Continuous forming ultrasonic braze coating device and method

Abstract

The invention discloses a continuous forming ultrasonic braze coating device and method. The device comprises a control cabinet, an ultrasonic vibration mechanism, a feeding mechanism, a forming cooling mechanism, a three-dimensional moving mechanism and a heating system. The forming cooling mechanism is provided with a melt groove of a bottomless structure, and the melt groove is attached to the surface of a workpiece to form a working cavity. A size control channel with the adjustable width is arranged on one side of the material melting groove, and a cooling flow channel is integrated on the top of the channel. During working, the feeding mechanism feeds molten brazing filler metal into the molten material groove, and the ultrasonic tool head immersed in the molten material groove generates a cavitation effect to activate the surface of a workpiece; the three-dimensional moving mechanism drives the device to move, the brazing filler metal in the molten material groove can be wetted and spread on the surface of a workpiece, and part of the brazing filler metal flows out through the size control channel and is cooled and shaped instantly. The device realizes synchronous continuous operation of feeding, activating, forming and cooling, and has the advantages of accurate coating size, less oxidation of active elements, high bonding strength and high production efficiency.

Description

Technical Field

[0001] This invention relates to the fields of materials surface engineering and special welding technology, specifically to an ultrasonic brazing apparatus and method for continuous forming on the flat surfaces of non-metallic materials such as ceramics and glass. This invention is particularly applicable to automated production lines for electronic packaging, power modules, and heat dissipation substrates that require pre-applied solder layers. Background Technology

[0002] In the field of electronics manufacturing, it is often necessary to pre-deposit metal layers on non-metallic substrates such as alumina, aluminum nitride ceramics, or silicon to achieve highly reliable subsequent soldering with metal components. However, the traditional process of pre-depositing metal layers on non-metallic material surfaces is cumbersome, pollutes the environment, and requires subsequent application of solder to complete the connection with metal components. Therefore, a simple, efficient, and pollution-free method is needed.

[0003] Currently, the traditional non-metallic surface pre-coating process mainly faces the following technical bottlenecks: (1) Traditional electroplating, magnetron sputtering and other coating processes are cumbersome and have environmental pollution problems; (2) When directly pre-plating brazing filler metal, traditional brazing filler metal is difficult to wet on non-metallic surfaces; (3) Although active brazing filler metal (such as those containing Ti, Zr and other elements) can react with non-metallic surfaces, it needs to be carried out at high temperatures, and the active elements are easily oxidized in the air. Traditional processes cannot effectively isolate the air throughout the process, resulting in a decrease in coating bonding performance and poor product consistency; (4) Although ultrasonic brazing technology can activate non-metallic surfaces at lower temperatures by utilizing the "acoustic cavitation" effect, existing technologies are mostly for spot welding of metal surfaces or three-dimensional additive manufacturing, using nozzle extrusion to print point by point. For rapidly forming continuous, uniform, and large-area non-metallic planar coatings, there are inherent defects such as low efficiency and difficulty in accurately controlling the coating width and thickness.

[0004] Therefore, the existing technology lacks an automated device that can integrate continuous feeding, ultrasonic interface activation, online coating dimensional forming and cooling and shaping, resulting in high cost and low efficiency of high-quality brazing filler metal pre-processing for non-metallic surfaces, which has become a bottleneck restricting the mass production of related products. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing technologies and provide a continuous ultrasonic brazing apparatus and method. This apparatus and method can solve the technical problems of complex processes, easy oxidation, poor coating dimensional accuracy, and inability to achieve continuous and efficient production when coating non-metallic workpieces with active brazing filler metals.

[0006] To achieve the above objectives, the specific solution adopted by the present invention is as follows: In a first aspect, the present invention provides a continuously forming ultrasonic brazing apparatus for brazing the surface of a non-metallic workpiece to form a continuous and dimensionally controllable brazing filler metal coating, comprising: A control cabinet is used for centralized control and parameter coordination of the various components in the device that are electrically connected to it; An ultrasonic vibration mechanism includes an ultrasonic generator, an ultrasonic guide rod, and an ultrasonic tool head connected in sequence. The ultrasonic tool head is used to immerse itself in liquid brazing filler metal to generate a cavitation effect. The feeding mechanism includes a wire feeding assembly for conveying the brazing wire and a wire guide for guiding the molten brazing wire after it melts; A forming cooling mechanism includes a molten metal tank, a size control channel, and a cooling channel. The molten metal tank is a bottomless structure with an opening at the lower end, and a solder outlet is provided on the side wall adjacent to the cooling channel. When the lower opening is in close contact with the upper surface of the non-metallic workpiece, they together form a working cavity to accommodate molten solder. The outlet of the molten wire guide is connected to the molten metal tank. The lower part of the ultrasonic tool head is immersed in the molten solder in the molten metal tank. The size control channel is used to constrain the shape of the solder flowing out of the molten metal tank. It is located on one side of the molten metal tank and connected to the solder outlet. The cooling channel is integrated above the size control channel and is used to cool and solidify the solder flowing through the channel. A three-dimensional moving mechanism is used to support and drive the ultrasonic vibration mechanism, the feeding mechanism and the forming and cooling mechanism to perform three-dimensional movements, and to control the lower opening of the molten material tank to keep it in close contact with the upper surface of the non-metallic workpiece during the brazing operation. The heating system is used to heat the brazing wire, ultrasonic tool head, molten brazing filler metal in the melting tank, and non-metallic workpieces.

