High-precision wire welding machine based on air floating guide rail

Abstract

The invention discloses a high-precision wire welding machine based on an air floating guide rail, and belongs to the field of ultrasonic welding. The high-precision wire welding machine based on the air-floating guide rail comprises a welding machine body and the air-floating guide rail, the air-floating guide rail comprises a moving part and two rails, fit clearances with V-shaped sections are formed between the rails and the moving part, and V-shaped openings of the fit clearance sections on the two sides are oppositely arranged; the moving part is provided with an air hole communicated with the fit clearance, and pressure air is sprayed out through the air hole to form an air film between the moving part and the track; the welding machine body is fixedly connected to the moving part. According to the wire welding machine, the overall rolling and deflection tendency of the wire welding machine caused by suspension of the welding head in the wire welding operation process can be effectively restrained, vibration of the welding head in the working process is reduced, and therefore the precision and quality of the wire welding operation are improved.

Description

Technical Field

[0001] The invention belongs to the field of ultrasonic welding, and in particular relates to a high-precision wire welding machine based on an air-floating guide rail. Background Art

[0002] Wire bonders are widely used in the manufacturing fields of semiconductor devices and integrated circuits. The moving accuracy and stability of the welding head of the wire bonder have a direct impact on the welding quality and efficiency. At present, wire bonders are usually driven by mechanical linear guides. There is friction between the moving parts and the guides of mechanical linear guides. At the same time, it is affected by factors such as structural rigidity and guide straightness, which makes it difficult to further improve the control accuracy and response speed, and cannot meet the requirements of precision welding.

[0003] Some welding equipment uses electromagnetic guide rails to drive, which can improve control accuracy and response speed, but the electromagnetic guide rail itself is heavy, and the electromagnetic field generated by the electromagnetic guide rail may have an adverse effect on the normal operation of the wire welding machine. Figure 1 As shown, the welding head 1 of the wire welding machine extends to the front end of the wire welding machine body 2 in a structure similar to a cantilever beam, which makes the center of gravity of the welding head 1 area not coincide with the center of gravity of the wire welding machine as a whole, generating additional torque. This causes the side where the welding head 1 of the wire welding machine is located to easily sink and the end away from the welding head 1 to easily tilt when a conventional air floating guide rail is used, which is not conducive to improving the welding accuracy.

[0004] Therefore, providing a wire bonding machine with higher precision has positive significance for improving the quality and efficiency of bonding processing. Summary of the invention

[0005] The object of the present invention is to provide a high-precision wire bonding machine based on an air-floating guide rail, so as to improve the machining accuracy of the wire bonding machine.

[0006] According to an embodiment of the present invention, a high-precision wire welding machine based on an air-floating guide rail is provided, and the wire welding machine includes a welding machine body and an air-floating guide rail. The air-floating guide rail includes a track and a moving part, the track is arranged in two pieces, the moving part is arranged between the two tracks and can slide along the track, a fitting gap is formed between the moving part and the track, the cross-section of the fitting gap is arranged in a V-shape, and the opening directions of the V-shape are arranged relatively; the moving part is provided with a plurality of air holes connected to the fitting gap, and pressurized gas is ejected through the air holes to form an air film between the moving part and the track. The welding machine body is fixedly connected to the moving part.

[0007] The wire welding machine drives the welding machine body through the air-floating guide rail with a V-shaped cross-section matching gap, which can effectively improve the stability of the welding machine body by limiting the vertical and horizontal directions of the welding machine body. Since the V-shaped cross-section can provide upward and downward limits for the welding machine body at the same time, it can effectively avoid the rolling tendency of the welding machine body in the vertical plane during welding; the rails arranged in pairs form horizontal limits for the welding machine body, inhibiting the rotation of the welding machine body in the horizontal plane.

[0008] Furthermore, in some embodiments, the moving part further includes a buffer cavity, the buffer cavity is communicated with the air hole, and the pressurized gas enters the air hole through the buffer cavity.

[0009] The buffer chamber can achieve uniform gas pressure and avoid pressure fluctuations of the pressurized gas delivered to the pores.

[0010] Furthermore, in some embodiments, the buffer cavity is configured as a symmetrical structure, and the symmetry plane of the buffer cavity is configured as a plane equidistant from the two guide rails.

[0011] The buffer chamber with a symmetrical structure can eliminate the pressure difference of the pressurized gas delivered to the tracks on both sides and improve stability.

[0012] Further, in some embodiments, the buffer cavity includes an air source interface, the air source interface is connected to an air source, and the air source interface is arranged on the symmetric plane of the buffer cavity.

[0013] Furthermore, in some embodiments, the V-shaped cross-section of the fitting gap has a horizontal symmetry plane.

