Device and method for measuring the angle of the cutting edge of a tool for machining optical micro-prism structures

Abstract

The application relates to a kind of optical micro-prism structure master tool processing cutter blade angle measuring device and method, wherein the optical micro-prism structure master tool processing cutter blade angle measuring device is characterized by comprising base, rotary table with high-precision rotary encoder, six-dimensional precision adjusting table, cutter mounting fixture, collimating laser fiber light source, light splitting prism, light spot CCD detector and light spot image processor;The application improves the measurement precision of cutter blade angle, improves the measurement precision to 0.01 °, breaks through the precision bottleneck of prior art;Solve the problem that traditional equipment cannot adapt to 1.2mm level micro diamond blade and is greatly affected by blade clearance angle, so as to eliminate the measurement error caused by clearance angle.

Description

Technical Field

[0001] This invention belongs to the technical fields of optical measurement, ultra-precision optical processing, and optical micro-pyramidal structure master mold manufacturing, specifically relating to a cutting edge angle measuring device and method for machining optical micro-pyramidal structure master molds. Background Technology

[0002] The ultra-precision machining of the master mold for optical micropyramidal functional films (such as reflective films, i.e., the microprism reflective film disclosed in the invention titled "Manufacturing Method of Microprism Reflective Film with Three Triangular Pyramidal Combinations and its Mold") largely depends on the machining accuracy of the cutting tools (including the metal base and the diamond particles embedded in the front of the metal base) and the measurement technology of the cutting edge angle. Due to the special structure of the cutting tool, i.e., the cutting edge has a back angle, the actual V-groove angle formed by the cutting tool is not simply determined by the bihedral angle formed by the two opposing cutting edges of the cutting tool, but by the included angle between the left cutting edge (the edge formed by the positive cutting edge A and the left cutting edge B) and the right cutting edge (the edge formed by the positive cutting edge A and the right cutting edge C) of the diamond particles of the cutting tool.

[0003] Existing technical solutions and their shortcomings:

[0004] 1. Currently, image microscopes are mainly used to measure the cutting edge angle of cutting tools. However, due to the small size of diamond particles (≈1.2mm) and the difficulty in eliminating the influence of the cutting edge clearance angle on the cutting edge angle measurement, the measurement accuracy can only reach ≈0.10 degrees, which has limitations.

[0005] 2. Traditional precision goniometers based on the self-collimation principle require a reflective surface with a size ≥3*3mm to obtain sufficient reflected light intensity and a clear crosshair on the CCD imaging detector. It is difficult to measure the dihedral angle between the cutting edges of the small diamond particles that form the cutting edge on a cutting tool.

[0006] 3. The indirect measurement method of the cutting angle uses a profilometer to measure and fit the profile of the machined V-groove PMMA sample to estimate the cutting angle. The fitting accuracy and the angular deviation between the test section and the V-groove machining direction will cause measurement deviation. The test accuracy can only reach ≈0.10 degrees, and the measurement efficiency is low.

[0007] 4. The accuracy of the above-mentioned knife angle measurement methods cannot meet the requirements of ultra-precision machining (e.g., 0.01 degrees) for the master mold of micro-pyramidal optical functional films (such as reflective films), which restricts the quality upgrade and industrialization development of micro-structured optical functional films.

[0008] In summary, existing technologies have several drawbacks: Firstly, current image measurement methods for cutting edge angles have low accuracy, typically only reaching around 0.10 degrees. Indirect measurement methods using V-groove samples also achieve only around 0.1 degrees of accuracy with low efficiency, failing to meet the requirements for high-precision measurements (e.g., 0.01 degrees). Secondly, traditional precision goniometers require larger blade reflective surfaces to meet instrument testing requirements. Thirdly, a long-standing technical bias exists in this field, generally believing that laser autocollimation angle measurement requires a reflective surface of at least 3×3mm. Therefore, those skilled in the art generally reject applying this principle to the detection of 1.2mm-level micro-diamond cutting edges. Furthermore, traditional detection methods fail to clarify the spatial geometric coupling relationship between the dihedral angle, clearance angle, and effective cutting edge angle, making it impossible to eliminate measurement interference from the clearance angle in principle. Additionally, traditional testing equipment lacks dedicated clamping structures, making it difficult to adapt to the same type of cutting edge with different dihedral angles and clearance angle specifications, resulting in insufficient versatility and further limiting the technology's implementation and mass production. Summary of the Invention

[0009] In view of the above-mentioned problems, the primary objective of this invention is to improve the measurement accuracy of the cutting edge angle of the cutting tool to 0.01°, thus breaking through the accuracy bottleneck of the existing technology. Secondly, it solves the problem that traditional equipment cannot be adapted to 1.2mm-level micro diamond cutting edges and is greatly affected by the back angle of the cutting edge, thereby eliminating the measurement error caused by the back angle.

[0010] The technical solution of the present invention is as follows:

[0011] A cutting edge angle measuring device for machining a cutting tool using an optical micro-pyramidal structure master mold is characterized by comprising a base, a turntable with a high-precision rotary encoder, a six-dimensional precision adjustment stage, a tool mounting fixture, a collimated laser fiber light source, a beam splitter, a spot CCD detector, and a spot image processor.

[0012] The base is a granite precision optical platform, which serves as the overall installation reference. The turntable with a high-precision rotary encoder is fixed on the base. The rotation axis of the turntable with the high-precision rotary encoder is perpendicular to and intersects with the incident light optical axis. The turntable with the high-precision rotary encoder integrates an air-bearing spindle bearing assembly, a coaxial absolute circular encoder, an air supply system, a locking knob, and a precision fine-tuning knob.

[0013] The six-dimensional precision adjustment stage is installed above a turntable equipped with a high-precision rotary encoder to achieve attitude adjustment of six degrees of freedom: x, y, z, θx, θy, and θz. The tool mounting fixture is fixed on the six-dimensional precision adjustment stage and has four fixing slots to accommodate the clamping and positioning of tools with different dihedral angles and different back angles.

[0014] The collimated laser fiber source is a single-mode semiconductor fiber laser and is matched with a collimating objective lens. The beam waist diameter of the laser spot is less than 1.0 mm within a working distance of 800 mm. The beam splitter is located in the optical path and is used to guide the laser to the tool under test and transmit the light reflected from the surface under test to the laser spot CCD detector.

[0015] The CCD detector collects the position information of the reflected laser spot and communicates with the spot image processor. The spot image processor has a built-in dihedral angle calculation function, which is used to complete spot processing, angle calculation and result output.

[0016] Furthermore, the first and second fixing slots of the aforementioned tool mounting fixture are oriented parallel to the y-direction of the six-dimensional precision adjustment stage, and are used to measure the dihedral angles between the positive cutting surface A and the left cutting surface B, and between the positive cutting surface A and the right cutting surface C, respectively; the third and fourth fixing slots are oriented parallel to the x-direction of the six-dimensional precision adjustment stage, the third fixing slot is used to measure the dihedral angles of the left and right cutting surfaces C with a back angle of 2-12°, and the fourth fixing slot is used to measure the dihedral angles of the left and right cutting surfaces C with a back angle of 0±5°.

[0017] Furthermore, the bottom of the first, second, and third fixing grooves is an inclined groove, wherein the bottom inclined grooves of the first and second fixing grooves form an angle of 53-56° with the z-axis normal plane, the bottom inclined groove of the third fixing groove forms an angle of 10-13° with the z-axis normal plane, and the bottom groove of the fourth fixing groove forms an angle of 0° with the z-axis normal plane.

[0018] Furthermore, the aforementioned base includes a base plate and a boss on the base plate. A turntable with a high-precision rotary encoder, a six-dimensional precision adjustment stage, and a tool mounting fixture are installed on the base plate. A collimated laser fiber light source, a beam splitter, and a spot CCD detector are installed on the boss.