[0007] Furthermore, the heating system includes: The first heater is an induction heating coil sleeved on the outside of the fuse guide tube and the ultrasonic tool head, used to melt the brazing wire into a liquid state and preheat the ultrasonic tool head; The second heater is a heating element disposed in the side wall of the molten metal tank, used to maintain the molten state of the brazing filler metal in the working chamber; The third heater is a workpiece preheating platform set on the workbench, used to support and preheat the non-metallic workpiece and to slowly cool the non-metallic workpiece after the brazing process is completed.

[0008] Furthermore, the heating element is a resistance heating element or a heating rod, and its operating temperature is 40-60°C higher than the melting point temperature of the brazing filler metal used.

[0009] Furthermore, a sealing cover is provided above the molten material tank, which is connected to a vacuum pump to create a vacuum environment in the molten material tank and the outlet area of ​​the fuse guide tube.

[0010] Furthermore, the feeding mechanism also includes an air source and a switching valve; the switching valve is disposed in the fuse guide tube, and its opening and closing state is controlled by the air pressure provided by the air source, thereby controlling the conveying of molten solder to the molten solder tank.

[0011] Furthermore, the cross-section of the size control channel is rectangular, with its height dimension fixed to limit the coating thickness, and its width dimension adjustable to accommodate coating requirements of different widths.

[0012] Furthermore, the size control channel is composed of two parallel side plates and a top plate; the two side plates are slidably disposed below the top plate, and the sliding direction is perpendicular to the moving direction of the molten material tank; the cooling channel is disposed inside the top plate; the gap between the two side plates constitutes the width of the size control channel; the two side plates are connected to the side wall of the molten material tank and the bottom wall of the top plate respectively through a slider guide structure, and the width of the size control channel can be continuously adjusted by adjusting the distance between the two side plates.

[0013] Furthermore, it also includes a cooling medium supply unit, which includes a cooling tank, a water pump and connecting pipes, for circulating and supplying cooling medium to the cooling channels in the top plate.

[0014] Furthermore, it also includes a visual positioning module, which is communicatively connected to the control cabinet and used to identify the pose of the non-metallic workpiece and guide the three-dimensional moving mechanism to perform initial positioning.

[0015] Secondly, the present invention provides a brazing method using the above-described continuous forming ultrasonic brazing apparatus, comprising the following steps: S1: Fix the non-metallic workpiece on the workpiece preheating platform and start the third heater to preheat the non-metallic workpiece. The preheating temperature is 20°C below the melting point of the brazing filler metal. S2: The ultrasonic tool head, melting tank and size control channel are moved to the starting position on the surface of the non-metallic workpiece by a three-dimensional moving mechanism; the lower opening of the melting tank is controlled to fit tightly with the surface of the non-metallic workpiece to form a working cavity, while the lower end face of the size control channel is kept at a forming gap for the brazing filler metal to flow out. S3: Start the cooling medium supply unit, feeding mechanism, first heater and second heater, so that the molten brazing filler metal is conveyed and gathered in the working cavity, flows from the working cavity to the size control channel and solidifies; S4: Activate the ultrasonic vibration mechanism to generate a cavitation effect in the molten brazing filler metal in the melting bath using the ultrasonic tool head; at the same time, drive the three-dimensional moving mechanism to carry the forming and cooling mechanism to move along a preset trajectory; S5: During the movement, the molten solder in the working chamber reacts with the surface of the non-metallic workpiece to activate it, allowing the molten solder to wet and spread on the surface of the non-metallic workpiece. At the same time, at least a portion of the molten solder in the working chamber flows out through the size control channel, covering the activated non-metallic workpiece area, and is cooled and solidified by the cooling channel during the flow, thereby forming a continuous, dimensionally controllable solid solder coating on the surface of the non-metallic workpiece. S6: After coating is completed, the feeding mechanism, ultrasonic vibration mechanism, heating system and cooling medium supply unit are stopped in sequence. The device is removed by the three-dimensional moving mechanism, and the non-metallic workpiece is removed after cooling.

