A laser processing head and a laser processing apparatus

Abstract

The application discloses a laser processing head and a laser processing device, and relates to the technical field of laser processing. The laser processing head comprises a blowing pipe, a laser channel and a suction pipe. The bottom end of the blowing pipe is provided with a blowing port. The blowing port is arranged at intervals from a workpiece and can blow protective gas to the workpiece. The laser channel is arranged at intervals from the blowing pipe and is located in the blowing pipe. The laser channel is provided with a light beam input end and a light beam output end arranged oppositely. A laser beam can enter the laser channel from the light beam input end and is output from the light beam output end to perform laser processing on the workpiece through the blowing port. The suction pipe is arranged at intervals from the blowing pipe and is sleeved outside the blowing pipe. The bottom end of the suction pipe is provided with a suction port. The suction port can suck the protective gas blown out from the blowing port. The laser processing head can effectively avoid the situation that the processing appearance is not symmetrical due to side sweeping, ensure good welding effect, avoid the pollution of the processing environment caused by the sweeping particles and protect the health of the operator.

Description

Technical Field

[0001] This invention relates to the field of laser processing technology, and more particularly to a laser processing head and a laser processing device. Background Technology

[0002] Laser processing technology (laser welding, laser drilling, laser cutting, etc.) is a core process in advanced manufacturing and has been widely used in industries such as automobiles, new energy, electronics, and medical. When processing workpieces with lasers, plasma is easily formed above the workpiece. To avoid the formation of a plasma cloud that reduces laser transmittance, the plasma cloud is usually dispersed by blowing it away from the side with a protective gas.

[0003] However, the disturbance of the molten pool by the inclined blowing airflow will have a negative impact on the stability of the welding process and the protection of the molten pool, and will also lead to asymmetry in the processing morphology, affecting the processing effect; moreover, the blown particles will also pollute the processing environment and affect the health of the operators. Summary of the Invention

[0004] The purpose of this invention is to provide a laser processing head and laser processing device that can effectively avoid the asymmetry of the processing morphology caused by side blowing, ensure good welding effect, and also avoid the pollution of the processing environment by the blown particles, thus protecting the health of the operators.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A laser processing head, comprising:

[0007] An air blowing pipe is provided at the bottom end of the air blowing pipe, and the air blowing port is spaced apart from the workpiece and can blow protective gas onto the workpiece.

[0008] A laser channel is located inside the air blowing pipe and spaced apart from the air blowing pipe. The laser channel has a beam input end and a beam output end that are arranged opposite to each other. The laser beam can enter the laser channel from the beam input end and be output from the beam output end, and perform laser processing on the workpiece through the air blowing port.

[0009] An air intake tube is sleeved outside the air blowing tube and spaced apart from the air blowing tube. An air intake port is provided at the bottom end of the air intake tube, which can draw in the protective gas blown out by the air blowing port.

[0010] As an alternative to the aforementioned laser processing head, the laser processing head further includes a laser tube, the laser channel is disposed inside the laser tube, the beam input end and the beam output end are respectively opened at opposite ends of the laser tube, and the laser tube is disposed inside the air blowing tube.

[0011] As an alternative to the aforementioned laser processing head, the distance between the beam output end and the workpiece is greater than the distance between the air outlet and the workpiece.

[0012] As an optional solution for the aforementioned laser processing head, the distance between the air blowing port and the workpiece is smaller than the distance between the air suction port and the workpiece.

[0013] As an optional solution for the aforementioned laser processing head, the air intake is spaced apart from the workpiece.

[0014] As an alternative to the aforementioned laser processing head, the distance between the air blowing pipe and the air suction pipe first decreases and then increases along the direction closer to the workpiece.

[0015] As an optional solution for the aforementioned laser processing head, the air blowing tube includes an air passage section and a flow-retarding section. The air passage section is connected to the flow-retarding section, and the air passage section is located at the end of the flow-retarding section closer to the workpiece. The inner diameter of the flow-retarding section is larger than the inner diameter of the air passage section.

[0016] As an alternative to the aforementioned laser processing head, the inner diameter of the slow-flow section first increases and then decreases along the direction closer to the workpiece.

