatability based on the measurement results;

[0015] The center of the first standard ball is measured using a probe, and the upper surface of the base around the first standard ball is measured. The distance between the center of the ball and the upper surface of the base is calculated. The measurement is repeated at least three times. The Z-axis measurement accuracy and Z-axis measurement repeatability are determined based on the measurement results.

[0016] The probe is used to measure the center of the first standard ball and the fifth standard ball respectively, and the distance between the two center of the ball is calculated. The measurement is repeated at least three times to determine the first absolute value of the largest difference between the absolute value of each measurement and the calibration value, and the first difference between the maximum and minimum values ​​of the measurement.

[0017] The probe is used to measure the center of the second standard sphere and the fifth standard sphere respectively, the distance between the two centers is calculated, the measurement is repeated at least three times, and the second absolute value of the largest difference between the absolute value of each measurement and the calibration value, and the second difference between the maximum and minimum values ​​of the measurement are determined.

[0018] The center of the third standard sphere and the fifth standard sphere are measured using a probe, the distance between the two centers is calculated, and the measurement is repeated at least three times. The third absolute value of the largest difference between the measurement and the calibration value, and the third difference between the maximum and minimum values ​​of the measurement are determined.

[0019] The probe is used to measure the center of the fourth standard sphere and the fifth standard sphere respectively, and the distance between the two center of the sphere is calculated. The measurement is repeated at least three times to determine the fourth absolute value of the largest difference between the measurement and the calibration value, and the fourth difference between the maximum and minimum values ​​of the measurement.

[0020] The maximum value among the first absolute value, the second absolute value, the third absolute value, and the fourth absolute value is determined as the diagonal measurement accuracy;

[0021] The maximum value among the first difference, the second difference, the third difference, and the fourth difference is determined as the diagonal measurement repeatability;

[0022] The maximum value among the X-axis measurement accuracy, the Y-axis measurement accuracy, the Z-axis measurement accuracy, and the diagonal measurement accuracy is determined as the in-machine measurement accuracy;

[0023] The maximum value among the X-axis measurement repeatability, the Y-axis measurement repeatability, the Z-axis measurement repeatability, and the diagonal measurement repeatability is determined as the in-machine measurement repeatability.

[0024] Further, the determination of the first absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the first difference between the maximum and minimum measured values, specifically involves:

[0025] Record the three measurements as D S1-1 D S1-2 D S1-3 Take D S1-1 With calibration value L CR1 The absolute value of the difference, D S1-2 With calibration value L CR1 The absolute value of the difference, D S1-3 With calibration value L CR1 The maximum value among the absolute values ​​of the differences is denoted as S. A1 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R1 .

[0026] Further, the determination of the second absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the second difference between the maximum and minimum measured values, specifically involves:

[0027] Record the three measurements as D S2-1 D S2-2 D S2-3 Take D S2-1 With calibration value L CR2 The absolute value of the difference, D S2-2 With calibration value L CR2 The absolute value of the difference, D S2-3 With calibration value L CR2 The maximum value among the absolute values ​​of the differences is denoted as S. A2 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R2 .

[0028] Furthermore, the determination of the third absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the third difference between the maximum and minimum measured values, specifically involves:

[0029] Record the three measurements as D S3-1 D S3-2 D S3-3 Take D S3-1 With calibration value L CR3 The absolute value of the difference, D S3-2 With calibration value L CR3 The absolute value of the difference, D S3-3 With calibration value L CR3 The maximum value among the absolute values ​​of the differences is denoted as S. A3 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R3 .

[0030] Further, the determination of the fourth absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the fourth difference between the maximum and minimum measured values, specifically involves:

[0031] Record the three measurements as D S4-1 D S4-2 D S4-3 Take D S4-1 With calibration value L CR4 The absolute value of the difference, D S4-2 With calibration value L CR4 The absolute value of the difference, D S4-3 With calibration value L CR4 The maximum value among the absolute values ​​of the differences is denoted as S. A4 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R4 .

[0032] Furthermore, determining the X-axis measurement accuracy and X-axis measurement repeatability based on the measurement results specifically involves:

[0033] Record the three measurements as D X1 D X2 D X3 Take D X1 With calibration value L C1 The absolute value of the difference, D X2 With calibration value L C1 The absolute value of the difference, D X3 With calibration value L C1 The maximum value of the absolute difference X A The difference between the maximum and minimum values ​​of the three measurements is taken as the X-axis measurement repeatability, denoted as X. R .

