Scratch / tool mark depth rapid measuring device and method for spaceflight

Abstract

The invention belongs to the technical field of spaceflight part surface quality detection, and particularly discloses a spaceflight scratch / tool mark depth rapid measuring device which comprises at least one comparison test block used for conducting visual comparison with the surface of a detected metal part, and the base material of the comparison test block is the same as the metal material of the detected metal part; a plurality of standard depth defects are sequentially processed on the comparison test block along the length direction, and identifiers for indicating the depth values of the standard depth defects are also arranged on the comparison test block. According to the method, standard scratches or steps with different depths are machined in advance, the defect depth can be judged only through visual comparison under the unified illumination and observation conditions during detection, and compared with a traditional optical microscopy, laser measurement or contact pin type contourgraph method, the detection efficiency is remarkably improved; the invention further discloses a measuring method, the reliability of judgment is improved, and the method has good adaptability to scratches and tool marks of different materials, different roughness and different types.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aerospace part surface quality detection, and relates to a scratch / cutting mark depth rapid measurement device and method for aerospace. BACKGROUND

[0002] Aerospace products largely use metal parts in the manufacturing process, such as 1Cr18Ni9Ti, LD10, LF6, LY12, LC9 and the like. Among them, the surface quality requirements of some sealing structure parts, actuating parts and butt joint parts are relatively high, and the depth of scratches and cutting marks on the outer surface needs to meet the requirement of being less than a given value δ. In the process of raw material processing, part machining, assembly and transportation, scratches and cutting marks of different depths are easily generated on the surface of the parts, and these defects need to be judged by inspection personnel.

[0003] The existing scratch and cutting mark depth detection methods mainly include optical microscopic detection, laser triangulation, stylus profilometer and non-destructive detection methods such as magnetic powder, penetration and eddy current. The optical microscopic detection obtains the three-dimensional features of the product surface by optical interference or laser scanning, and then indirectly measures the depth of scratches and cutting marks through three-dimensional modeling by engineering software, which has high precision, but the equipment cost is high, the environmental requirements are strict (such as constant temperature and humidity), and the detection period is long, which is not suitable for raw material acceptance and rapid detection in the production site. Laser triangulation is fast and suitable for online detection, but it is greatly affected by the optical properties of the product surface, and it is easy to miss detection for narrow and deep scratches. The stylus profilometer can measure narrow scratches with high precision by recording the height change of the diamond probe when it passes over the product surface, but it is a contact measurement method, which may cause secondary damage to the product surface. Other non-destructive detection methods have certain limitations in measuring the depth of scratches and cutting marks, and it is difficult to meet the needs of complex surface quality detection.

[0004] In summary, the existing methods have problems such as high cost, strong environmental dependence, low detection efficiency and limited applicability, and cannot meet the needs of rapid, economical and efficient scratch and cutting mark depth detection in the raw material acceptance and production process of aerospace metal parts. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings of the prior art, and to provide a scratch / cutting mark depth rapid measurement device and method for aerospace, which is simple in structure, low in cost, easy to operate and suitable for use in production sites. A series of standard defects with known depths are machined on the comparison test block matching the material and surface roughness of the detected part, and visual comparison is carried out under uniform lighting and observation conditions, so as to realize rapid, intuitive and high-precision measurement of the depth of scratches and cutting marks.

[0006] In order to achieve the above purpose, the present application adopts the following technical scheme: The device for quickly measuring scratch / scar depth for aerospace use comprises at least one comparison test block for visual comparison with the surface of the metal part to be inspected, the base material of the comparison test block is the same as the metal material of the metal part to be inspected; a plurality of standard depth defects are sequentially processed on the comparison test block along the length direction, and an identifier for indicating the depth value of the standard depth defects is further arranged.

[0007] Specifically, the standard depth defects are linear scratches sequentially distributed along the length direction of the comparison test block, the linear scratches are formed by scratching on the comparison test block by a diamond stylus, the radius of curvature of the diamond stylus is about 2 μm, the stylus vertex angle is one or more of 10°, 15° or 20°, and the depth of the scratches on the comparison test block changes sequentially at a predetermined interval in the range of 10 μm to 100 μm.

