Dual-beam laser device and method of machining

Abstract

The application belongs to the field of laser processing, and discloses a double-beam laser device and a processing method. The double-beam laser device comprises a collimation unit, a beam splitting unit and a focusing unit. The beam splitting unit comprises a specially-made wedge prism, one side of which is a plane perpendicular to the optical axis, and the other side comprises two planes which are neither coplanar nor parallel. After the collimated parallel laser beam passes through the wedge prism, two parallel light beams with different deflection directions are obtained, and two focal points with different positions on the focal plane are obtained after focusing. By rotating or reciprocating the wedge prism, relative rotation or oscillation of the double-beam laser can be realized. The laser processing method converts the single laser beam output by a conventional laser into a double-beam laser which can rotate or oscillate, and linear or point-like processing is carried out accordingly, so as to realize the processing effect of the combination of the double-beam laser and the oscillating laser.

Description

Technical Field

[0001] This invention belongs to the field of laser processing, and more specifically, relates to a laser device and a laser processing method. Background Technology

[0002] In laser processing, controlling the shape and action of the laser beam can alter the processing results. Dual-beam lasers are a common technique in laser processing, as is oscillating the laser beam within a certain range. Both can be applied to laser welding, additive manufacturing, and ultrafast laser processing. Dual-beam lasers include different forms such as two single-point laser beams, point and ring laser beams, etc. Existing dual-beam laser devices typically output two laser beams with relatively fixed positions, making it difficult to simultaneously oscillate or rotate at least one of the beams, thus limiting the application scenarios of dual-beam lasers. Summary of the Invention

[0003] To obtain a swingable or rotatable dual-beam laser in a simple manner, the present invention provides a dual-beam laser device, the specific solution of which is as follows:

[0004] The dual-beam laser device includes a collimation unit, a beam splitting unit, and a focusing unit along the laser beam optical path;

[0005] The collimation unit adjusts the divergent laser beam input from the laser connected to the device into a parallel laser beam;

[0006] The beam splitting unit includes a specially made wedge prism. One side of the wedge prism is a plane 11 perpendicular to the optical axis. The other side of the wedge prism includes two planes that are neither coplanar nor parallel to each other. The angle between each of the two planes and the plane 11 does not exceed 5°, and at least one of the planes has an angle greater than 0° with the plane 11.

[0007] Preferably, the plane 11 faces the collimation unit. The collimated parallel laser beam is incident on the plane 11 and, after passing through the two surfaces on the other side of the wedge prism, obtains two parallel beams with different deflection directions.

[0008] The focusing unit focuses two parallel beams of light with different deflection directions to obtain two focal points at different positions on the focal plane.

[0009] In a preferred embodiment, one of the two faces on the other side of the wedge prism is an inclined plane 12, and the other face is a plane 13 parallel to the plane 11. The plane 13 intersects the inclined plane 12 with a straight line. The plane 13 deflects part of the collimated laser beam with zero deflection, ultimately forming a focal point 21 located on the optical axis. The inclined plane 12 deflects part of the collimated laser beam, ultimately forming a focal point 22 that is off the optical axis and coplanar with the focal point 21.

[0010] In another preferred embodiment, the other side shared with the wedge prism inclined surface 12 is an inclined surface 14; the thinner part of the inclined surface 14 intersects the thinner part of the inclined surface 12 in a straight line; the inclined surface 12 and the inclined surface 14 deflect a portion of the collimated laser beam in opposite directions, and the two deflected laser beams finally form focal points 22 and 23 off the optical axis on the focal plane, respectively;

[0011] Optionally, the wedge angle between the inclined surface 14 and the plane 11 preferably does not exceed 3°.

[0012] Optionally, the beam splitting unit further includes a hollow direct-drive torque motor; the hollow torque motor can drive the wedge prism to rotate continuously, ultimately achieving the rotation of focus 22 around focus 21 on the focal plane, or the synchronous rotation of focus 22 and focus 23 around the optical axis respectively.

[0013] Optionally, the wedge prism can rotate continuously at a maximum speed of 10,000 revolutions per minute.

[0014] Optionally, the wedge prism can rotate continuously at a maximum speed of 3000 revolutions per minute.

[0015] In another preferred embodiment, the beam splitting unit further includes a finite-angle reciprocating rotation mechanism; the reciprocating rotation mechanism can drive the wedge prism to reciprocate at a small angle, ultimately achieving left-right swing of focus 22 relative to focus 21 at the focal plane, or synchronous relative swing of focus 22 and focus 23 respectively.

