High-dynamic five-axis laser processing apparatus based on dual optical wedges

Abstract

The present invention provides a high-dynamic five-axis laser processing apparatus based on dual optical wedges, which can effectively improve the performance of a five-axis laser processing apparatus. The high-dynamic five-axis laser processing apparatus based on dual optical wedges comprises a laser generator, an optical field modulation module, a dual-optical-wedge-based beam deviation module, a focusing and beam expanding module, a beam splitter, an observation system, a scanning module, a focusing module, a motion platform, a control system, and operating software; the laser generator generates a laser beam, and the laser beam is modulated by the optical field modulation module and then enters the dual-optical-wedge-based beam deviation module; the dual-optical-wedge-based beam deviation module causes the laser beam to deviate from an optical axis, and the laser beam is parallel to the optical axis and then enters the focusing and beam expanding module; the focusing and beam expanding module amplifies the off-axis distance of the laser beam and changes the divergence angle and diameter of the laser beam; then the laser beam passes through the beam splitter into the scanning module; 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 then transmitted to a processing surface on the motion platform.

Description

A High-Dynamic Five-Axis Laser Processing Device Based on Dual Optical Wedges Technical Field

[0001] This invention relates to the field of laser processing technology, and in particular to a highly dynamic five-axis laser processing device based on a dual-wedge. Background Technology

[0002] With the rapid development of modern manufacturing and intelligent sensing technologies, the demand for precision manufacturing of their core components is increasing. Microstructures are widely used in core components across various fields, such as high aspect ratio micropores and micropore arrays in aerospace engine injection components, film vents in aero-engine blades, and complex positive and negative taper functional microstructures in the sensitive units of flexible sensors. Currently used precision machining technologies, such as machining, electrical discharge machining, energy field-assisted machining, and electrochemical machining, are generally difficult to achieve precision machining of complex microstructures due to factors such as machining accuracy, efficiency, and process complexity. Ion beam etching and electron beam etching can achieve high-precision machining, but their processing efficiency and cost are high, and they have high requirements for the processing environment. Photolithography technology has strong processing capabilities and is widely used in the processing of semiconductor chips, microelectromechanical systems, and photonic devices, but its equipment costs are high, its 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. It offers high design freedom for the microstructures it can process and high material utilization. However, it is difficult to achieve the processing results of larger components, and it also has significant limitations in material selection. Furthermore, it has low processing efficiency and usually requires secondary processing and treatment.

[0003] Laser processing is a manufacturing method that uses the interaction between a high-energy-density laser beam and the material to remove material. It boasts significant advantages such as high precision, high efficiency, non-contact processing, and wide material adaptability, and has been widely applied in the precision manufacturing of microstructures across various fields. However, currently used two-axis or three-axis laser processing can only control the movement of the laser focus, not the entire laser beam, resulting in limited degrees of freedom. Furthermore, because the laser beam's energy is Gaussian distributed, the processed microholes or surfaces tend to be conical, making it difficult to control and eliminate the conical surface. It also cannot process complex microstructures such as straight-walled holes or negative-tapered microstructures. Five-axis laser processing, on the other hand, can control the angles α and β between the laser beam and the XOZ and YOZ planes. It can adjust the beam tilt angle in real time according to the structural characteristics and processing depth to control the shape and morphology of the processed surface, thereby achieving high-quality processing of various complex microstructures, such as high aspect ratio straight-walled holes, negative-tapered holes, irregularly shaped grooves, and positive and negative-tapered surface microstructures.

[0004] Currently, there are many publicly disclosed patents outlining five-axis laser processing methods, each with its own unique advantages and disadvantages. Five-axis lasers utilizing 2D or 3D galvanometers combined with a multi-dimensional motion platform typically have low processing efficiency, are difficult to synchronize and control, and struggle to achieve fixed-focus deflection. Five-axis lasers implemented using optical components, such as four-mirror and six-mirror reflective five-axis laser devices, suffer from problems like reflective film damage and aging, complex control, or large device space requirements. Planar refractive five-axis laser devices suffer from issues like thicker plates and poorer dynamic performance. Therefore, developing a high-dynamic five-axis laser processing device based on dual optical wedges 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] To address the aforementioned problems and practical application needs, this invention provides a high-dynamic five-axis laser processing device based on dual optical wedges. The two optical wedges achieve laser beam offset in two directions, thereby controlling the α and β angles of the focused laser beam. Furthermore, the wedges have low inertia and high dynamic performance. In this device, the focusing and beam-expanding module jointly achieves beam diameter adjustment, focal point Z-axis position adjustment, and beam offset amplification through focusing and beam expansion. By distributing beam diameter adjustment between the focusing and beam-expanding components, high dynamic response of the focal point Z-axis and significant beam offset amplification are achieved.

