A method for calibrating X-axis of a contour measuring instrument

Abstract

The present invention relates to a method for calibrating the X-axis of a contour measuring instrument, comprising the following steps: adjusting the parallelism of a special sample block and the X-axis guide rail of the contour measuring instrument; the measuring needle scans sequentially from the first triangular sawtooth in an automatic contact manner until the upper limit of the X-axis measurement range; the contour measuring instrument forms a contour graph of the special sample block in a computer, fits the center position of each tooth top in the contour graph, calculates the center distance using the measuring software provided by the contour measuring instrument, compares it with the nominal value of the special sample block, obtains the indication error of the X-axis of the contour measuring instrument, and calculates the indication error of the X-axis of the contour measuring instrument when detecting the contour of the workpiece. The present invention can quickly and accurately adjust the position of the special sample block, ensure that the special sample block is parallel to the X-axis guide rail of the contour measuring instrument, and the special sample block uses the distance between the tooth top fillets of two adjacent triangular sawtooth teeth as the measurement basis, which can effectively reduce the measurement error caused by the tooth top shape error, thereby obtaining the measurement error of the contour measuring instrument.

Description

Technical Field

[0001] The invention relates to the technical field of error calibration of a contour measuring instrument, and in particular to an X-axis calibration method of a contour measuring instrument. Background Art

[0002] The stylus-type surface profile measuring instrument (hereinafter referred to as the profiler) is a measuring instrument that uses a linear guide as a reference, moves the stylus along the surface of the workpiece, records the profile curve of the measured surface, calculates and evaluates the two-dimensional shape and position parameters of the measured profile, such as size, angle, arc, etc. According to the requirements of GB / T 19600-2004 "Technical Specifications for Product Geometric Measurement (GPS) Calibration of Contact (Stylus) Instruments for Surface Structure Profile Method" and JB / T 11271-2012 "Contact (Stylus) Surface Profile Measuring Instruments", the indication error of the profiler's X-axis is a very important technical indicator and needs to be calibrated.

[0003] The most widely used method for calibrating the X-axis indication error of the profiler is the laser interferometer calibration method. The laser interferometer calibration method requires the target mirror of the laser interferometer to be installed on the drive box and sensor connector of the profiler, but the target mirror is large in size and difficult to install, and its own heavy weight can easily damage the measuring force of the profiler, causing machine failure. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a method for calibrating the X-axis of a contour measuring instrument, which can quickly and accurately adjust the position of a special sample block, and use the distance between the centers of the tooth top circles of two adjacent triangular sawtooth teeth as the measurement basis, which can effectively reduce the measurement error caused by the tooth top shape error, thereby obtaining the measurement error of the contour meter, and the special sample block has good stability as a physical measuring tool.

[0005] The object of the present invention is achieved in that:

[0006] A method for calibrating the X-axis of a contour measuring instrument comprises the following steps:

[0007] Step 1: Adjust parallelism:

[0008] Place the position adjustment base holding the special sample block on the profilometer workbench, visually check that the length direction of the special sample block 1 is consistent with the X-axis direction of the profilometer, and then perform parallelism fine-tuning;

[0009] Adjust the height of the profilometer column, use the automatic contact method to make the profilometer's stylus contact the spherical protrusion on the left end, and use the adjustment pin on the left to fine-tune the position of the special sample block so that the stylus is accurately positioned at the top of the spherical protrusion on the left; lift the stylus, run the X-axis guide rail of the profilometer, make the stylus contact the spherical protrusion on the right, and use the adjustment pin on the right to fine-tune the position of the special sample block so that the stylus is accurately positioned at the top of the spherical protrusion on the right;

[0010] The top line of the left and right spherical protrusions is on the center line of the top surface of the special sample block. When the probe captures the top of the two spherical protrusions, it means that the length direction of the special sample block is parallel to the running direction of the X-axis guide rail of the profiler.

[0011] Step 2: Measure;

[0012] From left to right, the stylus scans in sequence from the first triangular sawtooth in an automatic contact manner until the upper limit of the X-axis measurement range;

[0013] Step 3: Data analysis;

[0014] The profiler forms a profile graph of a special sample block in the computer. In the profile graph, the center position of each tooth top is fitted, and the center distance is calculated using the profiler's own measurement software. This is compared with the nominal value of the special sample block to obtain the indication error of the profiler's X-axis. The indication error of the profiler's X-axis is calculated when detecting the workpiece profile.