[0016] Beneficial effects: Compared with the prior art, the continuous forming ultrasonic brazing apparatus and method provided by the present invention, through the integration and synergy of the above technical solutions, brings the following outstanding beneficial effects: (1) The core innovation of this invention lies in the high spatial integration of the "ultrasonic vibration mechanism", "feeding mechanism" and "forming cooling mechanism", and the driving force of the "three-dimensional moving mechanism" to form a functionally coupled processing unit. This unit can realize the synchronous and continuous execution of multiple key process links such as feeding melting, ultrasonic activation, size constraint and instant cooling solidification in time and space, thereby integrating the traditional multi-step, intermittent process into a one-step continuous dynamic process, which is particularly suitable for automated production line production and significantly improves production efficiency.

[0017] (2) Through the innovative design of the “forming cooling mechanism”, especially its precisely adjustable “size control channel” and integrated “cooling channel”, mechanical constraints and instant “freezing” shaping of the coating geometry are achieved. The coating thickness is determined by the channel height, and the width is controlled by adjusting the gap between the side plates. Its dimensions are directly defined by mechanical hardware, which is reliable in principle and avoids problems such as uneven thickness and edge diffusion caused by factors such as paste rheology and printing pressure in traditional processes, thereby obtaining a high-precision and highly consistent solder coating.

[0018] (3) By establishing a local vacuum environment in the key area of ​​the molten metal bath through a "sealing cover" and a "vacuum pump", and combining the design of melting the solder under a protective gas in the "feeding mechanism" and transporting the solder through the "fuse conduit", effective protection is provided for highly oxidizable active solders (such as Sn-Ag alloys containing Ti and Zr) from melting to coating. This design avoids the high cost and long cycle caused by evacuating the entire chamber where the workpiece is located, and is more targeted and efficient.

[0019] (4) Through centralized coordination of the "control cabinet", the present invention can independently and precisely adjust ultrasonic parameters (power, frequency), heating temperature (feeding melting, workpiece preheating), feeding speed, moving speed and cooling intensity, etc. Combined with the modular design of the adjustable width of the "size control channel", the same device can flexibly adapt to the needs of different workpiece materials, different brazing filler metals and coatings of different widths and thicknesses, with a wide process window and wide range of applications.

[0020] (5) The lower part of the "ultrasonic tool head" in this invention is directly immersed in the molten brazing filler metal in the molten filler metal bath. The cavitation effect generated by it acts on the contact interface between the brazing filler metal and the non-metallic workpiece, which can promote the reaction of active elements and the wetting and spreading of the brazing filler metal. Thus, a strong metallurgical bond between the coating and the substrate is achieved at a relatively low process temperature, providing a reliable interface basis for subsequent welding. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall device structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the molding and cooling mechanism.

[0023] Figure 3 This is one of the structural schematic diagrams of the molding and cooling mechanism for the sealing cover.

[0024] Figure 4 The second schematic diagram of the molding and cooling mechanism for the sealing cover.

[0025] Figure 5 for Figure 3 A sectional view.

[0026] Explanation of reference numerals in the attached drawings: 1. Ultrasonic generator; 2. Air source; 3. Pressure gauge; 4. Wire feeding assembly; 5. Brazing wire; 6. Ultrasonic guide rod; 7. Ultrasonic tool head; 8. Fuse guide tube; 9. Induction heating coil; 10. Switch valve; 11. Sealing cover; 12. Vacuum pump; 13. Heating element; 14. Melting tank; 15. Size control channel; 16. Workpiece preheating platform; 17. Non-metallic workpiece; 18. Cooling channel; 19. Water cooling pipe; 20. Water pump; 21. Cooling tank; 23. Three-dimensional moving mechanism; 24. Side plate; 25. Top plate. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0028] In the description of this invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and 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 limiting the scope of protection of this invention.

[0029] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0030] This invention provides a continuous forming ultrasonic brazing device. Its core design lies in constructing a stable working cavity and achieving precise spatial and temporal coordination of "ultrasonic activation," "molten material convergence," "dimensional constraint," "instant cooling," and "zoned heating." The device mainly includes a control cabinet, an ultrasonic vibration mechanism, a feeding mechanism, a forming and cooling mechanism, a three-dimensional moving mechanism 23, and a heating system. The following description, in conjunction with the appendix... Figure 1-5 The structure of each component is explained in detail.

