High-dynamic five-axis laser processing device based on double optical wedges

Abstract

The invention provides a high-dynamic five-axis laser processing device based on double optical wedges, which can effectively improve the performance of five-axis laser processing equipment, and comprises a laser generator, a light field regulation and control module, a double-optical-wedge light beam offset module, a focusing and beam expanding module, a spectroscope, an observation system, a scanning module, a focusing module, a motion platform, a control system and operation software. The laser generator generates a laser beam, and the laser beam enters the double-optical-wedge light beam offset module after being regulated and controlled by the light field regulation and control module. The double-optical-wedge light beam deviation module deviates a laser beam from an optical axis, and the laser beam is parallel to the optical axis and enters the focusing and beam expanding module; the focusing and beam expanding module amplifies the off-axis amount of the laser beam and changes the divergence angle and diameter of the laser beam; then the laser beam enters the scanning module through the spectroscope; the laser beam is not parallel to the optical axis after passing through the scanning module, and finally the laser beam is transmitted to the machining surface on the motion platform after being focused through the focusing module.

Description

Technical Field

[0001] The invention relates to the technical field of laser processing, and in particular to a high-dynamic five-axis laser processing device based on double optical wedges. Background Art

[0002] With the rapid development of high-end technologies such as modern manufacturing and intelligent sensing, the demand for precision manufacturing and processing of their core components is growing, and microstructures have been widely used in core components in various fields, such as high aspect ratio micropores and micropore arrays in aerospace engine injection components, air film holes in aerospace engine blades, and complex positive and negative taper functional microstructures of sensitive units in flexible sensors. Currently commonly used precision machining technologies, such as mechanical machining, electrical discharge machining, energy field assisted machining, and electrochemical machining, are usually difficult to achieve precision machining of complex microstructures due to factors such as machining accuracy, efficiency, and process complexity. Although ion beam etching and electron beam etching can perform high-precision machining, their machining efficiency and processing cost are high, and they have high requirements for the machining environment. Photolithography technology has strong processing capabilities and is widely used in the processing of semiconductor chips, micro-electromechanical systems, and photonic devices, but its equipment cost is expensive, the processing technology is complex, and its adaptability to materials is limited, which seriously restricts its application scope. Additive manufacturing technology is one of the most commonly used methods for manufacturing complex microstructures. The microstructures that can be processed have a high degree of freedom in design and a high material utilization rate. It belongs to additive processing, but it is difficult to achieve processing results for larger components. There are also great limitations in material selection, low processing efficiency, and secondary processing and treatment are usually required.

[0003] Laser processing is a manufacturing method that uses the interaction between a high-energy-density laser beam and a material to achieve material removal. It has outstanding advantages such as high precision, high efficiency, non-contact processing, and wide material adaptability. It has been widely used in precision manufacturing of microstructures in various fields. However, the commonly used two-axis or three-axis laser processing can only control the movement of the laser focus, but cannot control the movement of the laser beam, and the degree of freedom of movement is small. At the same time, due to the Gaussian distribution of the laser beam's own energy, the processed microholes or processed surfaces are in the shape of positive cones, and it is difficult to control and eliminate the cone surface. It is also impossible to process complex microstructures such as straight-wall holes or negative-taper microstructures. Five-axis laser can control the angles α and β between the laser beam and the planes XOZ and YOZ. The beam inclination can be adjusted in real time according to the structural characteristics and processing depth to control the shape and morphological characteristics of the processed surface, thereby achieving high-quality processing of various complex microstructures, such as high-aspect-ratio straight-wall holes, negative-taper holes, special-shaped holes and slots, and positive and negative-taper surface microstructures.

[0004] There are many ways to implement five-axis lasers in the currently disclosed patents, each with unique advantages and disadvantages. Five-axis lasers that combine 2D or 3D galvanometers with multi-dimensional motion platforms usually have low processing efficiency and are difficult to control synchronously, and it is difficult to achieve fixed focus deflection. For five-axis lasers implemented using optical components, common four-galvanometer and six-galvanometer reflective five-axis laser devices have problems such as damage and aging of the reflective film, complex control, or large device space; flat-plate refractive five-axis laser devices have problems such as thick flat plates and poor dynamic performance. Therefore, the development of a high-dynamic five-axis laser processing device based on a double optical wedge can effectively improve the performance of five-axis laser processing equipment, thereby broadening the application range of five-axis lasers. Summary of the invention

[0005] In view of the above-mentioned problems and the needs of practical applications, the present invention provides a high-dynamic five-axis laser processing device based on dual optical wedges, which realizes the offset of the laser beam in two directions through two optical wedges, thereby controlling the α and β angles of the focused laser beam, and the optical wedge has a small inertia and high dynamic performance; in the focusing and beam expanding module of the device, the focusing and beam expanding parts jointly realize the beam diameter adjustment, the focus Z-axis position adjustment and the beam offset amplification, and by distributing the beam diameter adjustment in the focusing and beam expanding parts, the focus Z-axis high dynamic response and the large beam offset amplification are achieved.