[0006] To address the aforementioned technical problems, this invention provides a high-dynamic five-axis laser processing device based on dual optical wedges, comprising a laser generator, a light field control module, a dual optical wedge beam shifting module, a focusing and beam expanding module, a beam splitter, an observation system, a scanning module, a focusing module, a motion platform, a control system, and operating software;

[0007] The laser generator produces a laser beam, which is then controlled by the optical field control module before entering the dual-wedge beam offset module. The dual-wedge beam offset module deflects the laser beam off the optical axis, making the laser beam parallel to the optical axis and entering the focusing and beam expanding module. The focusing and beam expanding module amplifies the off-axis amount of the laser beam and changes its divergence angle and diameter. Subsequently, the laser beam passes through the beam splitter and enters the scanning module. After passing through the scanning module, the laser beam is no longer parallel to the optical axis. Finally, the laser beam is focused by the focusing module and transmitted to the processing surface on the motion platform.

[0008] The direction of laser beam propagation is set as the Z-axis, and an XYZ spatial coordinate system is established with the Z-axis. The projection angles of the angle between the laser beam and the Z-axis onto the XOZ and YOZ planes are set as α and β, respectively. A first XYZ spatial coordinate system is established before the laser beam enters the scanning module, and a second XYZ spatial coordinate system is established after the laser beam enters the scanning module.

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

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

[0011] The focusing and beam expanding module includes several lenses, one of which is movable along the Z-axis to change the divergence angle of the laser beam.

[0012] The observation system includes a CCD camera and a lens. The laser beam is reflected by the beam splitter, passes through the lens, and is imaged on the CCD camera.

[0013] The scanning module includes two reflectors and two galvanometers. The two reflectors are placed at 45° and clamped on the galvanometers. The rotation axes of the two galvanometers are orthogonal.

[0014] The focusing module includes a lens group for deflecting the laser beam off the Z-axis and adjusting α and β;

[0015] The motion platform has movement in the XYZ three-axis directions; the control system issues control commands from the operating software to coordinate the control of the dual-wedge beam offset module, the focusing beam expansion module and the scanning module, and to control the movement of the motion platform.

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

[0017] The laser generator has a wavelength of 535nm to 1064nm, a power of ≤50W, an adjustable pulse width of 125fs to 1ps, an adjustable repetition frequency of 100kHz to 2000kHz, and a beam diameter of 0.5mm to 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 offset.

[0019] The two opposite sides of the first and second optical wedges are inclined planes, and the two inclined planes 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; the first optical wedge and the second optical wedge rotate by magnetic levitation or an air bearing-like mechanism.

[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 to adjust the distance between it and the second optical wedge, thereby controlling the off-axis amount of the laser beam; let the off-axis amount of the laser beam be Δd.

[0023] The calculation formula is:

[0024] Where i is the optical wedge angle, n i Let be the refractive index of the optical wedge, j be the angle of refraction of the laser beam in air, and n be the angle of refraction. j Let l1 be the air refractive index, and l2 represent the initial distance and the distance after the movement of the first and second optical wedges, respectively.

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

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

[0027] In a preferred embodiment, let the rotation angle of the first and second optical wedges be θ, and let the off-axis displacement of the laser beam along the OX and OY axes 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, both of which include two concave lenses and one convex lens;

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

[0031] In a preferred embodiment, the two reflectors can be deflected by an angle of 0°–(±10°).

[0032] In a preferred embodiment, the lens group of the focusing module is a focusing lens group, 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. This invention provides a high-dynamic five-axis laser processing device based on a dual-wedge laser beam offset module. The device includes a laser generator, a light field control module, a dual-wedge beam offset module, a focusing and beam expanding module, a mirror, a scanning module, a focusing module, an observation system, a motion platform, and a control system. The light field control module modulates the laser phase, polarization state, amplitude, and energy distribution to improve processing quality; the dual-wedge beam offset module achieves high-dynamic response to off-axis beam offset; the focusing and beam expanding module amplifies the off-axis beam offset and changes the Z-axis position of the laser focus; and the motion platform enables large-format splicing processing. This invention can be used for high-quality and high-efficiency processing of high-aspect-ratio microholes and hole groups with straight walls and positive / negative tapers, such as microholes in aerospace injection components and film vents in aero-engines; it can also be used for processing complex surface microstructures, such as the sensitive layer microstructure of flexible sensors and hydrophobic and oleophobic functional surfaces.