[0019] Furthermore, the aforementioned turntable with a high-precision rotary encoder has a second-level angle resolution and achieves 360° free rotation by relying on the air-bearing spindle bearing assembly. It also completes the fine-tuning and positioning of the angle by working with the locking knob and the precision fine-tuning knob.

[0020] Furthermore, the θx and θy direction fine-tuning knobs of the aforementioned six-dimensional precision adjustment stage are used to adjust the pitch angle deviation of the blade surface under test in order to correct the center height of the laser spot; the x, y, and z direction fine-tuning knobs are used to adjust the irradiation position of the laser on the blade surface under test.

[0021] The present invention provides a method for measuring the cutting edge angle of a tool used in machining an optical micro-pyramidal structure master mold, applied to the aforementioned measuring device, characterized by comprising the following steps:

[0022] S0. Place the cubic reference prism in the center area of ​​the tool mounting fixture. Adjust the θx and θy fine-tuning knobs of the six-dimensional precision adjustment stage so that the center of the reflected light spot of the two test surfaces coincides with the center of the receiving surface on the vertical line of the CCD detector receiving surface. Using the first test surface as the reference surface and the second test surface as the test surface, repeat the measurement 10 times to verify whether the measurement accuracy of the measuring device is within ±36″. After the measurement accuracy is within ±36″, proceed to the subsequent measurement steps S1-S2. If the measurement accuracy exceeds ±36″, calibrate the system to reach this range. S1. Clamp the tool to be tested and measure the dihedral angle α between the front cutting surface A and the left cutting surface B, the dihedral angle β between the front cutting surface A and the right cutting surface C, and the dihedral angle γ between the left cutting surface B and the right cutting surface C in sequence.

[0023] S2, according to the formula The effective cutting edge angle of the tool is calculated.

[0024] Furthermore, the specific steps for measuring the dihedral angle α described above are as follows:

[0025] S11. Position and fix the tool under test with the diamond particle's positive cutting face A facing the 3rd fixed groove and the tool tip at or near the rotation axis of the turntable equipped with a high-precision rotary encoder. The metal base of the tool under test should be in close contact with the inclined groove at the bottom of the 1st fixed groove.

[0026] S12. Rotate the turntable with a high-precision rotary encoder 180° so that the positive cutting surface A faces the incident beam. Adjust the y and z direction fine adjustment knobs of the six-dimensional precision adjustment stage so that the incident beam illuminates the positive cutting surface A. Observe the position difference between the incident beam and the reflected beam. Adjust the y, z, and θx fine adjustment knobs of the six-dimensional precision adjustment stage and the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the incident beam is located at the center of the positive cutting surface A of the tool, and the center of the reflected beam received by the spot CCD detector is located at the center of the receiving surface. Record the angle data 1 of the turntable with the high-precision rotary encoder at this time.

[0027] S13. Rotate the turntable with a high-precision rotary encoder so that the left blade surface B faces the incident beam. Adjust the x-direction fine adjustment knob of the six-dimensional precision adjustment stage so that the incident beam shines on the left blade surface B. Observe the position difference between the incident beam and the reflected beam. Adjust the x and θy fine adjustment knobs of the six-dimensional precision adjustment stage and the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the incident beam is located at the center of the left blade surface B, and the center of the reflected beam received by the spot CCD detector is located at the center of the receiving surface. Record the angle data 2 corresponding to the turntable with the high-precision rotary encoder at this time.

[0028] S14. Repeatedly rotate the turntable with high-precision rotary encoder to the positions of angle data 1 and 2, and make fine adjustments in the above manner until it is confirmed that the light spots of the reflected beams received by the two test surfaces by the spot CCD detector are located on the perpendicular line of the receiving surface, and the center of the light spot is located at the center of the receiving surface of the detector. At this time, the first edge AB of the tool is parallel to the rotation axis of the turntable with high-precision rotary encoder, that is, the normals of the two test surfaces are perpendicular to the rotation axis, and the calibration of the dihedral angle α measurement posture of the tool is completed.

[0029] S15. Rotate the turntable with high-precision rotary encoder to the position or near angle data 1, and then adjust the angle fine adjustment knob of the turntable with high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the positive cutting surface A is perpendicular to the incident light axis. The reference surface is initialized, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the positive cutting surface A after the deviation is corrected.

[0030] S16. Rotate the turntable with the high-precision rotary encoder to the position or near angle data 2, and then adjust the angle fine-tuning knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the left blade surface B is perpendicular to the incident light axis. The second test surface is measured, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the left blade surface B after the deviation is corrected is recorded and the measured value of the dihedral angle α is output.

[0031] Furthermore, the specific steps for measuring the dihedral angle β are as follows:

[0032] S21. Position the tool under test so that the diamond grain's positive cutting face A faces the 3rd fixed groove and the tool tip is at or near the rotation axis of the turntable equipped with a high-precision rotary encoder. The metal base of the tool under test is in close contact with and fixed to the inclined groove at the bottom of the 2nd fixed groove.

[0033] S22. Rotate the turntable equipped with a high-precision rotary encoder 180° (or approximately 180°) so that the positive cutting surface A faces the incident beam. Adjust the y and z direction fine-tuning knobs of the six-dimensional precision adjustment stage to make the incident beam illuminate the positive cutting surface A. Observe the positional difference between the incident beam and the reflected beam. Adjust the y, z, and θx fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the turntable equipped with the high-precision rotary encoder so that the incident beam is located at the center of the positive cutting surface A and the center of the reflected beam received by the spot CCD detector is located at the center of the receiving surface. Record the corresponding angle data 3 of the turntable equipped with the high-precision rotary encoder at this time.

[0034] S23. Next, rotate the turntable equipped with a high-precision rotary encoder so that the left cutting edge B faces the incident beam. Adjust the x-direction fine-tuning knob of the six-dimensional precision adjustment stage so that the incident beam illuminates the left cutting edge B of the tool. Observe the positional difference between the incident beam and the reflected beam. Adjust the x and θy fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the turntable equipped with the high-precision rotary encoder so that the incident beam is located at the center of the left cutting edge B of the tool and the center of the reflected beam received by the spot CCD detector is located at the center of the receiving surface. Record the angle data 4 of the turntable equipped with the high-precision rotary encoder at this time.

[0035] S24. Repeatedly rotate the turntable with the high-precision rotary encoder to the positions of angle data 3 and 4, and make fine adjustments in the above manner until it is confirmed that the spot of the reflected beam received by the spot CCD detector of the two test surfaces is located on the vertical line of the receiving surface, and the center of the spot is located at the center of the receiving surface of the detector. At this time, the second edge AC of the tool is parallel to the rotation axis, that is, the normal of the two test surfaces is perpendicular to the rotation axis, and the calibration of the dihedral angle β measurement posture of the tool is completed.

[0036] S25. Rotate the turntable with high-precision rotary encoder to the position or near angle data 3, and then adjust the angle fine-tuning knob of the turntable with high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the positive cutting surface A is perpendicular to the incident light axis. The reference surface is initialized, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the positive cutting surface A after the deviation is corrected.

[0037] S26. Rotate the turntable with the high-precision rotary encoder to the position or near angle data 4, and then adjust the angle fine-tuning knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the right edge C is perpendicular to the incident light axis. The second test surface is measured, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the right edge C after the deviation is corrected is recorded and the measured value of the dihedral angle β is output.

[0038] Furthermore, the specific steps for measuring the dihedral angle γ are as follows:

[0039] S31. Position the test tool with the diamond particle tip facing the 4th fixed groove and the tip at or near the rotation axis of the turntable equipped with a high-precision rotary encoder. The metal base of the test tool is in close contact with and fixed to the bottom inclined groove of the 3rd fixed groove.

