Detection device for four-axis coordinate measuring machine

Abstract

The utility model discloses a detection device for a four-axis coordinate measuring machine, which comprises a test bracket, a base is arranged below the test bracket, and a first standard ball and a second standard ball are fixed above the test bracket; a first gauge block, a second gauge block and a third gauge block which are obliquely arranged are fixed on the side of the test bracket, and the included angles between the gauge blocks and the horizontal plane are 30 degrees; a standard ring gauge is also fixed on the side surface of the test bracket; and all the gauge blocks and the standard ring gauge are fixed on the test bracket through magnetic attraction. According to the utility model, a plurality of standard measuring blocks are integrated on the same test support and can be installed on a coordinate measuring machine, so that the need of checking different checking items by using different standard devices respectively is avoided, and the checking efficiency is greatly improved; the coordinate measuring machine can be quickly and comprehensively checked, a user can conveniently know the working state of the coordinate measuring machine through checking at any time, and risks caused by problems occurring in the use period of the coordinate measuring machine are greatly reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of coordinate measuring machine calibration, and particularly relates to a detection device for a four-axis coordinate measuring machine. Background Art

[0002] A four-axis coordinate measuring machine uses three mutually perpendicular linear guide rails to form three axes of a machine coordinate system, and an additional rotation axis of a positioning turntable as the fourth axis. By operating a probe relative to an object through a control system, it collects the coordinates of surface points of a measured geometric element and calculates the parameters of the geometric element, which is a three-dimensional measuring instrument.

[0003] The coordinate measuring machine needs to regularly check its accuracy performance through calibration or verification to ensure the credibility of the detection results. The calibration period of the coordinate measuring machine is often one year, and the time span between two calibrations is relatively long. During this period, if the machine accuracy deteriorates, it is difficult for users to detect it during use, resulting in problems with the detection results of the coordinate measuring machine, thus bringing greater losses and risks.

[0004] Therefore, during the time interval between two calibrations of the coordinate measuring machine, the coordinate measuring machine should be regularly verified to avoid affecting the measurement accuracy of the coordinate measuring machine. Content of the Utility Model

[0005] In order to solve the above problems, the utility model provides a detection device for a four-axis coordinate measuring machine, which can comprehensively and timely understand the performance status of the four-axis coordinate measuring machine, maintain the credibility of its calibration state, shorten the traceability period after problems occur, and reduce the losses caused by incorrect measurement results.

[0006] To this end, the technical solution of the utility model is: a detection device for a four-axis coordinate measuring machine, including a test bracket, a base is provided below the test bracket, and a first standard ball and a second standard ball are fixed above; an inclined first gauge block, second gauge block and third gauge block are fixed on the side of the test bracket, and the included angle with the horizontal plane is 30 degrees; a standard ring gauge is also fixed on the side of the test bracket; all gauge blocks and the standard ring gauge are magnetically fixed on the test bracket.

[0007] Based on the above solution and as a preferred solution of the above solution: a plurality of first positioning pins are provided on the test bracket, and the first gauge block, second gauge block and third gauge block are all positioned by the first positioning pins.

[0008] Based on the above solution and as a preferred solution of the above solution: the length of the first gauge block is 100 mm, the length of the second gauge block is 200 mm, and the length of the third gauge block is 300 mm, and the three are fixed and arranged in sequence.

[0009] On the basis of the above solution and as a preferred solution of the above solution: the inner diameter of the standard ring gauge is 50 mm, a second positioning pin is provided below the standard ring gauge, and a limit bolt is provided above it.

[0010] On the basis of the above solution and as a preferred solution of the above solution: the diameters of the first standard ball and the second standard ball are 30 mm, the distance between the two is 300 mm, and the height difference is 100 mm.

[0011] On the basis of the above solution and as a preferred solution of the above solution: an installation circular groove is provided below the base, and the center of the installation circular groove is located on the center line of the first standard ball and the second standard ball.

[0012] On the basis of the above solution and as a preferred solution of the above solution: handles are provided above and on the side of the test bracket.

[0013] The verification items of the present utility model include the radial four-axis error, tangential four-axis error, axial four-axis error, probing error, and length indication error of the coordinate measuring machine.

