Ultrasonic wedge bonder, and bonding head assembly and design method therefor

Abstract

A bonding head assembly, comprising a transducer (1) and a capillary (2). A through hole (10) is formed in one end of the transducer, a locking hole (11) is formed in the end surface of the end, and the locking hole is communicated with the through hole; protruding parts (12) protruding inwards are arranged on the hole wall of the through hole, and the protruding parts are arranged opposite to the locking hole; when fixed, the capillary passes through the through hole, and a fastener (5) extends into the through hole through the locking hole and presses the capillary against the multiple protruding parts; and in a fixed state, the protruding parts abut against the capillary by means of contact points (120), there are multiple contact points, and at least two of the contact points are configured to be spaced apart by a first distance (d) in the extending direction of the through hole. The bonding head assembly can improve the transmission efficiency of ultrasonic in the ultrasonic wedge bonder, and can improve the bonding quality. The present invention further relates to an ultrasonic wedge bonder and a design method for the bonding head assembly.

Description

Ultrasonic wedge welding machine, welding head assembly and design method thereof Technical Field

[0001] The present invention relates to the technical field of bonding welding, and in particular to an ultrasonic wedge welding machine, a welding head assembly and a design method thereof. Background Art

[0002] In an ultrasonic wedge bonder, the welding head assembly is the working component that performs the bonding process. It includes a transducer and a wedge cutter. The transducer, also known as an ultrasonic transducer, converts the electrical signal from the sound source into high-frequency vibrations, which are transmitted to the wedge cutter. The wedge cutter has an internal lead channel. The metal wire for welding is guided through this channel. The working part of the wedge cutter's free end then applies heat, pressure, and high-frequency vibrations to the wire, causing it to bond to the substrate, completing the bonding process.

[0003] In order to ensure welding efficiency, the stability of the splitting knife in the transducer is very critical. Currently, in ultrasonic wedge welding machines, the splitting knife is fixed in the transducer by placing the splitting knife in a through hole at one end of the transducer and fixing it with a screw head.

[0004] However, the inventors have discovered that the existing method of fixing the splitter is likely to affect the welding quality and ultrasonic transmission efficiency.

[0005] Summary of the Invention

[0006] An object of the present invention is to provide a welding head assembly that can improve the transmission efficiency of ultrasound in an ultrasonic wedge welding machine and improve the welding quality.

[0007] To achieve the aforementioned purpose, a welding head assembly includes a transducer and a wedge knife, wherein a through hole is provided at one end of the transducer, the inner diameter of the through hole being larger than the outer diameter of the wedge knife, the through hole being opened at the one end along the radial direction of the transducer, and a locking hole is opened on the end surface of the one end, the locking hole being connected to the through hole;

[0008] The through hole wall is provided with an inwardly protruding convex portion, and the convex portion is arranged opposite to the locking hole. When fixed, the riving knife is inserted into the through hole, and the fastener extends into the through hole through the locking hole and tightens the riving knife against the plurality of convex portions.

[0009] Wherein, in a fixed state, the protrusion abuts against the riving knife through contact points, and the number of the contact points is multiple, including at least two contact points arranged to be spaced apart by a first distance along the extending direction of the through hole.

[0010] In one or more embodiments, among the plurality of contact points, at least two contact points are arranged to be spaced apart by a second distance along the circumference of the through hole.

[0011] In one or more embodiments, in a fixed state, the point where the fastener and the wrecking knife abut against each other is defined as a force application point, and in an orthographic projection along the axial direction of the transducer, the plurality of contact points are centrally symmetrically distributed relative to the force application point.

[0012] In one or more embodiments, the convex portion includes four protrusions, each of which contacts and cooperates with the riving knife point in the clamping state, and the protrusions include a pair of first protrusions and a pair of second protrusions, the pair of first protrusions are respectively arranged corresponding to the pair of second protrusions along the extension direction of the through hole, and the corresponding first protrusions and second protrusions are respectively separated by a first distance in the extension direction of the through hole;

[0013] The pair of first protrusions are spaced apart from each other along the circumference of the through hole, and the pair of second protrusions are spaced apart from each other along the circumference of the through hole by the same distance.

[0014] In one or more embodiments, the first distance satisfies the following relationship: d / 2>f·L toc / F;

[0015] Wherein, d is the first distance, f is the friction force on the splitter head when the working end of the splitter drives the welding wire to move on the surface of the welding material, L toc is the distance from the working end of the riving knife to the center of the transducer, and F is the external force applied by the fastener on the riving knife.

