Milling cutter section blade morphology measuring method based on point spectrum confocal

Abstract

The invention relates to the technical field of cutter detection, in particular to a point spectrum confocal-based milling cutter section blade morphology measurement method, which comprises the following steps of: acquiring point spectrum confocal calibration data, acquiring data of a circle of a milling cutter section, solving a current distance difference, solving a radius of a current blade point, and solving an angle of the current blade point based on a calibration triangle; and calculating the real angle of the current blade point on the blade, and drawing the section blade morphology of the milling cutter. According to the method, the problem that the complete three-dimensional morphology cannot be obtained due to the fact that the structured light reconstruction cutter is high is solved, and a new method is provided for measuring the cutter with the complex geometrical morphology.

Description

Technical Field

[0001] This invention relates to the field of cutting tool inspection technology, and in particular to a method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocal microscopy. Background Technology

[0002] When using existing 3D scanning technology to measure cutting tools, it is impossible to completely reconstruct the tool due to the high gloss and high reflectivity of the tool surface. If the tool surface is powder-coated to avoid the high gloss and high reflectivity problem, the reconstruction accuracy will decrease because the thickness and uniformity of the powder cannot be measured. In addition, powder coating can also damage the tool.

[0003] While existing confocal techniques are indeed useful for object detection, the data obtained are individual straight-line distances and are not integrated.

[0004] Chinese Patent Publication No. CN117029722A discloses a method for detecting the tooth profile shape of a gear disc milling cutter. The method includes mounting the disc milling cutter on a detection device, ensuring the laser is perpendicular to a reference plane, reading the height yh through a host computer program, keeping the height constant, adjusting the X-axis linear slide to measure the highest point data y1 of the cutting edge, moving it a fixed distance x, and measuring the highest point data y2 of the cutting edge. This process is repeated until the sum of distances x is close to and less than the cutting edge length, ending the measurement of one side of the cutting edge data. The cutter is then mounted in reverse on the detection device, and the tooth profile data of the other side of the cutting edge is measured. Based on the cutter design parameters, the cutter's symmetry center line and upper and lower reference planes are drawn in CAXA. The data points are then fitted according to the relationship between x, yh, y1, and y2. The involute gear tooth profile parameters are imported, a theoretical gear model is drawn, and the theoretical tooth profile shape is compared with the measured tooth profile shape to analyze the cutting tool installation error. It is evident that the above measurement method does not consider the problem of inaccurate measurement of highly reflective and bright cutting tools when using a laser. Summary of the Invention

[0005] Therefore, this invention provides a method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocalization, in order to overcome the problem in the prior art that the complete three-dimensional morphology cannot be obtained when reconstructing the tool with structured light due to high brightness and high reflection.

[0006] To achieve the above objectives, the present invention provides a method for measuring the cutting edge morphology of a milling cutter cross-section based on point spectral confocal microscopy, comprising:

[0007] Step S1: Place the milling cutter to be tested on the horizontally rotating spindle, keeping the spindle and the milling cutter axis aligned.

[0008] Step S2: Replace the milling cutter under test with a concentric stepped shaft standard part and collect point spectral confocal calibration data, wherein the calibration data includes standard distance difference and calibration angle;

[0009] Step S3: Replace the concentric stepped shaft standard part with the milling cutter to be tested, collect the milling cutter cross-section data for one lap, and calculate the current distance difference;

[0010] Step S4: Calculate the radius of the current cutting edge point;

[0011] Step S5: Calculate the angle of the current blade point based on the calibration triangle;

[0012] Step S6: Calculate the true angle of the current blade point on the blade.

[0013] Step S7: Draw the cutting edge shape of the milling cutter cross section.

[0014] Further, step S1 includes:

[0015] Set up a confocal system, adjust and ensure that the laser beam plane of the point spectrum confocal lens is parallel to the axis of the main shaft, and focus the lens of the confocal system on the cutting edge of the milling cutter under test;

[0016] After focusing is complete, keep the lens angle of the confocal system unchanged.

