Calibration device and method for calibrating parallelism of measuring surface of large outside micrometer

Abstract

The invention discloses a calibration device and method for calibrating the parallelism of a measuring surface of a large outside micrometer. The device comprises a mechanical adjustment module, an optical imaging module and an image processing and calculating module, the mechanical adjusting module is used for adjusting the position of the micrometer; the optical imaging module comprises an autocollimator and a double-turning prism system, a high-resolution area array detector is arranged in the autocollimator, the double-turning prism system divides a single-path collimated light beam emitted by the autocollimator into two paths, the two paths of collimated light beams are respectively projected to two measuring surfaces of a micrometer and receive reflected light of the two paths of collimated light beams, and two independent cross images are formed on the detector; the image processing and calculating module displays a view field containing two cross images in real time, sets one image as a reference zero position, calculates the angle deviation of the other image relative to the reference zero position in the X direction and the Y direction, and converts the angle deviation into a linear parallelism deviation value. The method can realize non-contact, automatic and visual calibration in the whole process, and has the characteristics of high precision, high efficiency and high repeatability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of precision optical measurement and metrological calibration, in particular to a calibration device and method for calibrating the parallelism of the measuring surface of a large-scale outside diameter micrometer. BACKGROUND

[0002] The outside diameter micrometer is an indispensable length measurement tool in mechanical manufacturing and precision measurement. The core of its measurement accuracy depends on the flatness of the two measuring surfaces of the fixed anvil and the front end of the movable measuring rod, and the parallelism between them. For large-scale outside diameter micrometers with a diameter of 300mm to 2000mm, the calibration of parallelism is particularly difficult.

[0003] The traditional calibration method generally uses standard measuring rods or blocks for contact comparison measurement, which has inherent defects: 1) the contact force causes the elastic deformation of the micrometer bow, introducing errors; 2) multiple point measurements are required, which is cumbersome and inefficient, and highly dependent on the experience of the operator; 3) repeated contact between the block and the measuring surface can cause wear, affecting the accuracy of the micrometer itself; 4) the results are difficult to guarantee due to the interference of factors such as measurement force, heat conduction, and magnetism.

[0004] Although the digital autocollimator is a high-precision angle measurement instrument, it faces challenges when directly used for micrometer parallelism calibration: how to achieve synchronous capture and differentiation of the reflected images of the two measuring surfaces, how to establish a stable and accurate measurement reference, how to convert the small angle difference into a length value with high precision, and how to achieve convenient adjustment of large-size workpieces. Therefore, there is an urgent need for a systematic solution that integrates special optical design, precision mechanical adjustment mechanism, and intelligent software processing. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art and provide a calibration device and method for calibrating the parallelism of the measuring surface of a large-scale outside diameter micrometer, which can realize non-contact, automation, and visualization throughout the process, with high precision, high efficiency, and high repeatability.

[0006] To achieve the above purpose, one aspect of the present application provides a calibration device for calibrating the parallelism of the measuring surface of a large-scale outside diameter micrometer, comprising a mechanical adjustment module, an optical imaging module, and an image processing and calculation module. The mechanical adjustment module comprises an X-direction precision translation platform, a two-end adjustment mechanism, an adjustable support mechanism for the bow-shaped part, and a Y-direction auxiliary support platform. The X-direction precision translation platform is used to carry and adjust the position of the micrometer in the X-direction. The two-end adjustment mechanism is used to level the micrometer stand. The adjustable support mechanism for the bow-shaped part is used to support the bow-shaped part of the micrometer. The Y-direction auxiliary support platform is used to carry the micrometer in the Y-direction. The optical imaging module comprises a digital autocollimator and a double turning prism system, the digital autocollimator is internally provided with a high-resolution area array detector, the double turning prism system is used for dividing a single collimated light beam emitted by the autocollimator into two paths and projecting the two paths to two measuring surfaces of the micrometer respectively, and receiving reflected light, and forming two independent cross line images on the detector; The image processing and calculation module comprises an image acquisition and display unit, a feature recognition unit and an algorithm calculation unit, the image acquisition and display unit is used for displaying a field of view containing two cross line images in real time, the feature recognition unit is used for recognizing center coordinates of the two cross line images, and the algorithm calculation unit is used for setting one image as a reference zero position, calculating an angle deviation of the other image relative to the reference zero position in X and Y directions, and converting the angle deviation into a linear parallelism deviation value.