[0016] In one or more embodiments, the first distance further satisfies the following relationship:

[0017] d is less than 1 / 4 of the wavelength of the blade vibration.

[0018] In one or more embodiments, the locking hole is a threaded hole, and the fastener is a bolt.

[0019] On the other hand, according to some embodiments of the present application, an ultrasonic wedge bonding machine is provided, which includes the bonding head assembly as described above.

[0020] On the other hand, according to some embodiments of the present application, a method for designing a welding head assembly is provided, which includes the following steps:

[0021] a. Obtain the outer diameter of the wedge in the welding head assembly;

[0022] b. A through hole is provided at one end of the transducer of the welding head assembly, and the inner diameter of the through hole is larger than the outer diameter of the wedge;

[0023] c. A locking hole is provided on one end surface of the transducer, wherein the locking hole is connected to the through hole;

[0024] d. A protruding portion protruding inwardly is provided in the wall of the through hole, the protrusion being arranged opposite to the locking hole, and the configuration of the protrusion being configured such that, in a fixed state, the protrusion abuts against the riving knife through contact points, the number of the contact points being multiple, including at least two contact points arranged to be separated by a first distance along the extension direction of the through hole.

[0025] In one or more embodiments, in step d, the first distance satisfies the following relationship: d / 2>f·L toc / F;

[0026] Wherein, d is the first distance, f is the friction force on the splitter head when the working end of the splitter drives the welding wire to move on the surface of the welding material, L toc is the distance from the working end of the riving knife to the center of the transducer, and F is the external force applied by the fastener on the riving knife.

[0027] In one or more embodiments, in step d, the first distance is further set to satisfy the following relationship: λ / 4>d;

[0028] Where λ is the wavelength of the blade vibration.

[0029] In one or more embodiments, the amplitude wavelength of the wedge vibration is calculated by the following formula: nλ=mi(RC / ω) 1 / 2 ;

[0030] Where n is the number of wavelengths of the sound wave transmitted on the wedge in actual working conditions, R is the wedge radius, C is the longitudinal wave velocity, ω is the angular velocity, and mi is the reference constant.

[0031] The beneficial effects of the present invention are:

[0032] In this welding head assembly, the blade is clamped on both sides by fasteners and protrusions, creating a single-point and multi-point clamping structure. This provides better freedom of constraint and improves clamping rigidity, ensuring the blade's installation position and angle, while also providing sufficient clamping rigidity to withstand welding forces. This ensures that the blade's position and verticality remain stable and unchanged during the welding process. Furthermore, the protrusions and blade contact each other through multiple points, correspondingly increasing ultrasonic transmission channels to multiple channels. This provides highly efficient ultrasonic transmission and excellent ultrasonic energy transfer pathways, further ensuring weld quality.

[0033] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

[0034] Summary of the Figures

[0035] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0036] 1 to 4 show schematic diagrams of a conventional welding head assembly;

[0037] FIG5 shows a half-section schematic diagram of a transducer in a welding head assembly according to some embodiments of the present invention;

[0038] FIG6 is a front view schematic diagram showing some embodiments of the wedge fixing method in the welding head assembly;

[0039] FIG7 shows a partial enlarged schematic diagram of portion A of FIG6 ;

[0040] FIG8 is a schematic top view showing some embodiments of the wedge fixing method in the welding head assembly;

[0041] FIG9 is a schematic diagram showing the distribution of contact points in a fixed state according to some embodiments of the welding head assembly;

[0042] Figures 10 and 11 show schematic diagrams of the action of the splitter under working conditions;

[0043] FIG12 is a schematic diagram showing ultrasound transmission when the cleaver is tilted using single-channel excitation;

[0044] FIG13 is a schematic diagram showing ultrasound transmission when the wedge is vertical when single-channel excitation is used;

[0045] FIG14 shows a schematic diagram of ultrasound transmission when the cleaver is tilted when dual-channel excitation is used;

[0046] FIG15 is a schematic diagram showing ultrasound transmission when the cleaver is vertical when dual-channel excitation is used.