[0014] Furthermore, in some embodiments, the welding machine body includes a welding head, and the welding head is suspended on one side of the moving part along the extension direction of the track.

[0015] Furthermore, in some embodiments, the pores are configured as single pores or porous exhaust structures made of porous materials.

[0016] Furthermore, in some embodiments, protrusions are provided on both sides of the moving part, and the track is provided with a groove, and the protrusions cooperate with the groove to define the fitting gap.

[0017] Furthermore, in some embodiments, the pressure of the pressurized gas is 0.4MPa-0.5MPa.

[0018] Furthermore, in some embodiments, the linear accuracy of the air-floating guide rail does not exceed 0.01 μm / mm; the roll / pitch / yaw accuracy does not exceed ±0.01 arcsec. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of a wire bonding machine in one embodiment;

[0020] Figure 2 A schematic diagram of the cross-sectional structure of a wire bonding machine in one embodiment;

[0021] Figure 3 This is a schematic diagram of the local structure of the air-floating guide rail motion part in one embodiment;

[0022] Figure 4 This is a schematic diagram of the coordination structure between the air-floating guide rail moving part and the track in one embodiment;

[0023] Figure 5 1 is a frequency response curve of a wire bonding machine at different positions in an embodiment;

[0024] Figure 6 A pair of proportional frequency response curves of the wire bonding machine at different positions.

[0025] The meaning of the reference numerals: 1-welding machine body; 11-welding head; 12-cantilever; 2-air floating guide rail; 21-moving part; 22-air hole; 23-buffer chamber; 24-air source interface; 25-track; 26-matching flange; 27-air guide tube; 3-matching gap.

[0026] The purpose of the above drawings is to explain the present invention in detail so that those skilled in the art can understand the technical concept of the present invention, but it is not intended to limit the present invention. For the sake of simplicity, the above drawings only schematically illustrate the structures related to the technical features of the present invention, and do not strictly follow the actual proportions to draw the complete structure and all details. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0028] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The phrase appearing in various locations in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive independent or alternative embodiments. Those skilled in the art should be able to understand that the embodiments herein may be combined with other embodiments without causing structural conflicts.

[0029] In the description of this article, unless otherwise clearly specified and limited, the technical terms "installed", "connected", "connected" and the like should be understood in a broad sense, for example, it can be a movable connection, a fixed connection or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of this application can be understood according to specific circumstances.

[0030] In the description of this document, terms indicating orientation or positional relationships, such as "up", "down", "left", "right", "horizontal", "vertical", "height", "length", and "width", are intended to accurately describe the embodiments and simplify the description, but are not intended to limit the parts or structures involved to have a specific orientation, be installed or operate in a specific orientation, and should not be construed as a limitation on the embodiments in this document.

[0031] In the description of this article, the terms "first", "second" and the like are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the quantity, specific order or primary and secondary relationship of the described technical features. In the description of this article, the meaning of "plurality" is at least two.

[0032] The motion platform of the wire welding machine is usually based on a mechanical linear guide, such as a cross roller linear guide or a needle roller linear guide. The mechanical linear guide uses the rotation of the roller to achieve the relative motion between the stationary guide and the moving guide. Since the roller moves relative to the guide, the mechanical linear guide must reserve space for the roller to move, which makes it impossible to achieve full-length coverage of the roller in the motion path. In the blank area without rollers, the stability of the mechanical guide support is reduced and vibration is prone to occur. Furthermore, since the welding head of the wire welding machine itself is suspended, the load at the welding head leads to a decrease in the working accuracy of the wire welding machine. Furthermore, due to the relative motion between the roller and the moving guide, the roller support position of the mechanical linear guide movement is different at different positions, and the mechanical frequency response at different positions in the wire welding area is also different, which makes it difficult to always match the control and machinery at different positions, and it is impossible to achieve optimization in the welding work area.

[0033] In some precision machine tools, magnetic levitation guides are used to replace mechanical linear guides. However, wire bonders are used in chip manufacturing, and strong magnetic fields are not allowed to exist near the working area of ​​the wire bonder. In addition, the permanent magnets or electric cores of the magnetic levitation guides are heavy, which is not conducive to improving the motion response performance. The air-floating guide lacks constraints on the rotation or rolling tendency of the wire bonder, and it is difficult to ensure stability during the working process when the wire bonder welding head is suspended.

