Method for measuring arc radius of thin-walled workpiece and included angle between two holes

Abstract

In order to solve the problem that the arc radius of the thin-wall part and the included angle between the two holes cannot be directly measured, the invention discloses a method for measuring the arc radius of the thin-wall part and the included angle between the two holes, which comprises the following steps of: compiling a measurement program on a flash tester, and measuring the arc radius of the thin-wall part, the diameter of a small hole and the included angle between the two holes by using an image measurement technology; a camera arranged in the instrument is used for photographing the shape of the workpiece, and automatic identification and focusing are carried out; using a measuring tool to extract points, straight lines, circles, arcs and other elements needing to be measured; secondary element extraction is carried out, and straight lines and circles are made through circle centers; then, the needed size is marked through a marking program; the graph and data are stored, and a measurement template is generated; during subsequent measurement, a program is called out, and a continuous measurement button is used for measuring the marked size. The method is reasonable in design, is a brand-new method for measuring the arc radius of the thin-wall part and the included angle between the two holes, and has good actual use value.

Description

Technical Field

[0001] The invention belongs to the technical field of workpiece measurement, and relates to parameter measurement of a thin-walled workpiece, in particular to a method for measuring the arc radius of a thin-walled workpiece and the angle between two holes. Background Art

[0002] At present, the "control rod drive line parts and components" processed for a Beijing company have high precision requirements and complex shapes, requiring full-size inspection, which increases the difficulty of measurement work.

[0003] For example, the "sieve plate" on the spring box is a thin-walled arc-shaped part with circular holes and arcs of varying sizes, and a thickness of 3mm. Figure 1 shown.

[0004] Testing requirements: Arc radius—R2 (small), R4 (large), R5 (medium), in mm; The diameters of the six small circular holes are about Φ2mm (the values ​​are recorded as φ1, φ2, φ3, φ5, φ6, φ7 respectively), and the diameter of the one large circular hole is about Φ6mm (the value is recorded as φ4), the unit is mm; Arc radius—R1 and R3, in mm; The angle between two adjacent holes is 15°; The angle between the first small circle Ⅰ (φ1 hole) and the last small circle Ⅶ (φ7 hole) is 90°.

[0005] Commonly used measurement methods: The diameter of the large circular hole (φ4 hole) is measured with an inside micrometer or inside diameter gauge; The diameter of small round holes (φ1 hole, φ2 hole, φ3 hole, φ5 hole, φ6 hole, φ7 hole) is detected with a special plug gauge; R1 and R3 are tested using radius templates.

[0006] The arc radius and the angle between the two holes cannot be directly detected by general measuring tools, and are generally measured on a three-dimensional coordinate measuring machine. The measurement method is to collect a certain number of points, fit them into a circle, and calculate the value of the arc radius and the angle between the two holes. However, due to the small arc length (less than one-third) of the arc, the points collected in this method are limited and cannot accurately simulate the real full circle. Therefore, the numerical error of the calculated result is large and not accurate enough.

[0007] In addition, due to the small diameter of the small circular hole, general manufacturers do not equip probes with too small diameters, so the angle between the two holes cannot be directly measured on a three-dimensional coordinate measuring machine.

[0008] Generally speaking, the "problem of measuring a circular arc with a large radius and a small arc length" has always been a difficult problem in the field of measurement. Summary of the invention

[0009] In order to solve the problem that the arc radius of a thin-walled part and the angle between two holes cannot be directly measured, the present invention provides a method for measuring the arc radius of a thin-walled part and the angle between two holes. The purpose is to compile a measurement program on a "flash tester" and use image measurement technology to measure the radius of the arc of a thin-walled part, the diameter of a small hole and the angle between two holes, thereby achieving one-click fast and accurate measurement, saving detection time and improving detection efficiency.

[0010] The present invention is achieved by adopting the following technical solutions: A method for measuring the arc radius of a thin-walled part and the angle between two holes, by compiling a measurement program on a "flash tester", using image measurement technology to measure the arc radius of the thin-walled part, the diameter of a small hole and the angle between two holes; using a camera configured in the instrument to take a picture of the shape of the workpiece, automatically identifying and focusing; using a measuring tool to extract points, straight lines, circles, and arcs that need to be measured; performing secondary element extraction, drawing straight lines and circles through the center of the circle; then using a marking program to mark the required dimensions; saving graphics and data, and generating a measurement template; calling out the program for subsequent measurements, and using a continuous measurement button to measure the marked dimensions.