[0016] Optionally, the reciprocating rotation angle of the wedge prism does not exceed ±10°;

[0017] Optionally, the reciprocating oscillation frequency of the wedge prism is up to 2000Hz;

[0018] Optionally, the limited-angle reciprocating rotation mechanism is a hollow voice coil motor.

[0019] In another preferred embodiment, the collimating unit includes a collimating lens group consisting of at least two lenses; the focusing unit includes a focusing lens group consisting of at least two lenses to correct aberrations;

[0020] Optionally, the collimation unit includes a combination of a negative lens and a positive lens; the focusing unit includes a combination of a negative lens and a positive lens; both the negative lens and the positive lens are spherical lenses;

[0021] Optionally, the collimation unit includes a negative lens that is preferably a meniscus negative lens with its concave surface facing the incident laser direction; the positive lens included may be a biconvex or plano-convex lens with its convex surface facing the outgoing laser direction; the positions of the negative lens and the positive lens are fixed.

[0022] Optionally, both the negative lens and the positive lens included in the collimation unit are moved along the optical axis to change the diameter of the collimated beam, and ultimately change the size of the output focused spot.

[0023] Optionally, the collimation unit further includes a single negative meniscus lens with its concave surface facing the incident laser direction and its position relatively fixed; the negative lens that moves along the optical axis is a negative meniscus lens with its concave surface facing the fixed mirror direction; the positive lens that moves along the optical axis is a biconvex lens or a positive meniscus lens with its convex surface facing the outgoing light direction.

[0024] Optionally, the focusing unit includes a combination of a negative lens and a positive lens. The negative lens is preferably a negative meniscus lens with its concave surface facing the direction of the incident laser; the positive lens is preferably a positive meniscus lens with its convex surface facing the direction of the emitted laser.

[0025] In yet another preferred embodiment, the wedge angle of the wedge prism is preferably no more than 1°. In this case, the collimating unit comprises a single aspherical collimating lens; and the focusing unit comprises a single aspherical focusing lens.

[0026] Optionally, the collimation unit includes a single aspherical lens that is plano-convex or meniscus aspherical, with its convex aspherical surface facing the direction of collimated light emission; the focusing unit includes a single aspherical lens that is plano-convex or meniscus aspherical, with its convex aspherical surface facing the direction of incident parallel light.

[0027] In another embodiment, the intersection of the two non-coplanar and non-parallel surfaces on the other side of the wedge prism is a smooth transition; the intersection transition position is located in the middle of the prism and passes through the optical axis, so that the laser beams passing through the two surfaces have the same area or a difference of no more than 5%, and the two laser beams output have the same or equivalent laser energy.

[0028] Optionally, the intersection of the two non-coplanar and non-parallel surfaces on the other side of the wedge prism is a smooth transition; the intersection transition position is off the optical axis, so that the laser beam area passing through the two surfaces has a significant difference, preferably the laser beam area passing through one of the surfaces is not less than 60% and not more than 90%, and the two laser beams finally output have higher and lower laser energies respectively.

[0029] According to another aspect of the present invention, a dual-beam laser processing method is provided, the method comprising the following steps:

[0030] Using any of the laser devices described above, the laser fiber is connected to the laser device through a suitable interface (such as QBH, QD, etc.) to convert the single-beam laser output from a single laser into a dual-beam output.

[0031] Preferably, when the distance between the two final output focal spots is no greater than three times the sum of the diameters of the two focal spots, and at least one of the beams reciprocates and oscillates, the dual beams are used for linear synchronous processing, and the two laser beams act as heat sources along the processing direction in the same area.

[0032] Preferably, when the distance between the two final output focal spots is no greater than twice the sum of the diameters of the two focal spots, and at least one of the beams rotates continuously, the dual beams are used for linear synchronous processing, and the two laser beams act as heat sources alternately in the same area along the processing direction.

[0033] Preferably, when at least one of the two focal spots in the final output rotates continuously, the dual beams are used for point processing, and the two laser beams act as heat sources at different positions for a period of time to form a point processing area.