[0008] Specifically, the standard depth defects are steps sequentially distributed along the length direction of the comparison test block, the steps are formed by machining on the comparison test block by a diamond turning tool, and the height of the steps changes sequentially at a predetermined interval in the range of 10 μm to 100 μm.

[0009] Specifically, the comparison test block is multiple, and the base materials of different comparison test blocks are one or more of 304, 321, 410, 431 stainless steel or LD10, LF6, LY12, LC9 aluminum alloy.

[0010] Specifically, the surface roughness Ra of the comparison test block is at least one of 3.2, 1.6, 0.8 or 0.4.

[0011] Specifically, the finish of the comparison test block is at least one of 5, 6, 7 or 8.

[0012] Specifically, the comparison test block is a cuboid plate or a rod structure, the size of the plate-shaped comparison test block for scratch depth comparison is 15 mm x 30 mm x 5 mm, and the size of the rod-shaped comparison test block for scar depth comparison is 20 mm x 80 mm.

[0013] A method for using a device for quickly measuring scratch / scar depth for aerospace use, comprising the following steps: S1, according to the material grade and surface roughness of the metal part to be inspected, selecting a comparison test block with the same base material as the inspected part and the same surface roughness as the inspected part; S2, placing the metal part to be inspected and the comparison test block side by side on the same flat platform with a distance of 10 mm to 20 mm, and adjusting the ambient light intensity so that the average illumination of the surface of the inspected part and the comparison test block is not less than 300 lx; S3. The operator maintains an observation angle of approximately 45° relative to the surfaces of the inspected part and the comparison test block. If necessary, a magnifying glass with a magnification of approximately 10x is used to visually compare the scratches or knife marks on the surface of the inspected part with the standard depth defects on the comparison test block. The visual effects of the standard depth defects and the scratches or knife marks on the surface of the inspected part are compared sequentially in descending order of depth. The standard depth defect that has the closest visual effect to the scratches or knife marks under the same lighting and observation conditions is determined. The depth value corresponding to the standard depth defect is read as the depth of the scratches or knife marks on the inspected part, and the test results are recorded.

[0014] Throughout the comparison process, the comparison test block and the inspected part are kept as consistent as possible in terms of material, surface roughness, lighting conditions, and observation angle. A controlled variable method is used to ensure that other influencing factors, except for the depth of scratches or tool marks, are essentially the same. This ensures that scratches or steps of the same depth have similar brightness and outline, facilitating accurate visual judgment of defect depth by the operator. Practice shows that this method improves detection efficiency by approximately 10 times compared to traditional methods, with depth measurement errors controlled within ±0.01mm, and the inspection and acceptance accuracy rate increased from less than 40% to approximately 90%. Tool marks can also be combined with the detection of height differences in tool marks during CNC milling.

[0015] The present invention has the following advantages: (1) The present invention pre-processes standard scratches or steps of different depths on a comparison test block that matches the material and roughness of the test piece. During the inspection, the depth of the defect can be determined by visual comparison under uniform lighting and observation conditions. Compared with traditional optical microscopy, laser measurement or stylus profilometer methods, the detection efficiency is significantly improved.

[0016] (2) The present invention adopts the controlled variable method to conduct visual comparison under the same material, roughness and lighting conditions, so that the visual effect mainly depends on the defect depth, improves the reliability of judgment, the depth measurement error can be controlled within ±0.01mm, and the inspection and acceptance accuracy rate can be increased from less than 40% to about 90%.