[0047] Specific embodiments of the present invention

[0048] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0050] Figures 1 to 4 show schematic diagrams of a conventional welding head assembly. In this conventional welding head assembly, a splitting blade 91 is placed in a through-hole 93 near the end of a transducer 92 and secured with a screw head 94. The inner diameter of through-hole 93 is typically larger than the outer diameter of splitting blade 91 to facilitate assembly. In this state, because the material is not an absolutely rigid body and will deform under pressure, the actual effect, as shown in Figure 3, is that splitting blade 91 actually contacts the inner wall of through-hole 93 at point 910, securing splitting blade 91 at two points within through-hole 93, resulting in poor fixation. In actual working conditions, splitting blade 91 will tilt and wobble. Furthermore, due to the length of splitting blade 91, the skew angle causes a significant offset in the position of the working head 911 of splitting blade 91, which can significantly affect welding quality.

[0051] In order to solve the problems existing in the aforementioned existing splitting knife fixing method, on the one hand, according to some embodiments of the present application, a welding head assembly is provided. It can be understood that the figure marking system used to describe the welding head assembly in one or more of the following embodiments is independent of the figure marking system used for the various components of the aforementioned existing welding head assembly.

[0052] The welding head assembly includes a transducer 1 and a splitting knife 2. Figure 5 shows a half-section schematic diagram of some embodiments of the transducer in the welding head assembly, Figure 6 shows a front schematic diagram of some embodiments of the splitting knife fixing method in the welding head assembly, Figure 7 shows a partial enlarged schematic diagram of part A of Figure 6, and Figure 8 shows a top schematic diagram of some embodiments of the splitting knife fixing method in the welding head assembly.

[0053] A through hole 10 is provided at one end of the transducer 1. The inner diameter of the through hole 10 is larger than the outer diameter of the cleaver 2. The through hole 10 is opened in the transducer 1 along the radial direction of the transducer 1. A locking hole 11 is opened on the end surface of the transducer 1 with the through hole 10. The locking hole 11 is connected to the through hole 10.

[0054] An inwardly protruding convex portion 12 is provided on the hole wall of the through hole 10, that is, the convex portion 12 is provided to protrude from the inner wall of the through hole 10 toward the center of the through hole 10. It can be understood that the top of the convex portion 12 described in the article toward the center of the through hole 10 protrudes relative to the rest of the through hole 10. It can be a protrusion structure formed on the inner wall of the through hole 10 by, for example, welding, or it can be a protrusion structure formed by subtractive processing in an already formed hole structure that is higher than other areas of the inner wall of the hole.

[0055] The protrusion 12 is arranged opposite to the locking hole 11. When fixed, the riving knife 2 is inserted into the through hole 1. The relative arrangement of the protrusion 12 and the locking hole 11 described herein can be understood as, with the riving knife 2 fixed in the through hole 1 as a reference, the protrusion 12 and the locking hole 11 are respectively located on opposite sides of the riving knife 2, and with the through hole 1 itself as a reference, the protrusion 12 and the locking hole 11 are respectively located on opposite sides of the inner wall of the through hole 1.

[0056] Fastener 5 can extend into through-hole 1 through locking hole 11, pressing against blade 2 in through-hole 1 and moving toward the protrusions. Because protrusions 12 project from the inner wall of through-hole 10 toward the center of through-hole 10, they initially contact blade 2. The fastener then tightens blade 2 against the multiple protrusions 12, creating a secure structure within through-hole 1 where blade 2 is clamped by both the protrusions 12 and the fastener.

[0057] When the protrusion 12 and the fastener 5 are clamping the wedge 2, the point where the protrusion 12 contacts the wedge 2 is a contact point 120. FIG9 shows a schematic diagram of the distribution of contact points in the fixed state according to some embodiments of the welding head assembly. There are multiple contact points 120, including at least two contact points 120 spaced a first distance d apart along the extension direction of the through hole. It should be understood that the term "multiple" herein refers to two or more (including two), unless otherwise specifically defined.

[0058] In this welding head assembly, the blade 2 is clamped and secured on either side by fasteners 5 and protrusions 12, creating a single-point and multi-point clamping arrangement. This provides six degrees of freedom (DOF) and enhances clamping rigidity, ensuring the blade's installation position and angle. This clamping rigidity is sufficient to withstand welding forces, ensuring that the blade's position and verticality remain stable during the welding process. Furthermore, the protrusions 12 and the blade 2 contact each other through multiple contact points 120, correspondingly increasing the number of ultrasonic transmission channels. This ensures highly efficient ultrasonic transmission and excellent ultrasonic energy transfer, further ensuring weld quality.

[0059] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0060] In some embodiments of the present welding head assembly, as shown in FIG8 , at least two contact points are arranged at a second distance apart along the circumference of the through hole, thereby forming multiple contact points on the riving knife 2 along the circumference to achieve more stable clamping of the riving knife 2 .