[0007] Another aspect of the present application provides a large outer diameter micrometer measuring surface parallelism calibration method, using the above-mentioned device to calibrate the parallelism of the large outer diameter micrometer measuring surface, comprising: Placing the micrometer on the mechanical adjustment module, so that it is in a free state, adjusting the position until the image acquisition and display unit clearly displays the reflected cross line images of the two measuring surfaces; Confirming the one-to-one correspondence relationship between the two cross line images and the two measuring surfaces of the micrometer by alternately shielding one light path; Selecting the reflected cross line image of one measuring surface and setting it as a reference zero position; Shielding the light path that has been set as the reference, calculating and displaying the angle deviation of the reflected image of the other measuring surface relative to the reference zero position in real time, and converting the angle deviation into a linear parallelism deviation value.

[0008] According to the calibration device and method for large outer diameter micrometer measuring surface parallelism calibration according to the above-mentioned aspect of the present application, non-contact, automatic and visual calibration can be realized in the whole process, and the device has the characteristics of high precision, high efficiency and high repeatability. BRIEF DESCRIPTION OF DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings used in the description of the embodiments of the present application. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor: Figure 1 is the overall structure schematic diagram of the calibration device for large outer diameter micrometer measuring surface parallelism calibration according to an embodiment of the present application; Figure 2 is the structure schematic diagram of the two-end adjustment mechanism according to an embodiment of the present application; Figure 3Figure 1 is a structural schematic diagram of an adjustable support mechanism for the arch part of a micrometer according to an embodiment of the present application. DETAILED DESCRIPTION

[0010] In order to make the objectives, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0011] An embodiment of the present application provides a calibration device for calibrating the parallelism of a large outer diameter micrometer measuring surface, as shown in Figure 1. Figure 1 The calibration device according to the embodiment of the present application includes three modules: a mechanical adjustment module, an optical imaging module and an image processing and calculation module.

[0012] The mechanical adjustment module is the basis of support and positioning of the device, including a measuring platform 13 and an X-direction precision translation platform 2, two end adjustment mechanisms (a left end clamping adjustment mechanism 3 and a right end clamping adjustment mechanism 4), an arch part adjustable support mechanism 5, a Y-direction auxiliary support platform 6, a grinding and finishing accessory 7 and a gauge block auxiliary measurement accessory 8 installed on the measuring platform 13.

[0013] The measuring platform 13 is used to provide a stable installation reference. The X-direction precision translation platform 2 is used to carry and coarsely adjust the position of the micrometer 1 in the X-direction, so as to realize the coarse positioning of the micrometer 1. Figure 2 As shown in Figure 2, the two end adjustment mechanisms 3 and 4 include a compression screw 14, a self-positioning V-shaped block 15 and a lifting hand wheel 16, which are used to accurately clamp and level the micrometer frame. The core design is that the mechanism does not exert a compression force during parallelism calibration, so as to ensure that the micrometer is in a "free state" and avoid introducing clamping deformation errors.

[0014] In the parallelism calibration mode, the two ends of the frame are naturally placed on the two self-positioning V-shaped blocks 15. By rotating the lifting hand wheels 16 at the two ends, the attitude of the micrometer 1 is finely adjusted, mainly leveling. During the entire parallelism calibration process, the compression screw 14 is always loosened, and the mechanism only provides positioning and height adjustment functions, without generating clamping force that deforms the frame. When grinding or value indication verification is needed, the compression screw 14 is tightened to fix the micrometer 1.