[0040] S32. Rotate the turntable with a high-precision rotary encoder to 0° so that the tool tip faces the incident light beam; adjust the y and z direction fine adjustment knobs of the six-dimensional precision adjustment stage so that the incident light beam shines on the tool tip, and complete the initial adjustment of the y direction position offset.

[0041] S33. Rotate the turntable with a high-precision rotary encoder so that the left cutting edge B faces the incident beam. Adjust the x and z direction fine adjustment knobs of the six-dimensional precision adjustment stage so that the incident beam shines on the left cutting edge B of the tool. Observe the position difference between the incident beam and the reflected beam. Adjust the x, z, θy fine adjustment knobs of the six-dimensional precision adjustment stage and the angle fine adjustment knob of the turntable with a high-precision rotary encoder so that the center of the light spot of the reflected beam received by the CCD is located at the center of the receiving surface and the incident beam completely shines on the surface to be measured. Record the angle data 5 of the turntable with a high-precision rotary encoder at this time.

[0042] S34. Next, rotate the turntable with a high-precision rotary encoder so that the incident beam illuminates the right cutting edge C of the tool. By adjusting the y-direction fine adjustment knob of the six-dimensional precision adjustment stage and the angle fine adjustment knob of the turntable with the high-precision rotary encoder, the center of the reflected beam received by the CCD detector is located on the vertical axis. Observe the height difference between the center of the beam and the center of the receiving surface at this time. First, adjust the z and θy direction fine adjustment knobs of the six-dimensional precision adjustment stage to adjust the center of the beam to half the position between the center of the receiving surface and the initial position of the beam. Then, adjust the z and θx direction fine adjustment knobs of the six-dimensional precision adjustment stage to adjust the center of the reflected beam to the center of the receiving surface of the CCD detector, and the incident beam completely illuminates the surface to be measured. Record the angle data 6 of the turntable with the high-precision rotary encoder at this time.

[0043] S35. Repeatedly rotate the turntable with high-precision rotary encoder to the positions of angle data 5 and 6, and make fine adjustments in the above manner until the light spot of the reflected beam received by the two test surfaces by the light spot CCD detector is located on the vertical line of the receiving surface, and the center of the light spot is located at the center of the receiving surface of the detector. At this time, the third edge AD of the tool is parallel to the rotation axis of the turntable with high-precision rotary encoder, that is, the normal of the two test surfaces is perpendicular to the rotation axis, and the calibration of the dihedral angle γ measurement posture of the tool is completed.

[0044] S36. Rotate the turntable with high-precision rotary encoder to the position or near angle data 5, and then adjust the angle fine adjustment knob of the turntable with high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the left blade surface B is perpendicular to the incident light axis. The reference surface is initialized, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the left blade surface B after the deviation is corrected.

[0045] S37. Rotate the turntable with the high-precision rotary encoder to the position or near the angle data 6, and then adjust the angle fine-tuning knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the right edge C is perpendicular to the incident light axis. The second test surface is measured, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the right edge C after the deviation is corrected is recorded and the measured value of the dihedral angle γ is output.

[0046] Advantages of this invention:

[0047] 1. This invention is based on the principle of laser autocollimation to build a measurement system. It is equipped with a high-resolution circular grating angle turntable and a high-precision image analysis algorithm. After multiple sets of experimental verification, the measurement accuracy of this device can be stably reached 0.01°, which is 10 times higher than the measurement accuracy of 0.10° of the traditional method. It fully meets the stringent precision requirements of ultra-precision machining of optical micro pyramid master molds, and the measurement accuracy is significantly improved.

[0048] 2. This invention targets diamond cutting edges with an effective reflective surface size of less than 1.2 mm. With a collimated laser fiber light source at a standard working distance of 800 mm, the laser beam can completely irradiate the cutting edge surface and form an effective reflective spot. In contrast, the spot size of traditional self-collimating devices is generally larger than 3 mm, which cannot form a complete reflective spot on a 1.2 mm micro-cutting edge surface and therefore does not meet the detection requirements.

[0049] 3. By measuring the dihedral angle formed by the three sets of cutting edges of the tool step by step, and deriving the effective cutting edge angle by combining it with a special geometric calculation formula, the measurement deviation caused by the tool's back angle is completely avoided, ensuring the authenticity and accuracy of the test results from the principle level.

[0050] 4. Equipped with a multi-slot tool mounting fixture, enabling rapid tool positioning and disassembly; combined with a six-dimensional precision adjustment stage for fine-tuning of posture, the overall device has a high degree of integration and a clear operation process. Compared with the indirect measurement method of profilometer, it significantly shortens the detection time and improves detection efficiency. Attached Figure Description

[0051] The present invention will be further described below with reference to the accompanying drawings;

[0052] Figure 1 This is a schematic diagram of the main structure of the device of the present invention;

[0053] Figure 2 This is a three-dimensional structural diagram of the tool mounting fixture;

[0054] Figure 3 It is a 3D image of a diamond particle;

[0055] Figure 4 It is a three-dimensional view of the tool to be tested installed in the first fixing slot of the tool mounting fixture;

[0056] Figure 5 It is a three-dimensional view of the tool to be tested installed in the second fixing slot of the tool mounting fixture;

[0057] Figure 6 This is a three-dimensional view of the tool to be tested installed in the third fixing slot of the tool mounting fixture.

[0058] 1-Base, 2-Turntable with high-precision rotary encoder, 3-Six-dimensional precision adjustment stage, 4-Tool mounting fixture, 5-Collimating laser fiber light source, 6-Beam splitter prism, 7-Spot CCD detector, 8-Spot image processor, 101-Base plate, 102-Boss, 401-First fixing slot, 402-Second fixing slot, 403-Third fixing slot, 404-Fourth fixing slot, 405-Threaded hole; 01-Optical axis, 02-Tool under test, 03-Rotation axis, 04-Diamond particle. Detailed Implementation

[0059] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0060] like Figure 1 As shown, the cutting edge angle measuring device for machining the optical micro-pyramidal structure master mold of the present invention includes a base 1, a turntable 2 with a high-precision rotary encoder, a six-dimensional precision adjustment stage 3, a tool mounting fixture 4, a collimated laser fiber light source 5, a beam splitter 6, a spot CCD detector 7, and a spot image processor 8.

[0061] The base 1 is a granite precision optical platform, serving as the overall installation reference. The base includes a base plate 101 and a boss 102 on the base plate. Two high-resolution precision angle rotators, a six-dimensional precision adjustment stage 3, and a tool mounting fixture 4 are installed on the base plate 101. A beam splitter 6 and a spot CCD detector 7 are installed on the boss 102.

[0062] The turntable 2 with a high-precision rotary encoder is fixed on the base 1. The turntable with the high-precision rotary encoder is a commercially available component. It consists of a bearing rotary table, an air-bearing spindle assembly, an angle measurement system (coaxial absolute circular grating encoder), an air supply system, a locking knob, and a precision fine-tuning knob. It has a high-precision scale with second-level resolution, providing a rotation angle reference for measuring the dihedral angle between the blade surfaces to be measured. Its rotation axis is precisely perpendicular to and intersects the incident light axis 01. When the light spot of the beam reflected from the surface to be measured is imaged at the center of the receiving surface of the light spot CCD detector, the angular position information of the precision angle turntable is the direction information of the normal of the surface to be measured. When working, the air supply system needs to be turned on first to establish an air suspension state. Then, gently push the spindle table to rotate 360° at will until the surface of the surface to be measured is close to the target angle (the spot CCD detector can receive the spot of the reflected beam from the surface to be measured). Tighten the turntable locking knob, and then adjust the precision fine adjustment knob to make the center of the spot slowly rotate along the horizontal direction to the vertical line mark of the detector.