[0006] In order to solve the above technical problems, the present invention provides a high-dynamic five-axis laser processing device based on double optical wedges, including a laser generator, a light field control module, a double optical wedge beam offset module, a focusing and beam expansion module, a spectroscope, an observation system, a scanning module, a focusing module, a motion platform, a control system and operating software;

[0007] The laser generator generates a laser beam, and the laser beam enters the double-wedge beam offset module after being regulated by the light field regulation module; the double-wedge beam offset module deviates the laser beam from the optical axis, and the laser beam is parallel to the optical axis and enters the focusing and beam expansion module; the focusing and beam expansion module amplifies the off-axis amount of the laser beam and changes the divergence angle and diameter of the laser beam; then the laser beam enters the scanning module through the beam splitter; the laser beam is not parallel to the optical axis after passing through the scanning module, and finally the laser beam is focused by the focusing module and transmitted to the processing surface on the motion platform;

[0008] The Z axis is set along the propagation direction of the laser beam, and an XYZ space coordinate system is established with the Z axis. The projection angles of the angle between the laser beam and the Z axis on the XOZ and YOZ planes are set to α and β; a first XYZ space coordinate system is established before the laser beam enters the scanning module, and a second XYZ space coordinate system is established after the laser beam enters the scanning module;

[0009] The light field control module includes a spatial light modulator for laser modulation;

[0010] The dual-wedge beam offset module includes a first optical wedge and a second optical wedge for beam offset; the first optical wedge can be translated along the Z axis, and the first optical wedge and the second optical wedge can be rotated around the Z axis;

[0011] The focusing and beam expansion module includes a plurality of lenses, one of which is movable along the Z-axis direction to change the divergence angle of the laser beam;

[0012] The observation system includes a CCD camera and a lens, and the laser beam is reflected by the beam splitter and then passes through the lens and forms an image on the CCD camera;

[0013] The scanning module includes two reflective mirrors and two galvanometer mirrors, the two reflective mirrors are placed at 45 degrees and clamped on the galvanometer mirrors, and the rotation axes of the two galvanometer mirrors are orthogonal;

[0014] The focusing module includes a lens group, which is used to deviate the laser beam from the Z axis and adjust α and β;

[0015] The motion platform is capable of motion in three axes, XYZ; the control system receives control instructions from the operating software, which is used for coordinated control of the dual wedge beam offset module, the focusing and beam expansion module, and the scanning module, and controls the motion of the motion platform.

[0016] In a preferred embodiment, the laser generator uses a green femtosecond laser or an infrared femtosecond laser;

[0017] The wavelength of the laser generator is 535nm-1064nm, the power is ≤50W, the pulse width is adjustable from 125fs to 1ps, the repetition frequency is adjustable from 100kHz to 2000kHz, and the beam diameter is 0.5mm-4mm.

[0018] In a preferred embodiment, the first optical wedge and the second optical wedge are placed in parallel, and the central axes of the first optical wedge and the second optical wedge coincide with the laser beam before the offset;

[0019] The two opposite side surfaces of the first optical wedge and the second optical wedge are inclined surfaces, and the two inclined surfaces are parallel to each other.

[0020] In a preferred embodiment, the first optical wedge and the second optical wedge rotate synchronously along the Z-axis direction; the first optical wedge and the second optical wedge rotate by means of magnetic suspension or air bearing;

[0021] The first optical wedge is translated in the Z-axis direction by means of a voice coil motor or a linear motor.

[0022] In a preferred embodiment, the first optical wedge moves along the Z-axis direction to adjust the distance between the first optical wedge and the second optical wedge to control the off-axis amount of the laser beam; assuming that the off-axis amount of the laser beam is Δd;

[0023] The calculation formula is:

[0024] Where i is the wedge angle, n i is the refractive index of the optical wedge, j is the refraction angle of the laser beam in the air, n j is the refractive index of air, l 1 and l 2 Represent the initial distance and the distance after moving of the first optical wedge and the second optical wedge respectively.