[0011] The above method for measuring the arc radius of a thin-walled part and the angle between two holes specifically comprises the following steps: Step 1: Place the workpiece on the workbench of the flash tester. There is no need to clamp and position it. The instrument will automatically identify and focus according to the shape of the workpiece, and take a photo after adjusting the clarity.

[0012] Step 2: Extract arcs and circles Use a "ring frame" to enclose the arc or circle to be extracted, enter the first point, the second point, and the third point in the ring frame selection area in sequence (first determine by three points), and adjust the size of the ring frame selection area. After collecting data from countless points on the arc or circle in the ring frame selection area, "fit" them into arcs or circles.

[0013] Step 3: Take the circle twice through the center Click the "Secondary Circle" icon, select the "center" of the required circle respectively, press "OK" to end the selection, and "fit" all the selected circle centers into a new circle.

[0014] Step 4: Draw a line connecting the centers of the two circles, which is suitable for calculating the angles of adjacent direct angles.

[0015] Step 5: Mark the arc radius and circle diameter Calculate the arc and the secondary circle respectively, and "mark" the calculated values ​​on the arc to be measured; Then, the diameter and radius values ​​obtained by calculation are "marked" on the circle to be measured.

[0016] Step 6: Mark the angle of the circular hole Click the "Calculate Angle" icon, select the two straight lines for the desired angle, calculate the angle between the two straight lines, and "mark" them at their respective positions.

[0017] Step 7: Generate measurement template Save the above measurement process into a specified file to generate a measurement template.

[0018] Step 8: Take all dimensions Recall the stored program "Measurement Template", place the workpiece according to the position of the stored template, click "Measure", and the required size can be measured.

[0019] Step 9: Measurement and evaluation, report generation The measurement results are automatically recorded in a table, and the results are automatically evaluated to see if they meet the requirements based on the input design values. If they exceed the design values, the deviation values ​​are calculated.

[0020] After the measurement of the first workpiece is completed, when measuring the second workpiece subsequently, just call out the previously generated measurement template, place the workpiece on the instrument workbench, and press the continuous measurement button to directly complete the measurement and obtain the measurement results. After evaluation, a report can be generated and the measurement results can also be printed out.

[0021] Compared with the existing method for measuring the arc radius of thin-walled parts and the angle between two holes, the present invention has the following beneficial effects: First, the method of the present invention realizes one-click rapid and accurate measurement, and the measured data is accurate and reliable, thereby improving the detection efficiency.

[0022] Secondly, the method of the present invention solves the problem that general measuring tools cannot directly measure and three-coordinate measuring machines cannot accurately measure "large arc radius and small arc length", filling the gap in this measurement field.

[0023] The invention has reasonable design and is a new method for measuring the arc radius of a thin-walled part and the angle between two holes, and has good practical use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 Drawing showing a thin-walled workpiece (screen partition) (with dimensions marked).

[0027] Figure 2 Schematic diagram of a thin-walled workpiece (screen partition).

[0028] Figure 3 Schematic diagram showing automatic workpiece recognition and focusing.

[0029] Figure 4 Represents the schematic diagram of extracting arcs and circles.

[0030] Figure 5 It represents the schematic diagram of taking a circle through the center of a secondary circle.

[0031] Figure 6 It represents a schematic diagram of connecting the centers of two circles.

[0032] Figure 7 Represents the schematic diagram of arc radius annotation.

[0033] Figure 8 Represents a schematic diagram of circle diameter annotation.

[0034] Fig. 9 Schematic diagram of the angle annotations indicating the location of the circular holes.

[0035] Fig.10 Schematic diagram of production measurement template.

[0036] Fig.11 A schematic diagram showing the measurement results of all dimensions.

[0037] Fig.12 A schematic diagram showing measurement, evaluation and report generation. DETAILED DESCRIPTION

[0038] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0039] In the description, it should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0040] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all of the embodiments.

[0041] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0042] A method for measuring the arc radius of thin-walled parts and the angle between two holes. By compiling a measurement program on a "flash tester", the image measurement technology is used to measure the arc radius of thin-walled parts, the diameter of small holes and the angle between two holes. The measurement object can be automatically located, templates can be matched, measurements can be evaluated, and reports can be generated according to the shape of the workpiece, truly realizing one-click fast and accurate measurement.

