A material removal thickness measurement method for finishing of complex curved surface parts

Abstract

The present invention belongs to the technical field of surface finishing. In order to solve the problem that the thickness of micro-material removal in different areas of the surface of complex curved surface parts is difficult to measure, a material removal thickness measurement method for finishing of complex curved surface parts is provided, which comprises the following steps: making uniform micro-scratches on the surface to be processed of the complex curved surface parts, and using the uniform micro-scratches area as the measurement area to calculate the thickness removal of the complex curved surface parts, by comparing the three-dimensional feature data of the measurement area before and after the finishing process, determining the scratch overlap area before and after the finishing process, and then calculating the lowest point data of the scratch overlap area and the average value of the lowest point data, and finally calculating the removal thickness of the complex curved surface parts based on the average value of the lowest point data. The present invention can realize quantitative and localized measurement during finishing of complex curved surface parts, so as to more accurately obtain the removal thickness of complex curved surface parts.

Description

Technical Field

[0001] The invention belongs to the technical field of surface finishing, and in particular relates to a material removal thickness measurement method for finishing of complex curved surface parts. Background Art

[0002] With the advancement of science and technology, higher processing requirements are put forward for the surface quality of parts. Therefore, surface finishing technology has received increasing attention from researchers at home and abroad, prompting related technologies to continuously develop to a higher level and realize the development from micron and submicron finishing to nanometer finishing.

[0003] Surface finishing technology has the characteristic of extremely low machining allowance. At present, high-precision contact digital sensors and laser displacement sensors are mainly used to realize contact or non-contact measurement of part size changes before and after processing. The maximum measurement accuracy is 0.1μm, but it is difficult to solve the problem of measuring trace material removal in different areas on the surface of complex curved parts, such as the material removal thickness measurement of the top, middle and root of the high-precision gear tooth surface during finishing, the material removal thickness measurement of different parts of the blade body, and the circumferential material removal thickness measurement of the working surface of the high-performance bearing ring. Summary of the invention

[0004] In order to solve at least one of the above technical problems existing in the prior art, the present invention provides a material removal thickness measurement method for finishing processing of complex curved surface parts.

[0005] The present invention is implemented by the following technical solution: a material removal thickness measurement method for finishing of complex curved surface parts, comprising:

[0006] Create uniform micro scratches on the surface of complex curved parts to be processed;

[0007] Selecting an area containing the micro scratches as a measurement area;

[0008] Extracting three-dimensional feature data of micro scratches in the measurement area;

[0009] Performing finishing processing on the surface of the complex curved surface part to obtain three-dimensional feature data of micro scratches in the measurement area after finishing processing;

[0010] Comparing the three-dimensional feature data of micro scratches in the measurement area obtained before and after processing to obtain a scratch overlap area; the scratch overlap area is an area where micro scratches in the measurement area before and after processing overlap;

[0011] Extract the lowest point data of the scratch overlap area before and after processing, and calculate the average value of the lowest point data of the scratch overlap area before and after processing;

[0012] The removal thickness of complex surface parts is calculated based on the average value of the lowest point data in the scratch overlap area before and after processing.

[0013] Preferably, before determining the scratch overlap area, the method further includes:

[0014] Extracting the surface contour coordinates of N equal areas on the surface of the complex curved surface part before and after processing, wherein the N equal areas are selected away from the measurement area;

[0015] Obtaining average contour heights of the N equal areas based on the surface contour coordinates of the N equal areas;

[0016] The removal thickness of complex surface parts is calculated based on the average contour height of N equal areas before processing, the average contour height of N equal areas after processing, the average value of the lowest point data of the scratch overlap area before processing, and the average value of the lowest point data of the scratch overlap area after processing.

[0017] Preferably, the formula for calculating the thickness removed from complex curved surface parts is:

[0018]

[0019] in, is the average profile height of N equal areas before processing, is the average profile height of N equal areas after processing, is the average value of the lowest point data in the scratch overlap area before processing, is the average value of the lowest point data in the scratch overlap area after processing, Remove thickness from complex surface parts.

[0020] Preferably, comparing the three-dimensional feature data of micro scratches in the measurement area obtained before and after processing includes:

[0021] It is determined whether the three-dimensional feature data corresponding to the micro scratches in the measurement area before processing is completely consistent with the three-dimensional feature data corresponding to the micro scratches in the measurement area after processing. If they are consistent, the scratch overlap area is determined; if they are inconsistent, the image matching method is used to select the best matching overlap area in the measurement area before and after processing according to the preset image matching standard to determine the scratch overlap area.

