An aluminum wire anti-sticking welding process

Abstract

The application discloses an aluminum wire anti-sticking welding process, comprising the following steps: providing an aluminum wire to be welded and a terminal, the terminal is placed in a welding area of an ultrasonic welding machine; setting an intermediate layer between an aluminum wire core of the aluminum wire and a welding head of the ultrasonic welding machine, the material of the intermediate layer is a metal which does not react with the welding head to cause intermetallic compound; and performing a welding process on the aluminum wire and the terminal by the ultrasonic welding machine. Through the above scheme, the intermetallic compound layer formed on the surface of the aluminum wire in the welding process is prevented from being adhered to the welding head, so that the welding quality is improved.

Description

Technical Field

[0001] This application relates to the technical field of ultrasonic welding, specifically to an aluminum wire anti-sticking welding process. Background Technology

[0002] Ultrasonic welding utilizes high-frequency vibration waves transmitted to the surfaces of two objects to be welded. Under pressure, the surfaces of the two objects rub against each other, forming a fusion between molecular layers.

[0003] In traditional ultrasonic welding, when welding aluminum wires to terminals, on the one hand, when the aluminum temperature reaches a certain level, intermetallic compounds (IMCs) form on the aluminum surface, causing the aluminum wire to adhere to the welding head. On the other hand, when local adhesion occurs between the aluminum wire and the welding head in the welding area, it can further lead to breakage between the adhered and non-adhesive areas. Summary of the Invention

[0004] To address the aforementioned issues, this application provides an aluminum wire anti-sticking welding process.

[0005] This application provides an aluminum wire anti-sticking welding process, including: Provide aluminum wire and terminals to be welded, wherein the terminals are placed in the welding area of ​​an ultrasonic welding machine; An intermediate layer is provided between the aluminum wire core of the aluminum wire and the welding head of the ultrasonic welding machine. The intermediate layer is made of a metal that does not react with the welding head to form intermetallic compounds. The aluminum wire and the terminal are welded using the ultrasonic welding machine.

[0006] In some embodiments, the provision of an intermediate layer between the aluminum wire and the welding head of the ultrasonic welding machine includes: The provision of an intermediate layer between the aluminum wire and the welding head of the ultrasonic welding machine includes: The welding end of the aluminum wire is placed between the welding head and the terminal, with the aluminum wire core of the welding end exposed. The intermediate layer is placed between the welding end of the aluminum wire and the welding head; The intermediate layer is positioned so that the intermediate layer and the aluminum wire remain relatively stationary.

[0007] In some embodiments, the positioning process for the intermediate layer includes: The intermediate layer is pre-welded to the welding end of the aluminum wire.

[0008] In some embodiments, the provision of an intermediate layer between the aluminum wire and the welding head of the ultrasonic welding machine includes: An intermediate layer is wrapped around the exposed aluminum core at the welding end of the aluminum wire; Place the welding end of the aluminum wire between the welding head and the terminal.

[0009] In some embodiments, the provision of an intermediate layer between the aluminum wire and the welding head of the ultrasonic welding machine includes: Metal powder is coated on the exposed aluminum core at the welding end of the aluminum wire, and the metal powder constitutes the intermediate layer; The welding end of the aluminum wire is placed between the welding head and the terminal, and the metal powder is located between the exposed aluminum wire core and the welding head.

[0010] In some embodiments, before providing an intermediate layer between the aluminum wire and the welding head of the ultrasonic welding machine, the method further includes: The intermediate layer undergoes surface micro-roughening treatment; Clean the surface of the intermediate layer.

[0011] In some embodiments, the intermediate layer is included in the aluminum wire, and the intermediate layer is located between the aluminum wire core and the insulation layer of the aluminum wire. The provision of an intermediate layer between the aluminum wire and the welding head of the ultrasonic welding machine includes: Remove the insulation layer from the welded ends of the aluminum wire; The welding end of the aluminum wire is placed between the welding head and the terminal, such that the exposed intermediate layer is located between the welding head and the aluminum wire core.

[0012] In some embodiments, the intermediate layer covers at least half of the continuous outer peripheral sidewall of the aluminum wire core.

[0013] In some embodiments, prior to the welding process of the aluminum wire and the terminal using the ultrasonic welding machine, the method further includes: Adjusting the welding parameters of the ultrasonic welding machine, including Based on the basic welding parameters, increase the welding energy by 10-30%, increase the welding power by 5-25%, increase the welding head pressure by 5-10%, and increase the amplitude by 15-40%. Set the vibration frequency in the range of 10~30kHz; The basic welding parameters are the welding parameters set when welding the aluminum wire and the terminal without the intermediate layer.

