CN113319424B - Three-dimensional shape accurate control processing system and processing method - Google Patents

Abstract

The invention provides a three-dimensional topography precise control processing system and processing method, which solves the problem that the existing three-dimensional structure topography and size cannot be precisely processed. In the system and method of the invention, a confocal displacement sensor is arranged on the laser processing head. First, the spatial position and attitude of the workpiece are adjusted with high precision by the confocal displacement sensor, so as to complete the high-precision positioning and reference correction of the workpiece; secondly, the confocal calibration is performed. The relative position between the displacement sensor and the laser focus lays a foundation for the follow-up of the focus after the workpiece material is removed by subsequent laser scanning; thirdly, the confocal displacement sensor is used to measure the three-dimensional topography of each layer after laser scanning, combined with the orthogonal layer-by-layer scanning And the single-pulse energy method can greatly improve the roughness of the bottom surface and the control accuracy of the processing depth.

Description

A three-dimensional topography precise control processing system and processing method

technical field

The invention belongs to the field of laser processing, and in particular relates to a three-dimensional topography precise control processing system and a processing method.

Background technique

Laser processing technology has become a key technology for processing various functional structures and three-dimensional fine structures due to its advantages of non-contact, approximate "cold processing", no pollution, and wide applicability of materials. However, since the laser has a certain depth of focus, it is difficult to realize the precision machining of three-dimensional structures.

Chinese patent CN107498189A discloses a laser processing method for a three-dimensional V-shaped groove structure on a metal surface. In this method, after acquiring the data of the V-shaped groove, the processing of each layer of material and the control of the contour are realized by scanning a rectangular frame. However, this method does not realize closed-loop control processing, and the processing depth and bottom surface roughness of each layer are affected by various factors such as laser parameters, focus position, and air blowing, so the precise processing of a specific V-shaped structure cannot be achieved.

Chinese patent CN104439709A discloses a three-dimensional laser marking method, device and three-dimensional laser processing equipment. In this method, a three-dimensional galvanometer system is used to realize three-dimensional structure processing. The mirror system is directly processed to obtain a three-dimensional structure. However, the 3D galvanometer used in this method is expensive, which limits its wide application; in addition, the 3D galvanometer is limited by the slicing and layering accuracy of the micron-level structure, and cannot achieve micron-level high-precision and high-consistency processing, and This method also does not realize closed-loop control processing, and does not propose a control method for controlling bottom surface roughness and processing depth.

Because the laser focus has a certain depth of focus, it is not conducive to the precision machining of three-dimensional structures, and three-dimensional structures cannot be precisely processed, resulting in the fact that the laser processing method has not been practically applied in the field of three-dimensional structure precision machining.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem that the existing three-dimensional structure topography and size cannot be precisely processed, and to provide a three-dimensional topography precise control processing system and processing method.

To achieve the above object, the present invention adopts the following technical solutions:

A three-dimensional topography precise control processing method, comprising the following steps:

Step 1. A confocal displacement sensor is arranged on the laser processing head, and the laser processing head includes a two-dimensional scanning galvanometer and a telecentric flat field mirror;

Step 2, the laser processing head performs trial processing on the single-layer material, and determines the laser single pulse energy and pulse overlap rate range for processing the material;

Step 3: After determining the pulse overlap rate, establish the mapping relationship between the laser single pulse energy and the processing depth and the roughness of the bottom surface;

Step 4. Find the laser focus, calibrate the relative position between the confocal displacement sensor and the laser focus, and obtain the calibration value of the confocal displacement sensor. At the same time, record the coordinate value of the XY axis of the processing platform at this time as the initial position of the laser focus;

Step 5. Place the workpiece on the processing platform, and adjust the spatial attitude of the workpiece so that the plane formed by the four corners of the workpiece is parallel to the XY coordinate plane of the processing platform;

Step 6: Layer the three-dimensional structure of the workpiece according to the mapping relationship between the laser single pulse energy and the processing depth obtained in step 3;

