High power laser fiber strong heat dissipation mounting process

Abstract

The application discloses a high-power laser fiber strong heat dissipation mounting process, which comprises the following steps: S1, preparing a metal heat dissipation plate, machining a fiber mounting groove on the surface of the metal heat dissipation plate, and quickly vacuum cleaning and packaging the metal heat dissipation plate after the machining; S2, preparing a fiber and a filler prepared from metal powder, arranging the fiber in the fiber mounting groove of the metal heat dissipation plate, covering the filler on the fiber, then placing the metal heat dissipation plate on a heat radiation platform of a vacuum brazing furnace, and closing the vacuum brazing furnace; S3, first vacuumizing the vacuum brazing furnace to at least 2.4X10 ‑5 Pa, then heating the heat radiation platform to 240-260 DEG C, and keeping the temperature for 4 hours; and S4, after the internal temperature of the vacuum brazing furnace decreases to 80 DEG C, introducing atmosphere, and taking out the metal heat dissipation plate and the fiber as a whole after the brazing is completed. The process can significantly improve the heat dissipation efficiency of the fiber, and provides a solid technical foundation for large-scale development and application of high-power lasers.

Description

Technical Field

[0001] This invention belongs to the field of laser technology, specifically relating to a high-power laser fiber heat dissipation installation process. Background Technology

[0002] With the widespread application of products such as laser cutting and high-speed optical modules, high-power lasers have experienced rapid development. Among high-power lasers, especially continuous fiber lasers for industrial processing applications, output power is increasingly higher. Single-cavity fiber lasers have continuous output power in the range of 500W-5000W, while multimode fiber lasers have output power exceeding 30kW. The application range of high-power lasers is becoming increasingly broad.

[0003] High-power lasers generate significant heat when their optical fibers are in operation. If this heat is not absorbed promptly, the fiber can easily melt and break, affecting the laser's performance and lifespan. Current technology primarily utilizes heat sinks to dissipate the heat generated by the optical fiber. The specific installation method involves machining annular fiber grooves on the heat sink surface according to the fiber's outer diameter, embedding the fiber into the grooves, applying thermal grease, and transferring the fiber's heat to the heat sink through the grease. Finally, a cooling system is installed on the heat sink to achieve fiber heat dissipation.

[0004] Among the heat dissipation methods mentioned above, the thermal conductivity of thermal grease is generally 0.8-5.0 W / (mK), which has limited thermal conductivity and is not ideal for heat dissipation of high-power lasers. Therefore, in the era of widespread use of high-power lasers, it is necessary to develop a new fiber optic heat dissipation installation process to improve fiber optic heat dissipation efficiency. Summary of the Invention

[0005] In view of this, the present invention provides a high-power laser fiber heat dissipation installation process, which aims to enhance the heat dissipation efficiency of the fiber.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A high-power laser fiber optic heat dissipation installation process, the key points of which include the following steps:

[0008] S1: Prepare a metal heat sink, process fiber optic mounting grooves on the surface of the metal heat sink, and quickly vacuum clean and seal the metal heat sink after processing.

[0009] S2: Prepare optical fiber and brazing filler metal made from metal powder. First, lay the optical fiber in the optical fiber mounting groove of the metal heat sink, then cover the optical fiber with brazing filler metal, and then place the metal heat sink on the heat radiation platform of the vacuum brazing furnace and turn off the vacuum brazing furnace.

[0010] S3: The vacuum brazing furnace should be evacuated to at least 2.4 x 10⁻⁶.-5 Pa, then the thermal radiation platform is heated to 240-260℃ and kept at that temperature for 4 hours;

[0011] S4: After the internal temperature of the vacuum brazing furnace drops to 80°C, it is vented to the atmosphere, and the brazed metal heat sink and optical fiber assembly are removed.

[0012] Preferably, the brazing filler metal is composed of a mixture of copper powder, silver powder, aluminum powder, lead powder, indium powder and tin powder;

[0013] Among them, the particle size of copper powder is 1-6μm, the particle size of silver powder is 1-4μm, the particle size of aluminum powder is 1-3μm, the particle size of lead powder is 1-3μm, the particle size of indium powder is 20-30μm, and the particle size of tin powder is 20-30μm.