[0015] The compression screw 14 is used in the non-parallelism calibration mode, such as subsequent grinding or value error verification. At this time, the micrometer 1 needs to be fixed. By tightening the compression screw 14, downward pressure can be applied to firmly fix the frame on the self-positioning V-shaped block 15, preventing it from moving during operation.

[0016] Self-positioning V-shaped block 15 is the main supporting part in contact with the cylindrical part of the micrometer stand. Its V-shaped structure can automatically adapt and stably position the stand, limiting its movement in the horizontal plane, which is the key to achieving fast and repeated clamping.

[0017] Lifting hand wheel 16 is used to drive the fine lifting of self-positioning V-shaped block 15 in the vertical direction. By rotating hand wheel 16, the height of both ends of micrometer 1 can be adjusted, so that the two measuring surfaces of micrometer 1 (fixed anvil measuring surface and movable measuring rod measuring surface) are adjusted to the ideal position perpendicular to the optical path, ensuring that the reflected light can be smoothly received.

[0018] As shown in Figure 3 , the adjustable support mechanism 5 includes a measured piece placing plate 17, a pressing plate 18, a pressing nut 19, an adjustable height support screw 20, a lifting adjustment hand wheel 21, and a Y-direction movement locking hand wheel 22, which are used to provide an adjustable support point to support the micrometer arch part and assist in offsetting the deformation of the micrometer due to its own gravity.

[0019] Adjustable height support screw 20 is the main force and adjustment element, the top end is connected to the measured piece placing plate 17. Lifting adjustment hand wheel 21 is installed on screw 20. The whole assembly is connected to the slide or guide rail with Y-direction movement locking hand wheel 22 through the base.

[0020] The measured piece placing plate 17 is a support plate directly in contact with the lower surface of the micrometer 1 arch part, providing a stable bearing surface. The pressing plate 18 and the pressing nut 19 are used in the non-parallelism calibration mode. When grinding or verification is needed, the pressing plate 18 is placed across the micrometer 1 arch part, and the pressing nut 19 is locked, so that the arch part of the micrometer 1 is also fixed on the measured piece placing plate 17, achieving full constraint of the workpiece.

[0021] Adjustable height support screw 20 and lifting adjustment hand wheel 21 are the core adjustment components of the mechanism. Support screw 20 directly presses against placing plate 17, and by rotating lifting adjustment hand wheel 21, the height of the support point can be accurately adjusted to lift or release the support force on the arch part, thereby compensating for the gravity deflection.

[0022] Y-direction movement locking hand wheel 22 is used to fine-tune the position of the entire support mechanism in the horizontal plane, so that it can accurately align with the optimal stress point of the micrometer 1 arch part and be locked after adjustment.

[0023] Y-direction auxiliary support platform 6 is used to carry micrometer 1 in the Y-direction. Grinding and finishing accessories 7 and gauge auxiliary measurement accessories 8 are functional expansion accessories, which are used to provide extended functions, where grinding and finishing accessories 7 are used to repair the measuring surface, and gauge auxiliary measurement accessories 8 are used to verify the differential head.

[0024] The optical imaging module is responsible for the generation of the light path, light splitting and signal acquisition, including a digital autocollimator 9, a double turning prism system 10 and a bracket 11. The digital autocollimator 9 is a core sensor, with a built-in high-resolution area array CMOS detector, without calibration blind area. The double turning prism system 10 is a key optical component, which is used to skillfully divide the single collimated light beam emitted by the autocollimator 9 into two parallel light beams, which are respectively projected vertically to the fixed anvil and the movable measuring rod of the micrometer. The bracket 11 is used to install the digital autocollimator 9 above the X-precision translation platform 2.