[0022] Preferably, the image matching method is used to select the best matching overlap area in the measurement area before and after processing according to a preset image matching standard to determine the scratch overlap area, including:

[0023] The three-dimensional feature data of micro scratches in the measurement area before processing is set as a matching template, and the three-dimensional feature data of micro scratches in the measurement area after processing is set as an input image;

[0024] Obtaining pixel values ​​of the matching template and the input image, comparing the pixel values ​​of the two, and determining corresponding pixel values;

[0025] The best matching overlap area is determined according to the preset image matching standard and the pixel corresponding values, the corresponding matching coordinates are output, and the scratch overlap area is determined according to the corresponding matching coordinates.

[0026] Preferably, the two pixel values ​​are compared, and the specific number of comparisons is: ,in, , are the length and width of the input image respectively, , are the length and width of the matching template respectively.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention creates uniform micro-scratches on the surface to be processed of a complex curved surface part, and uses the uniform micro-scratches area as a measurement area to calculate the thickness removal of the complex curved surface part. By comparing the three-dimensional feature data of the measurement area before and after the finishing process, the scratch overlap area before and after the finishing process is determined, and then the lowest point data of the scratch overlap area and the average value of the lowest point data are calculated. Finally, the removal thickness of the complex curved surface part is calculated based on the average value of the lowest point data, thereby realizing quantitative and localized measurement during the finishing process of the complex curved surface part, thereby more accurately obtaining the removal thickness of the complex curved surface part. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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 will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A schematic flow chart of a material removal thickness measurement method for finishing of complex curved surface parts according to an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of uniform micro scratches according to an embodiment of the present invention;

[0032] Figure 3 A two-dimensional diagram of uniform micro scratches in a coordinate system according to an embodiment of the present invention;

[0033] Figure 4 The selected area of ​​the overlapped area of ​​the three-dimensional contour scratches on the surface before processing according to the embodiment of the present invention M 1 N 1 P 1Q 1. Location diagram;

[0034] Figure 5 The matching area of ​​the overlapped area of ​​the three-dimensional contour scratches on the processed surface according to the embodiment of the present invention M 2 N 2 P 2 Q 2. Location diagram of the device;

[0035] Figure 6 Schematic diagram of the positions of the equal areas A1 to A6 on the surface before processing according to an embodiment of the present invention;

[0036] Figure 7 Schematic diagram of the positions of the uniform areas B1 to B6 on the processed surface according to an embodiment of the present invention;

[0037] Figure 8 A schematic diagram of material removal thickness before and after finishing processing according to an embodiment of the present invention;

[0038] Fig. 9 for Figure 8 A magnified schematic diagram of center A. DETAILED DESCRIPTION

[0039] In conjunction with the drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention. It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any actual relationship or order between these entities.

[0041] The present invention provides an embodiment:

[0042] like Figure 1 As shown, a material removal thickness measurement method for finishing of complex curved surface parts includes the following steps:

[0043] Step S1: creating uniform micro scratches on the surface to be processed of the complex curved part;

[0044] Step S2: selecting an area containing the micro scratches as a measurement area;

[0045] Step S3: extracting three-dimensional feature data of micro scratches in the measurement area;

[0046] Step S4: performing finishing processing on the surface of the complex curved surface part, and obtaining three-dimensional feature data of micro scratches in the measurement area after finishing processing;

[0047] Step S5: Compare the three-dimensional feature data of micro scratches in the measurement area obtained before and after processing to obtain a scratch overlap area; the scratch overlap area is an area where micro scratches in the measurement area before and after processing overlap;

[0048] Step S6: extracting the lowest point data of the scratch overlap area before and after processing, and respectively calculating the average value of the lowest point data of the scratch overlap area before and after processing;

[0049] Step S7: Calculate the removal thickness of the complex curved surface part based on the average value of the lowest point data of the scratch overlap area before and after processing.

[0050] In this embodiment, Figure 2 , Figure 3 The figure shows uniform micro scratches made on the surface to be processed of a complex curved surface part by precision processing equipment. The processing equipment used in the present invention is a laser marking machine, and the surface to be processed of the complex curved surface part to be processed is the outer diameter surface of the model GCr15 bearing roller. When processing the surface to be processed, the processing power of the laser marking machine is 20W and the frequency is 20khz. The processing equipment can also be selected from a femtosecond laser etcher, a picosecond ultraviolet laser cutting machine, etc., but the present invention is not limited thereto.

[0051] In this embodiment, a fixture with a repeatability measurement accuracy of not less than 0.1 mm is used to select the area containing the micro scratches as the measurement area.