[0034] By adopting the above-described technical solution of the present invention, the following beneficial effects can be obtained:

[0035] 1. This invention provides a dual-beam laser device that, while converting a single laser beam into a dual-beam output, enables the two laser beams to move relative to each other, breaking the conventional technical characteristic of existing dual-beam lasers where the beams are relatively stationary. This is beneficial for expanding the application range and effectiveness of dual-beam lasers. This invention also provides a variety of optional dual-beam laser device schemes that can output controllable dual beams with different characteristics, thereby enabling laser processing based on the beam characteristics.

[0036] 2. The dual-beam laser device solution provided by this invention adopts a simple and flexible design and a mature component combination scheme. By designing the exit surface of a single wedge prism to be adjusted from a conventional single inclined plane to two different planes, the single-beam input laser output becomes two parallel beams with different directions. After focusing, two focal points with different positions are obtained. The positions of the two focal points and the distance between them can be designed by presetting the wedge angle of the two exit surfaces of the wedge prism and the focal length of the focusing unit. Within the range of wedge angle not exceeding 5° and focal length of 100~300mm, two focal points with distances greater than 0mm and less than 12mm from the optical axis can be obtained respectively. When one of the exit surfaces of the wedge prism is a plane parallel to the incident plane, one focal point is located on the optical axis. When the wedge angles of the two exit surfaces of the wedge prism are equal, two focal points with symmetrical positions relative to the optical axis are output. When the wedge angles of the two exit surfaces of the wedge prism are not equal, two focal points with different distances from the optical axis are output. Meanwhile, by using a mature hollow torque motor or hollow voice coil motor to drive the wedge prism to rotate at high speed or oscillate at a small angle, the stationary double beams can be made to rotate or oscillate relative to each other. This allows the laser device to be designed for both linear and point processing. The rotating or oscillating laser beam has the function of simultaneously performing front-end and / or back-end processing during the processing, and also has the function of oscillating beams. To a certain extent, it combines the advantages of existing double beam devices and galvanometers.

[0037] 3. The dual-beam system with at least one continuously rotating laser beam provided by the present invention is suitable for point or circular processing. Compared with single-beam galvanometer scanning processing, it is beneficial to improve processing efficiency and quality; compared with singing dual-beam lasers, it has better flexibility.

[0038] 4. The laser device provided by this invention can be used for laser processing, especially laser welding. Both linear and point processing can promote the homogenization of the weld pool. It is suitable for applications such as coated materials, filler solders or dissimilar materials, so as to reduce or avoid weld segregation.

[0039] 5. Using the continuous rotating or reciprocating rotating dual-beam laser provided by this invention for linear processing, such as welding, can increase the process's adaptability to welding gaps. Attached Figure Description

[0040] Figure 1 A schematic diagram of a dual-beam laser device using a specially designed wedge prism with an inclined plane and a flat plane as the exit surface and the intersection line passing through the optical axis.

[0041] Figure 2 A schematic diagram of a dual-beam laser device with a specially designed wedge prism having an inclined surface and a flat exit surface whose intersection line passes through the optical axis.

[0042] Figure 3 A schematic diagram of a dual-beam laser device consisting of a specially designed wedge prism with an inclined surface and a flat exit surface that intersects through the optical axis.

[0043] Figure 4 A schematic diagram of a dual-beam laser device with a specially designed wedge prism having two equal wedge angles (in opposite directions) as the exit surface and the intersection line passing through the optical axis.

[0044] Figure 5 A schematic diagram of a dual-beam laser device consisting of a specially designed wedge prism with two unequal wedge angles (in opposite directions) rotating outward surfaces and whose intersection lines pass through the optical axis.

[0045] Figure 6 A schematic diagram of a dual-beam laser device consisting of a specially designed wedge prism with a sloping surface and a flat exit surface, the intersection of which is deviated from the optical axis, to maximize the area of ​​the beam passing through the flat surface.

[0046] Figure 7 A schematic diagram of a dual-beam laser device is provided, which uses a specially designed wedge prism with two unequal wedge angles (in opposite directions) to rotate the exit surface, with the intersection line deviating from the optical axis, so that the beam area passing through the larger wedge angle slope is larger.

[0047] Figure 8 A schematic diagram of a collimating lens group consisting of one positive and one negative lens.

[0048] Figure 9 A schematic diagram of a collimating lens group consisting of a fixed negative lens and a set of movable positive and negative lenses.

[0049] Figure 10 A schematic diagram of a focusing lens group consisting of one positive and one negative lens. Detailed Implementation

[0050] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings.