[0017] As an alternative to the aforementioned laser processing head, the air blowing tube has a generatrix, and the tangent extension of the end of the generatrix at the location of the air blowing port intersects the surface of the workpiece at point A. Point A is located outside the range of the axial projection of the air blowing port onto the workpiece.

[0018] A laser processing apparatus includes the aforementioned laser processing head and a laser generator, wherein the laser generator is disposed at the beam input end and is capable of generating the laser beam.

[0019] The beneficial effects of this invention are:

[0020] This invention provides a laser processing head and a laser processing apparatus. In the laser processing head, a laser beam enters the laser channel through the beam input end, passes through the laser channel, and is output from the beam output end, irradiating the surface of the workpiece to perform laser welding, laser cutting, or laser drilling operations. Since the laser channel is located inside the air blowing pipe and spaced apart from it, the protective gas blown out by the air blowing pipe is directed towards the workpiece around the laser beam, ensuring uniform disturbance of the molten pool. The suction pipe is sleeved outside the air blowing pipe and spaced apart from it, enabling the plasma and particulate matter generated during processing to be quickly extracted with the protective gas, ensuring laser transmittance, improving laser energy utilization and welding efficiency, enhancing welding process stability, and effectively protecting the weld pool.

[0021] This laser processing head can effectively avoid asymmetry in the processing shape caused by side blowing, ensuring good welding results. It can also prevent the blowing particles from contaminating the processing environment and protect the health of operators. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the laser processing head provided by the present invention;

[0023] Figure 2 This is a dimensional diagram of the laser processing head provided by the present invention.

[0024] In the picture:

[0025] 100. Workpiece;

[0026] 1. Laser tube; 11. Laser channel; 12. Beam input end; 13. Beam output end;

[0027] 2. Air blowing pipe; 21. Air blowing port; 22. Ventilation section; 23. Slow flow section; 24. Busbar;

[0028] 3. Inhalation tube; 31. Inhalation port. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. The technical solutions of this invention are clearly and completely described. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0030] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The terms "first position" and "second position" refer to two different positions.

[0032] Unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and connections within two components or interactions between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0033] Unless otherwise expressly specified and limited, "above" or "below" a second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of a second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" of a second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] Laser processing technologies (laser welding, laser drilling, laser cutting, etc.) are core processes in advanced manufacturing and have been widely applied in industries such as automotive, new energy, electronics, and medical. Laser welding, in particular, is a precision joining process that uses a high-energy laser beam to locally heat materials to a molten state, followed by cooling to achieve a metallurgical bond. Its core process involves a laser generator (such as a fiber laser or CO2 laser) emitting a continuous or pulsed laser beam, which is focused by a focusing lens group into a micrometer-sized spot (0.1–0.5 mm in diameter) with a power density as high as 10⁶–10⁸ W / cm². 2Laser welding involves instantly melting materials to form a molten pool; this pool solidifies under the protection of surface tension and an auxiliary gas (such as argon or helium), achieving fillerless welding. Laser cutting is a highly efficient processing technology that uses a focused laser beam to melt, vaporize, or oxidize materials, supplemented by a high-speed gas flow (such as oxygen or nitrogen) to remove slag, achieving material separation. Laser drilling is a micromachining process that uses high-energy pulsed lasers (nanosecond, picosecond, or femtosecond levels) to remove material layer by layer from the material surface, forming through holes or blind holes.

[0036] This embodiment provides a laser processing apparatus, which includes a laser generator and a laser processing head, wherein the laser generator is used to generate a laser beam. Figure 1 As shown, the laser processing head includes a laser channel 11, which has a beam input end 12 and a beam output end 13 arranged opposite to each other. A laser generator is disposed at the beam input end 12. The laser beam can enter the laser channel 11 from the beam input end 12 and be output from the beam output end 13, thereby performing laser processing on the workpiece 100.

[0037] A high-energy laser beam passes through laser channel 11 and irradiates the surface of the material, interacting with it. After absorbing laser photons, the electrons in the material transition to an excited state, and the energy is converted into heat energy through collisions, causing a sharp increase in local temperature. Alternatively, it can directly break the chemical bonds of the material (such as polymers and ceramics) and induce electron ionization (metals) through multiphoton absorption. The photon energy is used to trigger physical or chemical changes in the material, thereby achieving processing purposes such as cutting, welding, and drilling.

