Laser processing device

Abstract

The utility model discloses a laser processing device. The laser processing device is used for performing laser processing on the interior of a to-be-processed material. The laser processing device comprises a laser unit, a detection unit, a beam combining unit, a light condensing unit and a lens unit. The laser unit is used for generating processing beams. The detection unit is used for generating a measuring light beam and can generate an electric signal. The beam combining unit is used for enabling optical axes of the processing beam and the measuring beam to coincide. The condensation unit is used for focusing the processing light beam and the measuring light beam. The lens unit is arranged between the light gathering unit and the laser unit or the detection unit and used for focusing the machining light beam at a first position and focusing the measuring light beam at a second position, the first position is located in the to-be-machined material, and the second position is located on the surface of the to-be-machined material. Through the arrangement, the position of the focus of the machining light beam is accurately positioned, and the machining precision of the interior of the to-be-machined material is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser processing, in particular to a laser processing device. BACKGROUND

[0002] In general laser processing applications, a laser beam is converged on a material surface by a focusing lens to process the material surface. In the processing process, in order to make the laser beam converge on the material surface at all times, an optical focus-pursuing sensor is used to measure the height of the material surface in real time, and a defocus distance signal is sent as feedback to a motion mechanism, which performs laser focus point position compensation to achieve dynamic tracking of the material surface.

[0003] The existing laser processing technology includes a coaxial focus-pursuing scheme, in which a solid / fiber laser generates a processing beam L1, an optical sensor generates a focus-pursuing measurement beam L2, and a beam combining unit is used to coaxially combine the measurement beam and the processing beam, which are then emitted through the focusing lens. When this scheme is applied to internal material processing, if the focal points of the processing beam L1 and the focus-pursuing measurement beam L2 are both aligned with the internal material, the focus-pursuing measurement beam L2 will be reflected on the material surface. Since the focus-pursuing measurement beam L2 fails to converge well on the material surface, a large spot is formed on the material surface, and the light rays cannot return to the sensor camera via the original path, thereby causing measurement failure. CONTENT OF THE INVENTION

[0004] In order to solve the problems of the prior art, the purpose of the present application is to provide a laser processing device capable of improving the internal material processing precision.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solution:

[0006] The present application provides a laser processing device, which comprises a laser unit, a detection unit, a beam combining unit, a condensing unit, and a lens unit. The laser unit is used to generate a processing beam. The detection unit is used to generate a measurement beam, and the initial divergence angle of the measurement beam is the same as that of the processing beam. The detection unit can generate an electrical signal according to the light signal reflected from the material to be processed. The beam combining unit is used to adjust the optical axis direction of the processing beam or the measurement beam, so that the optical axes of the processing beam and the measurement beam coincide. The condensing unit is used to focus the processing beam and the measurement beam that have passed through the beam combining unit. The lens unit is arranged between the condensing unit and the laser unit, or the lens unit is arranged between the condensing unit and the detection unit. The lens unit cooperates with the condensing unit to focus the processing beam and the measurement beam at a first position and a second position, respectively. The first position is inside the material to be processed, and the second position is on the surface of the material to be processed.

[0007] Further, the laser processing device further comprises a control unit and an execution unit, the control unit is electrically connected with the detection unit and the execution unit, the control unit is used for receiving the electrical signal and generating a corresponding adjustment signal according to the electrical signal; the execution unit is electrically connected with the control unit, and the execution unit is used for receiving the adjustment signal and adjusting the displacement of the condensing unit according to the adjustment signal.

[0008] Further, the lens unit is a positive lens, the positive lens is arranged between the beam combining unit and the detection unit, the processing beam and the measuring beam have the same divergence angle, and the divergence angle of the measuring beam is reduced by the positive lens in the case that the measuring beam passes through the positive lens.

[0009] Further, the focal length of the positive lens ranges from 200 mm to 1000 mm.

[0010] Further, the lens unit is a negative lens, the negative lens is arranged between the beam combining unit and the laser unit, the processing beam and the measuring beam have the same divergence angle, and the divergence angle of the processing beam is increased by the negative lens in the case that the processing beam passes through the negative lens.

[0011] Further, the focal length of the negative lens ranges from -1000 mm to -200 mm.

[0012] Further, the distance between the first position and the second position is defined as the focal depth, and the focal depth D satisfies the following relationship:

[0013] ;

[0014] In the formula, n represents the refractive index of the material to be processed, F represents the focal length of the condensing unit, f represents the focal length of the lens unit, and d represents the optical center distance between the condensing unit and the lens unit.

[0015] Further, the focal depth ranges from 0.2 mm to 1.5 mm.

[0016] Further, the laser processing device further comprises a lens adjustment unit, the lens adjustment unit is electrically connected with the control unit, the lens adjustment unit can obtain the adjustment signal, and the displacement of the lens unit is controlled according to the adjustment signal to increase or reduce the optical center distance.