[0051] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment herein. The phrase appearing in various places in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive, independent, or alternative embodiments. Those skilled in the art will understand that the embodiments herein can be combined with other embodiments without structural conflict.

[0052] This invention provides different schemes for a type of dual-beam laser device. The dual-beam laser device includes a collimation unit, a beam splitting unit, and a focusing unit. The collimation unit is connected to the laser via an interface, adjusting the diverging laser beam input from the laser into a collimated parallel beam. The beam splitting unit includes a specially designed wedge-shaped prism, one side of which is a plane perpendicular to the optical axis, and the other side contains two non-coplanar and non-parallel surfaces. When the collimated parallel laser beam passes through the wedge-shaped prism, it is deflected into two parallel beams with different directions. The focusing unit focuses the two parallel beams with different incident angles to obtain two focal points at different positions on the focal plane. In other words, the device converts a single laser beam into a dual laser beam. According to the scheme provided by this invention, the dual laser beams can be output in different combinations.

[0053] Example 1

[0054] like Figure 1 As shown, the diverging beam of laser 1 passes sequentially through a single aspherical collimating lens 2 in the collimating unit, a single specially designed wedge prism 3 in the beam splitting unit, and a single aspherical focusing lens 4 in the focusing unit of the laser device. The single aspherical collimating lens 2 in the collimating unit adjusts the diverging beam into a parallel laser beam; the specially designed wedge prism 3 in the beam splitting unit outputs the single parallel laser beam as two parallel laser beams with different directions; and the single aspherical focusing lens 4 in the focusing unit focuses the two parallel laser beams respectively, obtaining two separate focal points 21 and 22 on the focal plane. In this embodiment, the side of the specially designed wedge prism 3 facing the incident parallel laser beam is a plane 11 perpendicular to the optical axis, and the other side includes an inclined plane 12 and a plane 13. The plane 13 is parallel to the plane 11, and the thinner side of the inclined plane 12 intersects the plane 13 in a straight line, with the intersection line passing through the optical axis. The incident laser beam is divided into two parts of equal or comparable area. The inclined plane 12 has a wedge angle greater than 0° and not exceeding 5°, causing part of the laser beam to deflect before exiting and being focused to obtain a focal point 22 off the optical axis; the remaining laser beam passes through the plane 13 perpendicular to the optical axis without deflection and is focused to obtain a focal point 21 located on the optical axis. The distance of focal point 22 from the optical axis depends on the wedge angle of the inclined plane 12 and the focal length of the aspherical focusing lens 4, and can be estimated using the formula: S≈f*(n-1)*A, where S is the distance of the focal point off the optical axis, f is the focal length of the focusing lens, n is the refractive index of the lens material at the corresponding laser wavelength, and A is the value of the wedge angle corresponding to the wedge prism exiting the inclined plane 12 converted to rad. In this embodiment, the center distance between the light spots of focal point 22 and focal point 21 is also S.

[0055] Optionally, the laser 1 outputs a 1064nm wavelength laser. The collimating lens 2, wedge prism 3, and focusing lens 4 are all made of fused silica material, with a corresponding refractive index n of approximately 1.4496. When the wedge angle of the inclined plane 12 is 0.5° ≈ 0.00873 rad, the distance S ≈ 0.003925 * f from the optical axis of the focal point 22. When the focal length of the focusing lens 4 is designed to be 200mm, the focal point 22 will deviate from the optical axis by approximately 0.785mm; when the focal length of the focusing lens 4 is designed to be 300mm, the focal point 22 will deviate from the optical axis by approximately 1.178mm. Depending on the requirements, the wedge angle of the inclined plane 12 of the wedge prism 3 and the focal length of the focusing lens 4 can be selectively designed to obtain a focal point 22 with a specific distance from the optical axis. When the wedge angle of the inclined plane 12 does not exceed 5° and the focal length of the focusing lens 4 is 100~300mm, a focal point 22 with a distance greater than 0mm and less than 12mm from the optical axis can be obtained.

[0056] Example 2

[0057] like Figure 2 As shown, similar to Embodiment 1, the difference is that the beam splitting unit also includes a rotating mechanism, preferably a hollow torque motor, to drive the specially designed wedge prism 3 to rotate. During the rotation of the specially designed wedge prism 3, the inclined surface 12 and the plane 13 rotate together, causing the laser beams passing through the two exit surfaces to also rotate. After final focusing, the focal point 21 located on the optical axis remains unchanged, while the focal point 22, which is off the optical axis, rotates around the focal point 21 at the same speed as the specially designed wedge prism 3. The specially designed wedge prism 3 can be selected with a maximum rotation speed of 10,000 rpm, while laser devices used in conventional laser processing can be selected with a maximum speed of 3,000 rpm.