[0017] Further, step S2 includes:

[0018] Prepare a standard concentric stepped shaft with a known radius, and ensure that the radii of at least two stepped circles of the concentric stepped shaft do not exceed the confocal measurement range;

[0019] The first data is recorded by focusing the spectral point onto the small circle of the concentric stepped shaft standard part using a point spectral confocal system. Then, while keeping the laser beam plane parallel to the axis of the stepped shaft, the confocal lens is moved along the axis to focus the spectral point onto the large circle of the concentric stepped shaft standard part, and the second data is recorded.

[0020] Based on the first data and the second data, the difference between the spectral points at the small circle and the large circle is calculated and denoted as the standard distance difference;

[0021] The calibration angle is determined based on the calibration triangle formed by the radius of the large circle, the radius of the small circle, and the standard distance difference.

[0022] The first data is the distance between the confocal lens and the small circle of the concentric stepped shaft standard component, and the second data is the distance between the confocal lens and the large circle of the concentric stepped shaft standard component;

[0023] The solution formula is: ;

[0024] in For the calibration angle, R is the radius of the great circle, r is the radius of the small circle, and X is the standard distance difference.

[0025] Further, step S3 includes:

[0026] Replace the standard concentric stepped shaft with the end mill to be tested, and measure using a point spectral confocal system. Focus the spectral points on the cutting edge position. If data is transmitted, record the transmitted data as the third data. If no data is transmitted, repeat step S2 until data is transmitted. Record the difference between the second and third data as the current distance difference.

[0027] The third data is the distance between the confocal lens and the currently selected angle blade.

[0028] Furthermore, step S3 also includes:

[0029] Based on a point spectrum confocal controller and a fully automatic high-precision spindle, the encoder triggers the acquisition signal, and the spindle rotates at a constant speed for one revolution, recording the data of the milling cutter cross section for one revolution.

[0030] Further, step S4 includes:

[0031] The current cutting edge radius is calculated by forming a triangle with the calibration angle, the current distance difference, and the radius of the large circle of the concentric stepped shaft standard part.

[0032] The solution formula is: = + - ;

[0033] in R is the radius of the current blade point, R is the radius of the great circle, and x is the current distance difference. To calibrate the angle.

[0034] Further, step S5 includes:

[0035] Construct a triangle by the radius of the current cutting edge point, the current distance difference, and the radius of the great circle of the concentric stepped shaft standard part, and calculate the angle of the current cutting edge point based on the calibration triangle;

[0036] The solution formula is:

[0037] in R is the radius of the current blade point, R is the radius of the great circle, and x is the current distance difference. The current cutting edge point is based on the angle of the calibration triangle;

[0038] Further, step S6 includes:

[0039] The product of the current blade point's index and the bisector angle is recorded as the angle of the current calibration triangle; the sum of the current calibration triangle's angle and the current blade point based on the calibration triangle is recorded as the true angle of the current blade point on the blade.

[0040] The sequence number of the current cutting edge point is the number of the cutting edge points collected in one revolution of the milling cutter, arranged in sequence; the averaging angle is 2π divided by the number of cutting edge points collected in one revolution of the milling cutter.

[0041] The solution formula is: ;

[0042] in The current blade point represents the actual angle on the blade edge, where i is the current blade point index, and N is the number of blade points collected in one lap. The angle of the current blade point is based on the calibration triangle.

[0043] Further, step S7 includes:

[0044] Calculate the radius and true angle of all cutting edge points, and use MATLAB polar coordinate functions to fit and plot the cutting edge shape of the milling cutter cross section.