[0015] Preferably, in step one, it is also necessary to eliminate the Z-axis error, contact the tooth top of the triangular sawtooth in an automatic contact manner, adjust the Z-axis guide rail, observe the tooth top coordinates through graphic software, and when there is an obvious difference in the tooth top height, drive the cam to adjust the inclination of the special sample block through the height adjustment screw, so that the tooth top connection line of each triangular sawtooth is parallel to the direction of the X-axis guide rail, which can reduce the error introduced by the Z-axis during the X-axis calibration process.

[0016] Preferably, the special sample block in step 1 comprises a base, and spherical protrusions are provided at both ends of the top surface of the special sample block along the length direction, a plurality of triangular saw teeth are evenly spaced between the two spherical protrusions, and the tooth tops of the triangular saw teeth are rounded.

[0017] Preferably, the position adjustment base in step one comprises a base plate, and the base plate is provided with horizontal adjustment brackets front and back along the length direction, and the horizontal adjustment brackets clamp and adjust the special sample block.

[0018] Preferably, the horizontal adjustment bracket includes two vertical plates, an adjustment ejector pin and an elastic ejector pin, the two vertical plates are arranged on the front and rear sides of the base plate, and the adjustment ejector pin and the elastic ejector pin are correspondingly arranged on the two vertical plates.

[0019] Preferably, the base plate is provided with a cylindrical fulcrum on one side along the length direction and a cam on the other side. The base plate is provided with a cam accommodating cavity corresponding to the cam. The cam is connected to a height adjustment screw. One end of the height adjustment screw extends out of the base plate. The bottom surface of the special sample block is always in contact with the cylindrical fulcrum and the cam.

[0020] The beneficial effects of the present invention are:

[0021] The present invention can quickly and accurately adjust the position of the special sample block to ensure that the special sample block is parallel to the X-axis guide rail of the profiler. The special sample block uses the distance between the tooth top fillets of two adjacent triangular saw teeth as a measurement basis, which can effectively reduce the measurement error caused by the tooth top shape error, thereby obtaining the measurement error of the profiler, and the special sample block has good stability as a physical measuring tool. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the use state of the present invention.

[0023] Figure 2 It is the assembly diagram of the special sample block and the position adjustment base.

[0024] Figure 3 for Figure 2 Left view of .

[0025] Figure 4 This is a schematic diagram of the state of the special sample block after the inclination is adjusted.

[0026] Figure 5 This is a structural diagram of a special sample block.

[0027] Wherein: special sample block 1; base 1.1; spherical protrusion 1.2; triangular sawtooth 1.3; position adjustment base 2; base plate 2.1; horizontal adjustment bracket 2.2; vertical plate 2.2.1; adjustment ejector pin 2.2.2; elastic ejector pin 2.2.3; cylindrical fulcrum 2.3; cam 2.4; height adjustment screw rod 2.5; profilometer 3; measuring pin 3.1. DETAILED DESCRIPTION

[0028] See also Figure 1-5 The present invention relates to an X-axis calibration device for a contour measuring instrument, comprising a special sample block 1 and a position adjustment base 2, wherein the special sample block 1 comprises a base 1.1, and spherical protrusions 1.2 are arranged at both ends of the top surface of the base 1.1 along the length direction, and a plurality of triangular saw teeth 1.3 are evenly spaced between the two spherical protrusions 1.2, and the spherical protrusions 1.2 and the triangular saw teeth 1.3 are distributed on the center line of the top surface of the base 1.1, and the triangular saw teeth 1.2 are isosceles triangles, and the vertex angle of the triangular saw teeth 1.2 is greater than 60°, and the tooth top of the triangular saw teeth 1.2 is rounded, and the roundness error of the tooth top is less than 2μm, so that the stylus can crawl smoothly during the contour meter measurement process.

[0029] The base 1.1 has a width greater than 5 mm and a height greater than 10 mm and is made of steel, so that the special sample block 1 has good stability and is not easily deformed.

[0030] The tooth thickness of the triangular sawtooth is less than or equal to 3 mm, so that the tooth shape is easy to manufacture under the premise of ensuring the shape accuracy of the tooth top straightness and the tooth top arc.

[0031] The tooth height of the triangular saw teeth is less than 4 mm and less than the height of the measuring needle 3.1, so as to ensure that the measuring needle 3.1 always contacts the special sample block during the profilometer measurement process.

[0032] The distance between the tooth top fillets of two adjacent triangular saw teeth is the center distance. As the main technical indicator, the center distance can effectively reduce the measurement error caused by the tooth top shape error, and facilitate the traceability of special sample blocks.