[0025] In a preferred embodiment, the wedge angle of the first optical wedge is the same as the wedge angle of the second optical wedge, and the angle of the optical wedge is set at 30°-41°;

[0026] The effective diameter range of the first optical wedge is 1 mm-20 mm; the effective diameter range of the second optical wedge is 10 mm-50 mm.

[0027] In a preferred embodiment, let the rotation angle of the first optical wedge and the second optical wedge be θ, let the off-axis amount of the laser beam on the OX axis and the OY axis be Δd x , Δd y ;

[0028] The calculation formula is:

[0029] In a preferred embodiment, the focusing and beam expanding module includes a focusing part and a beam expanding part, and the focusing part and the beam expanding part both include two concave lenses and one convex lens;

[0030] One of the two concave lenses in the focusing part is movable along the Z-axis direction.

[0031] In a preferred embodiment, the two reflectors are deflectable, and the deflection angle is 0°-(±10°).

[0032] In a preferred embodiment, the lens group of the focusing module is a focusing lens group or a telecentric field lens or an F-θ field lens.

[0033] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0034] 1. The present invention provides a high-dynamic five-axis laser processing device based on a double wedge, and the device includes a laser generator, a light field control module, a double wedge beam offset module, a focusing and beam expansion module, a reflector, a scanning module, a focusing module, an observation system, a motion platform and a control system. The light field control module is used for modulating the laser phase, polarization state, amplitude, energy distribution, etc. to improve the processing quality; the double wedge beam offset module can achieve high dynamic response of the off-axis offset of the beam; the focusing and beam expansion module is used to realize the amplification of the off-axis offset of the beam and change the Z-axis position of the laser focus; the motion platform can realize large-scale splicing processing. The present invention can be used for high-quality and efficient processing of straight-walled, positive and negative taper high-aspect ratio microholes and hole groups, such as microholes of aerospace injection components, air film holes of aircraft engines, etc.; it can be used for the processing of complex surface microstructures, such as the sensitive layer microstructure of flexible sensors, hydrophobic and oleophobic functional surfaces, etc.

[0035] 2. Compared with the commonly used 2D and 3D laser processing equipment, it can independently control the inclination angle of the laser beam, has a higher degree of processing freedom, and can be combined with advanced laser processing technology to achieve one-time laser processing of various straight walls, negative cone microholes or special-shaped complex and difficult-to-process microstructures, effectively improving the processing capabilities of current laser processing technology.

[0036] 3. The present invention sets a light field control module to adjust parameters such as laser beam energy distribution, polarization state and phase according to the processing requirements of different complex microstructures, thereby effectively improving the processing capability of the device of the present invention.

[0037] 4. The offset module in the present invention uses a double optical wedge to achieve beam offset, and uses two optical wedges to achieve offset in two directions, thereby improving the compactness of the device; the beam offset is achieved by using the refraction principle, thereby avoiding the high requirements of high-power lasers on the damage threshold of the reflector, thereby improving the universality of different lasers.

[0038] 5. The offset module in the present invention uses a double optical wedge to achieve beam offset. The first optical wedge only needs to allow the light beam to pass through, so its format is relatively small (minimum diameter 1mm). The size of the second optical wedge only needs to meet a smaller offset amount, and the format can also be made smaller (minimum diameter 10mm). The double optical wedges work together to achieve high dynamic processing of the invention device.

[0039] 6. The focusing and beam expanding module in the present invention adopts the form of separating focusing and beam expanding, and the focusing part that needs to be moved is placed in front of the fixed beam expanding part. The movable lens size of the focusing module is relatively small, which meets the high dynamic adjustment requirements of the laser focus Z axis; focusing and beam expanding work together to amplify the offset twice, thereby realizing the control of a larger inclination angle of the laser beam.