[0014] In some embodiments, it also includes: Remove the insulation layer from the welding end of the aluminum wire and perform pre-welding pretreatment on the exposed aluminum wire core; The pre-welding treatment includes, but is not limited to: surface cleaning, preheating, chemical passivation, plasma treatment, electrochemical polishing, end leveling, and flattening.

[0015] In some embodiments, the end of the intermediate layer extends beyond the end of the exposed aluminum wire core, or the inward indentation of the end of the intermediate layer relative to the end of the exposed aluminum wire core is less than or equal to 0.5 mm.

[0016] The technical solution of this application has at least the following advantages: (1) By setting an intermediate layer between the welding head and the aluminum wire to be welded, and the material of the intermediate layer is a metal that does not react with the welding head to produce intermetallic compounds, the intermetallic compound layer formed on the surface of the aluminum wire core during the welding process is prevented from sticking to the welding head, thereby improving the welding quality. (2) It provides multiple ways to set up the intermediate layer, which improves its universality. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart of an exemplary embodiment of the aluminum wire anti-sticking welding process provided in this application; Figure 2 This is a schematic diagram provided by an exemplary embodiment of the present application to illustrate the relative positional relationship between the welding head, the intermediate layer and the aluminum wire; Figure 3 This is a schematic diagram illustrating the internal structure of an aluminum wire provided in an exemplary embodiment of this application; Figure 4 This is a schematic diagram illustrating another internal structure of aluminum wire provided by an exemplary embodiment of this application; Figure 5 This is a schematic diagram illustrating an alternative internal structure of an aluminum wire, provided as an exemplary embodiment of this application.

[0019] Explanation of reference numerals in the attached diagram: 1. Aluminum wire core; 2. Insulation layer; 3. Intermediate layer; 31. Intermediate core wire; 32. Intermediate foil; 4. Aluminum foil. Detailed Implementation

[0020] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, 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 this application 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 limitations on this application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0023] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0024] This application provides an aluminum wire anti-sticking welding process, referring to... Figure 1 The aluminum wire anti-sticking welding process includes the following steps: S1: Provide aluminum wire and terminals to be welded, with the terminals placed in the welding area of ​​the ultrasonic welding machine.

[0025] For example, the terminal to be welded is placed in the welding area of ​​the ultrasonic welding machine. In this embodiment, the movement path of the welding head of the ultrasonic welding machine is in the vertical direction, so the terminal is placed directly below the welding head.

[0026] S2: An intermediate layer is set between the aluminum wire core of the aluminum wire and the welding head of the ultrasonic welding machine.

[0027] The intermediate layer is made of a metal that does not react with the welding head to form intermetallic compounds. In this embodiment, the welding head is made of steel; therefore, the intermediate layer can be made of copper, silver, zinc, gold, etc. To save costs, copper is generally used as the intermediate layer.

[0028] S3: Welding process of aluminum wire and terminals using an ultrasonic welding machine.

[0029] For example, after the welding parameters are set, an ultrasonic welding machine is used to weld the aluminum wire and the terminal.

[0030] Furthermore, in one embodiment, step S2 described above may include the following: S201: Place the welding end of the aluminum wire between the welding head and the terminal.

[0031] The welding end of the aluminum wire refers to the end of the aluminum wire that needs to be welded to the terminal. The insulation layer on the surface of the welding end will be removed.

[0032] For example, the solder end of the aluminum wire is placed above the terminal, positioned between the solder head and the terminal.

[0033] S202: Place an intermediate layer between the welding end of the aluminum wire and the welding head.

[0034] For example, such as Figure 2 As shown, an intermediate layer is placed above the welding end of the aluminum wire, such that the intermediate layer is located between the welding end of the aluminum wire and the welding head. For example, the intermediate layer can be a sheet of copper. If the intermediate layer is too thin, it may break during welding; if the intermediate layer is too thick, it will increase the difficulty of welding. Therefore, in this embodiment, the thickness of the intermediate layer is set to 0.01mm to 2mm.

[0035] S203: Positioning treatment of the intermediate layer to keep the intermediate layer and aluminum wire relatively stationary.

[0036] For example, in order to prevent the intermediate layer from shifting during the welding process, the intermediate layer can be positioned so that the intermediate layer and the aluminum wire can remain stable during the welding process.

[0037] Furthermore, step S203 may include the following processing: The intermediate layer is pre-welded to the welding end of the aluminum wire.