[0045] On the other hand, the present invention provides a measurement system for the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy, comprising:

[0046] Point spectral confocal probe, including lens and controller;

[0047] An optical bracket is used to fix the probe and allow it to move precisely along the axial direction;

[0048] A high-precision rotary spindle is used to clamp and drive the rotation of milling cutters or standard parts;

[0049] An encoder is used to trigger data acquisition when the spindle rotates;

[0050] The data processing unit is configured to perform the steps of the method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocalization as described above, in order to obtain the cutting edge morphology of the complete milling cutter cross section.

[0051] Compared with the prior art, the beneficial effects of the present invention are that it provides a method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocal microscopy. According to the calibration data, the cutting edge morphology of the milling cutter cross section is obtained by data splicing and fitting. The method is simple to implement, reliable in results, and can accurately restore the cutting edge morphology, so as to facilitate the subsequent measurement of the geometric parameters contained in the cross section.

[0052] Furthermore, this invention provides a method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocal imaging. This method includes a calibration method and a method for restoring the milling cutter cross section morphology. It solves the problem that structured light reconstruction of the tool cannot obtain a complete three-dimensional morphology due to its height, and provides a new method for measuring tools with complex geometric morphologies. Attached Figure Description

[0053] Figure 1 This is a flowchart of the method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocalization according to the present invention;

[0054] Figure 2 This is a step diagram of the method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocalization according to the present invention; Figure 3 This is a schematic diagram of the calibration algorithm of the present invention;

[0055] Figure 4 This is a schematic diagram of the reconstruction algorithm of the present invention;

[0056] In the diagram: 1, standard concentric stepped shaft; 2, second data; 3, first data; 4, current cutting edge radius; 5, current distance difference; 6, current cutting edge angle based on the calibration triangle. Detailed Implementation

[0057] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0058] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0059] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0060] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0061] Please see Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, Figure 1 This is a flowchart of the method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocal imaging, as described in this invention. Figure 2 This is a step diagram illustrating the method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocal imaging according to the present invention. Figure 3 This is a schematic diagram of the calibration algorithm of the present invention. Figure 4 This is a schematic diagram of the reconstruction algorithm of the present invention.

[0062] This embodiment provides a method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocal microscopy. As a preferred embodiment of the present invention, taking a milling cutter of model HY004X-1400C as an example, the method includes the following steps:

[0063] Step S1: Place the milling cutter to be tested on the horizontally rotating spindle, keeping the spindle and the milling cutter axis aligned.

[0064] Step S2: Replace the milling cutter under test with a concentric stepped shaft standard part and collect point spectral confocal calibration data, wherein the calibration data includes standard distance difference and calibration angle;

[0065] Step S3: Replace the concentric stepped shaft standard part with the milling cutter to be tested, collect the milling cutter cross-section data for one lap, and calculate the current distance difference;

[0066] Step S4: Calculate the radius of the current cutting edge point;

[0067] Step S5: Calculate the angle of the current blade point based on the calibration triangle;

[0068] Step S6: Calculate the true angle of the current blade point on the blade.

[0069] Step S7: Draw the cutting edge shape of the milling cutter cross section.

[0070] Specifically, step S1 includes:

[0071] Before calibration, focus the lens on the blade of the cross section you want to reconstruct. Adjust and ensure that the laser beam plane of the point spectrum confocal lens is parallel to the axis of the main axis. After focusing, keep the lens in its current state. The lens can only be moved along the axis, and the angle cannot be changed.

[0072] Specifically, step S2 includes:

[0073] Please see Figure 3As shown, a standard part is measured by point spectral confocal focusing. The standard part is a concentric stepped shaft 1 with a known radius, and the radii of the large circle and the small circle must not exceed the confocal measurement range. The spectral point is focused on the small circle, and the distance value is recorded as the first data 2 (the distance between the confocal lens and the small circle of the concentric stepped shaft standard part). The laser beam plane is kept parallel to the axis of the stepped shaft, and the angle of the confocal lens is kept constant. The lens is moved along the axis and the spectral point is focused on the large circle. The distance value is recorded as the second data 3 (the distance between the confocal lens and the large circle of the concentric stepped shaft standard part). The difference between the spectral point on the large circle and the small circle is calculated from the two focusing data. This is the standard distance difference. The angle between the side of the standard distance difference and the side of the large circle is calculated from the calibration triangle formed by the radii of the large circle and the standard distance difference. This is the calibration angle.

