Laser collimation output head structure for quartz end cap

Abstract

The application relates to the field of high-power laser welding and additive manufacturing technology, and discloses a laser collimation output head structure of a quartz end cap, which comprises a quartz end cap, an optical fiber and a sealing component, the optical fiber output end face of the optical fiber is fused with the input end face of the quartz end cap in the sealing component, the sealing component comprises an inner shell and an outer shell, an annular sealing gas path is arranged between the inner shell and the outer shell, the input end of the sealing gas path is connected with an external gas source through a pipeline, the output end is used for outputting protective gas, one end of the inner shell is provided with an axially connected central through hole one, the other end is provided with a central through hole two, the optical fiber is fixed in the central through hole one of the inner shell, the input end face of the quartz end cap is matched with the inner side end face of the inner shell, and the outer circle on one side of the quartz end input end face is sealingly connected with the central through hole two. The application has the advantages of compact structure, good heat dissipation performance, high beam quality, guaranteed process and product quality, reduced use and maintenance cost, and is particularly suitable for robot welding applications sensitive to weight.

Description

Technical Field

[0001] This invention relates to the field of high-power laser welding and additive manufacturing technology, and specifically to a laser collimation output head structure with a quartz end cap. Background Technology

[0002] In high-power laser welding and additive manufacturing, the output quality of the laser beam and the integration of the equipment directly affect processing efficiency and precision. Existing laser output systems typically employ a split structure with a planar end cap and an independent collimating lens. This structure has the following drawbacks: 1) Optical path assembly errors: The diverging beam output from the planar end cap needs to be collimated and shaped by the collimating lens in the spatial optical path. Assembly errors in the coaxiality and parallelism between the lens and the end cap directly lead to a decrease in beam quality, resulting in aberrations and affecting the weld penetration and uniformity of the additive layer. 2) Complex and bulky structure: The independent collimating lens group, lens barrel, and adjustment mechanism increase the size and weight of the optical head, limiting its flexible application at the robot end and placing higher demands on the load capacity of the robotic arm. 3) Difficult gas path integration: The welding process usually requires auxiliary gas protection. Traditional solutions often use external additional gas paths or complex internal pipelines, resulting in a bulky overall structure, poor sealing, and increased assembly difficulty. 4) Poor interface versatility: Although common laser output heads on the market (such as QBH) have locking functions, their internal locking mechanisms are complex and contain many metal parts, resulting in a large overall weight and hindering lightweight design. 5) Poor thermal management: In high-power laser applications, the thermal management capabilities of traditional structures are limited, which can easily damage optical components.

[0003] Therefore, there is an urgent need in the existing technology for a laser output cap device that can overcome the above-mentioned defects and achieve simplified optical path, compact structure, integrated gas path and flexible interface. Summary of the Invention

[0004] This invention aims to overcome the shortcomings of the existing technology by providing a laser collimation output head structure with a quartz end cap. This invention is small in size, compact in structure, lightweight, highly integrated, and versatile. It simplifies the optical path, improves heat dissipation, and enhances beam quality. It eliminates beam aberration problems caused by lens assembly errors, effectively solves thermal management issues in high-power applications, reduces usage and maintenance costs, and improves the process stability of welding and additive manufacturing. It is particularly suitable for weight-sensitive robotic welding applications.

[0005] The technical solution adopted by this invention to solve its technical problem is: A laser collimation output head structure with a quartz end cap includes a quartz end cap, an optical fiber, and a sealing component. The output end face of the optical fiber extends into the sealing component from one end, and the input end face of the quartz end cap extends into the sealing component from the other end. The output end face of the optical fiber and the input end face of the quartz end cap are fused together within the sealing component. The sealing component includes an inner shell and an outer shell. An annular sealing gas passage is provided between the inner shell and the outer shell. The input end of the sealing gas passage is connected to an external gas source through a pipe, and the output end is used to output protective gas. One end of the inner shell has a small-diameter central through hole 1, and the other end has a larger-diameter central through hole 2. The central through hole 1 and the central through hole 2 are connected. The optical fiber is fixed in the central through hole 1 of the inner shell. The input end face of the quartz end cap mates with the inner end face of the inner shell, and the outer circle of one side of the input end face of the quartz end cap is sealed to the central through hole 2 of the inner shell.