[0034] In order to solve the above problems, an embodiment of one aspect of the present invention provides a high-precision wire bonding machine based on an air-floating guide rail. Figure 1 and Figure 2 As shown, it includes a welding machine body 1 and an air-floating guide rail 2 that carries and drives the welding machine body 1. The air-floating guide rail 2 includes two rails 25, which are combined Figure 2 A moving part 21 is arranged between the two rails 25, and the welding machine body 1 is fixedly connected to the moving part 21. Figure 4The moving part is provided with a matching flange 26 protruding to both sides, and the track 25 is provided with a groove portion matching therewith. A matching gap 3 with a V-shaped cross section is formed between the matching flange 26 and the track 25. The V-shaped cross-section openings of the matching gap 3 on both sides of the moving part 21 are opposite (towards the middle). The moving part 21 is provided with an air guide 27, and a plurality of air holes 22 connected to the matching gap 3 are opened on the air guide 27. Pressurized gas is sprayed into the matching gap 3 through the air holes 22 to form an air film to separate the moving part 21 from the track 25.

[0035] A cantilever 12 extends horizontally from one end of the welding machine body 1, and the cantilever 12 extends along the extension direction of the track 25, so that the welding head 11 fixed to the cantilever 12 is suspended on one side of the welding machine body 1, so that the welding head 11 performs the welding line operation without interfering with other parts of the welding machine body 1 or the moving part 21.

[0036] Since the matching gaps 3 on both sides are set to a relative V-shape, the air film provides horizontal and vertical constraints to the moving part 21. Among them, the horizontal constraint can prevent the welding machine from deflecting in the horizontal plane during welding; the vertical constraint includes an upward support force on the one hand, which lifts the moving part 21 to separate the moving part 21 from the track 25 to avoid friction; the vertical constraint includes a downward constraint on the other hand. When the suspended welding head 11 performs welding line operation, a torque will be generated due to the fact that the force and the center of gravity of the welding machine body 1 are not in the same plumb line. The vertical downward constraint can prevent the welding machine body 1 from flipping under this torque, thereby ensuring the stability of the welding head 11 during operation and improving the welding quality.

[0037] In a preferred embodiment, if Figure 3 As shown, the moving part 21 also includes a buffer chamber 23 ( Figure 3 The structure of the middle moving part 21 except the air path is not shown), the buffer chamber 23 is connected to the air pipes 27 on both sides respectively, and the pressure gas is ejected from the buffer chamber 23 through the air pipes 27 and finally through the air holes 22 to the fitting gap 3 to form an air film. The buffer chamber 23 is provided with an air source interface 24 and is connected to the pressure gas source through the air source interface 24. After the gas output by the pressure gas source enters the buffer chamber 23, the buffering of the buffer chamber 23 can eliminate the uneven pressure caused by the flow, and improve the uniformity of the pressure entering the air pipes 27 on both sides. In a further preferred embodiment, the buffer chamber 23 is set to a symmetrical structure, and the plane with an equal distance from the two tracks 25 is used as the symmetrical plane, and the air source interface 24 is also set on the symmetrical plane to ensure that the path of the pressure gas entering the air pipes 27 on both sides is also the same. After the flow is diverted by the buffer chamber 23, the flow difference and pressure difference of the air pipes 27 on both sides can be controlled below 1%.

[0038] In different embodiments, the V-shaped cross section of the matching gap 3 may adopt different angles according to different loads of the air-floating guide rail 2. In a preferred embodiment, the V-shaped cross section of the matching gap 3 is symmetrical about a horizontal plane passing through the V-shaped apex.

[0039] In different embodiments, the air holes 22 may adopt different structures. In some embodiments, independent single air holes may be used to reduce manufacturing costs and reduce resistance; in other embodiments, a porous exhaust structure made of porous materials may be used, for example, holes are opened on the side wall of the air guide tube 27 and a honeycomb structure is filled therein, so as to improve airflow uniformity, reduce the risk of air hole blockage, and reduce resonance.

[0040] In different embodiments, the fit gap 3 can be set to different fit sizes according to the different loads of the air-floating guide rail 2. When preloading the air-floating guide rail 2, the thickness of the air film can be adjusted by fixing one side and adjusting the other side. The width of the fit gap 3 is the thickness of the air film h, and the input pressure P 0 After throttling through the air hole 22, the pressure drops to P 1 , the pressure output to the outside through the matching gap 3 is reduced to P 2 When the bearing preload increases, the air film gap decreases, and the relationship between fluid resistance and air film thickness is expressed as: Rv∝(1 / h) 3 . As the air film gap decreases, R v The pressure acting on the wall of the fitting gap 3 increases rapidly, and the rigidity of the air-floating guide rail 2 increases accordingly, so that the steady-state balance can be maintained within a certain load range.