[0025] The image processing and calculation module is a special software system installed on the computer 12, which is used to control hardware, acquire images and process data. The functions thereof include image display, feature recognition, reference setting, angle and length value conversion, data recording and analysis. In one embodiment, the image processing and calculation module includes a hardware control unit, an image acquisition and display unit, a feature recognition unit, an algorithm calculation unit and a data management unit. The hardware control unit is used to initialize the device and adjust the camera parameters (gain, exposure time). The image acquisition and display unit is used to display the field of view containing two cross line images in real time. The feature recognition unit is used to automatically or manually (frame selection) identify the center coordinates of the two cross images. The algorithm calculation unit is used to set one image as the reference zero position, calculate the angle deviation (°) of the other image in the X and Y directions, and convert it into the linear parallelism deviation value (μm) according to the optical lever principle. The data management unit is used to display the data and curve in real time and automatically save the calibration results.

[0026] The embodiment of the present application also provides a large outer diameter micrometer measuring surface parallelism calibration method, which uses the calibration device of the above-mentioned embodiment to calibrate the parallelism of the large outer diameter micrometer measuring surface. The calibration method of the embodiment of the present application includes the following steps: S1: Device preparation and initialization Connect the autocollimator 9 and the computer 12, start the software system, perform hardware initialization and calibration, and make the device enter a stable working state.

[0027] S2: Micrometer clamping and coarse adjustment Place the micrometer 1 to be measured on the mechanical adjustment module. Key steps: ensure that the micrometer is in a free state, that is, the two end adjustment mechanisms 3, 4 and the arc-shaped adjustable support mechanism 5 only play a positioning and supporting role, rather than being pressed tightly. Manually adjust the hand wheels and the platform, and observe the software interface until the reflected cross images of the two measuring surfaces are clearly presented.

[0028] Specifically, the two ends of the ruler are naturally placed on the two self-positioning V-shaped blocks 15 of the two end adjustment mechanisms 3, 4, and the attitude of the micrometer 1 is finely adjusted by rotating the lifting handwheels 16 at the two ends respectively, mainly leveling, until the reflected cross images of the two measuring surfaces are clear and centered in the software interface.

[0029] S3: Image optimization and image source confirmation Adjust the light source brightness of the autocollimator or the detector parameters through the light intensity indication bar in the software interface to make the cross image clear and sharp, and ensure that the calibration state is optimal. By alternately blocking one light path, observe which cross image disappears in the software, thereby confirming the unique correspondence between the two images and the two measuring surfaces of the micrometer, distinguishing the true reflected image from the device virtual image, and excluding the interference of the device internal virtual image.

[0030] S4: Establishing an absolute reference datum In the software, select the reflected cross image of one measuring surface (usually the fixed anvil surface), and set the center coordinates of this image as the angle zero position (0'0") of this calibration.

[0031] S5: Performing parallelism calibration Block the light path that has been set as the reference. At this time, the software displays the angular deviation (AngleX, AngleY) of the center of the reflected image of the other measuring surface (movable measuring rod surface) relative to the reference point in real time. The software synchronously converts this angle value into a linear deviation value (μm) on the diameter of the measuring surface and displays it. This value is the parallelism error in that direction. In this step S5, the "single calibration" or "continuous calibration" mode can be selected, and in the continuous calibration mode, the software displays the parallelism change curve in real time.

[0032] S6: Data recording and analysis The software automatically records the measurement data (including time, angle value, and linear value) into a designated text file, facilitating subsequent analysis, tracing, and report generation.

[0033] In one embodiment, the calibration method of the present application further includes the following functional extension steps: S7: Polishing and finishing function When the measurement finds that the parallelism is out of tolerance and the measuring surface needs to be polished and finished, use the polishing and finishing accessory 7. At this time, the micrometer needs to be pressed tightly. Install the polishing and finishing accessory 7 in place, adjust the polishing block to make it press against the surface to be polished, and apply polishing paste for polishing. The workpiece can be released at any time, and the polishing effect can be detected by repeating steps S2-S5 to achieve precise polishing and finishing.