[0017] (3) The measuring device and method of the present invention are applicable to the processes of raw material release, machining, sheet metal and assembly, and surface quality inspection of aerospace metal parts. They are well adaptable to different materials, roughness, and types of scratches and tool marks. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the surface quality control of a typical austenitic stainless steel actuator according to the present invention; Figure 2 This is a schematic diagram of the quality control of a typical aluminum alloy flange surface according to the present invention; Figure 3 This is a schematic diagram of the scratch depth comparison and measurement device of the present invention; Figure 4 This is a schematic diagram of the scratch depth comparison and measurement device of the present invention; Figure 5 This is a schematic diagram of the vehicle mark height comparison and measurement device of the present invention; Figure 6 This is a schematic diagram of the actual device for comparing and measuring the height of vehicle tracks according to the present invention; Figure 7 This is a schematic diagram of the scratch depth detection structure of the present invention; Figure 8 This is a schematic diagram of the vehicle mark height detection structure of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0020] This invention provides a combination of comparison test blocks with various materials and surface roughnesses to reduce visual errors caused by differences in material reflectivity and surface roughness during the comparison process. For example... Figure 1 As shown, for austenitic stainless steel products, stainless steel materials such as 304, 321, 410, and 431 can be selected as the matrix material for the comparison test blocks; for example... Figure 2 As shown, for aluminum alloy products, LD10, LF6, LY12, LC9, and other aluminum alloys can be selected as the base material for the comparison test block. Each material can be processed into multiple surface roughness grades, such as Ra=3.2, 1.6, 0.8, 0.4, etc., so that the most suitable comparison test block can be selected according to the actual surface finish of the inspected part during testing, thereby improving the accuracy and stability of the comparison.

[0021] Example 1 like Figure 3 , Figure 4 As shown, this embodiment of the invention provides a comparison test block for rapid measurement of scratch depth on aerospace metal parts.

[0022] The comparison block uses a metal sheet of the same grade as the test piece, such as 304 stainless steel or LY12 aluminum alloy, with dimensions of approximately 15mm × 30mm × 5mm. First, the measuring surface of the comparison block is machined to achieve a surface roughness Ra ≤ 0.4. Then, using a diamond stylus with a radius of curvature of approximately 2μm and a apex angle of 10°, a series of linear scratches are uniformly etched along the length of the measuring surface. The scratch depths are successively 10μm, 20μm, 30μm… up to 100μm, with the spacing between each scratch being basically consistent. Depending on the actual testing requirements, diamond styluses with apex angles of 15° and 20° can also be used to process scratches of different shapes to expand the testing range and improve comparison accuracy. After the metrology department confirms the accuracy of each scratch depth value, a laser is used to engrave the corresponding depth value markings, such as “10μm”, “20μm”, and “30μm”, on the measuring surface near each scratch.

[0023] During the production process, a comparison block with the same raw material and similar gloss as the inspected part can be selected according to actual needs. Measuring surfaces with different surface roughnesses can be processed according to the requirements in Table 1 to meet the matching requirements of different inspected parts' surface roughness. Finally, a scratch depth comparison device is fabricated using the above method.

[0024] Table 1. Surface roughness requirements for various materials under different surface finishes Example 2 like Figure 5 , Figure 6 As shown, this embodiment of the invention provides a comparison test block for rapid measurement of the depth of machining marks or tool marks on aerospace metal parts.

[0025] The comparison test block uses a metal rod of the same grade as the inspected part, with dimensions of approximately 20mm × 80mm. The measuring surface of the comparison test block is machined to ensure its surface roughness is essentially the same as the working surface roughness of the inspected part, for example, Ra ≤ 0.4. Subsequently, a series of steps are uniformly machined along the length of the measuring surface using a diamond turning tool. The heights of each step are 10μm, 20μm, 40μm, 60μm, 80μm, and 100μm, respectively. The steps are evenly spaced along the length. After the height of each step is verified by the metrology department, the corresponding height values, such as "10μm," "20μm," and "40μm," are engraved on the measuring surface near each step using a laser. This comparison test block is used for visual comparison with the machining marks or tool marks on the surface of the inspected part to determine whether its depth or height meets the design requirements.

[0026] Example 3 A method for using a rapid scratch / knife mark depth measurement device for aerospace applications includes the following steps: S1. Based on the material grade and surface roughness of the metal parts under inspection, select a comparison test block whose base material is the same as that of the test part and whose measured surface roughness is consistent with that of the test part. S2. Place the metal part to be inspected and the comparison test block side by side on the same flat platform with a spacing of 10mm to 20mm, and adjust the ambient light intensity so that the average illuminance of the surface of the part to be inspected and the comparison test block is not less than 300lx. S3. The operator maintains an observation angle of approximately 45° relative to the surfaces of the inspected part and the comparison test block. If necessary, a magnifying glass with a magnification of approximately 10x is used to visually compare the scratches or knife marks on the surface of the inspected part with the standard depth defects on the comparison test block. The visual effects of the standard depth defects on the surface of the inspected part are compared sequentially in descending order of depth. The standard depth defect whose visual effect is closest to the scratch or knife mark under the same lighting and observation conditions is determined. The depth value corresponding to this standard depth defect is read as the depth of the scratch or knife mark on the inspected part, and the test results are recorded. Figure 7 , Figure 8 As shown.