[0063] The six-dimensional precision adjustment stage 3 is a commercially available component. It is mounted above the turntable 2, which is equipped with a high-precision rotary encoder. It enables fine-tuning of the six degrees of freedom (x, y, z, θx, θy, θz) of the tool under test, ensuring parallelism between the cutting edge formed by the blade surface and the rotation axis of the precision angle rotary stage (i.e., the installation and debugging requirement that the normal of the surface under test is perpendicular to the rotation axis of the precision angle rotary stage). The θx and θy direction fine-tuning knobs are used to adjust the pitch angle deviation of the surface under test, thereby fine-tuning the height of the center position of the reflected beam spot received by the CCD detector. To facilitate quick confirmation of the angular coordinates of the precision angle rotary stage corresponding to the normal of the surface under test, the x-direction is generally positioned along the line connecting 0° and 180°, and the y-direction is positioned along the line connecting 90° and 270°.

[0064] like Figure 2As shown, the tool mounting fixture 4 is a special fixture specially designed for this application, adapted to the three dihedral angle measurement and clamping requirements of diamond tools processed from micro-pyramidal master molds. It can be quickly disassembled and positioned so that the normal of the surface to be measured is nearly perpendicular to the rotation axis of the precision angle rotary table, and completes accurate attitude calibration in conjunction with the six-dimensional precision adjustment table. The tool mounting fixture 4 includes four fixing slots (fixing slot 1 401, fixing slot 2 402, fixing slot 3 403 and fixing slot 404), wherein fixing slot 1 401 and fixing slot 2 402 are oriented parallel to the y-direction of the six-dimensional precision adjustment table 3, and are used to test the dihedral angle between the positive cutting face A and the left cutting face B and the dihedral angle between the positive cutting face A and the right cutting face C, respectively. The third fixing groove 403 and the fourth fixing groove 404 are oriented parallel to the x-direction of the six-dimensional precision adjustment stage 3. The third fixing groove 403 is used to test the dihedral angle between the left cutting edge B and the right cutting edge C with a back angle of 2~12°. The fourth fixing groove is used to test the dihedral angle between the left cutting edge B and the right cutting edge C with a back angle in the range of 0±5°.

[0065] The bottom of the first fixing groove 401, the second fixing groove 402, and the third fixing groove 403 are inclined grooves. The bottom inclined grooves of the first fixing groove and the second fixing groove form an angle of 53-56° with the z-axis normal plane, preferably 54.75° (after the tool is installed in the groove, the normal of the side cutting edge of the reference 70.50° tool is close to perpendicular to the rotation axis of the angle rotary table). The bottom inclined groove of the third fixing groove forms an angle of 10-13° with the z-axis normal plane, preferably 12° (after the tool is installed in the groove, the normal of the two sides with a 7° back angle is close to perpendicular to the rotation axis of the angle rotary table). The bottom groove of the fourth fixing groove forms an angle of 0° with the z-axis normal plane.

[0066] The first fixing groove 401 and the second fixing groove 402 have a 53-56° inclined groove at the bottom, designed according to the conventional 70-50° dihedral angle of the cutting edge of the tool under test. After clamping, the normal of the cutting edge is close to perpendicular to the rotation axis, which greatly reduces the difficulty of subsequent six-dimensional stage attitude adjustment. The third fixing groove has a 10-13° inclined groove, designed for spatial attitude matching of the tool with a 7° back angle, which cancels out the attitude deviation caused by the back angle and ensures that the left and right cutting edges can receive laser reflected light normally. The fourth fixing groove has a 0° flat bottom structure: it is suitable for tool types with a back angle close to 0°, and achieves full-specification tool coverage.

[0067] The tool mounting fixture has slots with different tilt angles and layouts that can pre-counteract the attitude deviation caused by the tool back angle during the clamping stage, making the normal of the test cutting surface approach perpendicular to the rotation axis of the turntable with a high-precision rotary encoder, which greatly simplifies the attitude calibration operation of the subsequent six-dimensional precision adjustment table.

[0068] The layout of the grooves in the x and y directions is designed differently based on the spatial distribution of the three sets of dihedral angles (α / β / γ) to meet the clamping requirements of different measurement conditions.

[0069] The collimated laser fiber source 5 uses a single-mode semiconductor fiber laser as the light source, matched with a precisely designed collimating objective lens. It controls the laser beam to have a beam waist diameter of less than 1.0 mm within a working distance WD=800 mm after the objective lens transformation, which is suitable for the detection of 1.2 mm-level micro diamond blade reflective surfaces.

[0070] The beam splitter 6 is located in the optical path and is used to guide the laser beam emitted by the reflected collimated laser fiber source to the surface of the tool under test 02, while transmitting the self-collimated laser beam reflected by the surface under test to the spot CCD detector.

[0071] The center of the receiving surface of the CCD detector 7 is located directly behind the beam splitter 6, and it collects the position information of the laser spot reflected from the surface under test in real time, capturing the change in the deflection angle of the reflected beam with high precision. When the normal of the surface under test is perpendicular to the rotation axis 03 of the precision angle rotating stage and parallel to the incident optical axis, the spot of the reflected beam received by the CCD detector is located at the center of the receiving surface.

[0072] The laser spot image processor 8 has built-in laser spot image processing and analysis software, which is used to reduce noise, locate, extract the center and calculate the angle of the spot image acquired by CCD. The laser spot image processing and analysis software has a special calculation formula for dihedral angle measurement and automatically completes data calculation and result output.

[0073] A granite base serves as a rigid reference, working in conjunction with an air-floating, second-level angle rotary table to eliminate angular errors caused by mechanical vibration and rotational backlash. A six-dimensional precision adjustment stage and tool mounting fixture form a two-stage positioning system, enabling rapid and precise clamping of micro-diamond cutting edges. A small-spot collimated laser source (beam waist < 1.0mm), along with CCD spot detection and an image processor, forms a closed-loop detection chain, specifically matched to a 1.2mm micro-reflective surface, breaking the limitations of traditional self-collimating devices on the size of the reflective surface. The beam-splitting prism optical path layout, combined with the spatial orientation of the rotary table, ensures that the incident optical axis and the rotation axis always intersect perpendicularly, providing a stable optical reference for dihedral angle calculation.

[0074] This application allows for the calibration of the measuring device. A cubic reference prism (20*20mm in size, with a dihedral angle of 90°±5″ between adjacent sides) is placed in the center area of ​​the tool mounting fixture. The θx and θy fine-tuning knobs of the six-dimensional precision adjustment stage are adjusted so that the center of the reflected light spot on the two test surfaces coincides with the center of the receiving surface on the vertical line of the CCD detector receiving surface. Using the first test surface as the reference surface and the second test surface as the test surface, the measurement is repeated 10 times to verify whether the measurement accuracy of the measuring device is within the range of ±36″. If the measurement accuracy is within the range of ±36″, subsequent measurement steps S1-S3 are performed. If the measurement accuracy exceeds the range of ±36″, the system is adjusted to reach that range (10 sets of measurement data are as follows).

[0075] Due to the special structure (with a back angle) of the cutting tool used to process microprism reflective film, the cutting edge has three edges AB, AC, and AD, and three cutting surfaces (i.e., the front cutting surface A, the left cutting surface B, and the right cutting surface C). Edge AB is the left cutting edge of the tool, formed by the front cutting surface A and the left cutting surface B; edge AC is the right cutting edge of the tool, formed by the front cutting surface A and the right cutting surface C; and edge AD is the back clearance edge of the tool, formed by the left cutting surface B and the right cutting surface C. These three cutting surfaces form three dihedral angles: α (front cutting surface A and left cutting surface B), β (front cutting surface A and right cutting surface C), and γ (left cutting surface B and right cutting surface C). From these three dihedral angles α, β, and γ, the formula for calculating the effective cutting edge angle of the tool can be derived.