[0006] The output end face of the quartz end cap is an outwardly convex arc-shaped surface. The arc-shaped surface is used to collimate the diverging beam output from the optical fiber into a large-spot parallel beam. The input end face of the quartz end cap is provided with a quartz end cap input end face boss, which is connected to the output end face of the optical fiber.

[0007] The inner shell has a fixing seat installed at one end of the central through hole. The fixing seat has a central hole, through which the optical fiber passes and is fixed.

[0008] The outer end of the fixed base is provided with a protective sleeve. The optical fiber passes through the protective sleeve and enters the central hole of the fixed base and then enters the central through hole one. The protective sleeve is connected to the fixed base.

[0009] The tail of the fixed base is connected to a sleeve connection part, and the end of the protective sleeve is sealed to the sleeve connection part.

[0010] The sealing gas path includes an annular groove formed on the outer cylindrical surface of the inner shell, an air inlet and an air inlet channel connected to the air inlet at one end of the outer shell, the air inlet channel being connected to the air inlet of the annular groove, and an air outlet and an air outlet channel connected to the air outlet at the other end of the outer shell, the air outlet channel being connected to the air outlet of the annular groove. The air inlet is connected to an external gas source through a pipeline, and the air outlet is used to output protective gas.

[0011] The outer casing has a mounting flange on the end face near the air outlet. The mounting flange has screw holes, and the mounting flange is connected to the laser welding head or additive manufacturing equipment by screws and screw holes.

[0012] In addition, the mounting flange is provided with pin holes, which are used to achieve precise positioning of the mounting flange with the laser welding head or additive manufacturing equipment by engaging the pins with the pin holes.

[0013] The radius of curvature of the arc-shaped surface is precisely matched with the numerical aperture of the optical fiber, and the divergence angle of the output beam is controlled within ±0.5mrad.

[0014] The laser collimation output head adopts a large spot diameter structure. The spot diameter d and the end cap diameter D are obtained by the following formula: d = 2L·NA / n; Where d is the beam diameter, L is the overall length of the end cap, n is the refractive index of the end cap, and NA is the numerical aperture of the fiber. The diameter D of the end cap is obtained by the following formula: D = 2d + 1; Where D is the end cap diameter and d is the spot diameter.

[0015] The optical fiber output end face is located at the object-side focus f of the end cap output spherical surface, and the distance between the optical fiber output end face and the end cap output surface is L=f; The relationship between the object-side focal length f and the radius of curvature R of the curved surface is obtained through the following formula for refraction of a single spherical surface:

[0016] Substituting L=f into the above formula, the radius of curvature can be calculated as: R = L·(n-1) / n; R is the radius of curvature, n is the refractive index of the end cap, and L is the overall length of the end cap.

[0017] The beneficial effects of this invention are: 1. The quartz end cap for optical path collimation and the sealing component for auxiliary gas path are integrated into a single structure. The mounting base integrates fiber optic fixing and protective sleeve fixing functions, replacing the design that requires additional components for fixing the fiber optic cable and sleeve separately. The structure is compact and the size of the equipment is greatly reduced. At the same time, the structure and fit of the inner and outer shells make the end cap adaptable to a variety of laser processing equipment of different specifications, with strong versatility.

[0018] 2. This invention has high reliability and good stability. The sealed air path design can ensure the stability of airflow. The protective airflow through the air path can remove dust particles, preventing dust particles in the environment from entering the optical path and causing heat generation, which could lead to device burnout. This effectively extends the service life of the end cap and reduces maintenance costs.

[0019] 3. The sealed gas path formed by the inner shell and outer shell of the present invention directly covers the quartz end cap. When the laser is running, the airflow in the gas path directly cools the inner shell. This integrated heat dissipation structure does not require an additional heat dissipation system, has good heat dissipation performance, and effectively solves the thermal management problem in high-power applications.

[0020] 4. The optical path of the present invention is simplified, eliminating the collimating lens and its adjustment mechanism in the spatial optical path, fundamentally eliminating the beam aberration problem caused by lens assembly error, resulting in high beam quality and excellent optical performance.

[0021] Among them, the arc-shaped quartz end cap structure directly achieves collimated large spot output, with uniform spot energy distribution and better beam quality, which is conducive to improving the process stability of welding and additive manufacturing.

[0022] 5. The invention is lightweight and has a flexible interface: It adopts a screw and pin positioning and locking method, which replaces the complex and bulky buckle locking mechanism in the existing QBH interface, achieves high-precision positioning, significantly reduces the weight of the device, reduces the number of parts, simplifies the assembly process, and is particularly suitable for weight-sensitive robot welding applications.