[0014] During verification, the base is stably clamped on the turntable of the coordinate measuring machine to ensure no displacement during the entire measurement process. Use the configured and calibrated probe set to gradually measure the gauge blocks, ring gauges, and standard balls in the standard device according to the procedure. The gauge blocks, ring gauges, and standard balls in the standard device are all standards calibrated by a higher-level measurement standard and assigned reference values. Compare the data obtained by measuring each standard device with the coordinate measuring machine to be verified with the reference values of the standard devices or calculate according to the methods specified in the verification standard to obtain the error data of each verification item of the coordinate measuring machine to be verified, and judge whether the error data of each verification item exceeds the maximum allowable error (MPE) specified by the equipment manufacturer or the control limits (UCL, LCL) required by the user.

[0015] Compared with the prior art, the beneficial effects of the present utility model are:

[0016] 1. Integrate multiple standard measuring blocks on the same test bracket, which can be installed on the coordinate measuring machine for rapid and comprehensive verification, facilitating users to understand the working status of the coordinate measuring machine through verification at any time, greatly reducing the risk brought by problems during the use of the coordinate measuring machine. At the same time, it also eliminates the need to use different standard devices to verify different verification items respectively, greatly improving the verification efficiency.

[0017] 2. Multiple gauge blocks with different lengths are configured on the test bracket, and the placement angle of the gauge blocks is 30° with respect to the horizontal plane. The verification of the indication error can cover three coordinate axes. A standard ring gauge and a standard ball set are configured, and different methods can be used to verify the detection error, and the roundness can also be output and its graph can be observed to understand the current state of the device. At the same time, the configured standard ball set can also quickly verify the four-axis error of the turntable. Brief Description of the Drawings

[0018] Figure 1 is a schematic structural view of the present utility model;

[0019] Figure 2 is a bottom view of the structure of the present utility model;

[0020] Figure 3 is a schematic view of the dimensions of the present utility model;

[0021] Figure 4 is a schematic structural view of the probe set for testing the present utility model.

[0022] In the figure, the markings are: test bracket 1, handle 11, first positioning pin 12, second positioning pin 13, limit bolt 14, base 2, mounting circular groove 21, first standard ball 31, second standard ball 32, first gauge block 41, second gauge block 42, third gauge block 43, standard ring gauge 5, probe set 6, suction cup 61, extension rod 62, No. 1 probe 63, No. 2 probe 64, No. 3 probe 65, No. 4 probe 66, No. 5 probe 67. Detailed Description of the Preferred Embodiment

[0023] In the description of the present utility model, it should be noted that for the orientation terms, if there are terms such as "center", "horizontal (X)", "longitudinal (Y)", "vertical (Z)", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., the indicated orientation and position relationship are based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of the present utility model.

[0024] In addition, if there are terms such as "first" and "second", they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, the meanings of "several" and "a number of" are two or more, unless otherwise specifically defined.

[0025] See the attached drawings. The detection device for a four-axis coordinate measuring machine described in this embodiment includes a test bracket 1. The test bracket 1 is the main bracket of the detection device, made of steel material, with stable structure and can carry various standard devices. Handles 11 are provided above and on the side of the test bracket 1 for convenient handling by users.

[0026] A base 2 is provided below the test bracket 1. An installation circular groove 21 is provided below the base 2, and the center line of the test bracket is vertically made with the center of the installation circular groove 21 as the center. The installation circular groove can be conveniently and quickly installed on the three-jaw chuck on the turntable of the four-axis coordinate measuring machine. At the same time, a sunken hole is also provided on the base, and the base can be fixed on the marble tabletop of the coordinate measuring machine through screws.

[0027] A first standard ball 31 and a second standard ball 32 are fixed above the test bracket 1. The center point of the distance between the first standard ball 31 and the second standard ball 32 falls on the center line. The diameters D1 of the first standard ball 31 and the second standard ball 32 are 30 mm, the distance L1 between the two is 300 mm, and the height difference H1 is 100 mm. When installed on the turntable, the first standard ball 31 and the second standard ball 32 are located on the turntable surface at positions with a radius of 150 mm centered on the turntable center and opposite (180°).

[0028] An inclined first measuring block 41, second measuring block 42, and third measuring block 43 are fixed on the test bracket 1, and the angle A with the horizontal plane is 30 degrees; the length of the first measuring block 41 is 100 mm, the length of the second measuring block 42 is 200 mm, and the length of the third measuring block 43 is 300 mm. The three are fixed and arranged in order from short to long. A number of first positioning pins 12 are provided on the test bracket 1, and the measuring blocks are positioned through the first positioning pins 12.