[0061] In some embodiments of the present welding head assembly, the point of contact between the fastener 5 and the riving knife 2 in the fixed state is defined as the force application point 3. As shown in FIG9 , in the orthographic projection along the axial direction of the transducer 1, multiple contact points 120 are centrally symmetrically distributed relative to the force application point 3. Arranging a fixed form with this configuration can achieve uniform clamping force on the riving knife 2, further ensuring improved stability of the clamping effect on the riving knife 2.

[0062] In some embodiments of the present welding head assembly, the protrusion 12 is composed of four bumps, each of which can be understood as a point-shaped protrusion structure protruding inward from the hole wall. The bumps include a pair of first bumps and a pair of second bumps. In the clamped state, each bump is in point contact with the riving knife 2. As shown in Figure 9, the point contact position between the first bump and the riving knife 2 is a pair of first contact points 121, and the point contact position between the second bump and the riving knife 2 is a pair of second contact points 122. The pair of first bumps are respectively arranged to correspond to the pair of second bumps along the extension direction of the through hole, that is, in the orthographic projection shown along the extension direction of the through hole, the pair of first bumps respectively coincide with the pair of second bumps. The corresponding first and second bumps are separated by a first distance d in the extension direction of the through hole. The pair of first protrusions and the pair of second protrusions are spaced the same distance apart along the circumference of the through-hole, thereby ensuring that, in an orthographic projection along the extension direction of the through-hole, the pair of first protrusions coincide with the pair of second protrusions. In the extension direction of the through-hole, the pair of first protrusions and the pair of second protrusions are located at the same extension position, thereby forming the structure shown in FIG9 . Clamping at four points ensures good stability in clamping the riving knife 2 and is easy to manufacture.

[0063] In other embodiments differing from the configuration shown in the figures, the protrusion 12 may have other configurations. For example, the protrusion may be composed of two, three, or five protrusions, each of which forms a point contact with the riving knife 2 when fixed. For example, in some embodiments, the protrusion 12 may be a protrusion extending along the extension direction of the through hole 10. In this case, the contact between the protrusion 12 and the riving knife can be considered a linear contact formed by multiple continuous points.

[0064] Figures 10 and 11 show schematic diagrams of the operation of the splitting knife under working conditions. The fixation of the splitting knife requires sufficient clamping torque to balance the torque thrown back by the splitting knife head during bonding. As shown in Figure 10, when the holding force is too small, the clamping stiffness is insufficient, which will make the splitting knife head 2a unable to overcome the friction force to vibrate, and it will seem to "stick" to the welding surface. The ultrasonic energy cannot be effectively transmitted to the bonding surface for effective bonding, resulting in poor bonding and failure to meet the bond thrust test standards. According to some embodiments of the present welding head assembly, the first distance d needs to satisfy the relationship: d / 2>f·L toc / F. Where d is the first distance, f is the friction force on the splitter head when the working end of the splitter drives the welding wire to move on the surface of the welding material, L toc is the distance from the working end of the splitter to the center of the transducer, and F is the external force applied by the fastener to the splitter. As shown in Figure 10, when the first distance d satisfies the relationship: d / 2>f·L toc / F, the torque M at the fixed position of the riving knife 2 holding Greater than the torque M at the welding surface friction , at this time, the clamping stiffness is sufficient to effectively output ultrasound.

[0065] Furthermore, in some embodiments of the welding head assembly, the first distance d further satisfies the following relationship: d is less than 1 / 4 of the wavelength of the blade vibration. If the first distance d is greater than 1 / 4 of the wavelength of the blade vibration, the phase can easily exceed 180 degrees, which will also weaken the ultrasonic output and affect the welding quality.

[0066] Furthermore, in some embodiments of the welding head assembly, the locking hole 11 is a threaded hole, and the fastener 5 is a bolt, and the bolt is tightened in the threaded hole to achieve the clamping of the wedge. In other suitable embodiments, the fastener can also be a fixing component of other configurations, such as a rivet.

[0067] On the other hand, according to some embodiments of the present application, an ultrasonic wedge bonding machine is further provided, which includes a bonding head assembly as described in one or more of the above embodiments.