[0074] Solution formula:

[0075] in, To calibrate the angle, The radius of the great circle, The radius of the smaller circle, This is the standard distance difference.

[0076] Specifically, step S3 includes: maintaining the lens state, replacing the standard stepped axis with the target milling cutter, and rotating the high-precision spindle to position the cutting edge at the point spectral confocal focal point. Observing the data, if data is transmitted, milling cutter data acquisition can proceed; if no data is transmitted, recalibration is required. Based on the point spectral confocal controller and the fully automatic high-precision spindle, the encoder triggers the acquisition signal. The spindle is required to rotate uniformly for one revolution, acquiring milling cutter cross-section data for one revolution. The data is limited by the point spectral confocal measurement range and the milling cutter's own occlusion; therefore, subsequent processing is only effective for the cutting edge. Since the lens state remains unchanged, the current distance difference and the standard distance difference are on the same straight line. The difference between the second data recorded when the spectral point is focused on the great circle and the data at the currently selected point is the current distance difference 5(x).

[0077] Specifically, step S4 includes: forming a triangle with the calibration angle obtained in step S1, the current distance difference obtained in step S2, and the radius of the great circle, and calculating the current blade point radius 4 ( Please see Figure 4 As shown The length.

[0078] The solution formula is: = + - ;

[0079] in The radius of the current blade point is 4, R is the radius of the great circle, and x is the current distance difference of 5. To calibrate the angle.

[0080] Specifically, step S5 includes: constructing a triangle using the current cutting edge point radius, the current distance difference, and the radius of the large circle of the concentric stepped shaft standard part, and solving for the angle 6 of the current cutting edge point based on the calibration triangle. Please see Figure 4 As shown.

[0081] The solution formula is:

[0082] in R is the radius of the current blade point, R is the radius of the great circle, and x is the current distance difference. The current blade point is based on the angle 6 of the calibration triangle;

[0083] Specifically, step S6 includes: the actual angle of the current cutting edge point on the cutting edge is the sum of the angle of the current calibration triangle and the angle of the current cutting edge point based on the calibration triangle, and the angle of the current calibration triangle is the product of the current cutting edge point number and the average angle.

[0084] The solution formula is: ;

[0085] in The current blade point represents the actual angle on the blade edge, where i is the current blade point index, and N is the number of blade points collected in one lap. The angle of the current blade point is based on the calibration triangle.

[0086] Specifically, step S7 includes: calculating the radius and true angle of all collected cutting edge points, and using MATLAB polar coordinate functions to fit and draw the cutting edge shape of the milling cutter cross section.

[0087] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for measuring the cutting edge morphology of a milling cutter cross-section based on point spectral confocal microscopy, characterized in that, include: Step S1: Place the milling cutter to be tested on the horizontally rotating spindle, keeping the spindle and the milling cutter axis aligned. Step S2: Replace the milling cutter under test with a concentric stepped shaft standard part and collect point spectral confocal calibration data, wherein the calibration data includes standard distance difference and calibration angle; Step S3: Replace the concentric stepped shaft standard part with the milling cutter to be tested, collect the milling cutter cross-section data for one lap, and calculate the current distance difference; Step S4: Calculate the radius of the current cutting edge point; Step S5: Calculate the angle of the current blade point based on the calibration triangle; Step S6: Calculate the true angle of the current blade point on the blade. Step S7: Draw the cutting edge shape of the milling cutter cross section.