[0035] 2. Compared with commonly used 2D and 3D laser processing equipment, it can autonomously control the tilt 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-walled, negative-cone micro-holes or irregularly shaped complex and difficult-to-process micro-structures, effectively improving the processing capabilities of current laser processing technology.

[0036] 3. By setting up an optical field control module, the present invention can control parameters such as laser beam energy distribution, polarization state, and phase according to the processing requirements of processing different complex microstructures, effectively improving the processing capability of the device of the present invention.

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

[0038] 5. The offset module in this invention uses a double optical wedge to achieve beam offset. The first optical wedge only needs the beam to pass through, so its area is small (minimum diameter 1mm). The size of the second optical wedge only needs to meet a small offset amount, and its area can also be manufactured to be small (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 this invention adopts a separate focusing and beam expanding form, placing the focusing part that needs to be moved in front of the fixed beam expanding part. The lens size that the focusing module moves is small, which meets the high dynamic adjustment requirements of the laser focus Z-axis. The focusing and beam expanding work together to amplify the offset twice, realizing the control of a large tilt angle of the laser beam.

[0040] 7. The core components of the device of the present invention are modularized, with no complex coupling between the modules, and there are many commercially available modules, which facilitates the rapid integration and maintenance of the device of the present invention and saves equipment integration time and costs. Attached Figure Description

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

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

[0043] Figure 3 is a schematic diagram of the beam deflection principle achieved by the dual-wedge beam deflection module in a preferred embodiment of the present invention;

[0044] Figure 4 is a data graph showing the influence of optical wedge angle and distance on offset in a preferred embodiment of the present invention;

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

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

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

[0049] Figure 9 is a schematic diagram of the machining of the negative taper structure in a preferred embodiment of the present invention.

[0050] Explanation of reference numerals in the attached figures: 1. Laser generator; 2. Laser beam; 21. Projection of the laser beam in the YOZ plane; 22. Projection of the laser beam in the XOZ plane; 3. Optical field control module; 4. Dual-wedge beam shifting module; 41. First wedge; 42. Second wedge; 5. Focusing and beam expanding module; 51. Focusing section; 511. First concave lens; 512. Second concave lens; 513. Third convex lens; 52. Beam expanding section; 521. First concave lens; 522. Second concave lens; 523. Third convex lens; 6. Beam splitter; 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 Implementation

[0051] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0052] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0053] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. 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 or an indirect connection through an intermediate medium, or a connection within two components. For those skilled in the art, the specific meaning of the above terms in this invention should be understood according to the specific circumstances.

[0054] Example 1

[0055] Referring to Figures 1-9, this embodiment provides a high-dynamic five-axis laser processing device based on a dual-wedge, including a laser generator 1, a light field control module 3, a dual-wedge beam shifting module 4, a focusing and beam expanding module 5, a beam splitter 6, an observation system 7, a scanning module 8, a focusing module 9, a motion platform 10, a control system 11, and operating software 12. This device can be used for high-quality and high-efficiency processing of microholes and hole groups with straight walls and positive and negative tapers, such as microholes in aerospace injection components and film vents in aero-engines; it can also be used for processing complex surface microstructures, such as the sensitive layer microstructure of flexible sensors and hydrophobic and oleophobic functional surfaces.

[0056] In this embodiment, the direction of laser beam 2 propagation is set as the Z-axis, and an XYZ spatial coordinate system is established with the Z-axis (as shown in Figure 1). A first XYZ spatial coordinate system is established before laser beam 2 enters the scanning module 8, and a second XYZ spatial coordinate system is established after laser beam 2 enters the scanning module 8. Based on the projection 21 of the laser beam in the YOZ plane and the projection 22 of the laser beam in the XOZ plane, the projection angles of the angle between laser beam 2 and the Z-axis in the XOZ and YOZ planes are α and β (as shown in Figure 2). The laser beam 2 parallel to the optical axis affects α and β after passing through the focusing module 9, while the laser beam 2 not parallel to the optical axis affects the X and Y axes of the focal point after passing through the focusing module 9. The divergence angle of the laser beam 2 after passing through the focusing module 9 affects the Z axis of the focal point.