[0068] On the other hand, according to some embodiments of the present application, a method for designing a welding head assembly is provided, characterized in that it includes the following steps:

[0069] a. Obtain the outer diameter of the wedge in the welding head assembly;

[0070] b. A through hole is provided at one end of the transducer of the welding head assembly, and the inner diameter of the through hole is larger than the outer diameter of the wedge;

[0071] c. A locking hole is provided on one end surface of the transducer, the locking hole being connected to the through hole;

[0072] d. A protruding portion protruding inwardly is provided in the wall of the through hole, the protrusion being arranged opposite to the locking hole, and the configuration of the protrusion being configured such that, in a fixed state, the protrusion abuts against the riving knife through contact points, the number of contact points being multiple, and including at least two contact points arranged to be separated by a first distance along the extension direction of the through hole.

[0073] Furthermore, in some embodiments of the design method of the welding head assembly, in step d, the first distance is set to satisfy the following relationship: d / 2>f·L toc / F;

[0074] Where d is the first distance, f is the friction force on the splitter head when the working end of the splitter drives the welding wire to move on the surface of the welding material, and L toc is the distance from the working end of the riving knife to the center of the transducer, and F is the external force applied to the riving knife by the fastener.

[0075] Furthermore, in some embodiments of the design method of the welding head assembly, in step d, the first distance is further set to satisfy the following relationship: λ / 4>d;

[0076] Where λ is the wavelength of the blade vibration.

[0077] Furthermore, in some embodiments of the present method for designing a welding head assembly, the amplitude wavelength of the wedge vibration is calculated by the following formula: nλ=mi(RC / ω) 1 / 2 ;

[0078] Where n is the number of wavelengths of the sound wave transmitted on the wedge in actual working conditions, R is the wedge radius, C is the longitudinal wave velocity, ω is the angular velocity, and mi is the reference constant.

[0079] The present invention is further described below by a specific embodiment:

[0080] Taking the 60 kHz design as an example, the riving knife 2 can be regarded as a horn of bending vibration.

[0081] The reference constant mi can be calculated by the following formula: cos(mi)cosh(mi)=1.

[0082] The order i=5 is selected and mi=14.137 is calculated.

[0083] The resonance length L at this timere =mi(RC / ω) 1 / 2 In this embodiment, the wedge radius R is 1.585 mm, and the calculated L re The wavelength of the sound wave transmitted on the cleaver in actual working conditions is 3 wavelengths, so the amplitude wavelength of the cleaver vibration is λ=66 / 3=22mm.

[0084] During welding, the pressure applied to the splitter is F. bonding =6kgf, thus it is calculated that the friction force f = 1.8kgf is exerted on the splitter head when the working end of the splitter drives the welding wire to move on the surface of the welding material.

[0085] The distance from the working end of the splitter to the center of the transducer is 5 / 6 of the wavelength, so we get

[0086] The external force F exerted by the fastener on the splitter is 80 kgf, so 2f·L toc / F=2*1.8kgf*55mm / 80kgf=2.5mm.

[0087] In summary, 2f.L toc / F<d<λ / 4, that is, 2.5mm<d<5.5mm, and the preferred value of the first distance d is 4.5mm.

[0088] The original 1+1 butt-jointed design provides a maximum clamping length of 3mm, very close to the required lower limit of 2.5mm, with minimal margin. Furthermore, the tightening torque for the 1 / 8" splitter screw is 5kgf.cm. The hexagon socket screw is prone to deformation and slippage, requiring fewer than five uses and requiring custom customization. This new weld head assembly configuration nearly doubles the clamping length, increasing margins and reducing clamping force requirements, thus lowering tightening torque, preventing screw failure, and ensuring more reliable clamping.

[0089] Figure 12 shows a schematic diagram of ultrasonic transmission when the splitting knife is tilted when single-channel excitation is used, and Figure 13 shows a schematic diagram of ultrasonic transmission when the splitting knife is vertical when single-channel excitation is used. Comparing Figures 12 and 13, it can be seen that when the splitting knife 2 is installed with a deviation, when the node exceeds the excitation zone, the transmission of ultrasound on the splitting knife 2 drops sharply. By installing the splitting knife vertically, the node is not likely to exceed the excitation zone, thereby not affecting the welding quality.