[0058] Example 3

[0059] like Figure 3As shown, similar to Embodiment 1, the difference is that the beam splitting unit also includes a reciprocating rotation mechanism, optionally a hollow voice coil motor, to drive the specially designed wedge prism 3 to reciprocate at a small angle. During this process, the laser beam output from the inclined plane 12 also reciprocates, and the focal point 22, which is off-axis, will swing left and right relative to the focal point 21 on the optical axis output from the plane 13. The reciprocating rotation angle of the wedge prism 3 does not exceed ±10°, preferably not more than ±5°, and the corresponding reciprocating rotation frequency is preferably not less than 20Hz and not more than 2000Hz. The reciprocating rotation of the wedge prism 3 can be converted into the left and right swing amplitude of the focal point 22 (i.e., the arc length L of the reciprocating movement of the focused spot 22), which can be estimated according to the calculation formula: L=S*B≈f*(n-1)*A*B, where B is the value of the reciprocating rotation angle of the wedge prism converted to rad. Taking the wedge angle of the inclined plane 12 in Example 1 as 0.5° and the focal length of the focusing lens 4 as 300mm as an example, when the reciprocating rotation angle of the wedge prism 3 is 5°, the arc length L≈0.103mm, that is, the focusing spot 22 swings with an arc length of ±0.103mm.

[0060] Example 4

[0061] like Figure 4 As shown, similar to Embodiment 2, the difference is that the plane 13 on the same side as the inclined plane 12 in the special wedge prism 3 is replaced by an inclined plane 14. The wedge angle of the inclined plane 14 is opposite to that of the inclined plane 12, that is, the thinner side of the inclined plane 14 intersects with the thicker side of the inclined plane 12, and the line of intersection passes through the optical axis. In this embodiment, the wedge angle of the inclined plane 14 is the same as that of the inclined plane 12, and finally a focal point 23 is obtained that is offset from the optical axis by the same distance as the focal point 22. The positions of the two are symmetrically distributed with respect to the optical axis. During the continuous rotation of the special wedge prism 3, the focal points 22 and 23 rotate continuously relative to each other. The rotation trajectory of the two focal points is a circle with a radius of S, and the distance between the two focal points is 2S. For example, when the wedge angles of the inclined plane 12 and the inclined plane 14 are both 0.5° and the focal length of the focusing lens 4 is 200mm, the center distance between the focal points 22 and 23 is 1.57mm.

[0062] Example 5

[0063] like Figure 5As shown, similar to Embodiment 4, except that the inclined plane 14 has a smaller wedge angle than the inclined plane 12, and the distance of the focal point 23 from the optical axis is smaller than the distance of the focal point 22 from the optical axis. During the continuous rotation of the special wedge prism 3, the focal points 22 and 23 rotate around two circular trajectories, one large and one small. The radii of the two circular trajectories are the distances of the focal points 22 and 23 from the optical axis, respectively, and the distance between the focal points 22 and 23 is the sum of their respective distances from the optical axis. For example, if the wedge angle of the inclined plane 12 is 1°, the wedge angle of the inclined plane 14 is 0.5°, and the focal length of the focusing lens 4 is 200mm, then the rotation trajectory of the focal point 22 is a circle with a radius of 1.57mm, the rotation trajectory of the focal point 23 is a circle with a radius of 0.785mm, and the distance between the two focal points is 2.355mm. When the focal length of the lens remains constant at 200mm, the wedge angle of the inclined plane 12 is designed to be 3° and the wedge angle of the inclined plane 14 is 1°. In this case, the focusing unit uses... Figure 10 The two focusing lens groups 42 and 43 shown replace the single focusing lens 4; the rotation trajectory of focal point 22 is a circle with a radius of 4.712 mm, the rotation trajectory of focal point 23 is a circle with a radius of 1.57 mm, and the distance between the two focal points is 6.282 mm.