[0034] (3) Beneficial effects

[0035] In summary, this invention provides a basis for judging the key features of the workpiece during and after the process by using multiple standard spheres arranged in a specific spatial distribution. For machine tools with high on-machine measurement accuracy, this helps to improve their processing efficiency. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of an in-machine measurement accuracy evaluation device for a multi-axis CNC machine tool provided in an embodiment of the present invention;

[0038] Figure 2 This is a top view of an in-machine measurement accuracy evaluation device for a multi-axis CNC machine tool provided in an embodiment of the present invention;

[0039] Figure 3 This is a left view of an in-machine measurement accuracy evaluation device for a multi-axis CNC machine tool provided in an embodiment of the present invention.

[0040] In the picture:

[0041] 1-Base; 2-First standard ball; 3-Second standard ball; 4-Third standard ball; 5-Fourth standard ball; 6-Fifth standard ball; 7-Standard cue. Detailed Implementation

[0042] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments, and any modifications, substitutions and improvements to the parts, components and connection methods are covered without departing from the spirit of the present invention.

[0043] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0044] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0045] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "install" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Figure 1 This is a schematic diagram of the structure of an in-machine measurement accuracy evaluation device for a multi-axis CNC machine tool provided in an embodiment of the present invention, as shown below. Figure 1-3 As shown, the device may include a base 1 and at least five standard spheres; the centers of the first standard sphere 2, the second standard sphere 3, the third standard sphere 4 and the fourth standard sphere 5 are located at the eight vertices of the same cube, respectively, and the projection point of the fifth standard sphere 6 on the base 1 coincides with the center point of the projection surface of the cube on the base 1 and its height is half the height of the cube; the centers of the remaining standard spheres are all located on the diagonal of the cube.

[0047] In the above implementation, multiple standard spheres arranged in a specific spatial distribution provide a basis for judging the key feature detection of the workpiece during and after the machine tool probe operation. The probe measures the distance between the centers of the standard spheres parallel to the X and Y axes, the distance between the center of each standard sphere and the base, and the distance between the centers of the standard spheres on the diagonal sides. The on-machine measurement accuracy and repeatability of the CNC machine tool are then calculated. For machine tools with high on-machine measurement accuracy, this helps improve their processing efficiency.

[0048] like Figure 2-3 As shown, four standard balls are placed horizontally at equal intervals (2L spacing) on ​​a square base. The center of each standard ball is 2L from the top surface of the base. Another standard ball is placed at the center of the area enclosed by the four standard balls, with this ball also at a distance L from the top surface of the base. The distance between the centers of the first standard ball 2 and the second standard ball 3 is calibrated to L. C1 The distance between the centers of the first standard sphere 2 and the third standard sphere 4 has been calibrated to L. C2 The distance between the center of the first standard sphere 2 and the surface of the base is calibrated to L.C3 The distance between the centers of the first standard sphere 2 and the fifth standard sphere 6 has been calibrated to L. CR1 The distance between the centers of the second standard sphere 3 and the sixth standard sphere 6 has been calibrated to L. CR2 The distance between the centers of the third standard sphere 4 and the fifth standard sphere 6 has been calibrated to L. CR3 The distance between the centers of the fourth standard sphere 5 and the fifth standard sphere 6 has been calibrated to L. CR4 .

[0049] As an optional implementation, the number of standard balls is 4n+1, where n is a positive integer. The number of standard balls is selected based on the required accuracy. Except for the standard ball at the center, the remaining standard balls are arranged in groups of four in a square. If the accuracy requirement is higher, the number of standard balls will be increased accordingly, and the entire operation will become more complicated, requiring the distance between the centers of two standard balls to be measured multiple times.

[0050] As an optional implementation method, such as Figure 1 As shown, the in-machine measurement accuracy evaluation device for multi-axis CNC machine tools also includes multiple standard ball rods 7. One end of each standard ball rod 7 is fixed to the base 1, and the other end is used to fix the corresponding standard ball. The specific arrangement of the standard ball is not limited; it can be fixed and supported by the standard ball rod 7, or it can be fixed and suspended by a pull rod / rope above the standard ball.

[0051] As an optional implementation, the base 1 has a square cross-section. Specifically, the specific shape of the base 1 is not limited, but it is set to a square to fit a cube formed by several standard spheres, while limiting the size to a minimum to save costs.