[0033] The position adjustment base 2 comprises a base plate 2.1, and the base plate 2.1 is provided with a horizontal adjustment bracket 2.2 along the longitudinal direction. The horizontal adjustment bracket 2.2 is used to clamp and adjust the special sample block 1. The horizontal adjustment bracket 2.2 comprises two vertical plates 2.2.1, an adjustment ejector pin 2.2.2 and an elastic ejector pin 2.2.3. The two vertical plates 2.2.1 are arranged on the front and rear sides of the base plate 2.1. The adjustment ejector pin 2.2.2 and the elastic ejector pin 2.2.3 are correspondingly arranged on the two vertical plates 2.2.1. The spring sleeve is arranged on the elastic ejector pin 2.2.3. On the elastic ejector pin 2.2.2, the elastic ejector pin 2.2.2 is elastically compressed by a spring. When the special sample block 1 is not inserted into the horizontal adjustment bracket 2.2, the elastic ejector pin 2.2.2 is in an uncompressed state. When the special sample block 1 is inserted into the horizontal adjustment bracket 2.2, the special sample block 1 pushes the elastic ejector pin outward to compress the elastic ejector pin 2.2.3, thereby achieving the function of clamping the special sample block 1; when the front and rear position of the special sample block 1 needs to be adjusted horizontally, the ejector pin 2.2.2 is rotated to ensure that the special sample block 1 is parallel to the X-axis guide rail of the profiler.

[0034] The base plate 2.1 is provided with a cylindrical fulcrum 2.3 on one side along the length direction, and a cam 2.4 on the other side. The base plate 2.1 is provided with a cam accommodating cavity corresponding to the cam 2.4. The cam 2.4 is connected to a height adjustment screw 2.5, and one end of the height adjustment screw 2.5 extends out of the base plate 2.1. The bottom surface of the special sample block 1 is always in contact with the cylindrical fulcrum 2.3 and the cam 2.4. When it is necessary to fine-tune the height of the special sample block 1, the cam 2.4 on it is driven to rotate by rotating the height adjustment screw 2.5, thereby realizing fine-tuning of the height of the special sample block 1 on the cam 2.4 side, ensuring that the special sample block 1 is parallel to the X-axis guide rail of the profiler, eliminating the Z-axis error, and avoiding the Z-axis error introduced during the X-axis calibration process to interfere with the measurement result.

[0035] Profilometer X-axis calibration method:

[0036] The following steps are involved:

[0037] Step 1: Adjust parallelism: Ensure that the special sample block is parallel to the X-axis guide rail of the profiler;

[0038] Firstly, place the position adjustment base 2 holding the special sample block 1 on the profilometer workbench, visually check that the length direction of the special sample block 1 is consistent with the X-axis direction of the profilometer, and then adjust the parallelism;

[0039] Adjust the height of the profilometer column, use the automatic contact method to make the stylus 3.1 of the profilometer 3 contact the spherical protrusion on the left end, and fine-tune the position of the special sample block by adjusting the ejector pin on the left side to make the stylus 3.1 accurately positioned at the top of the spherical protrusion on the left side. When the stylus 3.1 is at the top of the spherical protrusion on the left side, the corresponding Z-axis indication is the largest, which is recorded as Z1;

[0040] Lift the stylus 3.1, run the X-axis guide rail of the profiler 3, make the stylus 3.1 contact the spherical protrusion on the right, and fine-tune the position of the special sample block by adjusting the ejector pin on the right, so that the stylus 3.1 is accurately positioned at the top of the spherical protrusion on the right. When the stylus 3.1 is at the top of the spherical protrusion on the right, the corresponding Z-axis indication is the maximum, which is recorded as Z2;

[0041] Since the top line of the left and right spherical protrusions is on the center line of the top surface of the special sample block, the probe 3.1 captures the top of the two spherical protrusions, which means that the length direction of the special sample block is parallel to the running direction of the X-axis guide rail of the profiler;

[0042] When measuring needle 3.1 captures the top of the spherical protrusion, the measuring needle is moved back and forth along the Y-axis section of the spherical protrusion by adjusting the ejector pin. The Z-axis indication is observed while moving. When the maximum Z-axis indication is found, it indicates that the top of the spherical protrusion has been located.

[0043] Eliminate Z-axis error: Make the stylus 3.1 contact the tooth top of the triangular sawtooth in an automatic contact mode, adjust the Z-axis guide rail, and observe the tooth top coordinates through the graphic software. If there is a significant difference in the tooth top height, use the height adjustment screw to drive the cam to adjust the inclination of the special sample block so that the tooth top connection line of each triangular sawtooth is parallel to the direction of the X-axis guide rail, which can reduce the error introduced by the Z-axis during the X-axis calibration process.