[0041] In a preferred embodiment, when the vertical load is about 2kg and the pressure gas of 0.4MPa-0.5MPa is filled in the matching gap 3, the air film stiffness can fully meet the precision requirements of the welding line operation. The linear accuracy of the air floating guide rail 2 does not exceed 0.01μm / mm, and the roll / pitch / yaw accuracy does not exceed ±0.01arcsec.

[0042] The high-precision wire welding machine based on the air-floating guide rail provided in the above embodiment effectively reduces the difficulty of applying preload; effectively improves the stability of the wire welding machine operating in different positions and the consistency of welding conditions; at the same time, the wire welding machine has a compact structure and light moving mass, which is convenient for deployment and production in an effective space, reducing the risk of production line interference; it can achieve large acceleration under small thrust and has a fast response speed; there is no mechanical contact between the moving part and the track, which effectively reduces component wear and reduces maintenance costs; the air-floating guide rail can also effectively play a vibration isolation role to prevent the welding head from being interfered by low frequency or similar frequencies during work.

[0043] In one embodiment, the frequency response curves of the wire bonding machine at different positions (FR, FL, HH, RL, RR) are as follows: Figure 5 As shown in the figure, it can be seen that the frequency response at different positions is highly consistent, which can effectively improve the accuracy and welding quality of the wire bonding machine production operation. In a comparative example, the frequency response curves of the wire bonding machine using mechanical linear guides at different positions (FR, FL, HH, RL, RR) are as follows: Figure 6 As shown, it can be seen that the frequency response of the wire bonding machine at different positions is significantly different, and there are even opposite peaks and valleys, which results in the same operation control strategy being unable to take into account different welding areas, and has a significant adverse effect on the quality and accuracy of the wire bonding operation. It can be seen that the high-precision wire bonding machine based on the air floating guide provided by the embodiment of the present invention has a significant effect on improving the processing quality of the wire bonding operation.

[0044] The purpose of the above embodiments is to further explain the present invention in detail in conjunction with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope of the present invention, the optimization or equivalent replacement of the part structure involved, and the combination of the implementation methods in different embodiments without conflict of structure and principle, all fall within the protection scope of the present invention.

Claims

1. A high-precision wire welding machine based on air-floating guide rail, characterized in that: It includes a welding machine body and an air-floating guide rail; The air-floating guide rail comprises a track and a moving part, wherein the track is provided in two pieces, the moving part is provided between the two tracks and can slide along the track, a fitting gap is formed between the moving part and the track, the cross section of the fitting gap is provided in a V-shape, and the opening directions of the V-shape are provided in opposite directions; the moving part is provided with a plurality of air holes connected to the fitting gap, and pressurized gas is ejected through the air holes to form an air film between the moving part and the track; The welding machine body is fixedly connected to the moving part.

2. The high-precision wire bonding machine based on air-floating guide rail according to claim 1, characterized in that: The moving part further includes a buffer cavity, which is communicated with the air hole, and the pressure gas enters the air hole through the buffer cavity.

3. The high-precision wire bonding machine based on air-floating guide rail according to claim 2, characterized in that: The buffer cavity is configured as a symmetrical structure, and the symmetry plane of the buffer cavity is configured as a plane equidistant from the two tracks.

4. The high-precision wire bonding machine based on air-floating guide rail according to claim 3 is characterized in that: The buffer cavity comprises an air source interface, the air source interface is connected to an air source, and the air source interface is arranged on the symmetric plane of the buffer cavity.

5. The high-precision wire bonding machine based on an air-floating guide rail according to any one of claims 1 to 4, characterized in that: The V-shaped cross section of the fitting gap has a horizontal symmetry plane.

6. The high-precision wire bonding machine based on an air-floating guide rail according to any one of claims 1 to 4, characterized in that: The welding machine body comprises a welding head, and the welding head is suspended on one side of the moving part along the extending direction of the track.

7. The high-precision wire bonding machine based on an air-floating guide rail according to any one of claims 1 to 4, characterized in that: The pores are configured as single pores or porous exhaust structures made of porous materials.

8. The high-precision wire bonding machine based on an air-floating guide rail according to any one of claims 1 to 4, characterized in that: Both sides of the moving part are provided with protrusions, the track is provided with grooves, and the protrusions cooperate with the grooves to define the matching gap.

9. The high-precision wire bonding machine based on an air-floating guide rail according to any one of claims 1 to 4, characterized in that: The pressure of the pressurized gas is 0.4MPa-0.5MPa.

10. The high-precision wire bonding machine based on an air-floating guide rail according to any one of claims 1 to 4, characterized in that: The linear accuracy of the air-floating guide rail does not exceed 0.01 μm / mm; the roll / pitch / yaw accuracy does not exceed ±0.01 arcsec.

Images