[0052] This invention provides an evaluation method using the above-described multi-axis CNC machine tool in-machine measurement accuracy evaluation device. When there are five standard balls, the method includes the following steps:

[0053] S101. The machine measurement accuracy evaluation device is fixedly placed on the worktable of the multi-axis CNC machine tool, and a dial indicator is used to straighten it so that the X-axis of the machine tool is parallel to the base edge corresponding to the first standard ball and the second standard ball.

[0054] S102. Remove the probe from the machine tool and use the probe to measure the centers of the first and second standard spheres parallel to the X-axis. Calculate the distance between the two centers. Repeat the measurement at least three times. Determine the X-axis measurement accuracy and X-axis measurement repeatability based on the measurement results.

[0055] S103. Use a probe to measure the centers of the first and second standard balls parallel to the Y-axis of the machine tool, calculate the distance between the two centers, repeat the measurement at least three times, and determine the Y-axis measurement accuracy and Y-axis measurement repeatability based on the measurement results.

[0056] S104. Use a probe to measure the center of the first standard ball, measure the upper surface of the base around the first standard ball, calculate the distance between the center of the ball and the upper surface of the base, repeat the measurement at least three times, and determine the Z-axis measurement accuracy and Z-axis measurement repeatability based on the measurement results.

[0057] S105. Use the probe to measure the center of the first standard sphere and the fifth standard sphere respectively, calculate the distance between the two centers, repeat the measurement at least three times, and determine the first absolute value of the largest absolute value of the difference between each measurement and the calibration value, and the first difference between the maximum and minimum values ​​of the measurement.

[0058] S106. Use the probe to measure the center of the second standard sphere and the fifth standard sphere respectively, calculate the distance between the two centers, repeat the measurement at least three times, and determine the second absolute value of the largest absolute value of the difference between each measurement and the calibration value, and the second difference between the maximum and minimum values ​​of the measurement.

[0059] S107. Use the probe to measure the center of the third and fifth standard spheres respectively, calculate the distance between the two centers, repeat the measurement at least three times, and determine the third absolute value of the largest difference between the absolute value of each measurement and the calibration value, and the third difference between the maximum and minimum values ​​of the measurement.

[0060] S108. Use the probe to measure the center of the fourth and fifth standard spheres respectively, calculate the distance between the two centers, repeat the measurement at least three times, and determine the fourth absolute value of the largest difference between the absolute value of each measurement and the calibration value, and the fourth difference between the maximum and minimum values ​​of the measurement.

[0061] S109. Determine the maximum value among the first absolute value, the second absolute value, the third absolute value, and the fourth absolute value as the diagonal measurement accuracy;

[0062] S110. Determine the maximum value among the first, second, third, and fourth differences as the diagonal measurement repeatability;

[0063] S111. Determine the maximum value among the X-axis measurement accuracy, Y-axis measurement accuracy, Z-axis measurement accuracy, and diagonal measurement accuracy as the in-machine measurement accuracy;

[0064] S112. Determine the maximum value among the X-axis measurement repeatability, Y-axis measurement repeatability, Z-axis measurement repeatability, and diagonal measurement repeatability as the in-machine measurement repeatability.

[0065] In the above implementation, a probe is used to measure the distance between the center of a standard ball parallel to the X and Y axes, the distance between the center of the standard ball and the base, and the distance between the center of the standard ball on the diagonal. The on-machine measurement accuracy and repeatability of the CNC machine tool are then calculated.

[0066] As an optional implementation, in step 105, the first absolute value of the largest difference between each measurement and the calibration value, and the first difference between the maximum and minimum measured values ​​are determined. Specifically, the three measurement values ​​are denoted as D. S1-1 D S1-2 D S1-3 Take D S1-1 With calibration value L CR1 The absolute value of the difference, D S1-2 With calibration value L CR1 The absolute value of the difference, D S1-3 With calibration value L CR1 The maximum value among the absolute values ​​of the differences is denoted as S. A1 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R1 .

[0067] As an optional implementation, in step 106, the second absolute value of the largest difference between the absolute values ​​of each measurement and the calibration value, and the second difference between the maximum and minimum measured values ​​are determined. Specifically, the three measurement values ​​are denoted as D. S2-1 D S2-2 D S2-3 Take D S2-1 With calibration value L CR2 The absolute value of the difference, D S2-2 With calibration value L CR2 The absolute value of the difference, D S2-3 With calibration value L CR2 The maximum value among the absolute values ​​of the differences is denoted as S. A2 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R2 .