[0023] 6. The tail of the fixing base of the present invention is connected to a sleeve connection part, which ensures that the protective sleeve and the sleeve connection part are reliably fixedly connected, realizes accurate and reliable fixing of the optical fiber, resulting in high beam quality, uniform beam energy distribution, and improved process stability of welding and additive manufacturing. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a cross-sectional structural diagram of a specific embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the output end view of the present invention, i.e., the mounting flange end structure.

[0026] Figure 3 This is a schematic diagram of an arc-shaped quartz end cap structure.

[0027] Figure 4 This is a schematic diagram of the connection structure between the fixed base and the protective sleeve.

[0028] Figure 5 This is a schematic diagram of the gas path structure of the present invention.

[0029] In the figure, 1-quartz end cap, 2-optical fiber, 3-inner shell, 4-outer shell, 5-annular groove, 6-air inlet, 7-air outlet, 8-fixed base, 9-protective sleeve, 10-pin hole, 11-screw hole, 12-quartz end cap input end face boss, 13-quartz end cap output end face, 14-opening groove, 15-sleeve connection part. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments.

[0031] Example 1 like Figure 1-5 As shown, a laser collimation output head structure with a quartz end cap includes a quartz end cap 1, an optical fiber 2, and a sealing component. The quartz end cap 1 is connected to the optical fiber 2. Specifically, the output end face of the optical fiber 2 extends into the sealing component from one end, and the input end face of the quartz end cap extends into the sealing component from the other end. The output end face of the optical fiber 2 and the input end face of the quartz end cap are fused together within the sealing component. The sealing component includes an inner shell 3 and an outer shell 4. An annular sealing gas path is provided between the inner shell 3 and the outer shell 4. The sealing gas path is obtained by laser welding of the inner shell 3 and the outer shell 4 or by sealing with a sealing rubber ring. The input end of the sealing gas path is connected to an external gas source through a pipeline, and the output end outlet 7 is used to output protective gas. The inner housing 3 has a small-diameter central through hole 1 at one end and a larger-diameter central through hole 2 at the other end. The central through hole 1 and the central through hole 2 are connected. The optical fiber 2 is fixed in the central through hole 1 of the inner housing 3. The input end face or the incident end face of the quartz end cap 1 is matched with the inner end face of the inner housing 3. The outer circle of one side of the input end face of the quartz end cap 1 is sealed to the central through hole 2 of the inner housing 3, such as by using a threaded sealing connection.

[0032] The sealed gas path includes an annular groove 5 formed on the outer cylindrical surface of the inner shell 3. One end of the outer shell 4 is provided with an air inlet 6 and an air inlet channel communicating with the air inlet 6. The air inlet channel is connected to the air inlet of the annular groove 5. The other end of the outer shell 4 is provided with an air outlet 7 and an air outlet channel communicating with the air outlet 7. The air outlet channel is connected to the air outlet of the annular groove 5. The air inlet 6 is connected to an external gas source through a pipeline. The air outlet 7 is used to output protective gas. The raised cylindrical surfaces at both ends of the annular groove 5 are sealed and connected with the inner hole of the outer shell 4. Sealing rings or the like can be installed on the mating surfaces to achieve a reliable seal and prevent gas leakage.

[0033] like Figure 3 The quartz end cap 1 is an arc-shaped quartz end cap, meaning the output end face 13 of the quartz end cap is an outwardly convex arc-shaped surface. The input end face of the quartz end cap is provided with an input end face boss 12, which is connected to the output end face of the optical fiber. The arc-shaped surface is used to collimate the diverging beam output from the optical fiber 2 into a large-spot parallel beam. The radius of curvature of the arc-shaped surface is precisely matched with the numerical aperture of the optical fiber, so that the divergence angle of the output beam is controlled within ±0.5 mrad.

[0034] The inner housing 3 has a fixing seat 8 installed at one end of the central through hole. The fixing seat 8 has a central hole, through which the optical fiber 2 passes and is fixed. The optical fiber 2 is fixed to the central hole of the fixing seat using optical adhesive. The fixing seat 8 is connected to the inner housing 3 by a threaded connection.

[0035] The outer end of the fixed base 8 is connected to a protective sleeve 9. The optical fiber 2 passes through the protective sleeve 9 and enters the central hole of the fixed base and then enters the central through hole one.