[0027] The tool marks of this invention can also be combined with the detection of the height difference of tool marks in CNC milling.

[0028] It should be noted that the foregoing embodiments are described as combinations of a series of steps for the sake of brevity. However, those skilled in the art should understand that this application is not strictly limited by the order of the steps, and some steps may be performed in different orders or simultaneously depending on the actual situation. Furthermore, the embodiments described in the specification are all preferred solutions, and not all operations involved are necessary for this application.

[0029] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A rapid measurement device for scratch / knife mark depth in aerospace applications, characterized in that, It includes at least one comparison test block for visual comparison with the surface of the inspected metal part. The base material of the comparison test block is the same as the metal material of the inspected metal part, and the roughness of the measuring surface of the comparison test block is the same as or similar to the roughness of the working surface of the inspected metal part. Multiple standard depth defects are sequentially machined on the comparison test block along the length direction, and a mark is also provided to indicate the depth value of the standard depth defect.

2. The aerospace scratch / knife mark depth rapid measurement device according to claim 1, characterized in that, The standard depth defect is a linear scratch distributed sequentially along the length of the comparison test block. The linear scratch is formed by a diamond stylus on the comparison test block. The radius of curvature of the diamond stylus is 2 μm, and the stylus apex angle is one or more of 10°, 15° or 20°. The depth of the scratch on the comparison test block varies sequentially at predetermined intervals within the range of 10 μm to 100 μm.

3. The aerospace scratch / knife mark depth rapid measurement device according to claim 1, characterized in that, The standard depth defect is a step that is distributed sequentially along the length of the comparison test block. The step is formed by machining on the comparison test block with a diamond cutting tool. The height of the step varies sequentially at predetermined intervals within the range of 10μm to 100μm.

4. The aerospace scratch / knife mark depth rapid measurement device according to claim 1, characterized in that, The comparison test blocks are multiple blocks, and the base materials of the different comparison test blocks are one or more of the following: 304, 321, 410, 431 stainless steel or LD10, LF6, LY12, LC9 aluminum alloy.

5. The aerospace scratch / knife mark depth rapid measurement device according to claim 4, characterized in that, The surface roughness Ra of the comparison test block is at least one of 3.2, 1.6, 0.8 or 0.

4.

6. The aerospace scratch / knife mark depth rapid measurement device according to claim 4, characterized in that, The surface finish of the comparison test block is at least one of 5, 6, 7, and 8.

7. The aerospace scratch / knife mark depth rapid measurement device according to claim 1, characterized in that, The comparison test blocks are rectangular plate-shaped or rod-shaped structures. The plate-shaped comparison test blocks used for scratch depth comparison have a size of 15mm×30mm×5mm, and the rod-shaped comparison test blocks used for knife mark depth comparison have a size of 20mm×80mm.

8. A method of using the rapid scratch / knife mark depth measuring device for aerospace applications as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Based on the material grade and surface roughness of the metal parts under inspection, select a comparison test block whose base material is the same as that of the test part and whose measured surface roughness is consistent with that of the test part. S2. Place the metal part to be inspected and the comparison test block side by side on the same flat platform with a spacing of 10mm to 20mm, and adjust the ambient light intensity so that the average illuminance of the surface of the part to be inspected and the comparison test block is not less than 300lx. S3. The operator maintains an observation angle of approximately 45° relative to the surfaces of the inspected part and the comparison test block. If necessary, a magnifying glass with a magnification of approximately 10x is used to visually compare the scratches or knife marks on the surface of the inspected part with the standard depth defects on the comparison test block. The visual effects of the standard depth defects and the scratches or knife marks on the surface of the inspected part are compared sequentially in descending order of depth. The standard depth defect that has the closest visual effect to the scratches or knife marks under the same lighting and observation conditions is determined. The depth value corresponding to the standard depth defect is read as the depth of the scratches or knife marks on the inspected part, and the test results are recorded.

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