[0052] In this embodiment, a measuring device is used to extract the three-dimensional feature data of micro scratches in the measurement area. The present invention uses a surface profiler of model Zygo plus for repeated measurement, and the repeated measurement accuracy is ≤0.15nm. The coordinate system of the measurement area is established by the Zygo plus surface profiler. The coordinate axes and units of the coordinate system are as follows: Figure 3 The measuring equipment may also be a white light interferometer surface profiler, a laser confocal microscope, an ultra-depth microscope, etc., with a measuring accuracy of not less than 0.001 μm, but the present invention is not limited thereto.

[0053] In this embodiment, the Zygo plus surface profiler extracts array data of the measurement area before and after processing, and then uses matlab (Matrix Laboratory) to extract the minimum value of each column of data and uses it as the corresponding lowest point data.

[0054] In this embodiment, the finishing method adopts a centrifugal tumbling process, and may also adopt a cyclonic process or a vertical vibration process, but the present invention is not limited thereto.

[0055] Optionally, the three-dimensional feature data of micro scratches in the measurement area obtained before and after processing are compared, including: judging whether the three-dimensional feature data corresponding to the micro scratches in the measurement area before processing and the three-dimensional feature data corresponding to the micro scratches in the measurement area after processing are completely consistent, if they are consistent, determining the scratch overlap area; if they are inconsistent, using an image matching method to select the best matching overlap area in the measurement area before and after processing according to a preset image matching standard to determine the scratch overlap area.

[0056] Optionally, an image matching method is used to select the best matching overlapping area in the measurement area before and after processing according to a preset image matching standard to determine the scratch overlapping area, including: setting the three-dimensional feature data of micro scratches in the measurement area before processing as a matching template, and the three-dimensional feature data of micro scratches in the measurement area after processing as an input image; obtaining pixel values ​​of the matching template and the input image, comparing the pixel values ​​of the two, and determining pixel corresponding values; determining the best matching overlapping area according to the preset image matching standard and the pixel corresponding values, outputting corresponding matching coordinates, and determining the scratch overlapping area according to the corresponding matching coordinates.

[0057] In this embodiment, the micro scratches before and after processing are matched using Python image matching method to determine the scratch overlap area, and the corresponding data of the scratch overlap area is not less than 300 μm.

[0058] like Figure 4 As shown, set the measurement area before processing The three-dimensional feature data of the micro scratches in the measurement area after processing is used as the matching template, and the three-dimensional feature data of the micro scratches in the measurement area after processing is used as the input image. According to the coordinate system established by the Zygo plus surface profiler, in the embodiment of the present invention, the measurement area before processing is obtained The coordinates of the micro scratches in .

[0059] Get M 1 N 1 P 1 Q 1, and take the first pixel as the starting point, traverse the input image to match the pixels, determine the pixel values ​​in the matching template corresponding to the input image, and compare them comprehensively. times, among which, , are the length and width of the input image respectively, , are the length and width of the matching template respectively.

[0060] In this embodiment, As the preset image matching standard, the value range is , the smaller the value obtained, the higher the matching degree of the corresponding pixel value. The specific calculation formula is:

[0061]

[0062] In the formula, I represents the input image, T To match the template, R is the output image with high matching degree of corresponding pixel values ​​in the input image, x and y are the horizontal and vertical coordinates of the corresponding position coordinates in the input image, respectively. and are the horizontal and vertical coordinates of the corresponding pixel coordinates in the matching template, is a position in the input image, represents a pixel in the matching template. In this embodiment, by and Translate to the corresponding x and y Position, thereby achieving matching template and input image corresponding position pixel matching, in this embodiment, the coordinate system takes the upper left corner of the captured image as the coordinate origin, and the right is x Positive direction, downward y Positive direction.

[0063] In this embodiment, Figure 5 As shown, the output image with high matching degree of pixel corresponding values ​​in the input image is , that is, the image of the micro scratches in the measurement area after processing. In this embodiment, the coordinates corresponding to the output image are: .

[0064] Optionally, before determining the scratch overlap area, it also includes: extracting the surface contour coordinates of N equal areas on the surface of the complex curved surface part before and after processing, and the N equal areas are selected avoiding the measurement area; obtaining the average contour height of the N equal areas based on the surface contour coordinates of the N equal areas; and calculating the removal thickness of the complex curved surface part based on the average contour height of the N equal areas before processing, the average contour height of the N equal areas after processing, the average value of the lowest point data of the scratch overlap area before processing, and the average value of the lowest point data of the scratch overlap area after processing.

[0065] In this embodiment, Figure 6 , Figure 7 As shown, considering the influence of the surface state of complex curved parts, since instruments such as Zygo plus surface profilers may have different zero positions for different surfaces when extracting data, in order to eliminate the difference in zero position, it is necessary to avoid the measurement area where the scratches are located, and take the equal area selected in the non-scratched area as the reference, and take the difference between the reference plane and the lowest point of the measurement area as the scratch depth of the micro scratches in the measurement area. In this embodiment, the surface contour coordinates of six equal areas on the surface of the complex curved part before and after processing are extracted, and the average value of the difference between the corresponding reference plane and the lowest point of the micro scratch is obtained respectively, and the average contour height of the scratch overlap area before and after processing is obtained, and the average value of the difference between the corresponding reference plane and the lowest point of the micro scratch is obtained respectively, and the removal thickness of the complex curved part is calculated according to the following formula.

