JP2023026474A - Ultrasonic joining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic joining method enabling easy hard-to-view local joining.

SOLUTION: An ultrasonic joining method according to the present invention comprises the processes of: inserting a columnar or cylindrical anvil 7 into a cylindrical work Wa; inserting a linear work Wb into a gap between the cylindrical work Wa and anvil 7, and moving a tip end part thereof to a joining position X of an inner peripheral surface of the cylindrical work Wa; and bringing a horn chip 6 into contact with an outer peripheral surface of the cylindrical work Wa which corresponds to the joining position X, and imparting ultrasonic vibrations. On an outer peripheral surface of the anvil 7, a guide groove 7a is provided which guides the linear work Wb along up to the joining position X.

SELECTED DRAWING: Figure 2A

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to an ultrasonic bonding method for bonding workpieces such as metals and plastics by ultrasonic vibration.

Conventionally, welding technology has been used to join plastics used in food packs and the like, and metals such as battery parts. Also, as one of the welding techniques, ultrasonic welding is known, in which the tip of a welding tip is ultrasonically vibrated and pressure is repeatedly applied to the objects to be welded.

The electrode catheter of Patent Literature 1 has electrodes with excellent contrastability (visibility in X-ray images and the like) so that the metal ring inserted into the body can be visually recognized in the X-ray image and the like. Welding is used to attach the electrodes.

In the electrode portion, the coating resin is removed from the tip of the lead wire to expose the metal core wire, which is resistance-welded to the inner peripheral surface of the metal ring. A lead wire is thereby connected to each of the nine metal rings (Patent Document 1/paragraph 0056, FIG. 5).

JP 2012-034852 A

However, in Patent Literature 1, since welding is performed in a minute area, there is a problem that it is difficult to visually recognize the joining position and it is difficult to achieve reliable joining.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ultrasonic bonding method capable of easily performing local bonding that is difficult to see.

In the first invention, the bonding tip is vibrated by ultrasonic vibration that combines a vibration component in a first direction perpendicular to the direction in which the bonding tip presses and a vibration component in a second direction perpendicular to the first direction. An ultrasonic bonding method for joining workpieces by pressing, the step of inserting a cylindrical or cylindrical anvil having a diameter smaller than the inner diameter of the cylindrical workpiece into the interior of the cylindrical workpiece; a step of inserting a linear work having a diameter smaller than the gap into the gap between the shaped work and the anvil, and moving the tip of the linear work to a joining position of the inner peripheral surface of the cylindrical work; bringing the joining tip into contact with the position of the outer peripheral surface of the cylindrical work corresponding to the joining position to apply the ultrasonic vibration, wherein the linear work is placed along the outer peripheral surface of the anvil. It is characterized in that a guide groove is provided in the long axis direction to guide the joint to the joining position.

In the ultrasonic bonding method of the present invention, the tip of the bonding tip is pressed against the workpiece, and the ultrasonic vibration (composite vibration) to vibrate the bonding tip. As a result, the bonding is performed while removing impurities from the surfaces of the workpieces.

First, a columnar or cylindrical anvil is inserted inside the cylindrical work, and then the linear work is inserted into the gap between them. After that, it is necessary to move the tip of the linear work to the joining position of the inner peripheral surface of the cylindrical work. and guide it to the joining position. Furthermore, a joining tip is brought into contact with the position of the outer peripheral surface of the cylindrical work, and ultrasonic vibration is applied to join the work. As a result, local bonding that is difficult to see can be easily performed.

In the ultrasonic bonding method of the first invention, it is preferable that the guide groove is formed so that the groove becomes shallower as it approaches the end of the anvil.

When the linear work is moved along the guide groove of the present invention and its tip is moved to the joining position, the position of the linear work rises at the joining position, and the gap between the linear work and the cylindrical work is formed. decreases. Thereby, the cylindrical work and the linear work can be reliably joined.