[0057] The laser generator 1 generates a laser beam 2, which passes through the optical field control module 3. The optical field control module 3 controls the optical physical properties of the laser beam 2, and then it enters the dual-wedge beam offset module 4. The dual-wedge beam offset module 4 offsets the laser beam 2, making it deviate from the optical axis and parallel to the optical axis. Then it enters the focusing and beam expanding module 5. The focusing and beam expanding module 5 amplifies the off-axis amount of the laser beam 2 (the off-axis amount is the offset 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 no longer parallel to the optical axis, realizing beam X and Y plane position control. 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, where α and β work together with the focusing module 9 based on the off-axis amount in the X and Y directions, and Z works together with the focusing module 9 based on the beam divergence angle.

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

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

[0060] The dual-wedge beam shifting module 4 enables high dynamic response for off-axis beam shifting. The dual-wedge beam shifting module 4 includes a first wedge 41 and a second wedge 42 (as shown in Figure 3) for beam shifting. The first wedge 41 and the second wedge 42 are of different sizes. The first wedge 41 can translate along the Z-axis, and the first wedge 41 and the second wedge 42 can rotate around the Z-axis. Through the movement and rotation of the wedges, the optical axis of the laser beam 2 is rapidly translated in two directions within the XOY plane, thereby achieving beam optical axis shifting. After passing through the focusing module 9, the laser beam 2 deviates from the Z-axis, achieving α and β deflection angle control.

[0061] The first optical wedge 41 moves along the Z-axis to adjust the distance between it and the second optical wedge 42, thereby controlling the off-axis amount of the laser beam 2; let the moving distance of the first optical wedge 41 be Δl, and the off-axis amount of the laser beam 2 be Δd;

[0062] The calculation formula is:

[0063] Where i is the optical wedge angle, n i Let be the refractive index of the optical wedge, j be the angle of refraction of laser beam 2 in air, and n be the angle of refraction. j Let l1 be the air refractive index, and l2 represent the initial distance and the distance after the 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 materials such as N-BK7 and K9. The wedge angle of the first optical wedge 41 is the same as that of the second optical wedge 42, and the angle of the wedge is set between 30° and 41°. As shown in Figure 4, in this embodiment, N-BK7 is selected as the optical material for the optical wedge, and its wedge angle i and the moving distance Δl of the first optical wedge 41 are calculated. The calculation shows that the suitable wedge angle is 30° to 41°. When the wedge angle i = 41°, the proportionality coefficient between the moving distance Δl of the optical wedge and the off-axis amount Δd can reach more than 5, which is more conducive to the realization of high dynamic performance.

[0065] As shown in Figure 5, the first optical wedge 41 and the second optical wedge 42 are placed in parallel, and the central axis of the first optical wedge 41 and the second optical wedge 42 coincides with the laser beam 2 before entering the dual optical wedge beam deflection module 4 (the laser beam 2 before deflection). The two opposite sides of the first optical wedge 41 and the second optical wedge 42 are inclined planes, and the two inclined planes are parallel to each other.

[0066] The change in distance between the first optical wedge 41 and the second optical wedge 42 along the Z-axis can only cause the laser beam 2 to deviate off-axis in either the OX or OY direction. To reduce the complexity and control difficulty of the five-axis device, this embodiment sets the first optical wedge 41 (41) and the second optical wedge 42 (42) to rotate synchronously along the Z-axis. Let the rotation angle be θ, and let the off-axis displacement of the laser beam 2 in the OX and OY axes be Δd.x , Δd y :

[0067] The calculation formula is:

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

[0069] The calculation formula is

[0070] The effective diameter of the first optical wedge 41 ranges from 1mm to 20mm, with low inertia and high dynamic performance. The effective diameter of the second optical wedge 42 ranges from 10mm to 50mm, and 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 levitation or air bearing-like method. The translation of the first optical wedge 41 along the Z-axis direction is achieved by voice coil motor or linear motor.

[0071] The focusing and beam-expanding module 5 is used to achieve off-axis beam amplification and change the Z-axis position of the laser focus. The focusing and beam-expanding module 5 includes several lenses, one of which is movable along the Z-axis to change the divergence angle of the laser beam 2. By moving one of the lenses, the beam divergence angle is changed within a small range, thus moving the laser focus along the Z-axis. The lenses have a beam-expanding function, which can both change the beam diameter and increase the off-axis displacement of the laser beam 2 relative to the Z-axis caused by the dual-wedge beam deflection module 4.