[0066]

[0067] in, is the average profile height of N equal areas before processing, is the average profile height of N equal areas after processing, is the average value of the lowest point data in the scratch overlap area before processing, It is the average value of the lowest point data in the scratch overlap area after processing.

[0068] In this embodiment, the six equal areas are all square areas, and their measured values ​​are shown in Table 1 below. According to the measured data in Table 1, the final removal thickness result of the complex curved surface part is obtained as follows: Figure 8 , Fig. 9 shown.

[0069] Table 1

[0070]

[0071] The present invention creates uniform micro-scratches on the surface to be processed of a complex curved surface part, and uses the uniform micro-scratches area as a measurement area to calculate the thickness removal of the complex curved surface part. By comparing the three-dimensional feature data of the measurement area before and after the finishing process, the scratch overlap area before and after the finishing process is determined, and then the lowest point data of the scratch overlap area and the average value of the lowest point data are calculated. Finally, the removal thickness of the complex curved surface part is calculated based on the average value of the lowest point data, thereby realizing quantitative and localized measurement during the finishing process of the complex curved surface part, thereby more accurately obtaining the removal thickness of the complex curved surface part.

[0072] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A material removal thickness measurement method for finishing of complex curved surface parts, characterized in that: include: Create uniform micro scratches on the surface of complex curved parts to be processed; Selecting an area containing the micro scratches as a measurement area; Extracting three-dimensional feature data of micro scratches in the measurement area; Performing finishing processing on the surface of the complex curved surface part to obtain three-dimensional feature data of micro scratches in the measurement area after finishing processing; Compare the three-dimensional feature data of micro scratches in the measurement area obtained before and after processing to obtain the scratch overlap area; the scratch overlap area is the area where the micro scratches in the measurement area before and after processing overlap; before determining the scratch overlap area, it also includes: extracting the surface contour coordinates of N equal areas on the surface of the complex curved surface part before and after processing, and the N equal areas are selected away from the measurement area; based on the surface contour coordinates of the N equal areas, obtain the average contour height of the N equal areas; Extract the lowest point data of the scratch overlap area before and after processing, and calculate the average value of the lowest point data of the scratch overlap area before and after processing; The removal thickness of the complex curved surface parts is calculated based on the average contour height of N equal areas before processing, the average contour height of N equal areas after processing, the average value of the lowest point data of the scratch overlap area before processing, and the average value of the lowest point data of the scratch overlap area after processing; The formula for obtaining the removal thickness of complex curved surface parts is: in, is the average profile height of N equal areas before processing, is the average profile height of N equal areas after processing, is the average value of the lowest point data in the scratch overlap area before processing, is the average value of the lowest point data in the scratch overlap area after processing, Remove thickness from complex surface parts.

2. The material removal thickness measurement method for finishing of complex curved surface parts according to claim 1 is characterized in that: The three-dimensional feature data of micro scratches in the measurement area obtained before and after the comparison processing includes: It is determined whether the three-dimensional feature data corresponding to the micro scratches in the measurement area before processing is completely consistent with the three-dimensional feature data corresponding to the micro scratches in the measurement area after processing. If they are consistent, the scratch overlap area is determined; if they are inconsistent, the image matching method is used to select the best matching overlap area in the measurement area before and after processing according to the preset image matching standard to determine the scratch overlap area.

3. The material removal thickness measurement method for finishing of complex curved surface parts according to claim 2 is characterized in that: The image matching method is used to select the best matching overlap area in the measurement area before and after processing according to the preset image matching standard to determine the scratch overlap area, including: The three-dimensional feature data of micro scratches in the measurement area before processing is set as a matching template, and the three-dimensional feature data of micro scratches in the measurement area after processing is set as an input image; Obtaining pixel values ​​of the matching template and the input image, comparing the pixel values ​​of the two, and determining corresponding pixel values; The best matching overlap area is determined according to the preset image matching standard and the pixel corresponding values, the corresponding matching coordinates are output, and the scratch overlap area is determined according to the corresponding matching coordinates.

4. The material removal thickness measurement method for finishing of complex curved surface parts according to claim 3 is characterized in that: The pixel values ​​of the matching template and the input image are compared for the following number of times: ,in, , are the length and width of the input image respectively, , are the length and width of the matching template respectively.

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