[0029] A standard ring gauge 5 is also fixed on the side of the test bracket 1. The inner diameter D2 of the standard ring gauge 5 is 50 mm. A second positioning pin 13 is provided below the standard ring gauge 5, and a limit bolt 14 is provided above. The first measuring block 41, second measuring block 42, third measuring block 43, and the standard ring gauge 5 are all magnetically fixed by neodymium magnets fixed on the test bracket 1, and the installation is very convenient.

[0030] Verification method:

[0031] During detection, the probe group structure for the four-axis coordinate measuring machine is as Figure 4 shown. The probe group 6 includes a suction cup 61. The suction cup can be fixed on the four-axis coordinate measuring machine. An extension rod 62 is provided below the suction cup 61, and 5 measuring needles extend from the bottom of the extension rod 62. In the direction of the machine coordinate system, the -Z direction is the 1st measuring needle 63, the +Y direction is the 2nd measuring needle 64, the +X direction is the 3rd measuring needle 65, the -Y direction is the 4th measuring needle 66, and the -X direction is the 5th measuring needle 67.

[0032] I. Verification of Four-Axis Errors:

[0033] Installation: When the turntable is at the initial position (angle 0), install the base 2 on the turntable. During installation, place the second standard ball 32 in the +X direction at the center of the turntable and the first standard ball 31 in the -X direction at the center of the turntable, and fix them using the three-jaw chuck on the turntable.

[0034] Positioning: At the initial position (angle 0) of the turntable, use the No. 1 probe (-Z direction) of the configured probe set to measure the first standard ball 31 and the second standard ball 32 respectively. Rotate the turntable to 90°, 180°, 270°. Set the coordinate system not to rotate with the turntable and measure the first standard ball 31 respectively. Use the four measurements to obtain the center of the first standard ball 31, and construct a plane. The normal direction of this plane is the axial direction of the turntable. Use the constructed plane normal direction (turntable axial direction) as the first axis, the line connecting the first standard ball 31 and the second standard ball 32 (turntable radial direction) as the second axis, and the first standard ball 31 as the zero point to establish coordinate system A. Use the constructed plane normal direction (turntable axial direction) as the first axis, the line connecting the first standard ball 31 and the second standard ball 32 (turntable radial direction) as the second axis, and the second standard ball 32 as the zero point to establish coordinate system B.

[0035] Measurement: Select the commonly used angle range in daily work for verification, such as the range from -360° to 360°. Call coordinate system A, set the coordinate system to rotate with the turntable, rotate the turntable and measure the first standard ball 31 at 0°, 90°, 180°, 270°, 360°, 270°, 180°, 90°, 0° respectively. Output the coordinate values X (radial), Y (tangential), Z (axial) of the center of the first standard ball 31 in coordinate system A at all positions. These values are respectively the radial error FRA, tangential error FTA, and axial error FAA of the turntable. Call coordinate system B, set the coordinate system to rotate with the turntable, rotate the turntable and measure the second standard ball 32 at 0°, -90°, -180°, -270°, -360°, -270°, -180°, -90°, 0° respectively. Output the coordinate values X (radial), Y (tangential), Z (axial) of the center of the second standard ball 32 in coordinate system B at all positions. These values are respectively the radial error FRB, tangential error FTB, and axial error FAB of the turntable. If the absolute values of all the above radial error FR, tangential error FT, and axial error FA results are less than the maximum allowable errors (MPEFR, MPEFT, MPEFA) for each item or the control limits specified by the user, it is judged that the four-axis error verification is qualified.

[0036] In an ideal situation, when the rotary table rotates, the coordinate system is set to rotate with the rotary table. The measured center position of the standard sphere remains fixed within the coordinate system, that is, the coordinate values X (radial), Y (tangential), and Z (axial) at each position are all 0. The above four-axis error evaluation method is to verify whether the measurement ability of the fourth axis of the coordinate measuring machine is within the maximum allowable error range by measuring the change in the center coordinates of two standard spheres installed on the rotary table at different rotation angles of the rotary table.

[0037] II. Verification of Probe Error:

[0038] 1. Verification of Probe Error Using a Standard Sphere:

[0039] When the rotary table is at the initial position (angle 0), install the base 2 on the rotary table. When installing, make the second standard sphere 32 be at the +X direction of the rotary table center, and the first standard sphere 31 be at the -X direction of the rotary table center, and fix it using the three-jaw chuck on the rotary table. During the verification process, the rotary table remains stationary at the initial position. Use the No. 1 probe of the configured probe group (-Z direction) to collect a sufficient number of measurement points on the second standard sphere 32, and the measurement range covers the 180° spherical crown range of the standard sphere. Calculate the center and radius r of the least-squares fitting sphere using all the measurement points. The difference between this radius r and the reference value r0 of the second standard sphere 32 is used as the dimensional probe error P STU ; Output the distance r from all measurement points to the center of the sphere i , and the difference between the maximum radius and the minimum radius is used as the shape probe error P FTU .