[0034] S8: Indication error verification function Use gauge block auxiliary measurement accessory 8. The micrometer must also be clamped down. Adjust gauge block auxiliary measurement accessory 8 into position, set the reference using the gauge block top rod, and then place gauge blocks of different sizes between the top rod and the measuring rod. Measure the angle change after the measuring rod moves using an autocollimator to verify the indication error of the micrometer head.

[0035] The following example provides a more detailed description of the parallelism calibration method for the measuring surfaces of a large outside micrometer according to an embodiment of the present invention.

[0036] First, such as Figure 1 As shown, connect all components of the device. Gently place the 1000mm outside micrometer 1 to be calibrated onto the V-blocks of the adjustment mechanisms 3 and 4 at both ends and the adjustable support mechanism 5 in the bow-shaped part, ensuring it is not compressed. Start the software and initialize the device. Roughly adjust the position of the micrometer; two crosshairs can be seen on the software interface. Fine-tune the light source brightness to make the image clear. Block the right light path; the left image disappears, confirming that the left image corresponds to the fixed anvil. Select the left image with the mouse in the software and click "Absolute Reference" to set it to zero. Then block the left light path; the software's real-time parallelism deviation is: X-axis 4.90μm, Y-axis 0.45μm, total deviation 4.92μm. Calibration is complete, and the data is automatically saved. If the deviation exceeds the tolerance, use a grinding attachment for repair and repeat the above steps to verify until it is acceptable.

[0037] In summary, the calibration device and method for calibrating the parallelism of measuring surfaces of large outside micrometers according to the embodiments of the present invention adopts a non-contact optical calibration method, which avoids the force deformation error of traditional contact methods. Through a high-resolution area array detector, a dedicated software module and a mechanical adjustment mechanism, it can achieve high-precision, high-efficiency and automated calibration of the parallelism of the two measuring surfaces of large outside micrometers ranging from 300mm to 2000mm. It also integrates grinding assistance and indication error verification functions, which significantly improves the accuracy and efficiency of calibration.

[0038] The calibration device and method for calibrating the parallelism of measuring surfaces of large outside micrometers according to embodiments of the present invention have the following beneficial effects: Non-contact measurement: Completely avoids deformation errors caused by contact stress, resulting in more accurate and reliable results; High efficiency and automation: Results can be obtained within seconds of a single clamping, and the software automatically calculates and records, greatly improving efficiency and reducing human error; High precision and visualization: High-resolution detectors ensure high precision; the entire process is clearly visible through real-time display, facilitating adjustment and judgment; Functional integration: One device integrates three major functions: parallelism calibration, grinding assistance, and indication verification, offering high cost-effectiveness; Data-driven management: Automatically saves data, facilitating quality traceability and digital management.

[0039] Certain exemplary embodiments of the present application have been described above by way of illustration, and it is to be understood that various modifications will be apparent to those of ordinary skill in the art, without departing from the spirit and scope of the present application. Therefore, the above description should not be construed as limiting the scope of the present application.

Claims

1. A calibration device for calibrating the parallelism of a measuring surface of a large outside diameter micrometer, characterized in that, The mechanical adjustment module, the optical imaging module and the image processing and calculation module are comprised. The mechanical adjustment module comprises an X-direction precision translation platform, a two-end adjustment mechanism, an arc part adjustable support mechanism and a Y-direction auxiliary support platform, the X-direction precision translation platform is used for carrying and adjusting the position of the micrometer in the X direction, the two-end adjustment mechanism is used for leveling the micrometer frame, the arc part adjustable support mechanism is used for supporting the arc part of the micrometer, and the Y-direction auxiliary support platform is used for carrying the micrometer in the Y direction. The optical imaging module comprises a digital autocollimator and a double turning prism system, the digital autocollimator is internally provided with a high-resolution area array detector, the double turning prism system is used for dividing the single collimated light beam emitted by the autocollimator into two paths and projecting them onto the two measuring surfaces of the micrometer respectively, and receiving the reflected light to form two independent cross line images on the detector. The image processing and calculation module comprises an image acquisition and display unit, a feature recognition unit and an algorithm calculation unit, the image acquisition and display unit is used for displaying the field of view containing the two cross line images in real time, the feature recognition unit is used for identifying the center coordinates of the two cross line images, and the algorithm calculation unit is used for setting one image as a reference zero position, calculating the angular deviation of the other image relative to the reference zero position in the X and Y directions, and converting it into a linear parallelism deviation value.