[0040] 7. The core part of the device of the present invention is modularized, there is no complex coupling relationship between the modules, and there are many market-productized modules, which facilitates the rapid integration and maintenance of the device of the present invention and saves equipment integration time and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a structural schematic diagram of a five-axis laser processing device in a preferred embodiment of the present invention;

[0042] Figure 2 It is a schematic diagram of the five-axis laser processing principle in a preferred embodiment of the present invention;

[0043] Figure 3 A schematic diagram of a double wedge beam deviation module for achieving beam deviation in a preferred embodiment of the present invention;

[0044] Figure 4 This is a data diagram showing the effect of the wedge angle and distance on the offset in a preferred embodiment of the present invention;

[0045] Figure 5 Schematic diagram of high dynamic control of the first optical wedge and the second optical wedge in a preferred embodiment of the present invention;

[0046] Figure 6 This is a schematic diagram of the working principle of the focusing and beam expanding module in a preferred embodiment of the present invention;

[0047] Figure 7 It is a schematic diagram of the working principle of the beam offset amplification of the focusing and beam expanding module in the preferred embodiment of the present invention;

[0048] Figure 8 This is a schematic diagram of the focusing working principle of the focusing and beam expanding module in a preferred embodiment of the present invention;

[0049] Fig. 9 It is a schematic diagram of processing a negative taper structure in a preferred embodiment of the present invention.

[0050] Explanation of the accompanying drawings: 1. Laser generator; 2. Laser beam; 21. Projection of the laser beam on the YOZ plane; 22. Projection of the laser beam on the XOZ plane; 3. Light field control module; 4. Double wedge beam offset module; 41. First wedge; 42. Second wedge; 5. Focusing and beam expansion module; 51. Focusing part; 511. First concave lens; 512. Second concave lens; 513. Third convex lens; 52. Beam expansion part; 521. Monoconcave lens; 522. Diconcave lens; 523. Triconvex lens; 6. Spectrometer; 7. Observation system; 8. Scanning module; 9. Focusing module; 10. Motion platform; 11. Control system; 12. Operating software; 13. Workpiece; 14. Negative cone microstructure. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0052] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0053] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installed", "provided with", "mounted / connected", "connected", etc. should be understood in a broad sense. For example, "connection" can be a wall-mounted connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention should be understood according to specific circumstances.

[0054] Example 1

[0055] refer to Figure 1-Figure 9 This embodiment provides a high-dynamic five-axis laser processing device based on a double wedge, including a laser generator 1, a light field control module 3, a double wedge beam offset module 4, a focusing and beam expansion module 5, a spectroscope 6, an observation system 7, a scanning module 8, a focusing module 9, a motion platform 10, a control system 11 and an operating software 12. This device can be used for high-quality and high-efficiency processing of straight-walled, positive and negative taper high-aspect ratio microholes and hole groups, such as microholes of aerospace injection components, air film holes of aircraft engines, etc.; it can be used for processing complex surface microstructures, such as sensitive layer microstructures of flexible sensors, hydrophobic and oleophobic functional surfaces, etc.

[0056] In this embodiment, the Z axis is set along the propagation direction of the laser beam 2, and the XYZ space coordinate system (such as Figure 1), assume that a first XYZ space coordinate system is established before the laser beam 2 enters the scanning module 8, and assume that a second XYZ space coordinate system is established after the laser beam 2 enters the scanning module 8. According to the projection 21 of the laser beam on the YOZ plane and the projection 22 of the laser beam on the XOZ plane, assume that the projection angles of the laser beam 2 and the Z axis on the XOZ and YOZ planes are α and β (such as Figure 2 ), wherein the laser beam 2 parallel to the optical axis affects α and β of the laser beam 2 after passing through the focusing module 9, the laser beam 2 not parallel to the optical axis affects X and Y of the focus after passing through the focusing module 9, and the divergence angle of the laser beam 2 after passing through the focusing module 9 affects Z of the focus.

[0057] The laser generator 1 generates a laser beam 2, which passes through the light field control module 3, and the light field control module 3 controls the optical physical properties of the laser beam 2, and then enters the double wedge beam offset module 4; the double wedge beam offset module 4 offsets the laser beam 2 to deviate from the optical axis, and the laser beam 2 is parallel to the optical axis, and then enters the focusing and beam expansion module 5; the focusing and beam expansion module 5 amplifies the off-axis amount of the laser beam 2 (the off-axis amount is the offset amount of the laser beam 2) and changes the divergence angle and diameter of the laser beam 2; then the laser beam 2 passes through the beam splitter 6 and enters the scanning module 8; after passing through the scanning module 8, the laser beam 2 is not parallel to the optical axis, and the X and Y plane position control of the beam is realized; finally, the laser beam 2 is focused by the focusing module 9 and transmitted to the processing surface on the motion platform 10; the focusing module 9 realizes the control of α, β and Z, wherein α and β act together with the focusing module 9 according to the off-axis amount in the X and Y directions, and Z acts together with the focusing module 9 according to the beam divergence angle.