[0014] The proportions of copper powder by mass are 28%-31%, silver powder by mass are 7%-9%, aluminum powder by mass are 3%-5%, lead powder by mass are 4%-8%, indium powder by mass are 20%-25%, and tin powder by mass are 20%-25%.

[0015] Preferably, in step S1, the metal heat sink is an aluminum plate, and the vacuum cleaning and sealing time of the aluminum plate after the fiber optic mounting groove is processed does not exceed 20 minutes, with a sealing vacuum value of 2.1 x 10⁻⁶. -4 Pa.

[0016] Preferably, in step S2, a gap of 0.1-0.15 mm should be ensured between the optical fiber and the sidewall and bottom of the optical fiber mounting groove.

[0017] Preferably, the upper part of the optical fiber mounting groove is configured as a V-shaped opening structure, and the brazing filler filler is placed inside the V-shaped opening.

[0018] Preferably, in step S2, the planarity error of the thermal radiation platform should also be checked to be less than 1 mm.

[0019] Preferably, the process of placing the optical fiber and brazing filler into the optical fiber mounting slot is carried out in a helium-protected chamber.

[0020] Preferably, the fiber optic mounting slot includes several continuous vortex segments, an arc-shaped segment located at the inner end of the vortex segments, and a straight lead-out segment located at the outer end of the vortex segments.

[0021] Preferably, the metal heat sink has an arc-shaped groove at the position corresponding to the inner end of the arc-shaped segment.

[0022] Preferably, the metal heat sink has a built-in cooling water circulation channel.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] The high-power laser fiber optic heat dissipation installation process provided by this invention uses low-temperature brazing technology to fix the fiber optic cable within a metal heat sink. This allows for a solid-state metal connection between the fiber optic cable and the heat sink. Compared to traditional thermal grease, the thermal conductivity of the metal increases exponentially, significantly improving the heat dissipation efficiency of the fiber optic cable. This provides a solid technical foundation for the large-scale development and application of high-power lasers. Furthermore, proper vacuum treatment and low-temperature brazing control prevent the formation of alumina on the metal heat sink, helping to ensure the stability, reliability, and high quality of the fiber optic brazing fixation. Attached Figure Description

[0025] Figure 1 A schematic diagram of an optical fiber mounting slot 1a opened on a metal heat sink 1.

[0026] Figure 2 A schematic diagram showing the fiber optic cable 2 being placed inside the fiber optic mounting slot 1a;

[0027] Figure 3 This is a schematic diagram showing the brazing filler metal 3 covering the fiber optic mounting slot 1a.

[0028] Figure 4 This is a reference diagram showing the usage state of fixing the optical fiber 2 to the metal heat sink 1 using a brazing process. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0030] A high-power laser fiber optic installation process with enhanced heat dissipation is disclosed. The core of this method lies in employing a novel process to directly coat the fiber surface with metal, thereby improving thermal conductivity. The specific process steps are as follows:

[0031] S1: Please refer to Figure 1 Prepare a metal heat sink 1, and machine an optical fiber mounting groove 1a on the surface of the metal heat sink 1. After the groove is machined, quickly vacuum clean and seal the metal heat sink 1.

[0032] S2: Prepare optical fiber 2 and brazing filler metal 3, where the brazing filler metal is a metal powder. Please refer to [reference needed]. Figure 2 First, lay fiber optic cable 2 in the fiber optic mounting slot 1a of the metal heat sink 1. Please refer to... Figure 3 Next, the brazing filler metal 3 is applied over the optical fiber 2. Finally, the metal heat sink 1, optical fiber 2, and brazing filler metal 3 are placed together on the heat radiation platform of the vacuum brazing furnace, and the vacuum brazing furnace is turned off.

[0033] S3: The vacuum brazing furnace should be evacuated to at least 2.4 x 10⁻⁶. -5Pa, then the thermal radiation platform is heated to 240-260°C and held at that temperature for 4 hours. In this embodiment, the preferred vacuum value of the vacuum brazing furnace is 2.4 x 10⁻⁶. -5 Pa, the preferred heating temperature of the thermal radiation platform is 250℃.