[0017] Further, the laser unit comprises a solid / fiber laser, and the detection unit is provided with an LED / LD light source.

[0018] The laser processing apparatus provided in this application generates a processing beam through a laser unit and a measurement beam with the same initial divergence angle as the processing beam through a detection unit. The processing beam and the measurement beam pass directly through a beam combiner unit or through a lens unit before passing through the beam combiner unit, and their optical axes coincide after passing through the beam combiner unit. The processing beam, after passing through the beam combiner unit, passes through a focusing unit, and its focal point converges inside the material to be processed. Similarly, the measurement beam, after passing through the beam combiner unit, passes through a focusing unit, and its focal point converges on the surface of the material to be processed. Based on this, the specific position of the processing beam inside the material to be processed can be effectively determined, thereby improving the processing accuracy inside the material. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the laser processing apparatus in the embodiments of this application;

[0020] Figure 2 This is a partial connection diagram of the laser processing apparatus in the embodiments of this application;

[0021] Figure 3 This is a schematic diagram of the reflection of the light spot generated in the embodiment of this application;

[0022] Figure 4 This is a schematic diagram of the laser processing apparatus equipped with a negative lens in an embodiment of this application.

[0023] Figure 5 (a) in the figure is a paraxial optical path diagram of the processing beam in the embodiment of this application; Figure 5 (b) in the figure is the paraxial optical path diagram of the measurement beam in the embodiment of this application;

[0024] Figure 6 This is a schematic diagram showing the connection of some units in the embodiments of this application. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present application, the technical solutions in specific embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0026] In this document, relational terms such as first and second and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0027] The present application provides a laser processing device 100 as shown in Figure 1 The laser processing device 100 comprises a laser unit 11, a detection unit 12, a beam combining unit 13, a condensing unit 14, and a lens unit 15. The laser unit 11 is configured to generate a processing beam. The detection unit 12 is configured to generate a measuring beam, which has the same initial divergence angle as the processing beam, and is capable of generating an electrical signal according to the light signal reflected from the material to be processed. The beam combining unit 13 is configured to adjust the optical axis direction of the processing beam or the measuring beam, so that the optical axes of the processing beam and the measuring beam coincide. The condensing unit 14 is configured to focus the processing beam and the measuring beam that have passed through the beam combining unit 13. The lens unit 15 is disposed between the condensing unit 14 and the laser unit 11, or the lens unit 15 is disposed between the condensing unit 14 and the detection unit 12. The lens unit 15 cooperates with the condensing unit 14 to focus the processing beam at a first position and focus the measuring beam at a second position. The first position is inside the material to be processed, and the second position is on the surface of the material to be processed.

[0028] Exemplarily, the laser unit 11 is configured as a solid-state laser or a fiber laser. The solid-state laser can be used when processing non-metallic materials, and the fiber laser can be used when processing metallic materials. The present application does not limit the type of the laser unit 11, and any laser capable of laser etching is within the scope of the present application.

[0029] The detection unit 12 is configured as a focus sensor with an embedded LED (Light-Emitting Diode) or LD (Laser Diode) light source. The condensing unit 14 is configured as an objective lens. The execution unit 17 is configured as a piezoelectric actuator.

[0030] The beam combination unit 13 is a dichroic mirror with a multi-layer film. The dichroic mirror is used to adjust the optical axis direction of the machining beam or the measurement beam. The machining beam and the measurement beam pass through the dichroic mirror and enter the light collection unit 14 in a collimated manner, that is, the optical axis of the machining beam coincides with the optical axis of the measurement beam. Based on the interference and reflection of light, when the machining beam and the measurement beam irradiate the surface of the dichroic mirror, the machining beam is substantially completely reflected, and the measurement beam passes through the dichroic mirror. Inside the dichroic mirror, the light rays interfere with the multi-layer film. According to the phase difference of light rays of different wavelengths in the multi-layer film, light rays of different wavelengths strengthen or cancel each other. The measurement beam is substantially completely transmitted, and the machining beam reflected by the dichroic mirror and the measurement beam transmitted by the dichroic mirror enter the light collection unit 14.

[0031] It should be noted that the same dichroic mirror has obviously different reflection or transmission characteristics at different wavelengths. That is, the reflection or transmission of light after passing through the dichroic mirror depends on the wavelength of the light and the arrangement of the multi-layer film in the dichroic mirror. It can be understood from the above description that by changing the arrangement of the multi-layer film in the dichroic mirror, the reflection or transmission of light after passing through the dichroic mirror can be changed.

[0032] Optionally, by changing the arrangement of the multi-layer film in the dichroic mirror, the machining beam can be transmitted after passing through the dichroic mirror, and the measurement beam can be reflected by the dichroic mirror.