Moreover, in the ultrasonic bonding method of the first invention, it is preferable to include a step of pressing the cylindrical workpiece from both ends in the longitudinal direction.

By pressing and restraining the cylindrical work from both ends in the long axis direction, it is possible to prevent rotation of the cylindrical work during bonding and improve bonding quality.

In the second invention, the bonding tip is vibrated by ultrasonic vibration that combines a vibration component in a first direction perpendicular to the direction in which the bonding tip presses and a vibration component in a second direction perpendicular to the first direction. An ultrasonic bonding method for bonding workpieces by causing a step of inserting a protrusion of the bonding tip having a diameter smaller than that of the cylindrical workpiece into the interior of the cylindrical workpiece; a step of inserting a linear work into the interior of the cylindrical work, moving the tip of the linear work to a joining position on the inner peripheral surface of the cylindrical work; and a step of applying ultrasonic vibration, wherein in the step of inserting the linear work, the linear work is fixed to a guide block and the relative position of the guide block with respect to the cylindrical work is changed. and

In the ultrasonic bonding method of the present invention, the bonding tip has a protrusion smaller in diameter than the cylindrical work, and the protrusion is inserted into the cylindrical work. After that, the linear work is inserted into the cylindrical work and moved to the joining position. At this time, the linear work is fixed to the guide block, and the relative position of the guide block is changed so as to reach the joining position. After that, the projecting portion of the bonding tip is moved to the bonding position, and ultrasonic vibration is applied for bonding. This makes it possible to easily perform local bonding that cannot be visually recognized.

In the ultrasonic bonding method of the second aspect of the invention, it is preferable that the protrusion is detachable from the bonding tip.

According to this configuration, the projection can be used by being attached to an existing bonding chip, so that the shape of the projection can be changed according to the bonding application.

BRIEF DESCRIPTION OF THE DRAWINGS The figure explaining the whole structure of the ultrasonic bonding apparatus which concerns on embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram (sectional drawing) explaining the ultrasonic bonding method of 1st Embodiment. (a) Sectional drawing which looked at the joining position vicinity from the front side. (b) Side view of the anvil. 4 is a flowchart of the ultrasonic bonding method of the first embodiment; The schematic diagram (sectional view) explaining the ultrasonic bonding method of 2nd Embodiment. Enlarged view of the horn tip. 6 is a flowchart of an ultrasonic bonding method according to the second embodiment;

An embodiment of the ultrasonic bonding apparatus of the present invention will be described below with reference to the drawings.

[First embodiment]
First, referring to FIG. 1, the overall configuration of an ultrasonic bonding apparatus 1 used in the ultrasonic bonding method of the present invention will be described. The ultrasonic bonding apparatus 1 is an apparatus for bonding (welding) objects to be bonded (workpieces) such as metal plates using ultrasonic complex vibrations, which will be described later. The ultrasonic bonding apparatus 1 is mainly used for bonding electrodes of lithium ion batteries and semiconductor elements, and metals of the same kind or different kinds.

The ultrasonic bonding apparatus 1 includes an ultrasonic vibrator 2 , an ultrasonic expansion horn 3 , an ultrasonic LT (Langevin Type) horn 4 , a horn tip 6 and an anvil 7 . The oscillator 8 , pressure device 10 , sensor 12 , control device 13 and display device 14 are also part of the ultrasonic bonding apparatus 1 .

When a power supply voltage (not shown) is applied to the oscillation device 8, a voltage signal is transmitted to the + electrode and - electrode of the ultrasonic transducer 2, and the ultrasonic transducer 2 vibrates, causing ultrasonic vibration (about 20 KHz). occurs. Ultrasonic vibrations generated by the ultrasonic transducer 2 are transmitted to a cylindrical ultrasonic magnifying horn 3 attached to one end of the ultrasonic transducer 2, and the vibration amplitude is magnified. Furthermore, the ultrasonic vibrations are transmitted to a cylindrical ultrasonic LT horn 4 attached to one end of the ultrasonic expansion horn 3 (the end on the side without the ultrasonic transducer 2).