2. The apparatus of claim 1, wherein, The two-end adjustment mechanism comprises a self-positioning V-shaped block and a lifting hand wheel, the self-positioning V-shaped block has a V-shaped structure and can automatically adapt to and position the frame to limit the movement of the frame in the horizontal plane; the lifting hand wheel is used to drive the self-positioning V-shaped block to lift in the vertical direction, thereby adjusting the height of the two ends of the micrometer.

3. The apparatus of claim 2, wherein, The two-end adjustment mechanism further comprises a pressing screw, which can fix the frame on the self-positioning V-shaped block by applying downward pressure to prevent the frame from moving during operation.

4. The apparatus of any one of claims 1-3, wherein, The arc part adjustable support mechanism comprises a measured piece placing plate, an adjustable height support screw and a lifting adjustment hand wheel, the top end of the support screw supports the measured piece placing plate, the measured piece placing plate is in contact with the lower surface of the arc part of the micrometer to provide a stable bearing surface, and the lifting adjustment hand wheel is installed on the support screw, which can adjust the height of the support point of the support screw by rotating the lifting adjustment hand wheel to lift or release the support force on the arc part, thereby compensating for the gravity deflection.

5. The apparatus of claim 4, wherein, The arc part adjustable support mechanism further comprises a pressing plate and a pressing nut, which are used to fix the arc part of the micrometer on the measured piece placing plate by locking the pressing nut when grinding or checking.

6. The apparatus of claim 5, wherein, The arc part adjustable support mechanism further comprises a Y-direction movement locking hand wheel, which is used to fine-tune the position of the entire support mechanism in the horizontal plane, thereby aligning the best stress point of the arc part of the micrometer.

7. The apparatus of any one of claims 1-3, wherein, The mechanical adjustment module further comprises a grinding and finishing accessory and a gauge auxiliary measurement accessory, the grinding and finishing accessory is used to repair the measuring surface, and the gauge auxiliary measurement accessory is used to check the differential head of the micrometer.

8. The apparatus of any one of claims 1-3, wherein, The mechanical adjustment module further comprises a measuring platform, an X-direction precision translation platform, a two-end adjustment mechanism, an arcuate part adjustable support mechanism and a Y-direction auxiliary support platform are installed on the measuring platform; the optical imaging module further comprises a support, and the autocollimator is installed above the X-direction precision translation platform through the support.

9. A large outside diameter micrometer measuring face parallelism calibration method, characterized in that, The parallelism calibration of a large-scale outside diameter micrometer measuring surface is performed by using the device according to any one of claims 1-8, comprising: Placing the micrometer on the mechanical adjustment module, making it in a free state, adjusting the position until the image acquisition and display unit clearly displays the reflected cross line images of the two measuring surfaces; Confirming the one-to-one correspondence between the two cross line images and the two measuring surfaces of the micrometer by alternately shielding one light path; Selecting the reflected cross line image of one measuring surface and setting it as the reference zero position; Shielding the light path that has been set as the reference, calculating and displaying the angular deviation of the reflected image of the other measuring surface relative to the reference zero position in real time, and converting it into a linear parallelism deviation value.

10. The method of claim 9, wherein, Further comprising: When the parallelism is out of tolerance, using a grinding and finishing accessory to press and hold against the measuring surface to be ground, and detecting the grinding effect in real time; Using a gauge auxiliary measuring accessory, setting a reference with a gauge top rod, placing gauges of different sizes between the top rod and the measuring rod, and measuring the angular change of the measuring rod after moving through the autocollimator to detect the indication error of the differential head.

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