2. The method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy according to claim 1, characterized in that, Step S1 includes: Set up a confocal system, adjust and ensure that the laser beam plane of the point spectrum confocal lens is parallel to the axis of the main shaft, and focus the lens of the confocal system on the cutting edge of the milling cutter under test; After focusing is complete, keep the lens angle of the confocal system unchanged.

3. The method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy according to claim 2, characterized in that, Step S2 includes: Prepare a standard concentric stepped shaft with a known radius, and ensure that the radii of at least two stepped circles of the concentric stepped shaft do not exceed the confocal measurement range; The first data is recorded by focusing the spectral point onto the small circle of the concentric stepped shaft standard part using a point spectral confocal system. Then, while keeping the laser beam plane parallel to the axis of the stepped shaft, the confocal lens is moved along the axis to focus the spectral point onto the large circle of the concentric stepped shaft standard part, and the second data is recorded. Based on the first data and the second data, the difference between the spectral points at the small circle and the large circle is calculated and denoted as the standard distance difference; The calibration angle is determined based on the calibration triangle formed by the radius of the large circle, the radius of the small circle, and the standard distance difference. The first data is the distance between the confocal lens and the small circle of the concentric stepped shaft standard component, and the second data is the distance between the confocal lens and the large circle of the concentric stepped shaft standard component.

4. The method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy according to claim 3, characterized in that, Step S3 includes: Replace the standard concentric stepped shaft with the end mill to be tested, and measure using a point spectral confocal system. Focus the spectral points on the cutting edge position. If data is transmitted, record the transmitted data as the third data. If no data is transmitted, repeat step S2 until data is transmitted. Record the difference between the second and third data as the current distance difference. The third data is the distance between the confocal lens and the currently selected angle blade.

5. The method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy according to claim 1, characterized in that, Step S3 further includes: Based on a point spectral confocal controller and a fully automatic high-precision spindle, the acquisition signal is triggered by an encoder; the spindle rotates at a constant speed for one revolution, and the data of the milling cutter cross section for one revolution is recorded.

6. The method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy according to claim 4, characterized in that, Step S4 includes: The radius of the current cutting edge point is calculated by forming a triangle with the calibration angle, the current distance difference, and the radius of the large circle of the concentric stepped shaft standard part.

7. The method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy according to claim 6, characterized in that, Step S5 includes: Construct a triangle by combining the radius of the current cutting edge point, the current distance difference, and the radius of the great circle of the concentric stepped shaft standard part, and calculate the angle of the current cutting edge point based on the calibration triangle.

8. The method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy according to claim 7, characterized in that, Step S6 includes: The product of the current blade point's index and the bisector angle is recorded as the angle of the current calibration triangle; the sum of the angle of the current calibration triangle and the angle of the current blade point based on the calibration triangle is recorded as the true angle of the current blade point on the blade. The sequence number of the current cutting edge point is the number of all cutting edge points collected during one revolution of the milling cutter, arranged in sequence; the averaging angle is obtained by dividing 2π by the number of cutting edge points collected during one revolution of the milling cutter.

9. The method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy according to claim 8, characterized in that, Step S7 includes: Calculate the radius and true angle of all cutting edge points, and use MATLAB polar coordinate functions to fit and plot the cutting edge shape of the milling cutter cross section.

10. A measurement system for the cutting edge morphology of a milling cutter cross section based on point spectral confocal microscopy, comprising the method for measuring the cutting edge morphology of a milling cutter cross section based on point spectral confocal microscopy as described in any one of claims 1-9, characterized in that, include: Point spectral confocal probe, including lens and controller; An optical bracket is used to fix the probe and allow it to move precisely along the axial direction; A high-precision rotary spindle is used to clamp and drive the rotation of milling cutters or standard parts; An encoder is used to trigger data acquisition when the spindle rotates; The data processing unit is configured to perform the steps of the method for measuring the cutting edge morphology of a milling cutter section based on point spectral confocal microscopy as described in any one of claims 1-9.

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