[0034] S4: The internal temperature of the vacuum brazing furnace drops to 80°C. After the molten brazing filler metal has cooled and solidified sufficiently, it is vented to the atmosphere, and the brazed metal heat sink 1 and optical fiber 2 are taken out as a whole.

[0035] Based on the above process, brazing filler metal 3 is solidified between optical fiber 2 and metal heat sink 1 using low-temperature brazing technology. After brazing, the space between optical fiber 2 and metal heat sink 1 is filled with solid metal. Compared to traditional thermal grease, the thermal conductivity of metal is increased by tens of times, thus significantly improving the heat dissipation efficiency of optical fiber 2 and providing a technical foundation for the large-scale development and application of high-power lasers. Of course, the exponential increase in the thermal conductivity of optical fiber 2 also simplifies the cooling system configured on the heat sink, even allowing for the use of only air-cooled units to achieve the desired cooling effect, greatly reducing the application difficulty of high-power lasers. Furthermore, using brazing to fix optical fiber 2 to metal heat sink 1 also makes the installation of optical fiber 2 more stable.

[0036] In the above process, the fiber optic mounting slot 1a is immediately vacuum-sealed after machining to prevent the formation of metal oxides on the surface of the metal heat sink 1. The vacuum brazing furnace is first evacuated to 2.4 x 10⁻⁶. -5 Pa, and then the thermal radiation platform is heated to 250℃, also to avoid the formation of metal oxides on the metal heat sink 1. At the same time, the low-temperature brazing at over 200℃ can also minimize the formation of oxides. The absence of metal oxides effectively overcomes the technical difficulty of welding the optical fiber 2 into the metal heat sink 1, because if metal oxides, such as alumina, are formed on the metal heat sink 1, even a very thin layer of alumina can lead to defects such as slag inclusions, incomplete fusion, and incomplete weld penetration.

[0037] In this embodiment, the metal heat sink 1 is preferably made of aluminum, and the thermal conductivity of aluminum is generally between 120-217.7 W(mK), which helps to ensure the heat dissipation effect of the optical fiber. Furthermore, in step S1, after the optical fiber mounting groove 1a is processed, the vacuum cleaning and sealing time of the aluminum plate does not exceed 20 minutes, and the sealing vacuum value is 2.1×10-4 Pa. This consideration can minimize the generation of aluminum oxide on the aluminum plate during the processing of the groove.

[0038] This embodiment provides a solder 3 mixed powder, specifically composed of copper powder, silver powder, aluminum powder, lead powder, indium powder, and tin powder. Copper has a thermal conductivity of 400-410 W / (mK), silver 420-430 W / (mK), indium 80-90 W / (mK), lead 34-36 W / (mK), and tin 65-67 W / (mK). In contrast, thermal grease typically has a thermal conductivity of only 0.8-5.0 W / (mK). Therefore, the solder composed of these metals has a thermal conductivity more than 30 times that of thermal grease.

[0039] In each component, copper powder accounts for 28%-31% by mass, silver powder 7%-9% by mass, aluminum powder 3%-5% by mass, lead powder 4%-8% by mass, indium powder 20%-25% by mass, and tin powder 20%-25% by mass. In this embodiment, the preferred ratio is: 28% copper powder, 9% silver powder, 5% aluminum powder, 8% lead powder, 25% indium powder, and 25% tin powder. Indium powder and tin powder have relatively low melting points, 150℃ and 230℃ respectively. At 250℃, both indium powder and tin powder can be fully melted. The fact that these two components account for nearly half of the total composition makes low-temperature brazing of optical fibers feasible.

[0040] Furthermore, in each component, the particle size of copper powder is 1-6 μm, silver powder is 1-4 μm, aluminum powder is 1-3 μm, lead powder is 1-3 μm, indium powder is 20-30 μm, and tin powder is 20-30 μm. This design results in a more uniform and denser solidification effect of the metal filler after low-temperature brazing.