[0043] like Figure 1 , 2 As shown, the thin-walled workpiece is an arc-shaped plate; a large circle IV (diameter φ4) with a center of O4 is provided in the middle of the arc-shaped plate, and three small circles are symmetrically provided on both sides of the large circle IV. The small circles on the left side of the large circle IV are successively recorded as small circle I (diameter φ1) with a center of O1, small circle II (diameter φ2) with a center of O2, and small circle III (diameter φ3) with a center of O3; the small circles on the right side of the large circle IV are successively recorded as small circle V (diameter φ5) with a center of O5, small circle VI (diameter φ6) with a center of O6, and small circle VII (diameter φ7) with a center of O7. The inner arc side of the arc plate is recorded as arc II, the outer arc side is recorded as arc IV, the left arc side is recorded as semicircular arc I, and the right arc side is recorded as semicircular arc III. The centers O1, O2, O3, O4, O5, O6, and O7 are located on the same arc V. The radius of semicircular arc I is recorded as R1, the radius of arc II is recorded as R2, the radius of semicircular arc III is recorded as R3, the radius of arc IV is recorded as R4, and the radius of arc V is recorded as R5; the centers of arc II, arc IV, and arc V coincide and are recorded as O.

[0044] The measuring principle of the flash tester: a camera is installed inside the instrument to take pictures of the shape of the workpiece, automatically identify and focus; use measuring tools to extract elements, such as points, lines, circles, arcs and other elements that need to be measured; perform secondary element extraction, such as drawing lines and circles through the center of a circle; then use the marking program to mark the required dimensions; save graphics and data, and generate a measurement template; for subsequent measurements, you only need to call out the program, and use the continuous measurement button to measure the marked dimensions.

[0045] The specific steps are as follows: Step 1: Place the thin-walled workpiece on the workbench of the flash tester. No clamping or positioning is required. The instrument automatically recognizes and focuses according to the shape of the workpiece, adjusts the clarity, and then takes a photo. Figure 3 shown.

[0046] The image contour of the workpiece being measured is reduced by using a telecentric lens with a large viewing angle and depth of field. These images are transmitted to a high-resolution CMOS camera for digital processing and converted into measurable data. The background drawing software quickly captures and compares the workpiece contour with the scale according to the preset programming instructions, and calculates the precise size and tolerance.

[0047] Step 2: Extract arcs and circles like Figure 4 As shown, the arcs to be extracted, i.e., semi-arc Ⅰ, arc Ⅱ, semi-arc Ⅲ, arc Ⅳ and the extracted circles, i.e., small circle Ⅰ, small circle Ⅱ, small circle Ⅲ, large circle Ⅳ, small circle Ⅴ, small circle Ⅵ and small circle Ⅶ, are framed with a "ring frame" on the operation page. For each arc or circle, firstly, the first point, the second point and the third point are entered in sequence in the ring frame selection area, and the size of the ring frame selection area is adjusted. Secondly, after collecting data of countless points on the arcs and circles in the ring frame selection area, they are "fitted" into all the arcs and circles.

[0048] Step 3: Take the circle twice through the center like Figure 5 As shown, click the "Secondary Circle" icon on the operation page, select the "centers" of the required circles respectively, namely O1, O2, O3, O4, O5, O6, and O7, and press "OK" to end the selection. All the selected center points will be "fitted" into a new circle, namely arc V, [R5]53.4320.

[0049] Step 4: Draw a line connecting the centers of the two circles like Figure 6 As shown, connect the center O of the circle [R5]53.4320 with the centers of the six small circles and one large circle (i.e., the centers O1, O2, O3, O4, O5, O6, and O7) into a straight line, for a total of seven lines.

[0050] Step 5: Mark the arc radius and circle diameter like Figure 7 , Figure 8 As shown, the arc II, arc IV, and arc V are calculated respectively, and the calculated values ​​are "marked" on the arc to be measured, that is, the arc radius: [R2] 47.4881, [R4] 59.4070, [R5] 53.4320.

[0051] Then, the calculated diameter values ​​of small circle Ⅰ, small circle Ⅱ, small circle Ⅲ, large circle Ⅳ, small circle Ⅴ, small circle VI, and small circle VII (6 small circles and 1 large circle) are "marked" on the circles to be measured, that is, the diameters: [φ1] 2.0119, [φ2] 2.0125, [φ3] 2.0130, [φ4] 6.0032, [φ5] 2.0130, [φ6] 2.0103, [φ7] 2.0094.

[0052] Then, the radius values ​​of semicircle I and semicircle III (two semicircles R1 and R3) are calculated and "marked" on the circles to be measured, with the radii: [R1] 5.9720, [R3] 5.9726.