[0058] The laser beam 2 is a parallel beam generated by a laser generator 1, which is then transmitted through different modules until it is transmitted to the processing surface on the motion platform 10. The wavelength of the laser generator 1 is 535nm-1064nm, the power is ≤50W, the pulse width is 125fs-1ps adjustable, the repetition frequency is 100kHz-2000kHz adjustable, and the beam diameter is 0.5mm-4mm. The laser generator 1 is a parallel light source with different wavelengths, powers, pulse widths and other parameters that can be selected according to actual processing requirements.

[0059] The light field control module 3 includes optical elements such as a spatial light modulator, and uses an electrical drive signal to modulate the laser phase, polarization state, amplitude, energy distribution, etc. to improve processing quality.

[0060] The dual-wedge beam shift module 4 can achieve high dynamic response of off-axis beam shift. The dual-wedge beam shift module 4 includes a first wedge 41 and a second wedge 42 (such as Figure 3), for beam offset, the first optical wedge 41 and the second optical wedge 42 are of different sizes. The first optical wedge 41 can be translated along the Z axis, and the first optical wedge 41 and the second optical wedge 42 can be rotated around the Z axis. The optical axis of the laser beam 2 can be quickly translated in two directions in the XOY plane through the movement and rotation of the optical wedge, thereby achieving the optical axis offset of the beam. After passing through the focusing module 9, the laser beam 2 deviates from the Z axis to achieve α and β deflection angle control.

[0061] The first optical wedge 41 moves along the Z-axis direction to adjust the distance between the first optical wedge 41 and the second optical wedge 42 to control the off-axis amount of the laser beam 2; assuming that the moving distance of the first optical wedge 41 is Δl, and the off-axis amount of the laser beam 2 is Δd;

[0062] The calculation formula is:

[0063] Where i is the wedge angle, n i is the refractive index of the wedge, j is the refraction angle of the laser beam 2 in the air, n j is the refractive index of air, l 1 and l 2 They represent the initial distance and the distance after movement of the first optical wedge 41 and the second optical wedge 42 respectively.

[0064] The optical materials of the first optical wedge 41 and the second optical wedge 42 can be commonly used N-BK7, K9 and other materials, and the wedge angle of the first optical wedge 41 is the same as the wedge angle of the second optical wedge 42, and the angle of the optical wedge is set at 30°-41°. Figure 4 As shown, in this embodiment, N-BK7 is selected as the optical wedge material, and its optical wedge angle i and the moving distance Δl of the first optical wedge 41 are calculated. The calculation shows that the appropriate optical wedge angle is 30° to 41°, and when the optical wedge angle i=41°, the proportionality coefficient of the optical wedge moving distance Δl and the off-axis amount Δd can reach more than 5, which is more conducive to the realization of high dynamic performance.

[0065] like Figure 5 , the first optical wedge 41 and the second optical wedge 42 are placed in parallel, and the central axes of the first optical wedge 41 and the second optical wedge 42 coincide with the laser beam 2 before entering the double optical wedge beam shift module 4 (the laser beam 2 before shifting). The two opposite side surfaces of the first optical wedge 41 and the second optical wedge 42 are inclined surfaces, and the two inclined surfaces are parallel to each other.

[0066] The change in the distance between the first optical wedge 41 and the second optical wedge 42 along the Z axis can only achieve the deflection of the laser beam 2 in one of the directions OX or OY. In order to reduce the complexity and control difficulty of the five-axis device, the first optical wedge 41 (41) and the second optical wedge 42 (42) are set to rotate synchronously along the Z axis. The rotation angle is θ, and the deflection amount of the laser beam 2 in the OX axis and the OY axis is Δd. x , Δdy :

[0067] The calculation formula is:

[0068] The first optical wedge 41 only needs to pass through the laser beam 2, so its effective diameter is small. The first optical wedge 41 can be moved to change the distance between the first optical wedge 41 and the second optical wedge 42. The moving distance is Δl. Then, the off-axis distance Δd of the laser beam 2 on the OX axis is assumed to be x and the off-axis distance Δd on the OY axis y :

[0069] The calculation formula is

[0070] The effective diameter range of the first optical wedge 41 is 1mm-20mm, with small inertia and high dynamic performance, and the effective diameter range of the second optical wedge 42 is 10mm-50mm, which can be selected according to actual needs. The synchronous rotation of the first optical wedge 41 and the second optical wedge 42 around the Z axis can be achieved by magnetic suspension or air bearing, and the translation of the first optical wedge 41 along the Z axis is achieved by a voice coil motor or a linear motor.