[0041] Furthermore, the above process step S1 also includes sub-step S1.1: After the fiber mounting groove 1a on the metal heat sink 1 is processed, the metal heat sink 1 is placed in a nitrogen or argon protective chamber. Indium powder is blown onto the fiber mounting groove 1a on the metal heat sink under high-pressure circulation of the protective gas. Indium is then deposited onto the surface of the fiber mounting groove 1a using laser sputtering coating technology. In addition, the above process step S2 also includes sub-step S2.2: The fiber 2 is placed in a nitrogen or argon protective chamber. Indium powder is blown onto the fiber under high-pressure circulation of the protective gas. Indium is then deposited onto the surface of the fiber 2 using laser sputtering coating technology. The advantage of this treatment is that it allows both the surface of the fiber 2 and the surface of the fiber mounting groove 1a to be pre-attached with an indium film layer. Since the brazing filler metal also contains a relatively high proportion of indium powder, it enhances the fusion coefficient of the weld, avoids the formation of inferior interlayers between the fiber 2 and the fiber mounting groove 1a, and significantly improves the brazing quality.

[0042] For example Figure 2 and3 As shown, after the optical fiber 2 is placed into the optical fiber mounting groove 1a, it is necessary to ensure that there are gaps between the optical fiber 2 and the two side walls and the bottom of the optical fiber mounting groove 1a. This design allows the powdered brazing filler metal to completely coat the optical fiber 2, making the brazing connection more reliable. The gap between the optical fiber 2 and the optical fiber mounting groove 1a is 0.1-0.15mm, and in this embodiment, the preferred gap is 0.1mm. This gap is larger than the particle size of any of the aforementioned powders, ensuring that the brazing filler metal powder falls smoothly to the bottom of the optical fiber mounting groove 1a.

[0043] Furthermore, the upper part of the fiber optic mounting groove 1a is constructed with a V-shaped open structure. This design facilitates the covering of the brazing filler metal 3. The initial installation height of the brazing filler metal 3 is slightly higher than the upper surface of the metal heat sink 1. After the brazing filler metal 3 powder melts, cools, and solidifies, the excess portion will shrink and be absorbed. After the weld has cooled and solidified, it can be placed in a grinding machine to grind away the rough or protruding parts at the brazing position, thereby giving the metal heat sink 1 a better appearance quality. This also overcomes the appearance defect of a large number of irregular protrusions on the surface of the metal heat sink 1 after the traditional thermal grease has solidified.

[0044] In this embodiment, the vacuum brazing furnace and its thermal radiation platform used in step S2 are both existing, mature equipment, and their working principles will not be elaborated here. The purpose of the vacuum brazing furnace is to provide a vacuum environment, and the thermal radiation platform is to provide a heating environment. In specific use, after the metal heat sink 1, optical fiber 2, and brazing filler metal 3 are placed on the thermal radiation platform, the flatness of the thermal radiation platform should be checked, requiring a planar error of less than 1mm. During the brazing process, the brazing filler metal 3 will become liquid. This consideration ensures that the brazing filler metal 3 is welded more uniformly within the entire optical fiber mounting groove 1a, improving the welding quality and uniformity.

[0045] In step S2 above, to avoid the formation of aluminum oxide on the metal heat sink 1, the entire operation time should not exceed 20 minutes. If the filler metal 3 and the installation length of the optical fiber 2 are large enough, step S2 can be performed in a helium-protected chamber to minimize the formation of aluminum oxide.

[0046] In this embodiment, the metal heat sink 1 has a built-in cooling water circulation channel. After the metal heat sink 1 is applied to a high-power laser, the water circulation channel can be used to assist in cooling the metal heat sink 1 and improve the heat dissipation efficiency of the optical fiber.

[0047] In this embodiment, please refer to the attached document. Figure 4As shown, the metal heat sink 1 is a square plate, and the fiber optic mounting groove 1a includes two continuous spiral sections a. These two spiral sections a increase the contact area between the fiber optic cable 2 and the metal heat sink 1, enhancing heat dissipation. The inner spiral section a has an arc-shaped section b at its starting end. This arc-shaped section b is a variable-diameter arc that smoothly connects to the inner spiral section a, facilitating the secure mounting of the inner end of the fiber optic cable 2. The outer spiral section a has a straight lead-out section c tangentially connected to its end, which helps to guide the fiber optic cable out of the metal heat sink 1. Furthermore, the metal heat sink 1 has an arc-shaped groove 1b corresponding to the inner end of the arc-shaped section b. (See reference...) Figure 4 The enlarged schematic diagram shows that during the installation of fiber 2, the innermost end of the fiber is placed in the arc-shaped groove 1b. This section of fiber smoothly transitions with the fiber within the arc-shaped section b, and the inner end of fiber 2 rests against the side wall d of the arc-shaped groove 1b. This design not only facilitates the installation of fiber 2 but also prevents the inner end of fiber 2 from breaking.