[0036] like Figure 4 As shown, the tail of the fixing base 8 is connected to a sleeve connection part 15, and the end of the protective sleeve 9 is connected to the sleeve connection part 15. If the end of the protective sleeve 9 is press-fitted to the sleeve connection part 15, a reliable fixed connection is ensured. Alternatively, the sleeve connection part 15 can have an opening groove 14, the outer diameter of the protective sleeve 9 matches the inner diameter of the inner hole of the sleeve connection part 15, the protective sleeve 9 passes through the opening groove 14, and then adhesive is applied at the opening groove 14 to reliably bond the protective sleeve 9 to the sleeve connection part 15 to prevent detachment.

[0037] The outer casing 4 has a mounting flange on its end face near the air outlet 7. The mounting flange has screw holes 11, and the laser welding head or additive manufacturing equipment also has connection holes. The mounting flange and the connection holes of the laser welding head or additive manufacturing equipment are reliably connected and locked through the screw holes 11 and screws. There are multiple screw holes.

[0038] like Figure 2 Additionally, the mounting flange is provided with pin holes 10, and the laser welding head or additive manufacturing equipment is also provided with pin holes. The pins and pin holes enable precise positioning of the mounting flange and the laser welding head or additive manufacturing equipment.

[0039] The pin holes 10 are provided in two symmetrically distributed at both ends of the flange diameter; the screw holes are provided in four or six symmetrically distributed around the pin holes. During installation, the pins are first used to engage with the pin holes 10 for precise positioning, and then the screw holes are used to engage with the screws for reliable fastening.

[0040] During installation, first insert the pin into the pin hole 10 to accurately position the flange and the positioning hole on the mounting surface of the laser welding head or additive manufacturing equipment. Then, use the screw through the screw hole 11 to securely connect and lock the entire end cap assembly to the connection hole on the mounting surface of the laser welding head or additive manufacturing equipment.

[0041] Working principle of this invention: In practical applications, high-power laser light is output from optical fiber 2 and directly collimated into a large-spot beam through an arc-shaped quartz end cap. Simultaneously, protective gas enters the annular groove 5 from the air inlet 6 of the outer shell 4 and is blown out from the air outlet 7 of the outer shell 4, forming a coaxial protective gas flow. This achieves integrated light and gas output, resulting in a compact structure, stable performance, and fully meeting the stringent requirements of high-power laser welding and additive manufacturing.

[0042] Example 2 The laser collimation output head of the quartz end cap of this invention adopts a large spot diameter structure. When the laser enters the quartz end cap from fiber 2, it is in a divergent state. The degree of laser divergence is reflected by the numerical aperture NA of the fiber. When it reaches the output end face of the quartz end cap, it forms a sufficiently large spot, which can effectively reduce the energy density and avoid the risk of the end cap burning out due to excessive energy density. The spot diameter d is obtained by the following formula: d = 2L·NA / n; Where d is the beam diameter, L is the overall length of the end cap, n is the refractive index of the end cap, and NA is the numerical aperture of the optical fiber.

[0043] The diameter of the end cap is obtained by the following formula: D = 2d + 1; Where D is the end cap diameter and d is the spot diameter.

[0044] The preferred values ​​are L = 60mm-80mm, refractive index n = 1.45, spot diameter = 5.4mm-7.2mm, and end cap diameter = 11.8mm-15.4mm.

[0045] The laser collimation output head of the quartz end cap can realize laser collimation output. The fiber output end face, as the source of the diverging beam, must be located at the object-side focus f of the output spherical surface of the end cap. At this time, the distance between the fiber output end face and the output surface of the end cap is the length L of the end cap, i.e., L=f. The relationship between the object-side focal length f and the radius of curvature R of the curved surface is obtained through the following formula for refraction of a single spherical surface:

[0046] n is the refractive index of the end cap. If we assume L = f = 80 mm and n = 1.45 and substitute them into the above formula, we can obtain the radius of curvature R of the arc-shaped surface of the quartz end cap as 24.83 mm.

[0047] In the description of this invention, the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "vertical," and "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only to describe the invention and not to require the invention to be constructed or operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected" and "linked" in this invention should be interpreted broadly. For example, they can refer to a connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms based on the specific circumstances.