[0064] Example 6

[0065] Similar to Embodiment 3, the difference is that the straight line intersecting the inclined plane 12 and the plane 13 deviates from the optical axis, causing the area of ​​the incident laser beam passing through one of the planes to be larger, resulting in two laser beams with significantly different output energies. In this embodiment, the area of ​​the laser beam passing through the plane 13 is larger than the area of ​​the laser beam passing through the inclined plane 12. When the wedge prism 3 rotates back and forth at a small angle, the focal point 22 with lower energy oscillates back and forth at the same frequency. For example, the area of ​​the laser beam passing through the plane 13 accounts for 80% of the area of ​​the incident laser beam, and the final output laser beam has an energy ratio of 80% at focal point 21 and approximately 20% at focal point 22.

[0066] Example 7

[0067] Similar to Embodiment 5, the difference is that the intersection line of the inclined plane 12 and the inclined plane 14 deviates from the optical axis, resulting in a larger area of ​​the laser beam passing through one of the planes, ultimately outputting two laser beams with significant energy differences. In this embodiment, the incident area of ​​the laser beam passing through the inclined plane 12 is larger than that of the laser beam passing through the inclined plane 14. When the wedge prism 3 rotates continuously, the focal point 23 with lower energy rotates with a smaller radius, while the focal point 22 with higher energy rotates with a larger radius.

[0068] Example 8

[0069] In the above embodiments, the following are used: Figure 8The two-piece collimating lens group 25 and 26 shown serve as collimating lenses in the collimating unit, replacing the single-piece collimating lens 2. Lens 25 is a meniscus negative lens with its concave surface facing the laser incident direction, and lens 26 is a biconvex positive lens with its flatter side facing the emitted laser direction.

[0070] Optionally, both lens 25 and lens 26 can be moved along the optical axis to change the diameter of the collimated parallel light output, and ultimately change the diameter of the focused spot.

[0071] Optionally, use such as Figure 9 The three-element collimating lens group 27, 28, and 29 shown serve as collimating lenses in the collimating unit, replacing the single collimating lens 2. Lens 27 is a meniscus negative lens with its concave surface facing the laser incident direction, lens 28 is a meniscus negative lens with its concave surface facing the laser incident direction, and lens 29 is a biconvex positive lens with its flatter side facing the emitted laser direction. Furthermore, the position of lens 27 is fixed, while lenses 28 and 29 move along the optical axis to change the diameter of the collimated parallel beam, thereby adjusting the diameter of the focused spot.

[0072] All of the above lenses are spherical lenses.

[0073] Example 9

[0074] In the above embodiments, the following are used: Figure 10 The two-piece focusing lens group 42 and 43 shown serve as the focusing lens of the focusing unit, replacing the single-piece focusing lens 4. Lens 42 is a meniscus negative lens with its concave surface facing the direction of the incident parallel light, and lens 43 is a meniscus positive lens with its convex surface facing the direction of the emitted laser. Both lenses 42 and 43 are spherical lenses.

[0075] Example 10

[0076] According to the laser device of the present invention, when the output focal point 22, which deviates from the optical axis, rotates continuously around the focal point 21 located on the optical axis, and the distance between the two focal points is no greater than 1.0 mm, the laser device can be applied to the processing of a dot-shaped area with a diameter of about 3 mm. In this case, the laser beam generating focal point 21 acts continuously for a period of time, and the laser beam generating focal point 22 rotates around the optical axis during this time, and the two together form a dot-shaped processing area; it can also be used for linear synchronous processing. In this case, the laser beam generating focal point 21 moves forward along the processing direction, and the laser beam generating focal point 22 rotates around focal point 21, that is, moves forward in a detour along the processing direction, forming the effect of simultaneously performing pre-processing and post-processing on the processing area; if both laser beams generate a molten pool, the rotating laser beam synchronously achieves the effect of stirring the molten pool.

[0077] According to another aspect of the present invention, the laser beam that generates focal point 22 oscillates back and forth at a small angle. The laser device is used in linear processing and is located after the laser beam that generates focal point 21 along the processing direction, which can also achieve the effect of stirring the molten pool. In this case, the distance between focal point 21 and focal point 22 is preferably no more than 2.0 mm.

[0078] According to another aspect of the present invention, when the distance between focal points 22 and 23 is no greater than 3 mm and they oscillate back and forth at a small angle, the laser device is used for linear processing, preferably with focal point 23 having lower energy and located after focal point 22 along the processing direction. When focal points 22 and 23 rotate continuously along circular trajectories of different radii, the laser device is used for point processing, preferably with focal point 23 having lower energy and rotating along a circular trajectory with a smaller radius.