Step 7: According to the result of layering in step 6, through orthogonal scanning layer by layer and variable single pulse energy mode, three-dimensional structure processing of different depths and different roughness is realized;

7.1) According to the layering results, select the laser single pulse energy and pulse overlap rate corresponding to the processing depth, and the two-dimensional scanning galvanometer realizes single-layer scanning processing in the X direction. At this time, the laser single pulse energy for X direction scanning processing is a ;

7.2) After the scanning in the X direction is completed, move the processing platform in the XY coordinate plane to move the confocal displacement sensor to the X direction to scan the processing area, and move the Z axis of the machine tool according to the difference between the real-time display value and the calibration value of the confocal displacement sensor , so that the laser focus follows the machined surface;

7.3) The confocal displacement sensor measures the processing area scanned in the X direction again, measures the topography data of the scanned processing area in the X direction, and obtains the depth and roughness of the scanned processing area in the X direction. Move the processing platform in the XY coordinate plane to make the laser The focus returns to the initial position;

7.4) According to the measured depth and roughness of the X-direction scanning processing area, select the appropriate laser single-pulse energy and pulse overlap rate to achieve single-layer scanning processing in the Y-direction. At this time, the laser single-pulse scanning processing in the Y-direction is The energy is b, and b<a;

7.5) After the scanning in the Y direction is completed, move the processing platform in the XY coordinate plane to move the confocal displacement sensor to the scanning processing area in the Y direction, and move the Z axis of the machine tool according to the difference between the real-time display value of the confocal displacement sensor and the calibration value , so that the laser focus follows the machined surface;

7.6) The confocal displacement sensor measures the scanning processing area in the Y direction, obtains the topographic data of the scanning processing area in the Y direction, and obtains the depth and roughness of the scanning processing area in the Y direction, which provides the laser single pulse energy selection for the next layer. Basis; move the processing platform in the XY coordinate plane to make the laser focus return to the initial position;

Step 8: Repeat step 7 to realize the precision machining of the three-dimensional structure with certain structural depth and roughness requirements.

Further, in step 5, the workpiece is placed on the processing platform, the processing platform is moved, the confocal displacement sensor measures the spatial position of the four corners of the workpiece, and the spatial attitude of the workpiece is adjusted according to the data measured by the confocal displacement sensor, The plane formed by the four corners of the workpiece is made parallel to the XY coordinate plane of the processing platform, so as to complete the high-precision positioning and reference correction of the workpiece.

Further, in step 1, the focal length of the telecentric plan lens is within 60mm.

Further, in step 7.4), a is 2-4 times of b.

Further, in step 2, within the parameters of the pulse overlap rate range, the surface of the processed material has no recast layer, no microcracks, and no recrystallization, and the surface roughness of the processed area is Ra≤0.2.

At the same time, the present invention also provides a three-dimensional topography precise control processing system for realizing the above method. The system includes a laser, a beam expander, a laser energy distribution regulator, a wave plate, a diaphragm, a Z-axis translation mechanism, a laser processing head and a confocal displacement sensor; the laser is used to emit a laser processing beam; the beam expander, the laser energy distribution regulator, the wave plate, the diaphragm and the laser processing head are sequentially arranged on the outgoing optical path of the laser; the beam expander It is used to expand the laser beam to make it into flat-top light; the laser energy distribution regulator is used to adjust the energy distribution of the laser beam focus; the wave plate is used to convert linearly polarized light into circularly polarized flat-top light, The adjustment of the polarization state is realized; the diaphragm is used to shape the laser beam and to filter out the low-energy laser; the laser processing head includes a two-dimensional scanning galvanometer and a telecentric flat field mirror, and the laser processing head is arranged at On the Z-axis translation mechanism, the Z-axis translation mechanism can drive the laser processing head to move in the direction of the optical path, so as to focus the laser beam on the surface to be processed; the confocal displacement sensor is arranged on the laser processing head and is used for processing The machining depth and bottom surface topography of the parts are precisely measured.