Up to this point, the ultrasonic vibration generated by the ultrasonic transducer 2 was transmitted in the longitudinal direction of the ultrasonic expansion horn 3 and the ultrasonic LT horn 4 (longitudinal vibration of ultrasonic waves). A plurality of oblique slits 4a generate a vibration component converted from longitudinal vibration to lateral vibration. The ultrasonic vibration (complex vibration) is applied to the horn tip 6 (the "bonding tip" of the present invention) screwed to one end of the ultrasonic LT horn 4 (the end on the side without the ultrasonic expansion horn 3). equivalent).

The horn tip 6 is composed of a truncated conical base portion 6a and a tip portion 6b that contacts the workpiece during welding. That is, by adjusting the phase of the ultrasonic vibration with the oscillation device 8, a compound vibration (for example, elliptical vibration) is generated at one end of the ultrasonic LT horn 4, and the tip 6b of the horn tip 6 moves along the surface of the work in an elliptical manner. Draw a trajectory and vibrate. This vibration removes impurities from the surface of the workpiece and further promotes plastic deformation of the surface of the workpiece. The horn tip 6 has various shapes, and can be used by exchanging it according to the kind of work.

Supplementing the compound vibration, when the tip 6b (end surface 6c) of the horn tip 6 presses a workpiece, the vibration component in the first direction perpendicular to the pressing direction and the vibration component in the second direction perpendicular to the first direction It is a vibration combined with the vibration component of If the vibration component in the first direction and the vibration component in the second direction are 1:1, the vibration is circular, and if it is 2:1, the vibration is elliptical.

A pressurizing block (not shown) having high rigidity is in contact with the flange portion 3a of the ultrasonic magnifying horn 3. As shown in FIG. Therefore, the pressure device 10 can be controlled by the control device 13 to move the ultrasonic bonding device 1 in the vertical direction via the pressure block that moves up and down.

In this embodiment, a linear work Wb, which is a thin metal wire, is joined to the inner peripheral surface of a metal cylindrical work Wa. Therefore, a columnar or cylindrical anvil 7 having a smaller diameter than the inner diameter of the cylindrical workpiece Wa is used.

The diameter of the linear work Wb is smaller than the gap between the cylindrical work Wa and the anvil 7. The linear work Wb is inserted from the end of the cylindrical work Wa, and the tip thereof is moved to the joining position. . Then, the front end portion 6b of the horn tip 6 is brought into contact with the outer peripheral surface of the cylindrical work Wa at the joining position, and a static pressure (200 to 800 N at the time of joining) is applied.

The ultrasonic bonding apparatus 1 includes a sensor (stroke sensor) 12 that detects the displacement of the pressing block, and the sensor 12 acquires the pushing amount of the work (cylindrical work Wa) of the horn tip 6 . Further, the sensor 12 feeds back changes in the vertical coordinates of the horn tip 6 during bonding to the control device 13 (a broken line is a feedback signal), so that the pressing amount is kept constant. For this reason, an actuator having a high response speed is used for the pressurizing device 10 .

The pushing amount can be set by the operator from the display device 14 . Also, a pressure sensor may be provided in addition to the sensor 12 and controlled to keep the static pressure constant. In this way, when the workpieces are joined, the compound vibration is applied while adjusting the pushing amount and the static pressure, thereby promoting the joining (solid phase joining) reliably.

As a supplement to solid-phase bonding, for example, the surfaces of metal atoms are covered with oil or oxide film, which prevents the atoms from approaching each other. In ultrasonic bonding, ultrasonic vibration is applied to metal to generate a strong frictional force on the metal surface. As a result, oxide films and the like on the metal surface are removed, and clean and activated metal atoms appear on the joint surface.

In this state, by further applying ultrasonic vibration to the metal surface of the workpiece (the outer peripheral surface of the cylindrical workpiece Wa), the temperature rise due to the frictional heat activates the movement of the atoms, generating a mutual attraction force between the atoms. A state of solid phase bonding is produced.