[0053] Step 6: Mark the angle of the circular hole like Fig. 9 As shown, click the "Calculate Angle" icon on the operation page, select the two straight lines of the angle to be calculated, calculate the angle between the two straight lines, and "mark" them at their respective positions, that is, the angle between the straight line O1-O and the straight line O2-O is [∠1] 15°00′37″, The angle between the straight line O2-O and the straight line O3-O is [∠2] 15°00′17″, The angle between the straight line O3-O and the straight line O4-O is [∠3] 15°00′57″, The angle between the straight line O4-O and the straight line O5-O is [∠4] 15°02′24″, The angle between the straight line O5-O and the straight line O6-O is [∠5] 15°00′28″, The angle between the straight line O6-O and the straight line O7-O is [∠6] 15°00′53″, The angle [∠7] between the straight line O1-O and the straight line O7-O is 90°05′37″.

[0054] Step 7: Generate measurement template like Fig.10 As shown, the above measurement process is saved in a specified file to generate a measurement template.

[0055] Step 8: Take all dimensions Recall the stored program "Measurement Template", place the workpiece according to the position of the stored template, click "Measure", and the required size can be measured.

[0056] like Fig.11 As shown, the measurement results: the circle diameter and circle radius are consistent; The arc radius is [R2] 47.4833, [R4] 59.4028; The angles of the circular hole are [∠1] 15°01′36″, [∠2] 15°01′24″, [∠3]14°59′57″, [∠4]15°02′27″, [∠5]15°00′38″, [∠6]15°00′33″, [∠7]90°06′35″.

[0057] Step 9: Measurement and evaluation, report generation The measurement results are automatically recorded in a table, and the results are automatically evaluated to see if they meet the requirements based on the input design values. If they exceed the design values, the deviation values ​​are calculated.

[0058] From Table 1, we can see the deviation between the measured value and the design value (including upper deviation and lower deviation) of each measured element (feature name), as well as the evaluation results (OK-qualified, NG-unqualified), such as Fig.12 shown.

[0059] Table 1 Measurement results

[0060] For example: R2, design value 47.5000, upper deviation 0.1000, lower deviation 0.0000; actual measured value 47.4833, deviation value -0.0167, evaluation result NG.

[0061] The remaining measured values ​​are all within the deviation range of the design values, meet the requirements, and the evaluation results are OK.

[0062] When the measurement of the first workpiece is completed, when measuring the second workpiece, just call up the previously generated measurement template, place the workpiece on the instrument workbench, press the "Continuous Measurement" button, and the measurement can be completed directly, the measurement results can be obtained, and a report can be generated after evaluation. The measurement results can be printed out.

[0063] In summary, the method of the present invention has the advantage of being suitable for measuring a large number of workpieces.

[0064] The above is only a specific implementation of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions are given with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments, and they should all be covered by the protection scope of the claims.

Claims

1. A method for measuring the arc radius of a thin-walled part and the angle between two holes, characterized in that: By programming the measurement program on the flash tester, the radius of the arc of the thin-walled part, the diameter of the small hole and the angle between the two holes can be measured; Use the camera configured in the instrument to take pictures of the shape of the workpiece, automatically identify and focus; use the measuring tool to extract the points, lines, circles, and arcs that need to be measured; perform secondary element extraction and draw lines and circles through the center of the circle; then use the marking program to mark the required dimensions; save the graphics and data, and generate a measurement template; call out the program for subsequent measurements, and use the continuous measurement button to measure the marked dimensions.

2. A method for measuring the arc radius of a thin-walled part and the angle between two holes according to claim 1, characterized in that: The steps include: Step 1: Place the workpiece on the workbench of the flash tester. There is no need to clamp and position it. The instrument will automatically identify and focus according to the shape of the workpiece, and take a photo after adjusting the clarity. Step 2: Extract arcs and circles Use the "circle frame" to enclose the arc or circle to be extracted, enter the first point, the second point, and the third point in the circle frame selection area in sequence, and adjust the size of the circle frame selection area. After collecting data from countless points of the arc or circle in the circle frame selection area, "fit" it into an arc or circle; Step 3: Take the circle twice through the center Click the "Secondary Circle" icon, select the "center" of the required circle respectively, press "OK" to end the selection, and "fit" all the selected circle centers into a new circle; Step 4: Draw a line connecting the centers of the two circles, which is suitable for calculating the angle between adjacent straight lines; Step 5: Mark the arc radius and circle diameter Calculate the arc and the secondary circle respectively, and "mark" the calculated value on the arc to be measured; Then, the diameter and radius values ​​calculated by the circle are "marked" on the circle to be measured; Step 6: Mark the angle of the circular hole Click the "Calculate Angle" icon, select the two straight lines of the angle to be calculated, calculate the angle between the two straight lines, and "mark" them at their respective positions; Step 7: Generate measurement template Save the above measurement process into a specified file to generate a measurement template; Step 8: Take all dimensions Retrieve the stored program "Measurement Template", place the workpiece according to the position of the stored template, and click "Measure" to measure the required size; Step 9: Measurement and evaluation, report generation The measurement results are automatically recorded in a table, and the results are automatically evaluated to see if they meet the requirements based on the input design values. If they exceed the design values, the deviation values ​​are calculated.