Further, a first reflection mirror and a second reflection mirror are also arranged between the diaphragm and the two-dimensional scanning galvanometer, and the second reflection mirror is arranged on the Z-axis translation mechanism, which is used for the optical path direction of the laser beam. Adjustment.

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

1. The system and method of the present invention measure the three-dimensional topography of each layer after laser scanning through a confocal displacement sensor, combined with orthogonal layer-by-layer scanning and variable single-pulse energy methods, can greatly improve the roughness of the bottom surface topography and processing depth control At the same time, the number of scanning layers can be selected according to the processing depth of the three-dimensional structure, so as to realize the processing of three-dimensional structures with different depth and surface roughness requirements without generating thermal effects.

2. The system and method of the present invention can realize nano-level positioning and structure measurement through the confocal displacement sensor, which can greatly improve the positioning accuracy of the laser focus and the positioning accuracy of the workpiece in the coordinate system, and provide high-consistency processing for three-dimensional structures. Accuracy guaranteed.

3. The laser energy distribution regulator in the system and method of the present invention can adjust the beam energy, so that the laser energy at the focal point is distributed in a "flat-top" type, which is beneficial to reduce the roughness of the material processing surface.

4. The system and method of the present invention can provide a basis for the processing of three-dimensional structures of different depths of a single material by establishing a mapping relationship between single pulse energy and machining depth and bottom surface roughness after determining an appropriate pulse overlap rate.

5. The processing head of the system and method of the present invention adopts a two-dimensional scanning galvanometer, which greatly reduces the cost of the processing system.

Description of drawings

Fig. 1 is the schematic diagram of the three-dimensional topography precise control processing system of the present invention;

2 is a schematic diagram of the layered processing of the three-dimensional structure of the present invention;

3 is a schematic diagram of the control of the three-dimensional structure and morphology of the present invention;

FIG. 4 is the mapping relationship between single pulse energy and machining depth and bottom surface roughness according to the present invention.

Reference signs: 1-laser, 2-beam expander, 3-laser energy distribution regulator, 4-wave plate, 5-diaphragm, 6-first mirror, 7-laser beam, 8-second mirror , 9-Z-axis translation mechanism, 10-telecentric flat field mirror, 11-laser focus, 12-two-dimensional scanning galvanometer, 13-confocal displacement sensor, 14-workpiece, 15-processing platform, 16-industrial computer.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

The invention provides a three-dimensional topography precise control processing system and processing method, which can effectively control the bottom surface topography and processing depth of a three-dimensional structure by combining off-line detection and layered variable power control in the processing process, so as to realize three-dimensional Quality control of 3D profile topography during structural ultra-precision machining. The device required by the method is simple in structure and low in cost, and only needs to add a confocal displacement sensor to the scanning galvanometer system, which can be applied to the precision machining of three-dimensional structures on the surfaces of different materials. At the same time, the system and method can adjust the laser processing parameters on the spot according to the actual processing conditions, which improves the adaptability of the processing system. In addition, the system and method can realize the precision processing of any three-dimensional structure, and has wide applicability, which is very suitable for ultra-fast processing. The laser realizes the processing of three-dimensional structures.