[0038] For example, the intermediate layer can be pre-soldered to the welding end of the aluminum wire to ensure a stable connection between the intermediate layer and the aluminum wire. After pre-soldering, the excess intermediate layer outside the welding end can be removed using tools such as a cutter to avoid affecting the subsequent use of the aluminum wire.

[0039] In other embodiments, the intermediate layer can also be positioned by providing an additional positioning mechanism. For example, the positioning structure can be configured as two opposing push blocks that clamp the intermediate layer from both sides to achieve positioning of the intermediate layer.

[0040] Furthermore, in another embodiment, step S2 may also include the following: S211: A middle layer is wrapped around the welding end of the aluminum wire.

[0041] For example, after removing the insulation layer outside the aluminum wire welding end, an intermediate layer is wrapped around the exposed aluminum wire core. Compared to placing the intermediate layer between the welding head and the aluminum wire, wrapping reduces the difficulty of positioning. The intermediate layer can be a circular copper sheet. In this embodiment, the thickness of the intermediate layer is set to 0.01~2mm.

[0042] Furthermore, the end of the intermediate layer may extend beyond the end of the exposed aluminum wire core, or it may not extend beyond the end of the exposed aluminum wire core. When the end of the intermediate layer is recessed relative to the end of the aluminum wire core, the recess amount is less than or equal to 0.5 mm to prevent the aluminum wire core from warping.

[0043] S212: Place the welding end of the aluminum wire between the welding head and the terminal.

[0044] For example, the welding end of an aluminum wire with an outer layer wrapped around an intermediate layer is placed between the welding head and the terminal.

[0045] Furthermore, in another embodiment, step S2 may also include the following: S221: Metal powder is coated on the exposed aluminum core at the welded end of the aluminum wire, and the metal powder forms an intermediate layer.

[0046] For example, metal powder, such as copper powder, can be coated onto the exposed aluminum core at the welding end of the aluminum wire to serve as an intermediate layer.

[0047] S222: Place the welding end of the aluminum wire between the welding head and the terminal, with metal powder located between the exposed aluminum wire core and the welding head.

[0048] For example, the welding end of the aluminum wire is placed between the welding head and the terminal, with the exposed aluminum wire core covered with metal powder facing the welding head.

[0049] Furthermore, to ensure a good bond between the intermediate layer and the aluminum wire and terminals, and to improve the stability and consistency of the welding, in some embodiments, the intermediate layer can be treated as follows before being placed between the aluminum wire and the welding head of the ultrasonic welding machine: The intermediate layer is subjected to surface roughening treatment, and the surface of the intermediate layer is cleaned.

[0050] For example, by performing a surface micro-roughening treatment on the surface of the intermediate layer, the contact area between the intermediate layer and the aluminum wire and terminal can be increased, thereby improving the bonding strength. Afterwards, the surface of the intermediate layer is cleaned to remove oil and impurities, facilitating subsequent steps. The surface micro-roughening treatment method can be as follows: Use sandpaper to polish the surface of the intermediate layer. First, select sandpaper with an appropriate grit, such as 400-800 grit. Then, fix the intermediate layer on the fixture and use sandpaper to polish the surface evenly in one direction, avoiding over-polishing. After polishing, use compressed air or a clean cloth to remove surface dust and ensure the surface is clean.

[0051] Alternatively, sandblasting can be used. First, select a suitable abrasive, such as alumina or glass beads, with a particle size controlled between 50 and 100 micrometers. Then, fix the intermediate layer in the sandblasting equipment, adjust the sandblasting pressure and time, for example, setting the pressure to 0.3–0.5 MPa and the time to 10–30 seconds, and perform the sandblasting treatment. After sandblasting, rinse the surface of the intermediate layer with compressed air or clean water to remove residual abrasive and dust.

[0052] Alternatively, chemical etching can be used. First, prepare a chemical etching solution, such as dilute hydrochloric acid, dilute nitric acid, or sodium hydroxide solution. Then, immerse the intermediate layer in the chemical etching solution for 1-3 minutes, the specific time of which can be adjusted according to the material properties. Afterward, remove the intermediate layer, rinse it with clean water, and dry it to ensure that the surface of the intermediate layer is clean.

[0053] Alternatively, electrochemical micromachining can be used. First, the intermediate layer is used as the anode, and electrochemical machining is performed in an electrolyte for 1-2 minutes. Afterward, the intermediate layer is removed, rinsed with water, and dried to ensure a clean surface.