[0076] (1)

[0077] Therefore, it is necessary to use the above-mentioned device to measure the three dihedral angles α, β, and γ in sequence, and calculate the cutting edge angle of the tool according to formula (1). Figure 3 The diagram shows the blade structure, which includes three positive cutting surfaces A, a left cutting surface B, a right cutting surface C, and three edges AB, AC, and AD. The specific steps for measuring the dihedral angles α, β, and γ are as follows.

[0078] The specific steps for measuring the dihedral angle α are as follows (e.g.) Figure 4 (as shown)

[0079] S11. Position the test tool 02 with the diamond particle 04's positive cutting face A facing the third fixing groove 403 and the tool tip close to the rotation axis of the rotary table. Place and fix the metal base of the test tool in close contact with the bottom inclined groove of the first fixing groove 401 (it can be fixed by locking screws in the threaded holes 405 provided on the tool mounting fixture 4, and each tool mounting fixture 4 has threaded holes 405 on the groove wall of the fixing groove).

[0080] S12. Rotate the turntable with a high-precision rotary encoder 180° so that the positive cutting surface A faces the incident beam. Adjust the y and z direction fine-tuning knobs of the six-dimensional precision adjustment stage so that the incident beam illuminates the positive cutting surface A. Observe the positional difference between the incident beam and the reflected beam. Adjust the y, z, and θx fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the turntable with the high-precision rotary encoder so that the incident beam is located at the center of the positive cutting surface A of the tool, and the center of the reflected beam received by the spot CCD detector is located at the center of the receiving surface. Record the angle data 1 corresponding to the turntable with the high-precision rotary encoder at this time.

[0081] S13. Rotate the turntable 2 with a high-precision rotary encoder so that the left blade surface B faces the incident beam. Adjust the x-direction fine adjustment knob of the six-dimensional precision adjustment stage so that the incident beam illuminates the left blade surface B. Observe the position difference between the incident beam and the reflected beam. Adjust the x and θy fine adjustment knobs of the six-dimensional precision adjustment stage and the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the incident beam is located at the center of the left blade surface B, and the center of the reflected beam received by the spot CCD detector is located at the center of the receiving surface. Record the angle data 2 corresponding to the turntable with the high-precision rotary encoder at this time.

[0082] S14. Repeatedly rotate the turntable with the high-precision rotary encoder to the positions of angle data 1 and 2, and make fine adjustments in the above manner until it is confirmed that the light spots of the reflected beams received by the two test surfaces by the spot CCD detector are located on the perpendicular line of the receiving surface, and the center of the light spot is located at the center of the receiving surface of the detector. At this time, the first edge AB of the tool is parallel to the rotation axis of the turntable with the high-precision rotary encoder, that is, the normals of the two test surfaces are perpendicular to the rotation axis, and the calibration of the dihedral angle α measurement posture of the tool is completed.

[0083] S15. Rotate the turntable with the high-precision rotary encoder to the vicinity of the position of angle data 1, and then adjust the angle fine-tuning knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the positive cutting surface A is perpendicular to the incident light axis. The reference surface is initialized by the spot image processor (that is, the reference surface is initialized by clicking the initialization button of the image processing and analysis software on the laser spot image processing and analysis software), and the angle information corresponding to the normal of the positive cutting surface A after the deviation is corrected is calculated and recorded.

[0084] S16. Rotate the turntable with the high-precision rotary encoder to the vicinity of the position of angle data 2, and then adjust the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the left blade surface B is perpendicular to the incident light axis. The second test surface is measured, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the left blade surface B after the deviation is corrected is recorded and the measured value of the dihedral angle α is output.

[0085] The specific steps for measuring the dihedral angle β are as follows (e.g.) Figure 5 (as shown)

[0086] S21. Position the test tool with the diamond grain's positive cutting face A facing the 3rd fixed groove and the tool tip close to the rotation axis of the turntable equipped with a high-precision rotary encoder. The metal base of the test tool is in close contact with and fixed to the inclined groove at the bottom of the 2nd fixed groove.

[0087] S22. Rotate the turntable 2 equipped with a high-precision rotary encoder approximately 180° so that the positive cutting surface A faces the incident beam. Adjust the y and z direction fine-tuning knobs of the six-dimensional precision adjustment stage to ensure that the incident beam illuminates the positive cutting surface A. Observe the positional difference between the incident beam and the reflected beam. Adjust the y, z, and θx fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the precision angle rotary stage so that the incident beam is located at the center of the positive cutting surface A and the center of the reflected beam received by the spot CCD detector is located at the center of the receiving surface. Record the corresponding angle data 3 of the turntable equipped with the high-precision rotary encoder at this time.

[0088] S23. Next, rotate the turntable 2 equipped with a high-precision rotary encoder so that the left cutting edge B faces the incident beam. Adjust the x-direction fine-tuning knob of the six-dimensional precision adjustment stage to make the incident beam illuminate the left cutting edge B of the tool. Observe the positional difference between the incident beam and the reflected beam. Adjust the x and θy fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the turntable equipped with the high-precision rotary encoder so that the incident beam is located at the center of the left cutting edge B of the tool and the center of the reflected beam received by the spot CCD detector is located at the center of the receiving surface. Record the angle data 4 of the turntable equipped with the high-precision rotary encoder at this time.

[0089] S24. Repeatedly rotate the turntable with the high-precision rotary encoder to the positions of angle data 3 and 4, and make fine adjustments in the above manner until it is confirmed that the light spots of the reflected beams received by the two test surfaces by the spot CCD detector are located on the perpendicular line of the receiving surface, and the center of the light spot is located at the center of the receiving surface of the detector. At this time, the second edge AC of the tool is parallel to the rotation axis of the turntable with the high-precision rotary encoder, that is, the normals of the two test surfaces are perpendicular to the rotation axis, and the calibration of the dihedral angle β measurement posture of the tool is completed.

[0090] S25. Rotate the turntable with the high-precision rotary encoder to the vicinity of the position of angle data 3, and then adjust the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the positive cutting surface A is perpendicular to the incident light axis. The reference surface is initialized, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the positive cutting surface A after the deviation is corrected is recorded.

[0091] S26. Rotate the turntable with the high-precision rotary encoder to the vicinity of the position of angle data 4, and then adjust the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the right edge C is perpendicular to the incident light axis. The second test surface is measured, calculated and recorded by the spot image processor, and the angle information corresponding to the normal of the right edge C after the deviation is corrected is output. The measured value of the dihedral angle β is output.

[0092] The specific steps for measuring the dihedral angle γ are as follows (e.g.) Figure 6 (as shown)

[0093] S31. Position the test tool with the diamond particle tip facing the 4th fixed groove and the tip close to the rotation axis of the turntable equipped with a high-precision rotary encoder. The metal base of the test tool is in close contact with and fixed to the bottom inclined groove of the 3rd fixed groove.

[0094] S32. Rotate the turntable with a high-precision rotary encoder from 2 to 0° so that the tool tip faces the incident light beam; adjust the y and z direction fine adjustment knobs of the six-dimensional precision adjustment stage so that the incident light beam shines on the tool tip, completing the initial adjustment of the y-direction position offset.