As shown in FIG. 1 , the three-dimensional topography precise control processing system of the present invention includes a laser 1 , a beam expander 2 , a laser energy distribution regulator 3 , a wave plate 4 , a diaphragm 5 , a first reflection mirror 6 , and a second reflection mirror 8 , Z-axis translation mechanism 9, two-dimensional scanning galvanometer 12, telecentric flat field mirror 10 and confocal displacement sensor 13; wherein, laser 1 is used to emit laser processing beams, beam expander 2, laser energy distribution regulator 3, wave The plate 4 , the diaphragm 5 , the first reflecting mirror 6 and the second reflecting mirror 8 are sequentially arranged on the outgoing light path of the laser 1 , and the beam expander 2 is used to expand the laser beam 7 to make it a flat top light. The laser energy distribution adjuster 3 is used to adjust the energy distribution of the focal point of the laser beam 7, the wave plate 4 is used to convert the linearly polarized light into circularly polarized flat-top light, and realize the adjustment of the polarization state, and the diaphragm 5 is used to adjust the laser beam 7. Shaping is used to filter out low-energy laser light; the first mirror 6 and the second mirror 8 adjust the attitude and position of the laser beam 7 to make the system layout more reasonable; the two-dimensional scanning galvanometer 12 and the telecentric flat field mirror 10 is arranged on the outgoing light path of the second reflection mirror 8, and the two form a laser processing head, the laser processing head and the second reflection mirror 8 are arranged on the Z-axis translation mechanism 9, and the Z-axis translation mechanism 9 drives the laser head to realize along the optical path. The movement of the direction is used to focus the laser beam 7 to the surface to be processed. The confocal displacement sensor 13 is arranged on the laser processing head, and is used to precisely measure the processing depth and bottom surface topography of the workpiece 14. The workpiece 14 is arranged on the processing platform 15, and the processing platform 15 is a four-axis motion platform. It is controlled by the industrial computer 16 , and at the same time, the industrial computer 16 controls the working state of the laser 1 , the Z-axis translation mechanism 9 , and the laser processing head, and processes the data collected by the confocal displacement sensor 13 .

The system of the present invention is provided with a confocal displacement sensor 13. According to the data measured by the confocal displacement sensor 13, the laser processing power is selected (ie, the laser single pulse energy is selected), and the position of the laser focus 11 is adjusted at the same time, so that the laser focus 11 can follow the processing with high precision. The surface is then scanned and processed in the direction perpendicular to the initial direction. The three-dimensional structure processing of different depths can be realized through multiple orthogonal processing, so as to realize the control of the bottom surface roughness and processing depth, and then realize the precise processing of different three-dimensional structures.

The three-dimensional topography precise control processing method provided by the present invention specifically includes the following steps:

Step 1. Set a confocal displacement sensor 13 on the laser processing head. The laser processing head includes a two-dimensional scanning galvanometer 12 and a telecentric flat field mirror 10. The focal length of the telecentric flat field mirror 10 is within 60mm, so that the focal depth of the laser focus 11 is set. as small as possible;

Step 2. The laser processing head conducts trial processing on the single-layer material, and determines the suitable range of laser single pulse energy and pulse overlap rate for processing the material. Within the parameters of the pulse overlap rate range, the surface of the processed material has no recast layer, no Micro-cracks, no recrystallization, and surface roughness Ra≤0.2 of the processed area;

Step 3: After determining the appropriate pulse overlap rate, establish the mapping relationship between the laser single pulse energy and the processing depth and the roughness of the bottom surface, and the mapping relationship is shown in Figure 4;

Step 4: Find the laser focus 11, calibrate the relative position between the confocal displacement sensor 13 and the laser focus 11, and obtain the calibration value of the confocal displacement sensor 13. At the same time, record the coordinate value of the XY axis of the processing platform 15 at this time as the laser focus 11. the initial position;

Step 5. Place the workpiece 14 on the processing platform 15, move the processing platform 15, measure the spatial position of the four corners of the workpiece 14 with the confocal displacement sensor 13, and adjust the workpiece with high precision according to the data measured by the confocal displacement sensor 13. 14, so that the plane formed by the four corners of the workpiece 14 is parallel to the XY coordinate plane of the processing platform 15, so as to complete the high-precision positioning and benchmark calibration of the workpiece 14, and avoid inconsistent processing effects of the workpiece 14;

Step 6: According to the mapping relationship between the laser single pulse energy and the processing depth obtained in Step 3, the three-dimensional structure of the workpiece 14 is layered by the three-dimensional structure layering software, and the most reasonable layering method is selected;

Step 7: According to the result of layering in step 6, through orthogonal scanning layer-by-layer and variable single-pulse energy mode, three-dimensional structure processing with different depths and different roughness is realized, and the flatness of the bottom surface of the three-dimensional structure is improved;