[0071] The focusing and beam expansion module 5 is used to realize the off-axis offset amplification of the light beam and change the Z-axis position of the laser focus. The focusing and beam expansion module 5 includes a plurality of lenses, one of which is movable along the Z-axis direction, and is used to change the divergence angle of the laser beam 2. By moving one of the lenses, the divergence angle of the light beam is changed in a small range to realize the movement of the laser focus in the Z-axis direction; a plurality of surface lenses have a beam expansion function, which can change the beam diameter and also expand the off-axis amount of the laser beam 2 relative to the Z-axis offset by the double wedge beam offset module 4.

[0072] like Figure 6 The working principle of the focusing and beam expanding module 5 mainly includes three functions: adjusting the diameter of the laser beam 2, amplifying the offset of the laser beam 2, and adjusting the divergence angle of the laser beam 2. The focusing and beam expanding module 5 includes a focusing part 51 and a beam expanding part 52. The laser beam 2 enters the beam expanding part 52 after passing through the focusing part 51. The focusing part 51 and the beam expanding part 52 both include two concave lenses and one convex lens. One of the two concave lenses of the focusing part 51 can move along the Z-axis direction.

[0073] Specifically, the focusing part 51 includes a first concave lens 511, a second concave lens 512 and a third convex lens 513, wherein the second concave lens 512 and the third convex lens 513 work together to correct aberrations; the diameter of the first concave lens 511 is 5mm-10mm, with small inertia and high dynamic performance, and the first concave lens 511 can move at high speed along the Z axis. By adjusting the distance between the concave lens and the convex lens, the beam divergence angle can be changed, which is used to focus the movement of the laser focus in the Z axis direction. The beam expansion part 52 includes a concave lens 521, a second concave lens 522 and a third convex lens 523, wherein the second concave lens 522 and the third convex lens 523 work together to correct aberrations.

[0074] The focusing part 51 has high dynamic performance and has the functions of beam expansion and amplification offset. After that, a fixed-multiplier beam expansion part 52 is added to realize secondary beam expansion and offset amplification, which can meet both high dynamic requirements and large offset requirements. Assume that the beam expansion multiple of the focusing part 51 is M 1 The beam expansion part 52 has a beam expansion factor of M. 2 Adjusting the diameter of the laser beam 2 can improve the beam quality and reduce the size of the laser focus spot. After the focusing and beam expansion module 5, the laser beam 2 has a magnification of M = M 1 ×M 2 .

[0075] The principle of amplifying the offset of laser beam 2 is as follows Figure 7 As shown, when the laser beam 2 passes through the double wedge beam offset module 4 to generate an offset of Δd and enters the focusing and beam expansion module 5, after two offset amplifications, the offset of the laser beam 2 entering the focusing module 9 is ΔD=Δd×M=Δd×M 1 ×M 2 The projection angles α and β of the laser beam 2 are linearly related to the offset ΔD entering the focusing module 9. Therefore, when large α and β need to be satisfied, only a small Δd is required after introducing the double amplification of the focusing and beam expansion module 5, and the double wedge beam offset module 4 only needs a small movement to achieve it, thereby reflecting the high dynamics of the equipment.

[0076] The principle of adjusting the divergence angle of laser beam 2 is as follows Figure 8 As shown, the focusing part 51 moves forward and backward along the Z axis through the first concave lens 511, so that the divergence angle of the laser beam 2 can change within a certain positive and negative angle. After the laser beam 2 with a divergence angle enters the focusing module 9, the focal length will change, causing the Z axis of the laser focus to change.

[0077] The observation system 7 includes a CCD camera and a lens. The laser beam 2 is reflected by the beam splitter 6 and then passes through the lens and is imaged on the CCD camera. The laser beam 2 reflected by the processing surface on the motion platform 10 passes through the lens after beam splitting and reflection, and finally forms an image of the processing area on the imaging CCD camera for processing positioning and real-time observation of the processing process.

[0078] The scanning module 8 includes two reflective mirrors and two galvanometer mirrors. The two reflective mirrors are placed at 45 degrees and clamped on the galvanometer mirrors. The rotation axes of the two galvanometer mirrors are orthogonal to achieve the control of the laser focus positions X and Y. The two reflective mirrors can be deflected. The deflection angle of the two reflective mirrors is 0°-(±10°), the deflection range is small, and the dynamic response characteristics are good.