[0033] In the related art, if the inside of the material to be processed is processed, the machining beam and the measurement beam pass through the light collection unit, and the machining beam and the measurement beam are focused on the same height plane at the same time, and converge in the inside of the material to be processed. The machining beam enters the inside of the material to be processed, and the measurement beam is reflected on the surface of the material to be processed. Since the focal point of the measurement beam is located in the inside of the material to be processed, a large light spot is formed after reflection on the surface of the material to be processed (see Figure 3 ), and the light signal formed by reflection cannot be sent back to the detection unit, so that the specific position of the machining beam cannot be dynamically tracked. In the embodiment of the present application, the positions where the machining beam and the measurement beam are focused are coaxial by the beam combination unit 13, and the light signal formed by reflection can be sent back to the detection unit 12, so that the focal point of the machining beam converging in the inside of the material to be processed is accurately positioned, thereby improving the accuracy of the internal processing of the material to be processed.

[0034] As Figure 1 and Figure 2As shown, the laser processing apparatus further includes a control unit 16 and an execution unit 17. The control unit 16 is electrically connected to the detection unit 12 and the execution unit 17, respectively. The control unit 16 can receive the electrical signal generated by the detection unit 12 and generate a corresponding adjustment signal based on the electrical signal, which is then sent to the execution unit 17. The execution unit 17 can receive the adjustment signal and adjust the displacement of the focusing unit 14 according to the adjustment signal. Through the above configuration, the laser processing apparatus can achieve dynamic focusing by adjusting the displacement of the focusing unit 14 during the processing of the material to be processed, thereby improving the accuracy of the internal processing of the material to be processed.

[0035] In one implementation, the lens unit 15 is configured as a positive lens 151, which is positioned between the beam combining unit 13 and the detection unit 12. The processing beam and the measurement beam have the same divergence angle. When the measurement beam passes through the positive lens 151, the divergence angle of the measurement beam is reduced by the positive lens 151 so that the measurement beam can converge along the optical axis before the processing beam and the focal point of the measurement beam is aligned with the material surface.

[0036] The focal length range of the positive lens 151 is 200mm to 1000mm. Further, the focal length range of the positive lens 151 is 180mm to 900mm. More preferably, the focal length range of the positive lens 151 is 160mm to 800mm. These settings improve the accuracy of focus tracking.

[0037] like Figure 4 As shown, as an optional implementation, the lens unit 15 is configured as a negative lens 152, which is disposed between the beam combining unit 13 and the laser unit 11. The processing beam and the measurement beam have the same divergence angle. When the processing beam passes through the negative lens 152, the divergence angle of the processing beam is increased by the negative lens 152 so that the measurement beam can converge along the optical axis before the processing beam and the focus of the measurement beam is aligned with the material surface.

[0038] The negative lens 152 has a focal length range of -1000mm to -200mm. Further, the focal length range of the negative lens 152 is -900mm to -180mm. More preferably, the focal length range of the negative lens 152 is -800mm to -160mm. These settings improve the accuracy of focus tracking.

[0039] The above settings enable the measurement beam to achieve focus tracking. The embodiments of this application also consider the influence of focus depth on focus tracking accuracy.

[0040] As one implementation method, the distance between the first position and the second position is defined as the focus depth, and the focus depth D satisfies the following relationship:

[0041] ;

[0042] In the formula, n represents the refractive index of the material to be processed, F represents the focal length of the focusing unit 14, f represents the focal length of the lens unit 15, and d represents the optical center distance between the focusing unit 14 and the lens unit 15.

[0043] like Figure 5 Figures (a) and (b) show the paraxial optical paths of the processing beam and the measurement beam. If the processing beam is reflected by the beam combiner unit 13, the measurement beam is transmitted through the beam combiner unit 13, and the lens unit 15 is configured as a positive lens 151, with the optical center distance d being the distance of the optical path from the optical center point of the positive lens 151 to the optical center point of the focusing unit 14. If the processing beam is reflected by the beam combiner unit 13, the measurement beam is transmitted through the beam combiner unit 13, and the lens unit 15 is configured as a negative lens 152, with the optical center distance d being the distance of the optical path from the optical center point of the negative lens 152 to the optical center point of the focusing unit 14.

[0044] Specifically, the processing beam is refracted when it passes through the surface of the material to be processed from the air into the interior of the material. The refractive index n is one of the key factors affecting the depth of focus; the larger the refractive index n, the shallower the depth of focus D. In the embodiments of this application, as can be seen from the above-mentioned relationship regarding the depth of focus D, the depth of focus is limited to 0.2 mm to 1.5 mm by the refractive index n of the material to be processed. The above settings improve the accuracy of focusing.

[0045] like Figure 6 As shown, in one implementation, the laser processing apparatus 100 also includes a lens adjustment unit 18, which is electrically connected to the control unit 16. The lens adjustment unit 18 can acquire an adjustment signal and control the displacement of the lens unit 15 according to the adjustment signal to increase or decrease the optical center distance.