[0072] As shown in 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. Both the focusing part 51 and the beam expanding part 52 include two concave lenses and one convex lens. One of the two concave lenses in the focusing part 51 is movable along the Z-axis.

[0073] Specifically, the focusing section 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 first concave lens 511 has a diameter of 5mm-10mm, low inertia, and high dynamic performance, and can move at high speed along the Z-axis. By adjusting the distance between the concave and convex lenses, the beam divergence angle can be changed, which is used to focus the laser focal point in the Z-axis direction. The beam expanding section 52 includes a first 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 section 51 has high dynamic performance and features beam expansion and amplification offset functions. Adding a fixed-magnification beam expander 52 after it achieves secondary beam expansion and offset amplification, satisfying both high dynamic requirements and large offset requirements. Let the beam expansion factor of the focusing section 51 be M1, and the beam expander 52 be M2. Adjusting the diameter of the laser beam 2 can improve beam quality and reduce the size of the focused laser spot. After passing through the focusing and beam expanding module 5, the amplification factor of the laser beam 2 is M = M1 × M2.

[0075] The principle of amplifying the offset of laser beam 2 is shown in Figure 7. After laser beam 2 passes through the dual-wedge beam offset module 4 and generates an offset of Δd, it enters the focusing and beam expanding module 5. After two offset amplifications, the offset of laser beam 2 entering the focusing module 9 is ΔD = Δd × M = Δd × M1 × M2. The projection angles α and β of laser beam 2 are linearly related to the offset ΔD entering the focusing module 9. Therefore, when large α and β are required, only a smaller Δd is needed after the two amplifications introduced by the focusing and beam expanding module 5. The dual-wedge beam offset module 4 only needs a small amplitude movement to achieve this, thus demonstrating the high dynamics of the equipment.

[0076] The principle of adjusting the divergence angle of the laser beam 2 is shown in Figure 8. The focusing part 51 moves back and forth along the Z-axis through the first concave lens 511, which can make the divergence angle of the laser beam 2 change within a certain positive and negative angle. After the laser beam 2 with the divergence angle enters the focusing module 9, the focal length will change, which will change the Z-axis of the laser focus.

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

[0078] The scanning module 8 includes two reflectors and two galvanometers. The two reflectors are positioned at 45° and clamped onto the galvanometers. The rotation axes of the two galvanometers are orthogonal, enabling control of the laser focal point position in the X and Y directions. The two reflectors are deflectable, with a deflection angle of 0°–(±10°), exhibiting a small deflection range and good dynamic response characteristics.

[0079] The focusing module 9 includes a lens group for deflecting the laser beam 2 off the Z-axis and adjusting α and β. The lens group of the focusing module 9 can be a sampling focusing lens group, 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, realizing large-range high-precision XYZ three-axis motion, and realizing large-format splicing and large-format array processing. The control system 11 issues control commands from the operation software 12 for the coordinated control of the dual-wedge beam offset module 4, the focusing beam expander module 5 and the scanning module 8, and controls the motion platform 10.

[0081] As shown in Figure 9, a schematic diagram of a negative cone structure is fabricated using the device of this embodiment. For this type of negative cone microstructure 14, which is difficult to process, the three-dimensional model of the negative cone microstructure 14 is first imported into the operation software 12 and sliced ​​along the Z-axis. Based on the two-dimensional pattern coordinates (X, Y) and Z-axis position of the slice, the relevant control datasets of the scanning module 8 and the focusing beam expansion module 5 are calculated. Based on the α and β obtained from the process parameters, the control dataset of the dual-wedge beam offset module 4 is calculated and sent to the control system 11. Then, the workpiece 13 to be processed is placed on the motion platform 10 for processing, thereby realizing the five-axis laser high-quality and rapid processing of the negative cone structure.