[0054] Furthermore, in other embodiments, the aluminum wire can be pre-designed, such that an intermediate layer is included within the aluminum wire and disposed between the aluminum wire core and the insulation layer. In this case, the end of the intermediate layer may or may not extend beyond the exposed end of the aluminum wire core. When the end of the intermediate layer is recessed relative to the end of the aluminum wire core, the recess amount is less than or equal to 0.5 mm to prevent the aluminum wire core from warping. The aluminum wire core can be obtained by twisting together several aluminum wires, and its cross-section is generally circular. The intermediate layer can be configured in various ways.

[0055] In one possible embodiment, refer to Figure 3 At least one ring of insulating core wire is filled between the aluminum wire core 1 and the insulation layer 2. The insulating core wire includes an intermediate core wire 31, such as a copper core wire. This ring of intermediate core wire 31 constitutes the intermediate layer 3 mentioned above.

[0056] In another possible embodiment, refer to Figure 4 An intermediate foil 32, such as a copper foil, is placed between the aluminum wire core 1 and the insulation layer 2. The rectangular intermediate foil 32 is rolled into a ring and fixed to the outer peripheral wall of the aluminum wire core 1. The insulation layer 2 then surrounds the intermediate foil 32, thus forming the intermediate layer 3. The intermediate foil 32 can have several holes evenly distributed within it, thereby saving material.

[0057] Reference Figure 5 An aluminum foil 4 can also be used to separate the aluminum wire core 1 and the insulation layer 2. The aluminum foil 4 and the intermediate foil 32 together cover the inner peripheral sidewall of the insulation layer 2, and the intermediate foil 32 covers at least half of the continuous inner peripheral sidewall of the insulation layer 2. Thus, the annular intermediate foil 32 forms the intermediate layer 3. When welding is required, the part of the aluminum wire in which the intermediate foil 32 is formed faces the welding head.

[0058] In this case, step S2 may also include the following: S221: Remove the insulation layer from the soldered ends of the aluminum wire.

[0059] S222: Place the welding end of the aluminum wire between the welding head and the terminal, so that the exposed intermediate layer is located between the welding head and the aluminum wire core.

[0060] Furthermore, since an intermediate layer is provided between the aluminum wire and the welding head, in order to ensure the welding quality of ultrasonic welding, the following steps may be included before step S3 above: Adjust the welding parameters of the ultrasonic welding machine.

[0061] For example, based on the basic welding parameters, the welding energy is increased by 10-30%, the welding power by 5-25%, the welding head pressure by 5-10%, and the amplitude by 15-40%. The basic welding parameters are those set when welding aluminum wires and terminals without the aforementioned intermediate layer. Simultaneously, the vibration frequency is set within the range of 10-30 kHz.

[0062] The thicker the intermediate layer, the greater the required welding energy, welding power, and welding head pressure. For example, based on the basic welding parameters, for every 0.5mm increase in the thickness of the intermediate layer, the welding energy needs to be increased by 5-8%.

[0063] Furthermore, the above method may also include the following steps: Remove the insulation layer from the welding end of the aluminum wire and perform pre-welding treatment on the exposed aluminum wire core.

[0064] Among them, the pre-welding pretreatment includes, but is not limited to, at least one of the following: surface cleaning, preheating treatment, chemical passivation treatment, plasma treatment, electrochemical polishing treatment, and end leveling treatment.

[0065] For surface cleaning, methods such as chemical cleaning and mechanical cleaning can be used to remove the oxide layer, oil, dust, and other impurities from the surface of the aluminum wire core, ensuring the cleanliness of the welding interface and improving welding quality. For example, chemical cleaning can be used by soaking or wiping the surface of the aluminum wire with a neutral or weakly acidic cleaning agent (such as alcohol or acetone), followed by rinsing with clean water and drying. Alternatively, mechanical cleaning can be used, where sandpaper or a wire brush can be used to polish the surface of the aluminum wire to remove the oxide layer and contaminants.

[0066] For end flattening, a high-precision wire cutting machine can be used to cut the aluminum wire first to ensure that the end face of the internal aluminum wire core is flat. Then, the exposed aluminum wire core is chamfered to reduce burrs and stress concentration, ensuring that the end of the aluminum wire core is flat and burr-free, which facilitates close contact with the terminal and improves the welding effect.

[0067] For flattening, since the aluminum wire has a curvature along its length, it is not suitable for placing the intermediate layer, and it is easy for the intermediate layer to tilt and slip after being placed. Therefore, pre-welding or mechanical stamping processes can be used to flatten the aluminum wire, so that the surface of the aluminum wire used to place the intermediate layer is in a horizontal state, making it easier to fit with the intermediate layer and facilitating the alignment and placement of the intermediate layer.