[0038] The laser generator serves as the energy source for the laser processing apparatus. Its core function is to generate a high-brightness, monochromatic, and directional laser beam through stimulated emission. The laser processing head also includes a collimating and focusing optical module, which converts the diverging laser beam into parallel light (e.g., using a plano-convex lens with a focal length of 100mm), ensuring uniform energy distribution. A high-precision lens focuses the beam into a spot, and by placing the workpiece 100 at the focal point of this lens, laser processing can be performed on the workpiece 100 using this spot. Understandably, due to the high power density of the laser generated by the laser generator, the laser processing apparatus also includes a cooling system to cool the laser generator.

[0039] For the three laser processing technologies of laser welding, laser drilling, and laser cutting, laser processing heads can also be divided into laser welding heads, laser drilling heads, and laser cutting heads respectively.

[0040] However, when a high-energy laser beam is focused onto a material surface, its energy is absorbed by the material in a very short time, causing the local temperature to rise sharply to thousands or even tens of thousands of degrees Celsius, far exceeding the material's vaporization point. At this point, the surface material rapidly undergoes a phase transition from solid to liquid to gas, and ejects to form metal vapor. When gaseous atoms or molecules gain sufficient kinetic energy under high temperature and high energy conditions, their outer electrons break free from the atomic nucleus and form free electrons and positive ions through thermal ionization (collision ionization) or photoionization (direct excitation by laser photons), ultimately forming a plasma cloud composed of electrons, ions, neutral particles, and unionized vapor.

[0041] However, due to the large amount of plasma cloud generated during laser processing, when high-energy lasers continuously act on the material surface, the free electrons of the particles in the plasma cloud consume a large amount of laser energy through the inverse bremsstrahlung effect. Simultaneously, the scattering effect of the plasma on the laser beam further weakens the energy transmission efficiency, leading to a sharp drop in the effective energy density of the laser beam. This forces the processing to increase laser power or reduce processing speed to compensate for energy loss, directly increasing energy consumption and reducing production efficiency. Furthermore, the expansion and oscillation of the plasma can interfere with the stability of the molten pool or the kerf, causing uneven distribution of alloying elements or introducing impurities (such as ambient gases), reducing the mechanical properties of the weld, and causing defects such as spatter, porosity, and increased surface roughness. Moreover, the scattering effect of the plasma on the laser can cause distortion of the focused spot, and uneven energy distribution of the laser beam may cause fluctuations in the kerf width or inconsistent weld penetration. In addition, the plasma can interfere with the coaxial vision monitoring system, reducing the accuracy of real-time feedback and affecting the closed-loop control effect. In other words, the plasma cloud has a significant negative impact on the processing effect, seriously affecting the quality of laser processing.

[0042] like Figure 1 As shown, in order to solve the above problems, the laser processing head provided in this embodiment also includes an air blowing pipe 2. The bottom end of the air blowing pipe 2 is provided with an air blowing port 21. The air blowing port 21 is spaced apart from the workpiece 100 and can blow protective gas onto the workpiece 100.

[0043] Generally, under the action of a high-temperature laser, the metal material of workpiece 100 is prone to oxidation with oxygen in the air, forming brittle compounds (such as the Cr2O3 oxide layer when cutting stainless steel), leading to a decrease in the mechanical properties of the processed area or a rough surface. However, the shielding gas blown onto workpiece 100 can form a protective atmosphere on its surface. By blowing inert gases (such as argon or nitrogen) or reducing gases (such as a helium-hydrogen mixture), a localized oxygen-free environment can be created around the molten pool or cut, inhibiting harmful chemical reactions. For example, argon protection during titanium alloy welding can prevent the formation of brittle phases in the weld and improve joint toughness. Furthermore, the shielding gas reduces energy loss by lowering plasma density (e.g., high-ionization-energy helium can inhibit electron density growth) or accelerating plasma diffusion (the gas flow carries away ionized particles). For example, using helium-assisted welding can increase the penetration depth of aluminum alloy welding by approximately 30%.