[0040] 2. Verification of Probe Error Using a Ring Gauge:

[0041] When the rotary table is at the initial position (angle 0), install the base 2 on the rotary table. When installing, make the second standard sphere 32 be at the +X direction of the rotary table center, and the first standard sphere 31 be at the -X direction of the rotary table center, and fix it using the three-jaw chuck on the rotary table. Use the No. 2 probe of the configured probe group (+Y direction) to collect a sufficient number of measurement points on the inner diameter of the standard ring gauge 5, and the measurement range covers the 360° range of the inner diameter of the ring gauge. Calculate the center and radius r of the least-squares fitting circle using all the measurement points. The difference between this radius r and the reference value r0 of the standard ring gauge 5 is used as the dimensional probe error P STU ; Output the distance r from all measurement points to the center of the circle i , and the difference between the maximum radius and the minimum radius is the shape probe error P FTU . When the rotary table is rotated to angles of 90°, 180°, and 270° respectively, then use the No. 5 probe, No. 4 probe, and No. 3 probe respectively, and use the same measurement method to calculate the dimensional probe error P STU and the shape probe error P FTU .

[0042] All of the above-mentioned dimensional detection errors P STU and shape detection errors P FTU are less than the maximum allowable error for each item or the control limit specified by the user, and it is determined that the detection error verification is qualified.

[0043] III. Verification of length indication error:

[0044] When the turntable is at the initial position (angle 0), install the standard device on the turntable. When installing, place the second standard ball 32 in the +X direction of the turntable center and the first standard ball 31 in the -X direction of the turntable center, and fix it using the three-jaw chuck on the turntable. Use the No. 2 probe of the configured probe group (+Y direction) to establish the coordinate system of the gauge block on three gauge blocks respectively. Collect one measurement point at the center position of the two working end faces of the gauge block respectively. Calculate the coordinate axis distance L between the two points on the working end face in the gauge block coordinate system. The difference between the output distance and the reference dimension L0 of the gauge block is used as the length indication error E, and three indication error results E 100 、E 200 、E 300 are obtained respectively.

[0045] When the turntable is rotated to angles of 90°, 180°, and 270° respectively, use the No. 5 probe, No. 4 probe, and No. 3 probe respectively, and calculate the length indication error at each position using the same measurement method.

[0046] All of the above-mentioned length indication errors E are less than the maximum allowable length error or the control limits specified by the user for each item, and it is determined that the length indication error verification is qualified.

[0047] The above is only the preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the idea of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, several improvements and refinements made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A detection device for a four-axis coordinate measuring machine, characterized in that: It includes a test bracket. There is a base below the test bracket, and a first standard ball and a second standard ball are fixed above it. An inclined first gauge block, second gauge block, and third gauge block are fixed on the side of the test bracket, and the included angle with the horizontal plane is 30 degrees for all of them. A standard ring gauge is also fixed on the side of the test bracket. All the gauge blocks and the standard ring gauge are fixed on the test bracket by magnetic attraction.

2. The detection device for a four-axis coordinate measuring machine according to claim 1, wherein: There are several first positioning pins on the test bracket, and the first gauge block, second gauge block, and third gauge block are positioned by the first positioning pins.

3. The inspection device for a four-axis coordinate measuring machine according to claim 1, characterized in that: The length of the first gauge block is 100 mm, the length of the second gauge block is 200 mm, and the length of the third gauge block is 300 mm. The three are fixed and arranged in sequence.

4. The inspection device for a four-axis coordinate measuring machine according to claim 1, wherein: The inner diameter of the standard ring gauge is 50 mm. There is a second positioning pin below the standard ring gauge and a limit bolt above it.

5. The inspection device for a four-axis coordinate measuring machine according to claim 1, wherein: The diameters of the first standard ball and the second standard ball are 30 mm, and the distance between the two is 300 mm, and the height difference is 100 mm.

6. The inspection device for a four-axis coordinate measuring machine according to claim 1, characterized in that: There is an installation circular groove below the base, and the center of the installation circular groove is located on the center line of the first standard ball and the second standard ball.

7. The inspection device for a four-axis coordinate measuring machine according to claim 1, characterized in that: There are handles on both the upper and side surfaces of the test bracket.

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