[0082] Example 2

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

[0084] Example 3

[0085] In this embodiment, the high-dynamic five-axis laser processing device based on dual optical wedges is basically the same as that in Embodiment 1. The difference is that an infrared femtosecond laser with a power of 10W, a pulse frequency of 500kHz, and a pulse width of 500fs is used to process negative taper array microstructures of polymer surfaces such as PDMS. Since the laser has a certain depth of focus, it is not necessary to adjust the laser focus Z-axis or perform slicing operations. The laser incident angle is planned according to the designed microstructure path. Since the array area is large, the path allocation is required using the operation software 12. After allocation, the control dataset is calculated and sent to the control system 11. The control system 11 controls the motion platform 10, the dual optical wedge beam offset module 4, the scanning module 8, and the focusing and beam expanding module 5 respectively, and finally completes the efficient processing of negative taper array microstructures of polymer surfaces for use on functional surfaces such as superhydrophobic, anti-icing, or electromagnetic shielding surfaces.

[0086] The above description is merely a preferred embodiment of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention by those skilled in the art within the scope of the technology disclosed in the present invention using this concept shall be deemed as an infringement of the protection scope of the present invention.

Claims

1. A high dynamic five-axis laser machining device based on double optical wedge, characterized in that: It includes a laser generator, a light field control module, a dual-wedge beam shifting module, a focusing and beam expanding module, a beam splitter, an observation system, a scanning module, a focusing module, a motion platform, a control system, and operating software; The laser generator produces a laser beam, which is then controlled by the optical field control module before entering the dual-wedge beam offset module. The dual-wedge beam offset module deflects the laser beam off the optical axis, making the laser beam parallel to the optical axis and entering the focusing and beam expanding module. The focusing and beam expanding module amplifies the off-axis amount of the laser beam and changes its divergence angle and diameter. Subsequently, the laser beam passes through the beam splitter and enters the scanning module. After passing through the scanning module, the laser beam is no longer parallel to the optical axis. Finally, the laser beam is focused by the focusing module and transmitted to the processing surface on the motion platform. The direction of laser beam propagation is set as the Z-axis, and an XYZ spatial coordinate system is established with the Z-axis. The projection angles of the angle between the laser beam and the Z-axis onto the XOZ and YOZ planes are set as α and β, respectively. A first XYZ spatial coordinate system is established before the laser beam enters the scanning module, and a second XYZ spatial coordinate system is established after the laser beam enters the scanning module. The optical field modulation module includes a spatial light modulator for laser modulation; The dual-wedge beam deflection module includes a first wedge and a second wedge for beam deflection; the first wedge can be translated along the Z-axis, and the first and second wedges can be rotated around the Z-axis. The focusing and beam expanding module includes several lenses, one of which is movable along the Z-axis to change the divergence angle of the laser beam. The observation system includes a CCD camera and a lens. The laser beam is reflected by the beam splitter, passes through the lens, and is imaged on the CCD camera. The scanning module includes two reflectors and two galvanometers. The two reflectors are placed at 45° and clamped on the galvanometers. The rotation axes of the two galvanometers are orthogonal. The focusing module includes a lens group for deflecting the laser beam off the Z-axis and adjusting α and β; The motion platform has movement in the XYZ three-axis directions; the control system issues control commands from the operating software to coordinate the control of the dual-wedge beam offset module, the focusing beam expansion module and the scanning module, and to control the movement of the motion platform.

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

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

4. The high dynamic five-axis laser processing device based on double optical wedge according to claim 3, characterized in that: The first and second optical wedges rotate synchronously along the Z-axis; the first and second optical wedges rotate via magnetic levitation or an air bearing-like mechanism. 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 wedge according to claim 4, characterized in that: The first optical wedge moves along the Z-axis to adjust the distance between it and the second optical wedge, thereby controlling the off-axis amount of the laser beam; let the off-axis amount of the laser beam be Δd. The calculation formula is: wherein, wherein i is the wedge angle, n i is the refractive index of the wedge, j is the refractive angle of the laser beam in air, n j is the refractive index of air, and l1 and l2 represent the initial distance and the distance after moving of the first wedge, the second wedge, respectively.

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

7. The high dynamic five-axis laser processing device based on double optical wedge according to claim 5, characterized in that: The rotation angle of the 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 dual optical wedges according to claim 1, characterized in that: The focusing and beam-expanding module includes a focusing section and a beam-expanding section, and both the focusing section and the beam-expanding section include two concave lenses and one convex lens. One of the two concave lenses in the focusing section is movable along the Z-axis.

9. The high dynamic five-axis laser processing device based on dual optical wedges according to claim 1, characterized in that: The two reflectors can be deflected by an angle of 0°–(±10°).

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

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