[0044] However, the disturbance of the molten pool by the protective gas flow will have a negative impact on the stability of the welding process and the protection of the molten pool, and will also lead to asymmetry in the processing morphology, affecting the processing effect; moreover, the particles blown out will also pollute the processing environment and affect the health of the operators.

[0045] like Figure 1 As shown, in order to solve the above problems, in this embodiment, the laser processing head also includes an air suction pipe 3, and the laser channel 11 is located inside the air blowing pipe 2 and spaced apart from the air blowing pipe 2. The laser beam performs laser processing on the workpiece 100 through the air blowing port 21. The air suction pipe 3 is sleeved outside the air blowing pipe 2 and spaced apart from the air blowing pipe 2. An air suction port 31 is opened at the bottom end of the air suction pipe 3, and the air suction port 31 can draw in the protective gas blown out by the air blowing port 21.

[0046] Since the laser channel 11 is located inside the air blowing pipe 2 and spaced apart from it, the protective gas blown out by the air blowing pipe 2 is blown around the laser beam toward the workpiece 100, making the disturbance of the molten pool by the protective gas uniform, thus ensuring that the workpiece 100 has a symmetrical shape after laser processing. The suction pipe 3 is sleeved outside the air blowing pipe 2 and spaced apart from it, which enables the plasma and particulate matter generated during the processing to be quickly extracted with the protective gas, greatly reducing the negative impact of the plasma cloud on laser welding, ensuring the laser transmittance, improving the utilization rate of laser energy and welding efficiency, improving the stability of the welding process, and effectively protecting the weld pool.

[0047] This laser processing head can effectively avoid asymmetry in the processing shape caused by side blowing, ensuring good welding results. It can also prevent the blowing particles from contaminating the processing environment and protect the health of operators.

[0048] It is worth noting that the laser channel 11 refers to the channel structure that allows the laser to pass through. If the laser beam emitted by the laser generator passes directly through the air blowing tube 2, then part of the space inside the air blowing tube 2 is the laser channel 11. At this time, it is only necessary to ensure that the laser beam does not come into contact with the air blowing tube 2, which is equivalent to the structure in which the laser channel 11 and the air blowing tube 2 are set apart.

[0049] Generally, to ensure that the shielding gas provides good protection during laser processing, the laser transmission direction is the same as the axis of the air blowing pipe 2. That is, the laser channel 11 (or laser tube 1) and the air blowing pipe 2 are coaxially arranged. Furthermore, the axis of the suction pipe 3 is also the same as the axis of the air blowing pipe 2. This coaxial delivery of shielding gas not only protects the workpiece 100, but also ensures that the propagation direction of the laser beam and the flow direction of the shielding gas are the same. This allows the air blowing pipe 2 to serve as a reference for the laser path, facilitating observation of the optical path position and preventing damage to the workpiece 100 caused by laser irradiation of non-welding areas. Furthermore, the coaxial arrangement of the air blowing pipe 2 along the laser optical path allows it to be made longer and thinner to accommodate weld protection needs in deep, narrow, or complex locations. In this embodiment, the example of the laser processing head processing the upper surface of the workpiece 100 downwards is used; that is, the propagation direction of the laser beam, the axis of the air blowing pipe 2, and the axis of the suction pipe 3 are all vertically arranged.

[0050] In the coaxial gas delivery method, the coaxial flow of the protective gas and the laser beam can easily induce turbulence or pressure fluctuations in the optical path, resulting in uneven distribution of the beam refractive index (such as the thermal lensing effect caused by the gas density gradient), causing beam distortion or focus drift (up to tens of micrometers).

[0051] like Figure 1 As shown, in this embodiment, the laser processing head also includes a laser tube 1, which is disposed inside the air blowing tube 2 and spaced apart from the air blowing tube 2. The laser channel 11 is disposed inside the laser tube 1, and the beam input end 12 and the beam output end 13 are respectively opened at opposite ends of the laser tube 1. The protective gas passes through the space between the laser tube 1 and the air blowing tube 2 to reach the air blowing port 21.

[0052] Laser tube 1 isolates the path of the gas from the laser beam through a rigid cavity, ensuring interference-free transmission of the laser beam in a vacuum or static gas environment. For example, when precision welding highly reflective materials (such as copper), it can avoid power fluctuations caused by airflow disturbances and ensure consistent energy density. Furthermore, laser tube 1 can be disassembled, cleaned, or replaced as an independent unit, avoiding the complete scrapping of traditional integrated laser processing heads due to localized contamination, thus reducing maintenance costs.