[0068] As an optional implementation, in step 107, the third absolute value of the largest difference between each measurement and the calibration value, and the third difference between the maximum and minimum measured values ​​are determined. Specifically, the three measurement values ​​are denoted as D. S3-1 D S3-2 D S3-3 Take D S3-1 With calibration value L CR3 The absolute value of the difference, D S3-2 With calibration value L CR3 The absolute value of the difference, D S3-3 With calibration value L CR3 The maximum value among the absolute values ​​of the differences is denoted as S. A3The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R3 .

[0069] As an optional implementation, in step 108, the fourth absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the fourth difference between the maximum and minimum measured values ​​are determined. Specifically, the three measurement values ​​are denoted as D. S4-1 D S4-2 D S4-3 Take D S4-1 With calibration value L CR4 The absolute value of the difference, D S4-2 With calibration value L CR4 The absolute value of the difference, D S4-3 With calibration value L CR4 The maximum value among the absolute values ​​of the differences is denoted as S. A4 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R4 .

[0070] As an optional implementation, in step 102, the X-axis measurement accuracy and X-axis measurement repeatability are determined based on the measurement results, specifically by recording the three measurement values ​​as D. X1 D X2 D X3 Take D X1 With calibration value L C1 The absolute value of the difference, D X2 With calibration value L C1 The absolute value of the difference, D X3 With calibration value L C1 The maximum value of the absolute difference X A The difference between the maximum and minimum values ​​of the three measurements is taken as the X-axis measurement repeatability, denoted as X. R .

[0071] It should be noted that the various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and techniques are omitted here.

[0072] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art without departing from the scope of the invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A device for evaluating the in-machine measurement accuracy of a multi-axis CNC machine tool, characterized in that, It includes a base (1) and at least five standard spheres; wherein the centers of the first standard sphere (2), the second standard sphere (3), the third standard sphere (4) and the fourth standard sphere (5) are located at the eight vertices of the same cube, respectively, and the center of the fifth standard sphere (6) is located at the center of the projection point of the cube on the base (1) and coincides with the center point of the projection surface of the cube on the base (1), and its center height is half the height of the cube; the centers of the remaining standard spheres are all located on the diagonal of the cube.

2. The multi-axis CNC machine tool in-machine measurement accuracy evaluation device according to claim 1, characterized in that, The number of standard balls is 4n+1, where n is a positive integer; except for the standard ball at the center, the other standard balls are arranged in groups of four in a square.

3. The multi-axis CNC machine tool in-machine measurement accuracy evaluation device according to claim 1, characterized in that, It also includes multiple standard cues (7), one end of each standard cue (7) is fixed to the base (1), and the other end is used to fix the corresponding standard ball.

4. The multi-axis CNC machine tool in-machine measurement accuracy evaluation device according to claim 1, characterized in that, The base (1) has a square cross-section.