[0046] In one implementation, the laser unit 11 includes a solid-state / fiber laser, and the detection unit 12 incorporates an LED (Light-Emitting Diode) / LD (Laser Diode) light source. Solid-state lasers are primarily used for processing non-metallic materials, while fiber lasers are primarily used for processing metallic materials.

[0047] In summary, the embodiment of the present application adjusts the position of the lens unit 15 through the lens adjusting unit 18 to change the optical center distance and the divergence angle of the measuring light beam or the processing light beam. The measuring light beam and the processing light beam with different divergence angles pass through the beam combining unit 13 into the condensing unit 14, so that the measuring light beam converges on the surface of the material to be processed, and the processing light beam converges in the interior of the material to be processed. The measuring light beam converging on the surface of the material to be processed transmits the light signal to the detection unit 12 through reflection. After receiving the light signal, the detection unit 12 generates an electric signal and transmits it to the control unit 16. After receiving the electric signal, the control unit 16 generates an adjusting signal and transmits it to the execution unit 17. After receiving the adjusting signal, the execution unit 17 adjusts the position of the condensing unit 14 according to the adjusting signal, so that the measuring light beam can always focus on the processing light beam, realizing dynamic tracking of the specific position of the focal point of the processing light beam and improving the processing precision in the interior of the material to be processed.

[0048] It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes shall belong to the protection scope of the claims attached to the present application.

Claims

1. A laser processing apparatus characterized by comprising: Comprising: a laser unit (11) for generating a machining light beam; a detection unit (12) for generating a measuring light beam, the measuring light beam having the same initial divergence angle as the machining light beam, the detection unit (12) being capable of generating an electrical signal from a light signal reflected back from a material to be machined; a beam combination unit (13) for adjusting the optical axis direction of the machining light beam or the measuring light beam so that the optical axes of the machining light beam and the measuring light beam coincide; a condensing unit (14) for focusing the machining light beam and the measuring light beam that have passed through the beam combination unit (13); and a lens unit (15) disposed between the condensing unit (14) and the laser unit (11) or between the condensing unit (14) and the detection unit (12), the lens unit (15) cooperating with the condensing unit (14) to focus the machining light beam and the measuring light beam at a first position and a second position, respectively, the first position being inside the material to be machined, and the second position being on the surface of the material to be machined.

2. The laser machining device according to claim 1, characterized in that the laser machining device further comprises a control unit (16) and an execution unit (17), the control unit (16) being electrically connected to the detection unit (12) and the execution unit (17), the control unit (16) being configured to receive the electrical signal and generate a corresponding adjustment signal according to the electrical signal, and the execution unit (17) being electrically connected to the control unit (16), the execution unit (17) being configured to receive the adjustment signal and adjust the displacement of the condensing unit (14) according to the adjustment signal.

3. The laser machining device according to claim 2, characterized in that the lens unit (15) is configured as a positive lens (151), the positive lens (151) being disposed between the beam combination unit (13) and the detection unit (12), the machining light beam and the measuring light beam having the same divergence angle, and the divergence angle of the measuring light beam being reduced by the positive lens (151) when the measuring light beam passes through the positive lens (151).

4. The laser machining device according to claim 3, characterized in that the focal length of the positive lens (151) ranges from 200 mm to 1000 mm.

5. The laser machining device according to claim 2, characterized in that the lens unit (15) is configured as a negative lens (152), the negative lens (152) being disposed between the beam combination unit (13) and the laser unit (11), the machining light beam and the measuring light beam having the same divergence angle, and the divergence angle of the machining light beam being increased by the negative lens (152) when the machining light beam passes through the negative lens (152).

6. The laser machining device according to claim 5, characterized in that the focal length of the negative lens (152) ranges from -1000 mm to -200 mm.

7. The laser processing apparatus according to claim 2, wherein a distance between the first position and the second position is defined as a focal depth, the focal depth D satisfying the following relationship: ； where n represents a refractive index of the material to be processed, F represents a focal length of the condensing unit (14), f represents a focal length of the lens unit (15), and d represents an optical center distance between the condensing unit (14) and the lens unit (15).

8. The laser processing apparatus according to claim 7, wherein the focal depth is in a range of 0.2 mm to 1.5 mm.

9. The laser processing apparatus according to claim 7, wherein the laser processing apparatus further comprises a lens adjustment unit (18) electrically connected to the control unit (16), the lens adjustment unit (18) being capable of acquiring the adjustment signal and controlling displacement of the lens unit (15) according to the adjustment signal to increase or decrease the optical center distance.

10. The laser processing apparatus according to claim 1, wherein the laser unit (11) comprises a solid / fiber laser, and the detection unit (12) comprises an LED / LD light source.

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