[0053] It is worth noting that when the protective gas passes through the gap between the laser tube 1 and the suction tube 3 and reaches the blowing port 21, the gas flow direction is away from the laser tube 1. Therefore, a pressure difference will be generated at the beam output end 13 of the laser tube 1, so that the gas near the beam output end 13 will be discharged from the blowing port 21 along with the protective gas, and no gas will enter the laser tube 1, thus ensuring the stability of the gas environment inside the laser tube 1.

[0054] Furthermore, the distance between the beam output end 13 and the workpiece 100 is greater than the distance between the air blowing port 21 and the workpiece 100. The beam output end 13 is the lower end of the laser tube 1. Since the molecules of the protective gas may absorb photons of specific wavelengths in the transmission path of the laser beam, the beam output end 13 should be as close as possible to the workpiece 100 to ensure that the laser only contacts the protective gas in the area of ​​action of the workpiece 100, reducing absorption loss throughout the process. However, the beam output end 13 should not be too close to the workpiece 100; at least the air blowing port 21 should be located between the beam output end 13 and the workpiece 100 to ensure that the protective gas can disperse the plasma cloud between the beam output end 13 and the workpiece 100.

[0055] Since plasma clouds and particles generated by laser processing are easily dispersed by the protective gas blown out of the air outlet 21, in this embodiment, to prevent them from drifting into the surrounding environment, the distance between the air outlet 21 and the workpiece 100 is smaller than the distance between the air inlet 31 and the workpiece 100. This structure ensures that the plasma clouds and particles generated by laser processing, dispersed by the protective gas, collide with the inner wall of the air inlet 3, significantly reducing their velocity. They are then drawn in by the negative pressure of the air inlet 3, greatly reducing the possibility and probability of the plasma clouds and particles escaping, thus improving the working environment for the operators.

[0056] It is worth noting that in this embodiment, it is only necessary to ensure that the height of the blowing port 21 is higher than the height of the suction port 31. This can be divided into two cases: First, the bottom end of the suction pipe 3 slides in contact with the workpiece 100, which is equivalent to the suction pipe 3 and the workpiece 100 forming a seal, ensuring that the plasma cloud and particles generated by laser processing are completely sucked away by the suction pipe 3 without polluting the environment. However, this structure is prone to affecting the state of the molten pool due to the negative pressure of the suction pipe 3, thereby affecting the effect of laser processing. Secondly, the bottom end of the suction pipe 3 is spaced apart from the workpiece 100, that is, the suction port 31 is spaced apart from the workpiece 100. At this time, the distance between the suction port 31 and the workpiece 100 is small, which can also ensure that the plasma cloud and the particles generated by laser processing are completely sucked away by the suction pipe 3. At the same time, since there is a gap between the suction port 31 and the workpiece 100, the gas sucked by the suction pipe 3 includes not only the protective gas but also external air. The external air can balance the negative pressure inside the suction pipe 3, thereby reducing the impact of negative pressure on the molten pool and ensuring the welding effect.

[0057] In summary, the small distance between the suction pipe 3 and the workpiece 100, and the constant negative pressure, prevents the plasma cloud and particles formed on the surface of the workpiece 100 due to laser processing from escaping into the working environment outside the suction pipe 3. This effectively provides a relatively closed welding environment for laser processing, preventing spatter and fumes generated during laser processing from spreading everywhere. It also effectively removes the high-temperature plasma accumulated on the surface of the workpiece 100, keeps the welding space clean, and ensures the service life of the laser welding window lens and the welding quality and appearance. The use of shielding gas can effectively prevent over-welding.

[0058] In this embodiment, the intake port 31 of the intake pipe 3 is in the form of a bell mouth, meaning that the diameter of the intake pipe 3 gradually increases along the direction close to the intake port 31. This structure can reduce flow resistance and suppress turbulence generation, significantly improving intake efficiency and system stability. At the same time, the bell mouth guides the fluid into the pipe along a smooth curvature, suppressing boundary layer separation and turbulence generation, ensuring that the streamlines smoothly conform to the pipe wall, and avoiding the formation of local high-speed and low-pressure areas. In addition, the bell mouth structure can also reduce turbulence pulsation and pressure fluctuations, suppress hydrodynamic noise, and improve the working environment for operators.