[0068] For preheating, hot air guns, preheating furnaces, or other preheating equipment can be used to preheat the exposed aluminum wire core. The preheating temperature can be controlled between 100℃ and 150℃, and the preheating time should be controlled within the range of 1 to 2 minutes. Preheating the aluminum wire core can improve its solderability and reduce stress problems caused by temperature differences during welding.

[0069] For chemical passivation, the following process can be used: Immerse the exposed aluminum wire core in a passivation solution (such as chromate or phosphate solution) for 5-10 minutes to form a dense passivation film on the surface of the aluminum wire core. This film prevents the formation of an oxide layer during welding and improves welding quality. Afterward, remove the aluminum wire and rinse it with clean water and dry it to ensure the uniformity and integrity of the passivation film. This ensures that the properties of the passivation film on the surface of the aluminum wire core are uniform, avoiding the influence of surface oxidation on the welding process and improving the consistency of the welding.

[0070] For plasma treatment, plasma cleaning equipment can be used to treat the exposed aluminum wire core surface for 1-3 minutes. This removes contaminants from the aluminum wire core surface, increases its surface activity, and improves the subsequent welding bond strength. Immediately after plasma treatment, the aluminum wire and terminals need to be welded using an ultrasonic welding machine to prevent a decrease in the surface activity of the aluminum wire.

[0071] For electrochemical polishing, the exposed aluminum wire core can be used as the anode, and electrochemical polishing can be performed in an electrolyte solution for 1-2 minutes. Afterwards, the aluminum wire is removed, rinsed with water, and then dried to ensure a smooth surface finish. Electrochemical polishing can remove microscopic imperfections on the surface of the aluminum wire core, improving surface smoothness and welding quality.

[0072] In practice, one or more of the above pretreatments can be selected for execution without interfering with each other. For example, pre-welding pretreatment may include sequential surface cleaning, chemical passivation, and preheating. Alternatively, pre-welding pretreatment may include sequential electrochemical polishing and plasma treatment.

[0073] The aluminum wire anti-adhesion welding process provided in this application embodiment improves welding quality by setting an intermediate layer between the welding head and the aluminum wire to be welded. The intermediate layer is made of a metal that does not react with the welding head to form intermetallic compounds.

[0074] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A process for preventing aluminum wire from sticking during welding, characterized in that, include: Provide aluminum wire and terminals to be welded, wherein the terminals are placed in the welding area of ​​an ultrasonic welding machine; An intermediate layer is provided between the aluminum wire core of the aluminum wire and the welding head of the ultrasonic welding machine. The intermediate layer is made of a metal that does not react with the welding head to form intermetallic compounds. The aluminum wire and the terminal are welded using the ultrasonic welding machine. The step of setting an intermediate layer between the aluminum wire core and the welding head of the ultrasonic welding machine includes: Remove the insulation layer from the welding end of the aluminum wire; place the welding end of the aluminum wire between the welding head and the terminal, such that the exposed intermediate layer is located between the welding head and the aluminum wire core, wherein the intermediate layer is contained in the aluminum wire and is located between the aluminum wire core and the insulation layer of the aluminum wire.

2. The aluminum wire anti-sticking welding process according to claim 1, characterized in that, The positioning process for the intermediate layer includes: The intermediate layer is pre-welded to the welding end of the aluminum wire.

3. The aluminum wire anti-sticking welding process according to claim 1, characterized in that, The intermediate layer covers at least half of the continuous outer peripheral sidewall of the aluminum wire core.

4. The aluminum wire anti-sticking welding process according to claim 1, characterized in that, Prior to the welding process of the aluminum wire and the terminal using the ultrasonic welding machine, the method further includes: Adjusting the welding parameters of the ultrasonic welding machine, including Based on the basic welding parameters, increase the welding energy by 10-30%, increase the welding power by 5-25%, increase the welding head pressure by 5-10%, and increase the amplitude by 15-40%. Set the vibration frequency in the range of 10~30kHz; The basic welding parameters are the welding parameters set when welding the aluminum wire and the terminal without the intermediate layer.

5. The aluminum wire anti-sticking welding process according to claim 1, characterized in that, The end of the intermediate layer extends beyond the end of the exposed aluminum wire core, or the inward indentation of the end of the intermediate layer relative to the end of the exposed aluminum wire core is less than or equal to 0.5 mm.

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