[0044] Step 2: Measure

[0045] From left to right, the stylus 3.1 scans in sequence from the first triangular sawtooth to the upper limit of the X-axis measuring range in an automatic contact manner.

[0046] Step 3: Data Analysis

[0047] The profiler forms a profile graph of a special sample block in the computer. In the profile graph, the center position of each tooth top is fitted. When fitting, the circular segment should be selected as large as possible to reduce the measurement error. The center distance is calculated using the measurement software that comes with the profiler and compared with the nominal value of the special sample block to obtain the indication error of the X-axis of the profiler. When detecting the workpiece contour, the indication error of the X-axis of the profiler is calculated to improve the accuracy of the profiler and reduce the measurement error.

[0048] In addition to the above embodiments, the present invention also includes other implementation modes. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. A method for calibrating the X-axis of a contour measuring instrument, characterized in that: The following steps are involved: Step 1: Adjust parallelism: Place the position adjustment base holding the special sample block on the profilometer workbench, visually check that the length direction of the special sample block is consistent with the X-axis direction of the profilometer, and then make a fine adjustment for parallelism; Adjust the height of the profilometer column, use the automatic contact method to make the profilometer's stylus contact the spherical protrusion on the left end, and use the adjustment pin on the left to fine-tune the position of the special sample block so that the stylus is accurately positioned at the top of the spherical protrusion on the left; lift the stylus, run the X-axis guide rail of the profilometer, make the stylus contact the spherical protrusion on the right, and use the adjustment pin on the right to fine-tune the position of the special sample block so that the stylus is accurately positioned at the top of the spherical protrusion on the right; The top line of the left and right spherical protrusions is on the center line of the top surface of the special sample block. When the probe captures the top of the two spherical protrusions, it means that the length direction of the special sample block is parallel to the running direction of the X-axis guide rail of the profiler. Step 2: Measure; From left to right, the stylus scans in sequence from the first triangular sawtooth in an automatic contact manner until the upper limit of the X-axis measurement range; Step 3: Data analysis; The profiler forms a profile graph of a special sample block in the computer. In the profile graph, the center position of each tooth top is fitted, and the center distance is calculated using the measurement software provided by the profiler. It is compared with the nominal value of the special sample block to obtain the indication error of the X-axis of the profiler. The indication error of the X-axis of the profiler is calculated when detecting the workpiece profile. In the step 1, the Z-axis error also needs to be eliminated. The probe is automatically contacted with the tooth top of the triangular sawtooth, the Z-axis guide rail is adjusted, and the tooth top coordinates are observed through the graphic software. When there is a significant difference in the tooth top height, the height adjustment screw drives the cam to adjust the inclination of the special sample block so that the tooth top connection line of each triangular sawtooth is parallel to the direction of the X-axis guide rail, which can reduce the error introduced by the Z-axis during the X-axis calibration process; The position adjustment base in step 1 comprises a base plate, and the base plate is provided with horizontal adjustment brackets in front and back along the length direction, and the horizontal adjustment brackets clamp and adjust the special sample block; The base plate is provided with a cylindrical fulcrum on one side along the length direction and a cam on the other side. The base plate is provided with a cam accommodating cavity corresponding to the cam. The cam is connected to a height adjustment screw. One end of the height adjustment screw extends out of the base plate. The bottom surface of the special sample block is always in contact with the cylindrical fulcrum and the cam.

2. The X-axis calibration method of a profile measuring instrument according to claim 1, characterized in that: The special sample block in step 1 comprises a base, and spherical protrusions are provided at both ends of the top surface of the special sample block along the length direction, and a plurality of triangular saw teeth are evenly spaced between the two spherical protrusions, and the tooth tops of the triangular saw teeth are rounded.

3. The X-axis calibration method of a profile measuring instrument according to claim 1, characterized in that: The horizontal adjustment bracket includes two vertical plates, an adjustment ejector pin and an elastic ejector pin. The two vertical plates are arranged on the front and rear sides of the base plate, and the adjustment ejector pin and the elastic ejector pin are correspondingly arranged on the two vertical plates.

4. The X-axis calibration method of a profile measuring instrument according to claim 1, characterized in that: When the stylus captures the top of the spherical protrusion, the stylus is moved back and forth along the Y-axis section of the spherical protrusion by adjusting the ejector pin. The Z-axis indication is observed while moving. When the maximum Z-axis indication is found, it indicates that the top of the spherical protrusion has been located.

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