[0059] Furthermore, the distance between the blowing pipe 2 and the suction pipe 3 first decreases and then increases along the direction closer to the workpiece 100. This structure causes the gas flow cross-sectional area to first decrease and then increase when the gas is drawn into the space between the suction pipe 3 and the blowing pipe 2. Along the flow direction of the gas in the suction pipe 3, the space between the blowing pipe 2 and the suction pipe 3 is divided into three parts: a contraction section, a throat, and a diffusion section. In other words, a Venturi tube structure is formed between the blowing pipe 2 and the suction pipe 3.

[0060] A Venturi tube is a variable cross-section pipe device designed based on Bernoulli's principle in fluid mechanics. When gas flows through a Venturi tube, the inlet cross-sectional area gradually contracts to the throat (the point of minimum cross-section). Because the gas velocity increases significantly with decreasing cross-sectional area, kinetic energy is accumulated, leading to an increase in gas velocity at the throat. This increased velocity causes a sharp drop in static pressure at the throat, forming a local low-pressure zone. This local low-pressure zone further increases the adsorption force on the gas at the inlet 21, thereby accelerating the gas flow rate.

[0061] In other words, in this embodiment, the change in distance between the blowing pipe 2 and the suction pipe 3 forms a Venturi tube structure. When the gas passes through the throat, a local low-pressure zone is formed at the blowing port 21, thereby increasing the rate at which the protective gas enters between the suction pipe 3 and the blowing pipe 2, further improving the dissipation speed of the plasma cloud and optimizing the welding effect. Furthermore, the outer wall of the blowing pipe 2 and the inner wall of the suction pipe 3 are machined into smoothly transitioning curved surfaces to further enhance the ability to draw in the protective gas.

[0062] To improve the welding effect of the laser processing head, the air pipe 2 includes an air passage section 22 and a slow flow section 23. The air passage section 22 is connected to the slow flow section 23, and the air passage section 22 is located at the end of the slow flow section 23 that is closer to the workpiece 100. The inner diameter of the slow flow section 23 is larger than the inner diameter of the air passage section 22.

[0063] When the protective gas flows in the blowing pipe 2, it first flows in the ventilation section 22. During this process, the flow rate of the protective gas is stable. Then, when the protective gas flows to the slow flow section 23, its flow cross-sectional area increases, which reduces the flow rate of the protective gas. This facilitates the uniform diffusion of the protective gas and ensures that the protective gas fills the gap between the slow flow section 23 and the laser tube 1. As a result, when the laser beam performs laser processing on the workpiece 100, there is protective gas blown out from the blowing port 21 around the processing position.

[0064] Furthermore, along the direction close to the workpiece 100, the inner diameter of the slow-flow section 23 first increases and then decreases. That is to say, the cross-sectional area of ​​the protective gas flow in the blowing pipe 2 first increases and then decreases. The increase in cross-sectional area leads to a decrease in flow velocity and an increase in static pressure (Bernoulli effect), forming a high-pressure slow-flow zone to stabilize the initial flow state. Subsequently, it enters the section with a decreasing inner diameter. The decrease in cross-sectional area forces an increase in flow velocity, and kinetic energy accumulates significantly. Finally, when it blows out of the blowing port 21, it achieves a secondary diameter expansion, and the flow velocity gradually decreases. Some of the kinetic energy is converted into pressure energy, which can effectively disperse the plasma cloud and the particles formed by welding, avoiding their impact on the laser welding effect.

[0065] like Figure 2 As shown, the air blowing pipe 2 has a generatrix 24, where the generatrix 24 refers to the intersection line formed by the plane containing the side wall of the air blowing pipe 2 and the axis of the air blowing pipe 2. A plane can form two opposing generatrixes 24 with the side wall of the air blowing pipe 2. The generatrix 24 can visually reflect the bending state of the side wall of the air blowing pipe 2. According to the above structure, along the direction close to the workpiece 100, the distance between the two opposing generatrixes 24 of the air blowing pipe 2 is initially equal. Near the air blowing port 21, the distance between the two opposing generatrixes 24 of the air blowing pipe 2 first increases and then decreases, forming the air blowing port 21 at the bottom end of the generatrix 24.