[0095] S33. Rotate the turntable with a high-precision rotary encoder so that the left cutting edge B faces the incident beam. Adjust the x and z fine-tuning knobs of the six-dimensional precision adjustment stage so that the incident beam illuminates the left cutting edge B of the tool. Observe the position difference between the incident beam and the reflected beam. Adjust the x, z, and θy fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the turntable with the high-precision rotary encoder so that the center of the reflected beam received by the CCD is located at the center of the receiving surface and the incident beam completely illuminates the surface to be measured. Record the angle data 5 of the turntable with the high-precision rotary encoder at this time.

[0096] S34. Next, rotate the turntable 2 with a high-precision rotary encoder so that the incident beam illuminates the right cutting edge C of the tool. By adjusting the y-direction fine adjustment knob of the six-dimensional precision adjustment stage and the angle of the turntable with the high-precision rotary encoder, the center of the reflected beam received by the CCD detector is located on the vertical axis. Observe the height difference between the center of the beam and the horizontal center at this time. First, adjust the z and θy direction fine adjustment knobs of the six-dimensional precision adjustment stage to adjust the center of the beam to half the position between the center of the receiving surface and the initial position of the beam. Then, adjust the z and θx direction fine adjustment knobs of the six-dimensional precision adjustment stage to adjust the center of the reflected beam to the center of the receiving surface of the CCD detector, and the incident beam completely illuminates the surface to be measured. Record the angle data 6 of the turntable with the high-precision rotary encoder at this time.

[0097] S35. Repeatedly rotate the turntable with the high-precision rotary encoder to the positions of angle data 5 and 6, and fine-tune it in the above manner until the light spot center of the reflected beam received by the two test surfaces by the spot CCD detector is located on the vertical line of the receiving surface and the center of the receiving surface of the detector is located at the center of the receiving surface. At this time, the third edge AD of the tool is parallel to the rotation axis, that is, the normal of the two test surfaces is perpendicular to the rotation axis, and the calibration of the dihedral angle γ measurement posture of the tool is completed.

[0098] S36. Rotate the turntable with the high-precision rotary encoder to the vicinity of the position of angle data 5, and then adjust the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the left blade surface B is perpendicular to the incident light axis. The reference surface is initialized, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the left blade surface B after the deviation is corrected is recorded.

[0099] S37. Rotate the turntable with the high-precision rotary encoder to the vicinity of the position of angle data 6, and then adjust the angle fine-tuning knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the right edge C is perpendicular to the incident light axis. The second test surface is measured, calculated and recorded by the spot image processor. The angle information corresponding to the normal of the right edge C after the deviation is corrected is recorded and the measured value of the dihedral angle γ is output.

[0100] To further illustrate the advantages of this application, the following explanation will elaborate on them:

[0101] A long-standing technical challenge in the microprism reflective film technology industry is the inability of manufacturers of cutting tools for forming triangular pyramidal surfaces to achieve high-precision (±0.005~0.01 degrees) measurement of the cutting edge angle. The main reasons are: 1. The complex polyhedral structure of the cutting tool, meaning the cutting edge angle depends on three cutting edges and the three bifacial angles formed between each pair of edges; 2. The cutting edge area is very small, typically not exceeding 1.2x1.8mm. Traditional precision goniometers based on the self-collimation principle require at least a ≥3x3mm optical reflective surface to use the crosshairs as an optical aiming reference. Furthermore, traditional precision goniometers are generally suitable for measuring the bifacial angles of regular prisms; however, they lack the ability to adjust the tool's edge orientation to perfectly align with the rotation axis, rendering them unsuitable for the complex cutting tools required for processing reflective film master molds.

[0102] The microprism reflective film manufacturing industry currently uses ultra-depth-of-field microscopes for magnified imaging measurement of cutting tool edge angles (image measurement method). Since the pixel size of the microscope's imaging sensor is typically 2-3 micrometers, a single pixel alignment error during cutting tool edge image processing results in a system measurement error of 0.0764-0.1146 degrees for a 1.50mm cutting edge. Furthermore, the misalignment of the image plane formed by the microscope and the sensor plane when the cutting tool is placed on the ultra-depth-of-field microscope stage also contributes to measurement errors. Therefore, the accuracy of existing measurement methods is difficult to meet the machining requirements of ±0.005-0.01 degrees for the conical angle of the reflective film master mold.

[0103] According to the optical design and manufacturing requirements of microprism reflective film, the cone angle of the microprism reflective film is A1, such as A1=70.84±(0.005~0.01) degrees (the cutting tool must at least meet this requirement). The cutting edge angle of the cutting tool provided by the cutting tool supplier is A2=70.84±0.10 degrees. In order to ensure that the processed reflective film master mold meets the technical requirements, N cutting tools are usually ordered in the past, with their cutting edge angles A2 distributed in the range of 70.74~70.94 degrees. The most suitable cutting tool is determined by verifying the performance of reflective film samples processed by N cutting tools in turn. The disadvantages of this operation are: 1. The number of cutting tools required increases, and the cost of cutting tools also increases; 2. The verification and testing cycle of the reflective film mold processing technology is long, and the equipment and labor costs also increase. On the other hand, when the selected cutting tool reaches the end of its service life, when reprocessing the master mold of the same reflective film design, it is necessary to repeat the above process of purchasing cutting tools, processing the master mold, and verifying the performance to select cutting tools, resulting in high cost and low efficiency in the production of reflective film master molds.

[0104] Using the measuring device and method of this invention, the measurement accuracy can be stabilized at 0.01°, which is 10 times higher than the 0.10° measurement accuracy of the traditional method. It fully matches the stringent accuracy requirements of ultra-precision machining of optical micro pyramid master molds, significantly improving measurement accuracy and also helping to improve the production efficiency of reflective film master molds and reduce costs.

[0105] The following provides two examples of measuring the cutting edge angle of the machining tools for reflective film master molds. The measurement results using two methods are shown in the table below (tool 1 and tool 2).

[0106]

[0107] The measurement method of this application has a mean of 70.311° and a standard deviation of 2.1". The image measurement method has a mean of 70.361° and a standard deviation of 189.4". The difference between the maximum and minimum values ​​(range) of the two measurement methods is 612" (image measurement method) and 6.5" (measurement method of this application). The difference between the image method and the method of this application is 70.361-70.311=0.05°.

[0108]

[0109] The measurement method of this application has a mean of 70.864° and a standard deviation of 3.4". The image measurement method has a mean of 70.835° and a standard deviation of 192.7". The difference between the maximum and minimum values ​​(range) of the two measurement methods is 576" (image measurement method) and 9.8" (measurement method of this application). The difference between the image method and the method of this application is 70.835-70.864=-0.029°.

[0110] The above test results show that the repeatability of the 10 sets of measurement data obtained by the measurement method of this application is very good, and the root mean square error is within a few arcseconds. The error is more than 20 times smaller than that of the image measurement method. The accuracy of the measurement method of this application is more than 20 times higher than that of the image measurement method, which is conducive to achieving consistency control and repeated batch production of reflective film master mold processing.