[0079] The focusing module 9 includes a lens group, which is used to make the laser beam 2 deviate from the Z axis and adjust α and β. The lens group of the focusing module 9 can be a focusing lens group or a telecentric field lens or an F-θ field lens. The focusing module 9 is used to focus the laser beam 2, generate the deflection angle of the laser beam 2, and compensate for optical errors, etc.

[0080] The motion platform 10 has XYZ three-axis motion, realizes XYZ three-axis large-range high-precision motion, and realizes large-format splicing and large-format array processing. The control system 11 issues control instructions from the operating software 12 for the coordinated control of the dual-wedge beam offset module 4, the focusing and beam expansion module 5, and the scanning module 8, and controls the motion of the motion platform 10.

[0081] like Fig. 9 As shown, a schematic diagram of a negative taper structure is processed using the device of this embodiment. For this type of negative cone microstructure 14 that is difficult to process, the three-dimensional model of the negative cone microstructure 14 is first imported into the operating software 12 for slicing along the Z axis. The relevant control data sets of the scanning module 8 and the focusing and beam expansion module 5 are calculated based on the sliced ​​two-dimensional pattern coordinates (X, Y) and the Z-axis position. The control data set of the dual wedge beam offset module 4 is calculated based on α and β explored according to the process parameters and sent to the control system 11. Subsequently, the workpiece 13 is placed on the motion platform 10 for processing, thereby realizing high-quality and rapid five-axis laser processing of the negative cone structure.

[0082] Example 2

[0083] In this embodiment, the high-dynamic five-axis laser processing device based on double wedges is basically the same as that in Embodiment 1, except that: a green light femtosecond laser with a power of 50 W, a pulse frequency of 100 kHz, and a pulse width of 500 fs is used to make an air film hole with a diameter of 300 μm and a depth of 150 mm on the aero-engine blade, the air film hole is modeled and imported into the operating software 12, the air film hole model is sliced ​​and the processing path is planned, the thickness of a single-layer slice is 500 μm, and the single-layer path adopts a spiral scanning processing method to improve the processing efficiency. The pitch is set to 5 μm, α=β=0° at the center, and gradually increases from the inside to the outside. The outermost circle of the first layer α=β=-3°, and then a single-layer trimming scan is performed; as the Z axis moves downward, the outermost circle α and β of the single-layer slice increase in gradient, and the outermost circle at the bottom α=β=-4° to compensate for the problem of blocking the laser beam 2 with increasing depth, and finally, up and down spiral scanning and trimming are performed, so as to efficiently and high-quality process the air film holes on the aero-engine blade.

[0084] Example 3

[0085] In this embodiment, the high-dynamic five-axis laser processing device based on dual wedges is basically the same as that in Embodiment 1, except that an infrared femtosecond laser with a power of 10 W, a pulse frequency of 500 kHz, and a pulse width of 500 fs is used to process negative taper array microstructures on polymer surfaces such as PDMS. Since the laser has a certain focal depth, there is no need to adjust the laser focus Z axis or slice operation. The microstructure path is designed and the laser incident angle is planned. The array format is large, and the operating software 12 is required to allocate the path. After allocation, the control data set is solved and sent to the control system 11. The control system 11 controls the motion platform 10 and the dual wedge beam offset module 4, the scanning module 8, and the focusing and beam expansion module 5 respectively, and finally completes the efficient processing of the negative taper array microstructure on the polymer surface for functional surfaces such as super-hydrophobicity, anti-icing or electromagnetic shielding.

[0086] The above is only a preferred specific implementation of the present invention, but the design concept of the present invention is not limited to this. Any technician familiar with the technical field who uses this concept to make non-substantial changes to the present invention within the technical scope disclosed by the present invention shall be deemed to infringe the protection scope of the present invention.