[0048] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A high-power laser fiber optic heat dissipation installation process, comprising the following steps: S1: Prepare a metal heat sink (1), process an optical fiber mounting groove (1a) on the surface of the metal heat sink (1), and after the optical fiber mounting groove (1a) on the metal heat sink (1) is processed, place it in a gas protection chamber and attach indium to the surface of the optical fiber mounting groove (1a) by laser sputtering; then quickly vacuum clean encapsulate the processed metal heat sink (1). S2: Prepare optical fiber (2) and brazing filler metal made of metal powder. Place the optical fiber (2) in a gas protection chamber and attach indium to the surface of the optical fiber (2) by laser sputtering. Then, first place the optical fiber (2) in the optical fiber mounting groove (1a) of the metal heat sink (1), then cover the optical fiber (2) with brazing filler metal, and then place the metal heat sink (1) on the heat radiation platform of the vacuum brazing furnace and turn off the vacuum brazing furnace. The brazing filler metal is composed of copper powder, silver powder, aluminum powder, lead powder, indium powder and tin powder mixed together. The mass percentage of copper powder is 28%, the mass percentage of silver powder is 9%, the mass percentage of aluminum powder is 5%, the mass percentage of lead powder is 8%, the mass percentage of indium powder is 25%, and the mass percentage of tin powder is 25%. The fiber mounting groove (1a) includes several continuous vortex segments (a), an arc segment (b) located at the inner end of the vortex segment (a), and a straight lead-out segment (c) located at the outer end of the vortex segment (a). The metal heat sink (1) is provided with an arc groove (1b) at the position corresponding to the inner end of the arc segment (b). The arc segment (b) is a variable diameter arc, which is smoothly connected to the inner vortex segment (a). After the fiber (2) is installed in the fiber mounting groove (1a), the inner end of the fiber (2) abuts against the side wall (d) of the arc groove (1b). S3: The vacuum brazing furnace should be evacuated to at least 2.4 x 10⁻⁶. -5 Pa, then the thermal radiation platform is heated to 240-260℃ and kept at that temperature for 4 hours; S4: After the temperature inside the vacuum brazing furnace drops to 80°C, it is vented to the atmosphere, and the brazed metal heat sink (1) and optical fiber (2) are taken out as a whole.

2. The high-power laser fiber heat dissipation installation process according to claim 1, characterized in that: The copper powder has a particle size of 1-6 μm, the silver powder has a particle size of 1-4 μm, the aluminum powder has a particle size of 1-3 μm, the lead powder has a particle size of 1-3 μm, the indium powder has a particle size of 20-30 μm, and the tin powder has a particle size of 20-30 μm.

3. The high-power laser fiber heat dissipation installation process according to claim 1, characterized in that: In step S1, the metal heat sink (1) is an aluminum plate. After the fiber optic mounting groove (1a) is processed, the vacuum cleaning and sealing time of the aluminum plate does not exceed 20 minutes, and the sealing vacuum value is 2.1 x 10⁻⁶. -4 Pa.

4. The high-power laser fiber heat dissipation installation process according to claim 1, characterized in that: In step S2, it should be ensured that there is a gap between the optical fiber (2) and the side wall and bottom of the optical fiber mounting groove (1a), and the gap value is 0.1-0.15mm.

5. The high-power laser fiber heat dissipation installation process according to claim 1, characterized in that: The upper part of the fiber mounting slot (1a) is constructed as a V-shaped opening structure, and the brazing filler fills the V-shaped opening.

6. The high-power laser fiber heat dissipation installation process according to claim 1, characterized in that: In step S2, the planarity error of the thermal radiation platform should also be checked to be less than 1 mm.

7. The high-power laser fiber heat dissipation installation process according to claim 1, characterized in that: The process of placing the optical fiber (2) and brazing filler into the optical fiber mounting slot (1a) is carried out in a helium-protected chamber.

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