[0111] In summary, this invention relies on the principle of laser self-collimation for angle detection, but it does not directly apply the existing architecture and usage mode of general self-collimation angle measuring equipment. This invention combines the unique spatial geometry of the triangular facet coupling of the machining tool for the optical micro-pyramidal master mold under test, the tiny 1.2mm diamond reflective cutting edge, and the inherent back angle of the cutting edge—three typical characteristics—to provide multi-dimensional customized adaptation. At the optical path level, a small-spot collimating laser fiber light source is selected, controlling the beam waist diameter within an 800mm working distance to 1.0mm. Within this invention, the reflective lighting requirements of tiny cutting edges are specifically matched, breaking the limitations of general autocollimation equipment that relies on large-sized reflective surfaces. In terms of attitude adjustment, a six-dimensional precision adjustment stage and multi-slot dedicated fixtures are used, employing a multi-round reciprocating attitude calibration process to gradually correct the pitch and positional offset of the cutting edge caused by the tool's back angle and clamping deviations, ensuring that the normal of the cutting edge under test can be accurately aligned with the reference optical axis. In terms of data processing, the invention abandons the general dihedral angle calculation logic and builds a dedicated angle calculation logic based on the spatial correlation of the tool's three sets of dihedral angles. By collecting multiple sets of normal angle data step by step, the interference of the back angle on the measurement results is eliminated, ultimately calculating the true and effective cutting edge angle. This invention optimizes the design of the optical path hardware, operation process, and calculation logic around the characteristics of the tool under test, fundamentally differing from the application methods of conventional autocollimation angle measuring equipment on the market. It successfully solves the industry problem that traditional angle measuring principles are difficult to apply in the detection scenarios of tiny, irregularly shaped tools with back angles; it also helps improve the efficiency and quality of reflective film master mold processing and reduce manufacturing costs.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A device for measuring the cutting edge angle of a cutting tool used in machining an optical micro-pyramidal structure master mold, characterized in that, The system includes a base (1), a turntable (2) with a high-precision rotary encoder, a six-dimensional precision adjustment stage (3), a tool mounting fixture (4), a collimated laser fiber light source (5), a beam splitter (6), a spot CCD detector (7), and a spot image processor (8). The base (1) is a granite precision optical platform, serving as the overall mounting reference. The turntable (2) with the high-precision rotary encoder is fixed on the base (1), and the rotation axis (03) of the turntable with the high-precision rotary encoder is aligned with the incident light optical axis (0). 1) Perpendicular and intersecting; the six-dimensional precision adjustment stage (3) is installed above the turntable (2) with a high-precision rotary encoder to realize the attitude adjustment of six degrees of freedom: x, y, z, θx, θy, and θz; the tool mounting fixture (4) is fixed on the six-dimensional precision adjustment stage (3), and the tool mounting fixture has four fixing slots to accommodate the clamping and positioning of tools with different dihedral angles and different back angles; the collimated laser fiber light source (5) is a single-mode semiconductor fiber laser and is matched with a collimating objective lens; the beam splitter (6) is located on the light In the path, it is used to guide the laser to the tool under test (02) and transmit the reflected light from the surface under test to the spot CCD detector (7); the spot CCD detector (7) collects the position information of the reflected laser spot and communicates with the spot image processor (8). The spot image processor (8) has a built-in dihedral angle calculation, which is used to complete the spot processing, angle calculation and result output; the first fixing groove (401) and the second fixing groove (402) of the tool mounting fixture are oriented parallel to the y-direction of the six-dimensional precision adjustment stage, respectively used for Measure the dihedral angles between the positive cutting surface A and the left cutting surface B, and between the positive cutting surface A and the right cutting surface C; the orientation of the third fixed groove (403) and the fourth fixed groove (404) is parallel to the x-direction of the six-dimensional precision adjustment table; the bottom of the first fixed groove, the second fixed groove and the third fixed groove are inclined grooves, wherein the bottom inclined grooves of the first fixed groove and the second fixed groove form an angle of 53-56° with the z-axis normal plane, the bottom inclined groove of the third fixed groove forms an angle of 10-13° with the z-axis normal plane, and the bottom groove of the fourth fixed groove forms an angle of 0° with the z-axis normal plane.

2. The blade angle measuring device according to claim 1, characterized in that, The base (1) includes a base plate (101) and a boss (102) on the base plate. A turntable (2) with a high-precision rotary encoder, a six-dimensional precision adjustment table (3) and a tool mounting fixture (4) are installed on the base plate. A collimated laser fiber light source (5), a beam splitter (6) and a spot CCD detector (7) are installed on the boss (102).

3. The blade angle measuring device according to claim 1, characterized in that, The turntable equipped with a high-precision rotary encoder has a second-level angle resolution and achieves 360° free rotation by relying on the air-bearing spindle assembly. It completes the fine-tuning and positioning of the angle by working with the locking knob and the precision fine-tuning knob.

4. The blade angle measuring device according to claim 1, characterized in that, The θx and θy direction fine-tuning knobs of the six-dimensional precision adjustment stage are used to adjust the pitch angle deviation of the blade surface under test in order to correct the center height of the laser spot; the x, y, and z direction fine-tuning knobs are used to adjust the irradiation position of the laser on the blade surface under test.

5. A method for measuring the cutting edge angle of a tool used in machining an optical micro-pyramidal structure master mold, applied to the measuring device described in any one of claims 3-4, characterized in that, Includes the following steps: S0. Place the cubic reference prism in the center area of ​​the tool mounting fixture mounting plane, and adjust the θx and θy direction fine adjustment knobs of the six-dimensional precision adjustment stage so that when the reflected light spots of the two test surfaces are on the vertical line of the CCD detector receiving surface, the center of the light spot coincides with the center of the receiving surface. Take the first test surface as the reference surface and the second test surface as the test surface, and repeat the measurement 10 times to verify whether the measurement accuracy of the measuring device is within the range of ±36″. After the measurement accuracy is within the range of ±36″, proceed with the subsequent measurement steps S1-S2. If the measurement accuracy exceeds the range of ±36″, adjust the system to reach this range. S1. Clamp the tool to be tested (02), and measure the dihedral angle α between the positive cutting surface A and the left cutting surface B, the dihedral angle β between the positive cutting surface A and the right cutting surface C, and the dihedral angle γ between the left cutting surface B and the right cutting surface C in sequence. S2. According to the formula The effective cutting edge angle of the tool is calculated.

6. The method for measuring the blade angle according to claim 5, characterized in that, The specific steps for measuring the dihedral angle α are as follows: S11, the tool to be tested is positioned with the diamond particle's positive cutting face A facing the third fixed groove and the tool tip at the rotation axis of the turntable equipped with a high-precision rotary encoder. The metal base of the tool to be tested is placed and fixed in close contact with the inclined groove at the bottom of the first fixed groove; S12, the turntable equipped with the high-precision rotary encoder is rotated 180° so that the positive cutting face A faces the incident light beam. By adjusting the y and z direction fine-tuning knobs of the six-dimensional precision adjustment stage, the incident light beam is made to illuminate the positive cutting face A. The positional difference between the incident light beam and the reflected light beam is observed. By adjusting the y, z, and θx fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the turntable equipped with the high-precision rotary encoder, the incident light beam is positioned at... The center of the cutting edge A is located at the center of the reflected beam received by the CCD detector, and the center of the reflected beam is located at the center of the receiving surface. Record the angle data 1 corresponding to the turntable with the high-precision rotary encoder at this time; S13, rotate the turntable with the high-precision rotary encoder so that the left cutting edge B faces the incident beam. Adjust the x-direction fine adjustment knob of the six-dimensional precision adjustment stage so that the incident beam illuminates the left cutting edge B. Observe the position difference between the incident beam and the reflected beam. Adjust the x and θy fine adjustment knobs of the six-dimensional precision adjustment stage and the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the incident beam is located at the center of the left cutting edge B, and the center of the reflected beam received by the CCD detector is located at the center of the receiving surface. At the center of the receiving surface, record angle data 2 corresponding to the turntable with high-precision rotary encoder; S14, repeatedly rotate the turntable with high-precision rotary encoder to the positions of angle data 1 and 2, and fine-tune according to steps S12 and S13 until it is confirmed that the light spots of the reflected beams received by the two test surfaces successively by the spot CCD detector are located on the perpendicular line of the receiving surface, and the center of the light spot is located at the center of the detector receiving surface. At this time, the first edge AB of the tool is parallel to the rotation axis, that is, the normals of the two test surfaces are perpendicular to the rotation axis, and the calibration of the dihedral angle α measurement posture of the tool is completed; S15, rotate the turntable with high-precision rotary encoder to the position of angle data 1, and then adjust the turntable with high-precision rotary encoder. The angle fine-tuning knob of the encoder's turntable is adjusted so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the positive cutting surface A is perpendicular to the incident optical axis. The light spot image processor initializes the reference surface, calculates and records the angle information corresponding to the normal of the positive cutting surface A after the deviation is corrected; S16, rotate the turntable with the high-precision rotary encoder to the position of angle data 2, and then adjust the angle fine-tuning knob of the turntable with the high-precision rotary encoder so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the left cutting surface B is perpendicular to the incident optical axis. The light spot image processor measures the second test surface, calculates and records the angle information corresponding to the normal of the left cutting surface B after the deviation is corrected, and outputs the measured value of the dihedral angle α.