Claims

1. A high-dynamic five-axis laser processing device based on a double optical wedge, characterized in that: Including laser generator, light field control module, double wedge beam offset module, focusing and beam expansion module, spectroscope, observation system, scanning module, focusing module, motion platform, control system and operating software; The laser generator generates a laser beam, and the laser beam enters the double-wedge beam offset module after being regulated by the light field regulation module; the double-wedge beam offset module deviates the laser beam from the optical axis, and the laser beam is parallel to the optical axis and enters the focusing and beam expansion module; the focusing and beam expansion module amplifies the off-axis amount of the laser beam and changes the divergence angle and diameter of the laser beam; then the laser beam enters the scanning module through the beam splitter; the laser beam is not parallel to the optical axis after passing through the scanning module, and finally the laser beam is focused by the focusing module and transmitted to the processing surface on the motion platform; The Z axis is set along the propagation direction of the laser beam, and an XYZ space coordinate system is established with the Z axis. The projection angles of the angle between the laser beam and the Z axis on the XOZ and YOZ planes are set to α and β; a first XYZ space coordinate system is established before the laser beam enters the scanning module, and a second XYZ space coordinate system is established after the laser beam enters the scanning module; The light field control module includes a spatial light modulator for laser modulation; The dual-wedge beam offset module includes a first optical wedge and a second optical wedge for beam offset; the first optical wedge can be translated along the Z axis, and the first optical wedge and the second optical wedge can be rotated around the Z axis; The focusing and beam expanding module includes a plurality of lenses, one of which is movable along the Z-axis direction to change the divergence angle of the laser beam; The observation system includes a CCD camera and a lens, and the laser beam is reflected by the beam splitter and then passes through the lens and forms an image on the CCD camera; The scanning module includes two reflective mirrors and two galvanometer mirrors, the two reflective mirrors are placed at 45 degrees and clamped on the galvanometer mirrors, and the rotation axes of the two galvanometer mirrors are orthogonal; The focusing module includes a lens group, which is used to deviate the laser beam from the Z axis and adjust α and β; The motion platform is capable of motion in three axes, XYZ; the control system receives control instructions from the operating software, which is used for coordinated control of the dual wedge beam offset module, the focusing and beam expansion module, and the scanning module, and controls the motion of the motion platform.

2. According to claim 1, a high-dynamic five-axis laser processing device based on double optical wedges is characterized in that: The laser generator adopts a green light femtosecond laser or an infrared femtosecond laser; The wavelength of the laser generator is 535nm-1064nm, the power is ≤50W, the pulse width is adjustable from 125fs to 1ps, the repetition frequency is adjustable from 100kHz to 2000kHz, and the beam diameter is 0.5mm-4mm.

3. The high-dynamic five-axis laser processing device based on double optical wedges according to claim 1, characterized in that: The first optical wedge and the second optical wedge are placed in parallel, and the central axes of the first optical wedge and the second optical wedge coincide with the laser beam before the offset; The two opposite side surfaces of the first optical wedge and the second optical wedge are inclined surfaces, and the two inclined surfaces are parallel to each other.

4. The high-dynamic five-axis laser processing device based on double optical wedges according to claim 3, characterized in that: The first optical wedge and the second optical wedge rotate synchronously along the Z-axis direction; the first optical wedge and the second optical wedge rotate by means of magnetic suspension or air bearing; The first optical wedge is translated in the Z-axis direction by means of a voice coil motor or a linear motor.

5. The high-dynamic five-axis laser processing device based on double optical wedges according to claim 4, characterized in that: The first optical wedge moves along the Z-axis direction to adjust the distance between the first optical wedge and the second optical wedge to control the off-axis amount of the laser beam; the off-axis amount of the laser beam is assumed to be Δd; The calculation formula is: Where i is the wedge angle, n i is the refractive index of the optical wedge, j is the refraction angle of the laser beam in the air, n j is the refractive index of air, l1 and l2 represent the initial distance and the distance after movement of the first and second optical wedges, respectively.

6. The high-dynamic five-axis laser processing device based on double optical wedges according to claim 5, characterized in that: The wedge angle of the first optical wedge is the same as the wedge angle of the second optical wedge, and the angle of the optical wedge is set at 30°-41°; The effective diameter range of the first optical wedge is 1 mm-20 mm; the effective diameter range of the second optical wedge is 10 mm-50 mm.

7. The high-dynamic five-axis laser processing device based on double optical wedges according to claim 5, characterized in that: Assume that the rotation angle of the first optical wedge and the second optical wedge is θ, and the off-axis amount of the laser beam on the OX axis and the OY axis is Δd x , Δd y ; The calculation formula is:

8. The high-dynamic five-axis laser processing device based on double optical wedges according to claim 1, characterized in that: The focusing and beam expanding module comprises a focusing part and a beam expanding part, and the focusing part and the beam expanding part both comprise two concave lenses and one convex lens; One of the two concave lenses in the focusing part is movable along the Z-axis direction.

9. The high-dynamic five-axis laser processing device based on double optical wedges according to claim 1, characterized in that: The two reflective mirrors are deflectable, and the deflection angle is 0°-(±10°).

10. The high-dynamic five-axis laser processing device based on double optical wedges according to claim 1, characterized in that: The lens group of the focusing module is a focusing lens group or a telecentric field lens or an F-θ field lens.

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