[0090] In some embodiments of the present horn assembly, dual (or multi) channel input excitation can be implemented. Figure 14 illustrates ultrasonic transmission when the blade is tilted using dual channel excitation, and Figure 15 illustrates ultrasonic transmission when the blade is vertical using dual channel excitation. Comparing Figures 12 and 13, it can be seen that even if blade 2 is tilted, the stability of ultrasonic transmission on blade 2 is not significantly affected when dual channel excitation is used. Implementing dual (or multi) channel input excitation with the present horn assembly improves the efficiency of ultrasonic transmission. The effective energy transmission area is increased, ensuring that the blade node always falls within the effective excitation area, reducing the blade's height sensitivity and achieving stable and balanced ultrasonic output.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A welding head assembly, characterized in that, It includes a transducer and a bonding tool. One end of the transducer is provided with a through hole, the inner diameter of the through hole is larger than the outer diameter of the bonding tool, the through hole is radially opened in the one end along the transducer, and a locking hole is opened on the end face of the one end, and the locking hole communicates with the through hole; A convex portion protruding inward is provided on the hole wall of the through hole, the convex portion is arranged opposite to the locking hole. When fixing, the bonding tool is inserted through the through hole, and a fastener extends into the through hole through the locking hole and presses the bonding tool against a plurality of the convex portions; Wherein, in the fixed state, the convex portion abuts against the bonding tool through contact points, the number of the contact points is a plurality, and at least two of the contact points are configured to be separated by a first distance along the extension direction of the through hole.

2. The soldering head assembly according to claim 1, characterized in that, Among the plurality of contact points, at least two contact points are configured to be separated by a second distance along the circumferential direction of the through hole.

3. The soldering head assembly according to claim 1, wherein In the fixed state, define the point where the fastener abuts against the bonding tool as the force application point. In the orthographic projection viewed along the axial direction of the transducer, the plurality of contact points are symmetrically distributed about the force application point.

4. The soldering head assembly according to claim 3, wherein The convex portion includes four convex points. In the clamping state, each convex point is in point contact with the bonding tool. The convex points include a pair of first convex points and a pair of second convex points. The pair of first convex points are respectively arranged corresponding to the pair of second convex points along the extension direction of the through hole, and the corresponding first convex point and the second convex point are separated by a first distance along the extension direction of the through hole; The pair of first convex points are separated by the same distance along the circumferential direction of the through hole, and the pair of second convex points are separated by the same distance along the circumferential direction of the through hole.

5. The soldering head assembly according to claim 1, characterized in that, The first distance satisfies the following relational expression: d / 2 > f·L toc / F; Wherein, d is the first distance, f is the frictional force received by the tip of the capillary when the working end of the capillary drives the welding wire to act on the surface of the welding material, L toc is the distance from the working end of the capillary to the center of the transducer, and F is the external force applied to the capillary by the fastener.

6. The soldering head assembly according to claim 5, wherein, The first distance further satisfies the following relationship: d is less than 1 / 4 of the amplitude wavelength of the vibration of the bonding tool.

7. The soldering head assembly according to claim 1, wherein, The locking hole is a threaded hole, and the fastener is a bolt.

8. An ultrasonic wedge welder, characterized in that, It includes the bonding head assembly according to any one of claims 1 to 7.

9. A design method for a welding head assembly, characterized in that, It includes the following steps: a. Obtain the outer diameter of the bonding tool in the bonding head assembly; b. Provide a through hole at one end of the transducer of the bonding head assembly, and make the inner diameter of the through hole larger than the outer diameter of the bonding tool; c. Open a locking hole on the end face of the one end of the transducer, and the locking hole communicates with the through hole; d. Provide a convex portion protruding inward in the hole wall of the through hole, the convex portion is arranged opposite to the locking hole, and configure the structure of the convex portion such that in the fixed state, the convex portion abuts against the bonding tool through contact points, the number of the contact points is a plurality, and at least two of the contact points are configured to be separated by a first distance along the extension direction of the through hole.

10. The design method of the welding head assembly according to claim 9, characterized in that, In step d, let the first distance satisfy the following relational expression: d / 2 > f·L toc / F; Wherein, d is the first distance, f is the frictional force on the tip of the capillary when the working end of the capillary drives the welding wire to act on the surface of the welding material, L toc is the distance from the working end of the capillary to the center of the transducer, and F is the external force applied to the capillary by the fastener.

11. The design method of the welding head assembly according to claim 10, characterized in that, In step d, make the first distance further satisfy the following relationship: λ / 4>d; Wherein, λ is the amplitude wavelength of the vibration of the bonding tool.

12. The design method of the welding head assembly according to claim 11, characterized in that, The amplitude wavelength of the capillary vibration is calculated by the following formula: nλ = mi(RC / ω) 1 / 2 ; Wherein, n is the number of wavelengths of the sound wave transmitted on the bonding tool under actual working conditions, R is the radius of the bonding tool, C is the longitudinal wave velocity, ω is the angular velocity, and mi is the reference constant.

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