[0079] The purpose of the above embodiments is to provide a further detailed description of the present invention in conjunction with the accompanying drawings, so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the claims of the present invention, any improvements, optimizations, or equivalent substitutions made to the structure or method of the present invention, as well as combinations of implementation methods in different embodiments without causing a conflict of principle, all fall within the protection scope of the present invention.

Claims

1. A dual-beam laser device, characterized in that, It includes a collimation unit, a beam splitting unit, and a focusing unit; the beam splitting unit includes a specially made wedge prism, one side of which is a plane 11 perpendicular to the optical axis, and the other side of which includes two non-coplanar and non-parallel planes, each of which forms an angle with plane 11 of no more than 5°; when the collimated parallel laser beam passes through the wedge prism, two parallel beams with different deflection directions are obtained, and after focusing, two focal points with different positions on the focal plane are obtained.

2. The laser device as described in claim 1, characterized in that, The wedge prism has two faces on the other side, one of which is an inclined plane 12 and the other is a plane 13 parallel to the plane 11. The plane 13 intersects the inclined plane 12 with a straight line. The plane 13 deflects part of the collimated laser beam with zero deflection, eventually forming a focal point 21 located on the optical axis. The inclined plane 12 deflects part of the collimated laser beam, eventually forming a focal point 22 that is off the optical axis and coplanar with the focal point 21.

3. The laser device as described in claim 2, characterized in that, The other side of the wedge prism inclined surface 12 is inclined surface 14; inclined surface 14 intersects inclined surface 12 in a straight line; inclined surface 12 and inclined surface 14 deflect a portion of the collimated laser beam in opposite directions, and the two deflected laser beams eventually form focal points 22 and 23 off the optical axis on the focal plane, respectively.

4. The laser device as described in claim 2 or 3, characterized in that, The beam splitting unit also includes a hollow direct-drive torque motor; the hollow torque motor can drive the wedge prism to rotate continuously, ultimately achieving the rotation of focus 22 around focus 21 on the focal plane, or the synchronous rotation of focus 22 and focus 23 around the optical axis.

5. The laser device as described in claim 2 or 3, characterized in that, The beam splitting unit also includes a finite-angle reciprocating rotation mechanism; the reciprocating rotation mechanism can drive the wedge prism to reciprocate at a small angle, ultimately achieving left-right swing of focus 22 relative to focus 21 on the focal plane, or synchronous relative swing of focus 22 and focus 23 respectively.

6. The laser device as described in claims 1 to 5, characterized in that, The collimation unit includes a collimation lens group consisting of at least two lenses; the focusing unit includes a focusing lens group consisting of at least two lenses.

7. The laser device as described in claims 1 to 5, characterized in that, The wedge angle of the wedge prism does not exceed 1°. In this case, the collimation unit includes a single aspherical collimating lens; the focusing unit includes a single aspherical focusing lens.

8. The laser device as described in claims 1 to 7, characterized in that, The intersection of the two non-coplanar and non-parallel surfaces on the other side of the wedge prism is a smooth transition; the intersection transition position passes through the optical axis, so that the laser beam areas passing through the two surfaces are the same or differ by no more than 5%.

9. The laser device as described in claims 1 to 7, characterized in that, The intersection of the two non-coplanar and non-parallel surfaces on the other side of the wedge prism is a smooth transition; the intersection transition position is off the optical axis, so that the area of ​​the laser beam passing through the two surfaces is significantly different, preferably the area of ​​the laser beam passing through one of the surfaces is not less than 60% and not more than 90%.

10. A dual-beam laser processing method, characterized in that, Using the laser device described in claims 1 to 9, a single laser beam input from a laser is converted into a dual-beam output, and the dual beam is applied to laser processing; Preferably, when the distance between the two final output focal spots is no greater than 3 times the sum of the diameters of the two focal spots, and at least one of the beams reciprocates and oscillates, the dual beams are used for linear synchronous processing, and the two laser beams act as heat sources along the processing direction and act on the same area sequentially. Preferably, when the distance between the two final output focal spots is no greater than twice the sum of the diameters of the two focal spots, and at least one of the beams rotates continuously, the dual beams are used for linear synchronous processing, and the two laser beams act as heat sources alternately in the same area along the processing direction. Preferably, when at least one of the two focal spots in the final output rotates continuously, the dual beams are used for point processing, and the two laser beams act as heat sources at different positions for a period of time to form a point processing area.

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