[0066] In this embodiment, the tangent extension of the end of the busbar 24 at the air outlet 21 intersects the surface of the workpiece 100 at point A, which is outside the range of the axial projection of the air outlet 21 onto the workpiece 100. The formation of the tangent extension can be categorized into two cases: First, the bottom end of the busbar 24 is an arc, in which case the tangent extension is a straight line connecting to and tangent to the bottom end of the busbar 24; second, the bottom end of the busbar 24 is an inclined straight line, in which case the tangent extension is simply the straight line directly extended from the bottom end of the busbar 24. When the protective gas flowing along the inner wall of the air pipe 2 is blown out from the air outlet 21, the flow direction of the protective gas is along the direction of the tangent extension. In other words, the flow direction of the protective gas when it exits the air outlet 21 can be determined by the tangent extension of the busbar 24.

[0067] In summary, after the protective gas exits through the blow-out port 21, part of the protective gas is directly blown towards the plasma cloud and the particles generated by laser processing, while the rest is blown along the direction of the tangential extension line to point A, and then reflected towards the inner wall of the suction pipe 3 after contacting the workpiece 100. It is understandable that the protective gas flowing along the tangential extension line can blow the plasma cloud and the particles generated by laser processing towards point A. Even after reflection from the workpiece 100, the reflected gas will enter the gap between the blow-out pipe 2 and the suction pipe 3, and will ultimately be sucked away by the suction pipe 3, rather than re-entering the blow-out pipe 2 through the blow-out port 21. This greatly improves the ability and efficiency of the laser processing head to sweep away the plasma cloud and the particles generated by laser processing, and also prevents the plasma cloud and the particles generated by laser processing from circulating near the blow-out port 21, thus avoiding any impact on the efficiency and effect of laser processing.

[0068] In this embodiment, the protective gas is one of helium, neon, or nitrogen.

[0069] Helium and neon, as inert gases, exhibit significant advantages in laser processing due to their unique physicochemical properties.

[0070] Helium has an extremely high ionization energy (24.59 eV). When lasers interact with materials, the free electrons in the vapor require extremely high energy to ionize helium atoms, thus significantly reducing plasma density. For example, in aluminum alloy laser welding, helium-assisted welding can reduce the plasma absorption rate of 1064 nm wavelength laser from 30% (when using nitrogen) to below 5%, reducing energy loss and improving weld penetration stability (weld penetration fluctuation < ±0.1 mm). Helium reacts almost no with any metals, avoiding oxidation or nitriding. For example, in copper alloy welding, the oxygen content of the weld can be controlled below 50 ppm under helium protection, while it may rise to 200 ppm in a nitrogen environment, leading to decreased conductivity. Moreover, helium has extremely low absorption in the ultraviolet to near-infrared bands (such as 355 nm picosecond lasers and 10.6 μm CO2 lasers), making it suitable for high-power continuous laser cutting (such as 20 kW fiber laser cutting 30 mm carbon steel) or ultrafast laser micromachining (such as femtosecond laser etching sapphire), ensuring lossless beam energy transmission.

[0071] While the ionization energy of neon (21.56 eV) is slightly lower than that of helium, it is still significantly higher than that of common metal vapors (such as aluminum at 5.98 eV), effectively suppressing the shielding effect of plasma on lasers. In deep penetration welding, neon-assisted welding can increase the penetration depth. Neon reacts almost no with any elements, making it particularly suitable for processing reactive metals (such as lithium and beryllium) or high-purity materials (such as zirconium alloys used for nuclear fuel cladding), avoiding the introduction of impurities. In lithium-ion battery tab welding, the impurity content of the weld can be below 0.01% under neon protection. Neon has a transmittance of up to 99.9% in the visible to near-infrared band (such as 532 nm green light and 1064 nm infrared), while its absorption rate for ultraviolet lasers (such as 355 nm) is extremely low, making it suitable for multi-wavelength composite processing. For example, in ultraviolet-infrared dual-beam laser microwelding, neon can simultaneously ensure the energy utilization rate of both wavelengths.