5. An evaluation method using the multi-axis CNC machine tool in-machine measurement accuracy evaluation device as described in any one of claims 1-4, characterized in that, When there are five standard balls, the method includes the following steps: The in-machine measurement accuracy evaluation device is fixedly placed on the worktable of a multi-axis CNC machine tool, and a dial indicator is used to straighten it so that the X-axis of the machine tool is parallel to the base edge in the direction corresponding to the first standard ball and the second standard ball; Remove the probe from the machine tool and use it to measure the centers of the first and second standard spheres parallel to the X-axis. Calculate the distance between the two centers and repeat the measurement at least three times. Determine the X-axis measurement accuracy and repeatability based on the measurement results. Use a probe to measure the centers of the first and second standard balls parallel to the Y-axis of the machine tool, calculate the distance between the two centers, repeat the measurement at least three times, and determine the Y-axis measurement accuracy and Y-axis measurement repeatability based on the measurement results; The center of the first standard ball is measured using a probe, and the upper surface of the base around the first standard ball is measured. The distance between the center of the ball and the upper surface of the base is calculated. The measurement is repeated at least three times. The Z-axis measurement accuracy and Z-axis measurement repeatability are determined based on the measurement results. The probe is used to measure the center of the first standard ball and the fifth standard ball respectively, and the distance between the two center of the ball is calculated. The measurement is repeated at least three times to determine the first absolute value of the largest difference between the absolute value of each measurement and the calibration value, and the first difference between the maximum and minimum values ​​of the measurement. The probe is used to measure the center of the second standard sphere and the fifth standard sphere respectively, the distance between the two centers is calculated, the measurement is repeated at least three times, and the second absolute value of the largest difference between the absolute value of each measurement and the calibration value, and the second difference between the maximum and minimum values ​​of the measurement are determined. The center of the third standard sphere and the fifth standard sphere are measured using a probe, the distance between the two centers is calculated, and the measurement is repeated at least three times. The third absolute value of the largest difference between the measurement and the calibration value, and the third difference between the maximum and minimum values ​​of the measurement are determined. The probe is used to measure the center of the fourth standard sphere and the fifth standard sphere respectively, and the distance between the two center of the sphere is calculated. The measurement is repeated at least three times to determine the fourth absolute value of the largest difference between the measurement and the calibration value, and the fourth difference between the maximum and minimum values ​​of the measurement. The maximum value among the first absolute value, the second absolute value, the third absolute value, and the fourth absolute value is determined as the diagonal measurement accuracy; The maximum value among the first difference, the second difference, the third difference, and the fourth difference is determined as the diagonal measurement repeatability; The maximum value among the X-axis measurement accuracy, the Y-axis measurement accuracy, the Z-axis measurement accuracy, and the diagonal measurement accuracy is determined as the in-machine measurement accuracy; The maximum value among the X-axis measurement repeatability, the Y-axis measurement repeatability, the Z-axis measurement repeatability, and the diagonal measurement repeatability is determined as the in-machine measurement repeatability.

6. The evaluation method of the multi-axis CNC machine tool in-machine measurement accuracy evaluation device according to claim 5, characterized in that, The determination of the first absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the first difference between the maximum and minimum measured values, specifically involves: Record the three measurements as D S1-1 D S1-2 D S1-3 Take D S1-1 With calibration value L CR1 The absolute value of the difference, D S1-2 With calibration value L CR1 The absolute value of the difference, D S1-3 With calibration value L CR1 The maximum value among the absolute values ​​of the differences is denoted as S. A1 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R1 .

7. The evaluation method of the multi-axis CNC machine tool in-machine measurement accuracy evaluation device according to claim 5, characterized in that, The determination of the second absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the second difference between the maximum and minimum measured values, specifically involves: Record the three measurements as D S2-1 D S2-2 D S2-3 Take D S2-1 With calibration value L CR2 The absolute value of the difference, D S2-2 With calibration value L CR2 The absolute value of the difference, D S2-3 With calibration value L CR2 The maximum value among the absolute values ​​of the differences is denoted as S. A2 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R2 .

8. The evaluation method of the multi-axis CNC machine tool in-machine measurement accuracy evaluation device according to claim 5, characterized in that, The determination of the third absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the third difference between the maximum and minimum measured values, specifically involves: Record the three measurements as D S3-1 D S3-2 D S3-3 Take D S3-1 With calibration value L CR3 The absolute value of the difference, D S3-2 With calibration value L CR3 The absolute value of the difference, D S3-3 With calibration value L CR3 The maximum value among the absolute values ​​of the differences is denoted as S. A3 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R3 .

9. The evaluation method of the multi-axis CNC machine tool in-machine measurement accuracy evaluation device according to claim 5, characterized in that, The determination of the fourth absolute value, which is the largest among the absolute values ​​of the differences between each measurement and the calibration value, and the fourth difference between the maximum and minimum measured values, specifically involves: Record the three measurements as D S4-1 D S4-2 D S4-3 Take D S4-1 With calibration value L CR4 The absolute value of the difference, D S4-2 With calibration value L CR4 The absolute value of the difference, D S4-3 With calibration value L CR4 The maximum value among the absolute values ​​of the differences is denoted as S. A4 The difference between the maximum and minimum values ​​of the three measurements is denoted as S. R4 .

10. The evaluation method of the multi-axis CNC machine tool in-machine measurement accuracy evaluation device according to claim 5, characterized in that, The determination of X-axis measurement accuracy and X-axis measurement repeatability based on measurement results is as follows: Record the three measurements as D X1 D X2 D X3 Take D X1 With calibration value L C1 The absolute value of the difference, D X2 With calibration value L C1 The absolute value of the difference, D X3 With calibration value L C1 The maximum value of the absolute difference X A The difference between the maximum and minimum values ​​of the three measurements is taken as the X-axis measurement repeatability, denoted as X. R .

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