7.1) According to the layering result, select the laser single pulse energy and pulse overlap rate corresponding to the processing depth, and the two-dimensional scanning galvanometer 12 realizes single-layer scanning processing in the X direction. At this time, the laser single pulse energy for scanning processing in the X direction is a ;

7.2) After the scanning in the X direction is completed, move the processing platform 15 in the XY coordinate plane, so that the confocal displacement sensor 13 is moved to the scanning processing area in the X direction, according to the real-time display value of the confocal displacement sensor 13 The difference between the displayed value and the calibration value, Move the Z axis of the machine tool so that the laser focus 11 follows the machined surface;

7.3) The confocal displacement sensor 13 measures the processing area scanned in the X direction again, and obtains the topographic data of the scanned processing area in the X direction. From this data analysis, the depth and roughness of the processing area can be obtained, and move in the XY coordinate plane again. The processing platform 15 makes the laser focus 11 return to the initial position;

7.4) According to the depth and roughness of the scanning processing area in the X direction measured in the previous step, select the appropriate laser single pulse energy and pulse overlap rate to realize the single-layer scanning processing in the Y direction, so that the laser can only remove materials with a very small depth, At this time, the laser single pulse energy for scanning processing in the Y direction is b, b<a, specifically, a can be 2-4 times b;

7.5) After the scanning in the Y direction is completed, move the processing platform 15 in the XY coordinate plane, so that the confocal displacement sensor 13 moves to the scanning processing area in the Y direction, and moves according to the difference between the real-time display value of the confocal displacement sensor 13 and the calibration value. The Z axis of the machine tool, so that the laser focus 11 follows the machined surface;

7.6) The confocal displacement sensor 13 re-measures the scanning processing area in the Y direction, and obtains the topographic data of the scanning processing area in the Y direction. From this data analysis, the depth and roughness of the processing area can be obtained, which is the single pulse of the next layer. The energy selection provides the basis, and then moves the processing platform 15 in the XY coordinate plane to make the laser focus 11 return to the initial position;

Step 8: Repeat step 7 to realize the precision machining of the three-dimensional structure with certain structural depth and roughness requirements.

The method and system of the present invention can greatly improve the positioning accuracy of the workpiece 14 through the confocal displacement sensor 13, and provide data support for the processing of the three-dimensional structure. First, the spatial position and attitude of the workpiece 14 is adjusted with high precision by the confocal displacement sensor 13, so as to complete the high-precision positioning and reference calibration of the workpiece 14, and avoid inconsistent processing effects of the workpiece 14; secondly, the confocal displacement sensor 13 is calibrated with the The relative position between the laser focal points 11 lays the foundation for the follow-up of the focal point after the subsequent laser scanning removes the workpiece material; again, on the premise that the processing parameters such as the pulse overlap rate remain unchanged, the scanning galvanometer scans in a fixed direction for processing, and the processing depth And the bottom surface topography is precisely measured by the confocal displacement sensor 13, thereby establishing the mapping relationship between different single pulse energy and processing depth and bottom surface roughness, which provides the basis for parameter selection for subsequent three-dimensional topography processing.

As shown in Figures 2 and 3, when the three-dimensional topography is processed by the method of the present invention, the scanning galvanometer is scanned and processed according to the method of orthogonally changing the single pulse energy, the odd-numbered layers use a large single-pulse energy, and the even-numbered layers use a small single-pulse energy to remove The bottom surface is undulating, which can greatly reduce the roughness of the bottom surface topography, and realize the control of the bottom surface roughness and processing depth of the three-dimensional structure. After the odd-numbered layers are processed, the processed topography is precisely scanned by the confocal displacement sensor 13. When processing the even-numbered layers, the position of the laser focus 11 is adjusted based on the value of the confocal displacement sensor 13, so that the laser focus 11 follows the surface of the workpiece. The data measured by the focal displacement sensor 13 provides the basis for the selection of the laser single pulse energy during the even-numbered layer scanning processing.