[0072] However, helium and neon are rare gases and scarce resources with limited global reserves and high prices, resulting in high costs for their use. Furthermore, helium's density (0.1785 kg / m³) is relatively low. 3 Helium, being only 1 / 7 the density of air, is easily dispersed and requires a high flow rate (typically 2-3 times that of nitrogen) to maintain an effective protective layer, increasing gas consumption. Helium at low temperatures (e.g., liquid helium at 4K) may cause material embrittlement, and cryogenic equipment is complex, limiting its widespread use in laser processing of superconducting materials. Neon requires specialized storage and transportation equipment (such as high-pressure Dewar flasks), has poor compatibility with common laser processing heads, and necessitates customized gas nozzles and sealing systems, resulting in high initial investment costs.

[0073] Compared to helium and neon, nitrogen makes up 78% of the volume of air and can be produced at low cost through air separation equipment, making it suitable for large-scale industrial applications. Moreover, a nitrogen molecule is composed of two nitrogen atoms bonded by a nitrogen-nitrogen triple bond, resulting in a high degree of overlap of the electron clouds between the two nitrogen atoms, forming a covalent bond with extremely high bond energy. This makes nitrogen inert at room temperature, effectively isolating it from oxygen and preventing materials from oxidizing.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A laser processing head, characterized in that, include: An air blowing pipe (2) is provided at the bottom end of the air blowing pipe (2), and the air blowing port (21) is spaced apart from the workpiece (100) and can blow protective gas onto the workpiece (100). A laser channel (11) is located inside the air blowing pipe (2) and spaced apart from the air blowing pipe (2). The laser channel (11) has a beam input end (12) and a beam output end (13) arranged opposite to each other. The laser beam can enter the laser channel (11) from the beam input end (12) and be output from the beam output end (13). The laser beam is used to perform laser processing on the workpiece (100) through the air blowing port (21). An air inlet (3) is sleeved outside the air inlet (2) and spaced apart from the air inlet (2). The bottom end of the air inlet (3) is provided with an air inlet (31), which can draw in the protective gas blown out by the air inlet (21).

2. The laser processing head according to claim 1, characterized in that, The laser processing head also includes a laser tube (1), the laser channel (11) is disposed inside the laser tube (1), the beam input end (12) and the beam output end (13) are respectively opened at opposite ends of the laser tube (1), and the laser tube (1) is disposed inside the air blowing tube (2).

3. The laser processing head according to claim 2, characterized in that, The distance between the beam output end (13) and the workpiece (100) is greater than the distance between the air outlet (21) and the workpiece (100).

4. The laser processing head according to claim 1, characterized in that, The distance between the air inlet (21) and the workpiece (100) is less than the distance between the air inlet (31) and the workpiece (100).

5. The laser processing head according to claim 4, characterized in that, The air intake (31) is spaced apart from the workpiece (100).

6. The laser processing head according to claim 1, characterized in that, The distance between the air blowing pipe (2) and the air suction pipe (3) first decreases and then increases along the direction closer to the workpiece (100).

7. The laser processing head according to any one of claims 1 to 6, characterized in that, The air blowing pipe (2) includes an air passage (22) and a slow flow section (23). The air passage (22) is connected to the slow flow section (23), and the air passage (22) is located at one end of the slow flow section (23) near the workpiece (100). The inner diameter of the slow flow section (23) is larger than the inner diameter of the air passage (22).

8. The laser processing head according to claim 7, characterized in that, Along the direction close to the workpiece (100), the inner diameter of the slow-flow section (23) first increases and then decreases.

9. The laser processing head according to any one of claims 1 to 6, characterized in that, The air blowing pipe (2) has a generatrix (24), the extension of the tangent of the generatrix (24) at the end of the air blowing port (21) intersects the surface of the workpiece (100) at point A, the point A being outside the range of the axial projection of the air blowing port (21) onto the workpiece (100).

10. A laser processing apparatus, characterized in that, The laser processing head, including any one of claims 1 to 9, further includes a laser generator, which is disposed at the beam input end (12) and is capable of generating the laser beam.

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