[0031] The control cabinet, as the "brain" of the device, combines an industrial PC and a PLC to centrally manage all process parameters such as ultrasonic vibration, heating temperature, feeding speed, three-dimensional movement trajectory, vacuum degree and cooling water flow rate. It can also intelligently adjust and coordinate control according to preset coating width, thickness and quality requirements.

[0032] The feeding mechanism consists of a wire feeding assembly 4, a molten wire conduit 8, a gas source 2, and a switching valve 10. Its core function is to continuously and stably feed the solder into the molten metal tank 14 in solid wire form, and to melt and protect the solder during the feeding process. The wire feeding assembly 4 pushes the solder wire 5 into the molten wire conduit 8 at a controllable speed. The molten wire conduit 8 is a tubular channel made of high-temperature resistant ceramic or quartz material, with an inner diameter preferably of 2-5 mm. The outer side of the molten wire conduit 8 is fitted with a first heater (induction heating coil 9) belonging to the heating system. The gas source 2 (usually argon or helium) is connected to the molten wire conduit 8 through a gas path, and its functions are to provide a protective atmosphere and to provide the power for conveying. The switching valve 10 is located in the molten wire conduit 8. By precisely adjusting the gas pressure acting on it through the control cabinet, the start and stop of the conveying of molten solder to the molten metal tank 14 and the flow rate can be precisely controlled, thereby ensuring the stability of the liquid level in the working chamber. Specifically, the switching valve 10 typically consists of a valve body, two openable and closable high-temperature resistant valve plates (such as semi-circular ceramic plates), and a return spring. Its specific structure is prior art and will not be described further in this invention. Its working principle is as follows: when the air pressure provided by the air source 2 reaches a set value, the air pressure overcomes the spring resistance and pushes the valve plates open, allowing molten solder to pass through; when the air pressure decreases or disappears, the spring returns to its original position, causing the valve plates to close and cutting off the solder flow. By precisely adjusting the magnitude and timing of the air pressure through the control cabinet, precise control of the start / stop, flow rate, and even pulsed supply of the molten solder can be achieved, thereby ensuring a stable liquid level in the working chamber and adapting to the needs of different coating speeds.

[0033] The forming and cooling mechanism is the core innovation of this invention. It is an integrated structure consisting of a molten metal tank 14, a size control channel 15, and a cooling channel 18, which together achieve the convergence, constrained forming, and rapid solidification of the molten solder. The molten metal tank 14 is a bottomless cavity structure with an opening at the lower end. Its lower edge is precision machined to ensure close contact with the surface of the workpiece 17. A second heater (heating element 13) belonging to the heating system is integrated into the side wall of the molten metal tank 14. The inner wall surface of the molten metal tank 14 that contacts the solder is preferably made of high-temperature and corrosion-resistant materials such as graphite, boron nitride, or metal alloys with a ceramic coating. During operation, under the control of the three-dimensional moving mechanism 23, the lower opening of the molten metal tank 14 presses against the surface of the workpiece 17, forming a working cavity to accommodate the molten solder. The size control channel 15 is located on one side of the molten metal tank 14 (opposite to the moving direction) as the outlet of the molten solder in the molten metal tank 14. The dimension control channel 15 has a rectangular cross-section and a fixed thickness (height), preferably 0.5 mm, which directly determines the coating thickness. Its width is adjustable, preferably within the range of 2 mm to 15 mm. Specifically, the channel consists of two parallel side plates 24 and a top plate 25. The two side plates 24 are slidably positioned below the top plate 25, with the sliding direction perpendicular to the moving direction of the melt tank 14. The gap between the two side plates 24 constitutes the width of the channel, which can be continuously adjusted by adjusting the spacing using a slider guide structure. The thickness of the side plates 24 determines the height of the dimension control channel 15. The cooling channel 18 is directly integrated into the top structure of the dimension control channel 15, i.e., inside the top plate 25. This channel is typically a meandering or parallel perforated structure, ensuring that the cooling medium can flow through the entire top area of ​​the dimension control channel 15. The cooling medium (e.g., water) is provided by a separate cooling medium supply unit, which includes a cooling tank 21, a water pump 20, and connecting pipes 19. The cooling medium is pumped into the cooling channel 18 via pipe 19 and circulates therein. Its flow rate and temperature can be adjusted by the control cabinet, thereby achieving precise control of the cooling capacity to match the solidification rate requirements of the brazing filler metal under different process conditions. When the molten brazing filler metal flows from the molten filler metal tank 14 into the dimension control channel 15 and moves forward under the combined action of the static pressure and the feeding air pressure, its upper part contacts the bottom wall of the cold top plate 25 integrated with the cooling channel 18, and the heat is quickly carried away. The brazing filler metal cools and solidifies during its flow through the channel, thereby "freezing" the rectangular cross-sectional shape of the channel onto the coating, achieving precise mechanical forming of the coating dimensions.