3. A method for measuring the arc radius of a thin-walled part and the angle between two holes according to claim 2, characterized in that: A thin-walled workpiece is provided, wherein the thin-walled workpiece is an arc-shaped plate; a large circle IV with a center O4 is provided in the middle of the arc-shaped plate, and three small circles are symmetrically provided on both sides of the large circle IV, namely, the small circles on the left side of the large circle IV are sequentially recorded as small circle I with a center O1, small circle II with a center O2, and small circle III with a center O3, and the small circles on the right side of the large circle IV are sequentially recorded as small circle V with a center O5, small circle VI with a center O6, and small circle VII with a center O7; The inner arc side of the arc plate is recorded as arc II, the outer arc side is recorded as arc IV, the left arc side is recorded as semicircular arc I, and the right arc side is recorded as semicircular arc III. The centers O1, O2, O3, O4, O5, O6, and O7 are located on the same arc V. The radius of semicircular arc I is recorded as R1, the radius of arc II is recorded as R2, the radius of semicircular arc III is recorded as R3, the radius of arc IV is recorded as R4, and the radius of arc V is recorded as R5. The centers of arc II, arc IV, and arc V coincide and are recorded as O. The specific steps are as follows: Step 1: Place the thin-walled workpiece to be tested on the workbench of the flash tester. There is no need to clamp and position it. The instrument automatically recognizes and focuses according to the shape of the workpiece, and takes a photo after adjusting the clarity. Step 2: Extract arcs and circles Frame the arcs to be extracted, i.e., semi-arc Ⅰ, arc Ⅱ, semi-arc Ⅲ, arc Ⅳ, and the extracted circles, i.e., small circle Ⅰ, small circle Ⅱ, small circle Ⅲ, large circle Ⅳ, small circle Ⅴ, small circle Ⅵ, small circle Ⅶ, with a "circle frame" on the operation page. For each arc or circle, first enter the first point, the second point, and the third point in the circle frame selection area in sequence, and adjust the size of the circle frame selection area. Secondly, collect data of countless points on the arcs or circles in the circle frame selection area, and "fit" them into arcs or circles. Step 3: Take the circle twice through the center Click the "Secondary Circle" icon on the operation page, select the "center" of the required circles, namely O1, O2, O3, O4, O5, O6, O7, and press "OK" to end the selection. All the selected center points will be "fitted" into a new circle, namely arc V; Step 4: Draw a line connecting the centers of the two circles Connect the center of circle O with the centers of circles O1, O2, O3, O4, O5, O6, and O7 into straight lines, for a total of 7 lines; Step 5: Mark the arc radius and circle diameter Calculate the arc II, arc IV, and arc V respectively, and "mark" the calculated values ​​on the arc to be measured, that is, the arc radius: R2, R4, R5; Then the diameter values ​​of the small circle Ⅰ, small circle Ⅱ, small circle Ⅲ, large circle Ⅳ, small circle Ⅴ, small circle Ⅵ and small circle Ⅶ are respectively "marked" on the circle to be measured, that is, diameters: φ1, φ2, φ3, φ4, φ5, φ6 and φ7; then the radius values ​​of the semicircular arc Ⅰ and semicircular arc Ⅲ are respectively "marked" on the circle to be measured, radii: R1 and R3; Step 6: Mark the angle of the circular hole Click the "Calculate Angle" icon on the operation page, select the two straight lines of the angle to be calculated, calculate the angle between the two straight lines, and "mark" them at their respective positions, namely: [∠1], [∠2], [∠3], [∠4], [∠5], [∠6], [∠7]; Step 7: Generate measurement template Save the above measurement process into a specified file to generate a measurement template; Step 8: Take all dimensions Retrieve the stored program "Measurement Template", place the workpiece according to the position of the stored template, and click "Measure" to measure the required size; Step 9: Measurement and evaluation, report generation The measurement results are automatically recorded in a table, and the results are automatically evaluated to see if they meet the requirements based on the input design values. If they exceed the design values, the deviation values ​​are calculated.

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