The method of the present invention will be described in detail below with specific examples.

Step 1. Build a laser precision machining system including a three-dimensional structure, including a two-dimensional scanning galvanometer 12, a telecentric flat field mirror 10, a confocal displacement sensor 13 and other components, the focal diameter is about 20 microns, and the focal depth is about 200 microns;

Step 2, carry out trial processing on the test piece of the processing material, and determine the more suitable laser single pulse energy and pulse overlap rate when processing the material;

Step 3. After determining the pulse overlap rate, use different single-pulse energies to process the test piece material, measure the processing depth and bottom surface roughness under different single-pulse energies, and obtain the mapping of single-pulse energy, processing depth and bottom surface roughness relation;

Step 4: Find the laser focus 11, calibrate the relative position between the confocal displacement sensor 13 and the laser focus 11, and obtain the calibration value of the confocal displacement sensor 13, which can be displayed as 0 for subsequent laser focus 11. Find, at the same time, record the initial position of the laser focus 11;

Step 5: Place the workpiece 14 on the processing platform 15, move the processing platform 15, obtain the specific values of the four corners of the workpiece through the confocal displacement sensor 13, and adjust the spatial attitude of the workpiece 14 with high precision accordingly, so that the workpiece The position and attitude accuracy of 14 is kept within 5 microns;

Step 6: Combine the mapping relationship between the single pulse energy and the processing depth, layer the three-dimensional structure through the three-dimensional structure layering software, and select the most reasonable layering method;

Step 7. Realize three-dimensional structure processing with different depths and different roughnesses by means of orthogonal layer-by-layer scanning and variable single-pulse energy mode;

7.1) According to the layering result, the two-dimensional scanning galvanometer 12 realizes single-layer scanning processing in the X direction;

7.2) After the scanning in the X direction is completed, move the processing platform 15 in the XY coordinate plane, so that the confocal displacement sensor 13 is moved to the scanning processing area in the X direction, according to the real-time display value of the confocal displacement sensor 13 The difference between the displayed value and the calibration value, Move the Z axis of the machine tool so that the laser focus 11 follows the machined surface;

7.3) The confocal displacement sensor 13 re-measures the scanning processing area in the X direction, and the processed topography is precisely measured by the confocal displacement sensor 13, and it is obtained that the processing depth of the three-dimensional structure after processing is 6 μm and the bottom topography fluctuation difference is about 2 μm, adjust the position of the laser focus 11 according to the value of the confocal displacement sensor 13, so that the laser focus 11 follows the machined surface with high precision, and the difference between the displayed value of the confocal displacement sensor 13 and the initial 0 value is within 0.5 μm;

7.4) Select the laser single-pulse energy according to the 2μm difference in the topography of the bottom of the processed layer to achieve Y-direction single-layer scanning processing. Under this parameter, the laser can only remove materials with a depth of 3μm;

7.5) After the scanning in the Y direction is completed, move the processing platform 15 in the XY coordinate plane, so that the confocal displacement sensor 13 moves to the scanning processing area in the Y direction, and moves according to the difference between the real-time display value of the confocal displacement sensor 13 and the calibration value. The Z axis of the machine tool, so that the laser focus 11 follows the machined surface;

7.6) The confocal displacement sensor 13 re-measures the scanning processing area in the Y direction, and obtains the topographic data of the scanning processing area in the Y direction. From this data analysis, the depth and roughness of the processing area can be obtained, which is the single pulse of the next layer. The energy selection provides the basis; move the processing platform 15 in the XY coordinate plane to make the laser focus 11 return to the initial position;

Step 8: Repeat step 7, and repeat the process for about 20 times to achieve precise machining of a three-dimensional structure with a depth of 150 μm and a roughness Ra of 0.15.