[0034] The ultrasonic vibration mechanism consists of an ultrasonic generator 1, an ultrasonic guide rod 6, and an ultrasonic tool head 7 connected in sequence. Its function is to provide the mechanical vibration energy required for interface activation. The ultrasonic tool head 7 is directly immersed in the molten solder in the molten solder bath 14. The ultrasonic waves it generates induce an "acoustic cavitation" effect in the molten solder, producing localized high temperature and pressure, which promotes the reaction between active elements (such as Ti and Zr) and the matrix, thereby achieving the wetting and spreading of the solder on the non-metallic surface. The ultrasonic frequency of the ultrasonic tool head 7 is preferably 20kHz-60kHz, the power is 100W-1500W, and the amplitude is 2-10 micrometers. Simultaneously, the ultrasonic tool head 7 requires corrosion-resistant strengthening treatment of the molten solder contact surface to inhibit the dissolution of the ultrasonic tool head material.

[0035] The three-dimensional moving mechanism 23 adopts a high-precision gantry or robotic arm structure. The ultrasonic vibration mechanism, feeding mechanism, and molding cooling mechanism are integrated into a movable processing unit through a rigid mounting bracket and fixedly mounted on the moving end of the three-dimensional moving mechanism 23 (such as a Z-axis slide). The three-dimensional moving mechanism 23 is used to drive the unit for precise positioning and to move along a preset trajectory during the coating process, while precisely controlling the contact state between the lower end of the melt tank 14 and the surface of the workpiece 17.

[0036] The heating system is key to achieving precise temperature management in this invention. It includes a first heater, a second heater, and a third heater, forming a multi-level temperature protection system covering the entire process under the coordination of the control cabinet. The first heater (induction heating coil 9): This heater operates by induction heating, with its coil tightly fitted around the outside of the fuse guide tube 8 and the ultrasonic tool head 6 (the part not inserted into the molten solder). Its core function is to achieve rapid, in-situ melting of the solder wire. When the solder wire 5 is fed into the fuse guide tube 8, the high-frequency alternating magnetic field generated by the induction coil 9 induces eddy currents inside the solder wire and in adjacent metal components, thereby generating Joule heating, causing the solder wire 5 to completely melt into a liquid state in a very short time (usually during its journey within the fuse guide tube 8). To ensure melting efficiency and prevent "cold blockage" of the solder within the fuse guide tube 8, the set temperature of its working area must be significantly higher than the melting point of the selected solder, typically about 100°C higher. Simultaneously, this coil is crucial for the synchronous preheating of the ultrasonic tool head 7. This prevents severe thermal shock when the low-temperature ultrasonic tool head 7 is suddenly immersed in the high-temperature molten brazing filler metal, thus protecting the ultrasonic vibration mechanism and maintaining the stability of vibration transmission. The second heater (heating element 13): This heater is a contact heater, typically in the form of a resistance heating element or heating rod, directly embedded or tightly fitted to the side wall of the molten filler bath 14. Its main function is to continuously and precisely maintain and compensate for the temperature of the molten brazing filler metal that has accumulated in the molten filler bath 14. Since the molten filler bath 14 is in contact with the non-metallic workpiece 17 through its lower opening, there is continuous heat conduction loss, and the molten brazing filler metal surface experiences radiative and convective heat dissipation. The heat generated by the melting of the first heater alone is insufficient to maintain the entire molten filler bath 14 (especially the area far from the ultrasonic tool head 7) in an ideal molten state. Therefore, the operating temperature of the second heater is precisely set within a range of 40-60°C above the liquidus line (melting point) of the brazing filler metal used. This temperature range ensures that the solder maintains good fluidity for easy flow and molding, while preventing excessive temperature from causing excessive volatilization of active elements or exacerbating erosion of the inner wall of the melt bath 14. Third heater (workpiece preheating platform 16): This heater is a support platform with uniform heating function, used to fix and preheat the non-metallic workpiece 17. It is fixedly installed on an independent worktable (preferably a worktable that can be moved by a conveyor mechanism to facilitate workpiece movement), positioned directly opposite and below the travel stroke of the movable processing unit (including the melt bath 14).The fundamental purpose of preheating the non-metallic workpiece 17 is threefold: First, by increasing the overall temperature of the non-metallic workpiece 17, the instantaneous temperature difference when it comes into contact with the high-temperature molten solder is significantly reduced, thereby effectively reducing the interfacial thermal stress caused by the mismatch in thermal expansion coefficients and preventing brittle substrates such as ceramics from cracking during the coating process. Second, a certain preheating temperature (usually set about 200°C below the melting point of the solder) helps improve the initial wettability of the solder on the surface of the non-metallic workpiece 17, creating better conditions for subsequent ultrasonic activation. Third, after coating, the non-metallic workpiece 17 is slowly and controllably cooled on the workpiece preheating platform 16, which is beneficial for the coating to further release residual stress in the solid state, improving the bonding strength and peel resistance of the coating. These three heaters, coordinated by the control cabinet, constitute a multi-level temperature protection system covering the entire process of "feeding-melting-holding-substrate preheating".