[0048] The above description represents preferred embodiments of the present invention. The specific embodiments are provided solely for a better understanding of the invention's concept. Those skilled in the art will recognize that various improvements or equivalent substitutions can be made based on the principles of the present invention, and these improvements or equivalent substitutions are also considered to fall within the scope of protection of the present invention.

Claims

1. A laser collimation output head structure with a quartz end cap, comprising a quartz end cap, an optical fiber, and a sealing component, wherein the output end face of the optical fiber extends into the sealing component from one end, and the input end face of the quartz end cap extends into the sealing component from the other end, and the output end face of the optical fiber and the input end face of the quartz end cap are fused together within the sealing component, characterized in that... The sealing component includes an inner shell and an outer shell. An annular sealing gas passage is provided between the inner shell and the outer shell. The input end of the sealing gas passage is connected to an external gas source through a pipeline, and the output end is used to output protective gas. One end of the inner shell is provided with a small-diameter central through hole 1, and the other end is provided with a larger-diameter central through hole 2. The central through hole 1 and the central through hole 2 are connected. The optical fiber is fixed in the central through hole 1 of the inner shell. The input end face of the quartz end cap mates with the inner end face of the inner shell, and the outer circle of one side of the input end face of the quartz end cap is sealed to the central through hole 2 of the inner shell.

2. The laser collimation output head structure with quartz end cap according to claim 1, characterized in that, The output end face of the quartz end cap is an outwardly convex arc-shaped surface. The arc-shaped surface is used to collimate the diverging beam output from the optical fiber into a large-spot parallel beam. The input end face of the quartz end cap is provided with a quartz end cap input end face boss, which is connected to the output end face of the optical fiber.

3. The laser collimation output head structure with quartz end cap according to claim 1, characterized in that, The inner shell has a fixing seat installed at one end of the central through hole. The fixing seat has a central hole, through which the optical fiber passes and is fixed.

4. The laser collimation output head structure with quartz end cap according to claim 3, characterized in that, The outer end of the fixed base is provided with a protective sleeve. The optical fiber passes through the protective sleeve and enters the central hole of the fixed base and then enters the central through hole one. The protective sleeve is connected to the fixed base.

5. The laser collimation output head structure with quartz end cap according to claim 4, characterized in that, The tail of the fixed base is connected to a sleeve connection part, and the end of the protective sleeve is connected to the sleeve connection part.

6. The laser collimation output head structure with quartz end cap according to claim 1, characterized in that, The sealing gas path includes an annular groove formed on the outer cylindrical surface of the inner shell, an air inlet and an air inlet channel connected to the air inlet at one end of the outer shell, the air inlet channel being connected to the air inlet of the annular groove, and an air outlet and an air outlet channel connected to the air outlet at the other end of the outer shell, the air outlet channel being connected to the air outlet of the annular groove. The air inlet is connected to an external gas source through a pipeline, and the air outlet is used to output protective gas.

7. The laser collimation output head structure with quartz end cap according to claim 1, characterized in that, The outer casing has a mounting flange on the end face near the air outlet, and the mounting flange has screw holes. The mounting flange is provided with pin holes, and the mounting flange is positioned relative to the laser welding head or additive manufacturing equipment by the cooperation of the pins with the pin holes.

8. The laser collimation output head structure with quartz end cap according to claim 1, characterized in that, The radius of curvature of the arc-shaped surface is matched with the numerical aperture of the optical fiber, and the divergence angle of the output beam is controlled within ±0.5mrad.

9. The laser collimation output head structure with a quartz end cap according to claim 8, characterized in that, The laser collimation output head adopts a large spot diameter structure. The spot diameter d and the end cap diameter D are obtained by the following formula: d = 2L·NA / n; Where d is the beam diameter, L is the overall length of the end cap, n is the refractive index of the end cap, and NA is the numerical aperture of the fiber. The diameter D of the end cap is obtained by the following formula: D = 2d + 1; Where D is the end cap diameter and d is the spot diameter.

10. The laser collimation output head structure with a quartz end cap according to claim 9, characterized in that, The optical fiber output end face is located at the object-side focus f of the end cap output spherical surface, and the distance between the optical fiber output end face and the end cap output surface is L=f; The relationship between the object-side focal length f and the radius of curvature R of the curved surface is obtained through the following formula for refraction of a single spherical surface: Substituting L=f into the above formula, the radius of curvature can be calculated as: R = L·(n-1) / n; R is the radius of curvature, n is the refractive index of the end cap, and L is the overall length of the end cap.

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