Claims (5)

1. A three-dimensional shape precise control processing method is characterized by comprising the following steps:

the method comprises the following steps that firstly, a confocal displacement sensor is arranged on a laser processing head, and the laser processing head comprises a two-dimensional scanning galvanometer and a telecentric flat field lens;

step two, the laser processing head performs trial processing on the single-layer material, and determines the laser single-pulse energy and the pulse overlapping rate range for processing the material;

step three, after the pulse overlapping rate is determined, establishing a mapping relation between the laser single pulse energy and the processing depth and the bottom surface roughness;

finding a laser focus, calibrating the relative position between the confocal displacement sensor and the laser focus to obtain a calibrated value of the confocal displacement sensor, and recording the coordinate value of the XY axis of the processing platform as the initial position of the laser focus at the same time;

placing the workpiece on a processing platform, and adjusting the spatial posture of the workpiece to enable a plane formed by four corners of the workpiece to be parallel to an XY coordinate plane of the processing platform;

step six, layering the three-dimensional structure of the workpiece according to the mapping relation between the laser single pulse energy and the processing depth acquired in the step three;

seventhly, according to the layering result of the sixth step, three-dimensional structure processing with different depths and different roughness is realized through orthogonal layer-by-layer scanning and a single pulse energy changing mode;

7.1) selecting laser single pulse energy and pulse overlapping rate corresponding to the processing depth according to the layering result, and realizing single-layer scanning processing in the X direction by the two-dimensional scanning galvanometer, wherein the laser single pulse energy for realizing the X-direction scanning processing is a;

7.2) after the X-direction scanning is finished, moving the processing platform in an XY coordinate plane, moving the confocal displacement sensor to an X-direction scanning processing area, and moving the Z axis of the machine tool according to the difference value between the real-time display value and the calibration value of the confocal displacement sensor to enable the laser focus to follow the processed surface;

7.3) the confocal displacement sensor measures the X-direction scanning processing area again, measures the shape data of the X-direction scanning processing area to obtain the depth and the roughness of the X-direction scanning processing area, and moves the processing platform in an XY coordinate plane to return the laser focus to the initial position;

7.4) selecting proper laser single pulse energy and pulse overlapping rate to realize Y-direction single-layer scanning according to the measured depth and roughness of the X-direction scanning processing area, wherein the Y-direction scanning processing laser single pulse energy is b, and b is less than a;

7.5) after the Y-direction scanning is finished, moving the processing platform in an XY coordinate plane to move the confocal displacement sensor to a Y-direction scanning processing area, and moving the Z axis of the machine tool according to the difference value between the real-time display value and the calibration value of the confocal displacement sensor to enable the laser focus to follow the processed surface;

7.6) the confocal displacement sensor measures the Y-direction scanning processing area, the shape data of the Y-direction scanning processing area is obtained through measurement, the depth and the roughness of the Y-direction scanning processing area are obtained, and a basis is provided for the selection of the laser single pulse energy of the next layer; moving the processing platform in the XY coordinate plane to return the laser focus to the initial position;

and step eight, repeating the step seven, and realizing the precision machining of the three-dimensional structure with certain structural depth and roughness requirements.

2. The method for accurately controlling the processing of the three-dimensional profile according to claim 1, wherein: and fifthly, placing the workpiece on the processing platform, moving the processing platform, measuring the spatial positions of four corners of the workpiece by the confocal displacement sensor, and adjusting the spatial posture of the workpiece according to the data measured by the confocal displacement sensor so that the plane formed by the four corners of the workpiece is parallel to the XY coordinate plane of the processing platform, thereby completing the high-precision positioning and reference correction of the workpiece.

3. The method for precisely controlling and processing the three-dimensional shape according to claim 2, wherein: in the first step, the focal length of the telecentric field lens is within 60 mm.

4. The method for precisely controlling the three-dimensional profile according to claim 1, 2 or 3, wherein: in the step 7.4), a is 2-4 times of b.

5. The method for precisely controlling and processing the three-dimensional topography of claim 4, wherein: in the second step, within the parameters of the pulse overlapping rate range, the surface of the processed material has no recast layer, no microcrack and no recrystallization, and the surface roughness Ra of the processed area is less than or equal to 0.2.

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