[0037] Preferably, the device further includes a vacuum system, which consists of a sealing cover 11 and a vacuum pump 12. The sealing cover 11 covers the molten metal tank 14 and the outlet area of ​​the fuse guide tube 8, and the vacuum pump 12 can draw a vacuum to effectively prevent the active solder from oxidizing at high temperatures.

[0038] Preferably, the device further includes a vision positioning module (not shown in the figure), which communicates with the control cabinet to automatically identify the precise position and posture of the workpiece on the production line, guide the three-dimensional moving mechanism 23 to perform initial positioning, and improve the degree of automation.

[0039] The soldering method of the present invention mainly includes the following steps: S1. Workpiece clamping and preheating: Fix the non-metallic workpiece 17 on the workpiece preheating platform 16 and start the third heater for preheating. The preheating temperature is 20°C below the melting point of the brazing filler metal. S2. Device positioning and working cavity formation: The ultrasonic tool head 7, melting tank 14 and dimension control channel 15 are moved to the starting position by the three-dimensional moving mechanism 23; the lower end of the melting tank 14 is controlled to fit tightly against the surface of the non-metallic workpiece 17 to form a working cavity, and the lower end face of the dimension control channel 15 is adjusted to maintain a small forming gap with the surface of the non-metallic workpiece 17. S3, Molten Material Conveying: The cooling medium supply unit, feeding mechanism, first heater and second heater are started in sequence to transport the molten brazing filler metal into the working chamber and flow to the size control channel 15 to solidify; S4. Ultrasonic activation and continuous movement: Start the ultrasonic vibration mechanism; at the same time, drive the three-dimensional moving mechanism 23 to carry the molding and cooling mechanism to move at a constant speed along the preset trajectory. S5. Forming and Cooling: During the movement, the molten solder in the molten solder bath 14 undergoes an activation reaction with the surface of the non-metallic workpiece under ultrasonic action, allowing the solder to wet and spread on the workpiece surface. Simultaneously, some of the solder in the working cavity flows out through the size control channel 15, covering the activated non-metallic workpiece area, and is cooled and solidified by the cooling channel 18, forming a continuous, dimensionally controlled solid coating. Preferably, the moving speed V of the three-dimensional moving mechanism 23 is controlled between 1 mm / s and 50 mm / s. More preferably, the solder feeding speed S, the moving speed V, the width W of the size control channel 15, and the preset coating thickness H satisfy the following relationship: S≈k·V·W·H, where k is a correction coefficient related to the solder density and flowability. Preferably, to achieve precise process completion and avoid material waste, the feeding mechanism and the three-dimensional moving mechanism 23 are coordinated and controlled by a control cabinet. Specifically, when the device is about to reach the end of the preset coating trajectory (i.e., the "emptying section"), the control cabinet commands the air source 2 or the switch valve 10 to shut off, stopping the supply of new molten solder to the molten solder tank 14. The three-dimensional moving mechanism 23 continues to move at its original speed, and the remaining solder in the molten solder tank 14 continues to flow out completely through the size control channel 15 and cool and solidify under static pressure and inertia. By precisely matching the length of the "emptying section", the moving speed and the solder flow rate in the working chamber, it can be ensured that when the device moves to the end of the trajectory, the solder in the working chamber has been basically emptied, so that no excess solder drips when the device is lifted. S6. Process completion and workpiece removal: After coating is completed, stop each mechanism in sequence, remove the device, and remove the workpiece after it has cooled down. Example 1

[0040] This embodiment is used to coat the surface of an alumina ceramic substrate with dimensions of 100mm×100mm with a Sn-3.5Ag-4Ti (wt%) active solder strip with a width of 3.0mm and a thickness of approximately 0.5mm.

[0041] Device configuration: Ultrasonic generator 1 (40kHz, 1500W), titanium alloy ultrasonic tool head 7; feeding mechanism equipped with 1.0mm diameter brazing wire 5 and 3mm diameter alumina molten wire conduit 8; forming and cooling mechanism adopts titanium alloy melting tank 14 with tin contact surface corrosion-resistant strengthening treatment, size control channel 15 with fixed height 0.5mm and preset width 3.0mm; heating system induction heating coil 9 set to 320℃, heating element 13 set to 260℃, workpiece preheating platform 16 set to 200℃; three-dimensional moving mechanism 23 is a high-precision three-axis gantry platform; equipped with vacuum system and vision positioning module.