7. The method for measuring the blade angle according to claim 5 or 6, characterized in that, The specific steps for measuring the dihedral angle β are as follows: S21, the tool to be tested is positioned with the diamond particle's positive cutting face A facing the third fixed groove and the tool tip at the rotation axis of the turntable equipped with a high-precision rotary encoder. The metal base of the tool to be tested is in close contact with and fixed to the inclined groove at the bottom of the second fixed groove; S22, the turntable equipped with the high-precision rotary encoder is rotated 180° so that the positive cutting face A faces the incident light beam. The incident light beam is then illuminated onto the positive cutting face A by adjusting the y and z direction fine-tuning knobs of the six-dimensional precision adjustment stage; the positional difference between the incident light beam and the reflected light beam is observed. The incident light beam is then positioned at the center of the positive cutting face A by adjusting the y, z, and θx fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the turntable equipped with the high-precision rotary encoder. Furthermore, the center of the reflected beam received by the CCD detector is located at the center of the receiving surface. Record the angle data corresponding to the turntable with the high-precision rotary encoder at this time; S23, then rotate the turntable with the high-precision rotary encoder so that the left cutting surface B faces the incident beam. Adjust the x-direction fine adjustment knob of the six-dimensional precision adjustment stage so that the incident beam illuminates the left cutting surface B of the tool; observe the position difference between the incident beam and the reflected beam. Adjust the x and θy fine adjustment knobs of the six-dimensional precision adjustment stage and the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the incident beam is located at the center of the left cutting surface B of the tool and the center of the reflected beam received by the CCD detector is located at the receiving surface. At the center, record the angle data 4 corresponding to the turntable with high-precision rotary encoder at this time; S24, repeatedly rotate the turntable with high-precision rotary encoder to the positions of angle data 3 and 4, and make fine adjustments according to the methods of S22 and S23 until it is confirmed that the light spots of the reflected beams received by the two test surfaces successively by the spot CCD detector are located on the perpendicular line of the receiving surface, and the center of the spot is located at the center of the receiving surface of the detector. At this time, the second edge AC of the tool is parallel to the rotation axis, that is, the normals of the two test surfaces are perpendicular to the rotation axis, and the calibration of the dihedral angle β measurement posture of the tool is completed; S25, rotate the turntable with high-precision rotary encoder to the position of angle data 3, and then adjust the high-precision rotary encoder. The angle fine-tuning knob of the turntable is adjusted so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the positive cutting surface A is perpendicular to the incident optical axis. The reference surface is initialized, calculated and recorded by the spot image processor, and the angle information corresponding to the normal of the positive cutting surface A after the deviation is corrected. S26, the turntable with high-precision rotary encoder is rotated to the position of angle data 4, and then the angle fine-tuning knob of the turntable with high-precision rotary encoder is adjusted so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the right cutting surface C is perpendicular to the incident optical axis. The second measured surface is measured, calculated and recorded by the spot image processor, and the angle information corresponding to the normal of the right cutting surface C after the deviation is corrected is output and the measured value of the dihedral angle β is output.

8. The method for measuring the blade angle according to claim 7, characterized in that, The specific steps for measuring the dihedral angle γ are as follows: S31, Position the tool to be tested with the diamond particle tip facing the 4th fixed groove and the tip positioned at the rotation axis of the turntable equipped with a high-precision rotary encoder. The metal base of the tool to be tested should be in close contact with and fixed to the inclined groove at the bottom of the 3rd fixed groove; S32, Rotate the turntable equipped with the high-precision rotary encoder to 0°, so that the tool tip faces the incident light beam; Adjust the y and z direction fine-tuning knobs of the six-dimensional precision adjustment stage to allow the incident light beam to irradiate the tool tip, completing the initial adjustment of the y-direction position offset; S33, Rotate the turntable equipped with the high-precision rotary encoder so that the left cutting edge B faces the incident light beam, and adjust the x and z direction fine-tuning knobs of the six-dimensional precision adjustment stage to allow the incident light beam to irradiate the tool tip, completing the initial adjustment of the y-direction position offset; The light beam illuminates the left cutting edge B of the tool. The positional difference between the incident and reflected beams is observed. By adjusting the x, z, and θy fine-tuning knobs of the six-dimensional precision adjustment stage and the angle fine-tuning knob of the turntable with a high-precision rotary encoder, the center of the reflected beam received by the CCD is positioned at the center of the receiving surface, and the incident beam completely illuminates the surface to be measured. The angle data corresponding to this moment is recorded as 5. S34. Next, the turntable with the high-precision rotary encoder is rotated so that the incident beam illuminates the right cutting edge C of the tool. By adjusting the y-direction fine-tuning knob of the six-dimensional precision adjustment stage and the angle of the turntable with the high-precision rotary encoder, the reflected beam received by the CCD detector is adjusted. With the spot center located on the vertical line, observe the height difference between the spot center and the horizontal center. First, adjust the z and θy direction fine-tuning knobs of the six-dimensional precision adjustment stage to adjust the spot center to halfway between the center of the receiving surface and the initial position of the spot. Then, adjust the z and θx direction fine-tuning knobs of the six-dimensional precision adjustment stage to adjust the spot center of the reflected beam to the center of the receiving surface of the spot CCD detector, and ensure that the incident beam completely illuminates the surface to be measured. Record the angle data 6 corresponding to the turntable with the high-precision rotary encoder at this time. S35: Repeatedly rotate the turntable with the high-precision rotary encoder to the positions of angle data 5 and 6, and perform fine-tuning according to the methods of S33 and S34 until the spot CCD detector first... When the light spots of the reflected beams from the two test surfaces are located on the perpendicular bisector of the receiving surface, the center of the light spot is located at the center of the receiving surface of the detector. At this time, the third edge AD of the tool is parallel to the rotation axis, that is, the normals of the two test surfaces are perpendicular to the rotation axis, thus completing the calibration of the tool's dihedral angle γ measurement posture; S36, rotate the turntable with the high-precision rotary encoder to the position of angle data 5, and then adjust the angle fine adjustment knob of the turntable with the high-precision rotary encoder so that the light spot of the reflected beam is located at the center of the receiving surface of the detector. At this time, the left cutting edge B is perpendicular to the incident light axis. The reference surface is initialized, calculated and recorded by the light spot image processor, and the angle information corresponding to the normal of the left cutting edge B after the deviation is corrected.S37. Rotate the turntable equipped with a high-precision rotary encoder to position 6 (angle data). Then, adjust the angle fine-tuning knob of the precision angle turntable so that the reflected beam spot is located at the center of the detector receiving surface. At this time, the right-side cutting edge C is perpendicular to the incident light axis. The spot image processor measures, calculates, and records the angle information corresponding to the normal of the right-side cutting edge C after correction of the deviation, and outputs the measured value of the dihedral angle γ.

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