[0042] Process: (1) Fix the alumina ceramic substrate (non-metallic workpiece 17) on the workpiece preheating platform 16, heat it to 200°C and keep it warm; (2) After visual positioning, the three-dimensional moving mechanism 23 drives the device to the starting point, so that the lower end of the melting tank 14 is in contact with the workpiece surface, and the lower end of the size control channel 15 is about 0.5mm away from the surface; (3) Start the cooling medium supply unit, vacuum pump 12, induction heating coil 9 and heating element 13. After the temperature stabilizes, push the molten brazing wire with constant argon gas pressure until an appropriate amount of brazing wire accumulates in the molten material tank 14. (4) Start the ultrasound, set the power to 1500W and the frequency to 40kHz; at the same time, the three-dimensional moving mechanism 23 moves along a straight path at a speed of 1mm / s. (5) During the movement, some of the brazing filler metal in the working cavity wets the surface of the workpiece under the action of ultrasound, and some of the brazing filler metal continuously flows out from the 3.0mm wide dimension control channel 15 and is rapidly cooled and shaped. (6) After coating a length of 100mm, the feeding mechanism, ultrasonic vibration mechanism, heating system and cooling medium supply unit are stopped in sequence, the device is lifted, and the workpiece is slowly cooled to room temperature on the platform before being removed.

[0043] Performance verification: Measurements using an optical image measuring instrument and micrometer showed that the solder coating was continuous and had a bright surface, with a width of 3.0±0.05mm and a thickness of 0.48±0.02mm, exhibiting good dimensional consistency. Tensile shear tests were performed on the coated specimens (referring to relevant standards), and the average bond strength between the coating and the alumina ceramic substrate reached 32MPa, indicating a reliable metallurgical bond that fully meets the reliability requirements for subsequent electronic packaging soldering.

[0044] It should be noted that the method described in this invention is also applicable to other non-metallic workpieces, such as aluminum nitride ceramics, glass, or silicon wafers; the solder is not limited to Sn-Ag-Ti system, but can also be other low-temperature active solders such as Sn-Ag, Sn-Sb, or Sn-Bi system containing at least one active element among Ti, Zr, Hf, Cr, and V.

[0045] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A continuous ultrasonic brazing apparatus for forming a continuous and dimensionally controllable brazing filler coating on the surface of a non-metallic workpiece, characterized in that, include: Control cabinet; An ultrasonic vibration mechanism includes an ultrasonic generator (1), an ultrasonic guide rod (6), and an ultrasonic tool head (7) connected in sequence. The ultrasonic tool head (7) is used to immerse itself in liquid brazing filler metal to generate a cavitation effect. The feeding mechanism includes a wire feeding assembly (4) for conveying the brazing wire (5) and a wire guide (8) for guiding the molten brazing wire after it melts. The forming cooling mechanism includes a molten material tank (14), a size control channel (15), and a cooling channel (18). The molten material tank (14) is a bottomless structure with an opening at the lower end, and a solder outlet is provided on the side wall adjacent to the cooling channel. When the lower opening is in close contact with the upper surface of the non-metallic workpiece (17), it forms a working cavity with the workpiece surface to accommodate the molten solder. The outlet of the molten wire guide (8) is connected to the molten material tank (14). The lower part of the ultrasonic tool head (7) is immersed in the molten solder in the molten material tank (14). The size control channel (15) is used to constrain the shape of the solder flowing out of the molten material tank (14). It is located on one side of the molten material tank (14) and connected to the solder outlet. The cooling channel (18) is integrated above the size control channel (15) and is used to cool the solder flowing through the channel to solidify it. The three-dimensional moving mechanism (23) is used to carry and drive the ultrasonic vibration mechanism, the feeding mechanism and the forming cooling mechanism to perform three-dimensional movement, and during the brazing operation, it controls the lower opening of the molten material tank (14) to keep it in close contact with the upper surface of the non-metallic workpiece (17); The heating system is used to heat the molten brazing wire (5), the ultrasonic tool head (7), the molten brazing tub (14), and the non-metallic workpiece (17).

2. The ultrasonic brazing apparatus according to claim 1, characterized in that, The heating system includes: The first heater is an induction heating coil (9) sleeved on the outside of the fuse guide (8) and the ultrasonic tool head (7), used to melt the brazing wire (5) into a liquid state and preheat the ultrasonic tool head (7), with the preheating temperature being 20°C below the melting point of the brazing wire; The second heater is a heating element (13) disposed in the side wall of the molten metal tank (14) to maintain the molten state of the brazing filler metal in the tank; The third heater is a workpiece preheating platform (16) set on the workbench, used to carry and preheat the non-metallic workpiece (17) and to slowly cool the non-metallic workpiece (17) after the brazing is completed.

3. The ultrasonic brazing apparatus according to claim 2, characterized in that, The heating element (13) is a resistance heating element or heating rod, and its working temperature is 40-60°C higher than the liquidus temperature of the brazing filler metal used.

4. The ultrasonic brazing apparatus according to claim 1, characterized in that, A sealing cover (11) is provided above the molten material tank (14). The sealing cover (11) is connected to a vacuum pump (12) to form a vacuum environment in the molten material tank (14) and the outlet area of ​​the molten wire guide tube (8).

5. The ultrasonic brazing apparatus according to claim 1, characterized in that, The feeding mechanism also includes an air source (2) and a switching valve (10); the switching valve (10) is located in the fuse guide tube (8), and its opening and closing state is controlled by the air pressure provided by the air source (2), thereby controlling the conveying of molten solder to the molten solder tank (14).

6. The ultrasonic brazing apparatus according to claim 1, characterized in that, The cross-section of the size control channel (15) is rectangular, with its height dimension fixed to limit the coating thickness, and its width dimension adjustable to accommodate coating requirements of different widths.

7. The ultrasonic brazing apparatus according to claim 6, characterized in that, The size control channel (15) is composed of two parallel side plates (24) and a top plate (25); the two side plates (24) are slidably disposed below the top plate (25), and the sliding direction is perpendicular to the moving direction of the molten material tank (14); the cooling channel (18) is disposed inside the top plate (25); the gap between the two side plates (24) constitutes the width of the size control channel (15); the two side plates (24) are connected to the side wall of the molten material tank (14) and the bottom wall of the top plate (25) respectively through a slider guide structure, and the width of the size control channel (15) can be continuously adjusted by adjusting the distance between the two side plates (24).

8. The ultrasonic brazing apparatus according to claim 7, characterized in that, It also includes a cooling medium supply unit, which includes a cooling tank (21), a water pump (20) and a connecting pipe (19) for circulating cooling medium to the cooling channel (18) in the top plate (25).

9. The ultrasonic brazing apparatus according to claim 1, characterized in that, It also includes a visual positioning module, which is communicatively connected to the control cabinet and is used to identify the pose of the non-metallic workpiece (17) and guide the three-dimensional moving mechanism (23) to perform initial positioning.

10. A brazing method using the continuous forming ultrasonic brazing apparatus according to any one of claims 1-9, characterized in that, Includes the following steps: S1: Fix the non-metallic workpiece (17) on the workpiece preheating platform (16) and start the third heater to preheat the non-metallic workpiece (17); S2: The ultrasonic tool head (7), the melt tank (14) and the size control channel (15) are moved to the starting position on the surface of the non-metallic workpiece (17) by the three-dimensional moving mechanism (23); the lower opening of the melt tank (14) is controlled to fit tightly with the surface of the non-metallic workpiece (17) to form a working cavity, while the lower end face of the size control channel (15) and the surface of the non-metallic workpiece (17) maintain a forming gap for the brazing filler metal to flow out. S3: Start the cooling medium supply unit, feeding mechanism, first heater and second heater, so that the molten brazing filler metal is transported and gathered in the working cavity, flows from the working cavity to the size control channel (15) and solidifies; S4: Start the ultrasonic vibration mechanism and use the ultrasonic tool head (7) to generate cavitation effect in the molten brazing filler metal in the molten filler metal tank (14); at the same time, drive the three-dimensional moving mechanism (23) to carry the forming and cooling mechanism to move along a preset trajectory; S5: During the movement, the molten brazing filler metal located in the working cavity reacts with the surface of the non-metallic workpiece (17) to activate it, so that the molten brazing filler metal can wet and spread on the surface of the non-metallic workpiece (17); at the same time, at least part of the molten brazing filler metal in the working cavity flows out through the size control channel (15) and covers the non-metallic workpiece area that has undergone the activation reaction, and is cooled and solidified by the cooling channel (18) during the flow, thereby forming a continuous, dimensionally controllable solid brazing filler metal coating on the surface of the non-metallic workpiece (17); S6: After coating is completed, the feeding mechanism, ultrasonic vibration mechanism, heating system and cooling medium supply unit are stopped in sequence. The device is removed by the three-dimensional moving mechanism (23), and the non-metallic workpiece (17) is removed after cooling.

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