Next, a specific example of the first embodiment (first ultrasonic bonding method) of the present invention will be described with reference to FIGS. 2A and 2B.

First, FIG. 2A shows a cross-sectional view near the joining position X. FIG. The cylindrical work Wa is a metal pipe having a diameter of a and a wall thickness of b (inner diameter a-2b). The diameter a is approximately 2.0 to 3.0 [mm], and the thickness b is approximately 0.05 to 0.08 [mm]. The linear work Wb is a thin metal wire having a diameter d (approximately 0.05 to 0.10 [mm]), and the core wire is exposed by peeling off the coating resin at the tip.

The anvil 7 has a columnar shape with a diameter c (c<a-2b), and when inserted into the cylindrical work Wa, it becomes a pedestal at the time of joining. Since the gap (=a-2b-c) between the cylindrical work Wa and the anvil 7 is about 0.20 to 0.25 [mm], the linear work Wb is passed through this gap to separate the linear work Wb. Set the tip to the joining position X.

A guide groove 7a for guiding the linear workpiece Wb is formed on the outer peripheral surface of the anvil 7 (position facing the joining position X) (see FIG. 2B(b)). The linear work Wb is moved along the guide groove 7a to the joint position X, or the tip of the linear work Wb reaches the joint position X while the linear work Wb is fitted in the guide groove 7a. Anvil 7 is moved so as to

After that, the front end of the horn tip 6 is brought into contact with the outer peripheral surface of the joining position X of the cylindrical work Wa, and ultrasonic vibration is applied to join them. The maximum amplitude of ultrasonic vibration is about 5.0 [μm]. Although the worker cannot see the joint from the outside, he or she can reliably join the linear work Wb to the inner peripheral surface of the cylindrical work Wa.

FIG. 2B(a) is a cross-sectional view of the vicinity of the joining position X viewed from the front side. As shown in the figure, the linear work Wb is in a state in which at least a portion thereof is fitted in the guide groove 7a, and is set on the inner peripheral surface of the cylindrical work Wa at the joining position X with almost no gap. Note that the tip 6b of the horn tip 6 is located outside the joining position X. As shown in FIG.

FIG. 2B(b) is a side view of the anvil 7 alone. The anvil 7 is formed with a two-stage groove, which is composed of a guide groove 7a and a shallowest portion 7b and which becomes shallower toward the left end. If the left end of the anvil 7 is moved to the vicinity of the joining position X, and the linear work Wb is inserted from the right end side of the anvil 7 later, the position of the linear work Wb becomes higher at the joining position X, and the gap decreases (or , the linear work Wb contacts the inner peripheral surface of the cylindrical work Wa).

When the linear work Wb is inserted from the right side in the drawing, the front end (coating resin) of the linear work Wb is caught and stopped at the shallowest portion 7b. The shallowest portion 7b has a depth at which about 70% of the diameter d of the linear work Wb protrudes upward from the anvil 7. As shown in FIG. The anvil 7 may have a cylindrical shape as long as it is thick enough to form the guide groove 7a and the shallowest portion 7b.

Alternatively, the anvil 7 with the linear workpiece Wb fitted in the guide groove 7a (the shallowest portion 7b) may be moved to the joining position X (leftward in the figure). Also by this method, the cylindrical work Wa and the linear work Wb can be reliably joined.

Next, a flowchart of the first ultrasonic bonding method will be described with reference to FIG.

First, a cylindrical work Wa is fixed (step S01). Specifically, the cylindrical work Wa is pressed from both ends and fixed. As a result, when the linear work Wb is moved to the joining position X, positional deviation does not occur, and furthermore, rotation of the cylindrical work Wa can be prevented during joining.

Next, the anvil 7 is inserted into the cylindrical work Wa and moved to the joining position X (step S02), and the linear work Wb is inserted along the guide groove 7a of the anvil 7 (step S03). Due to the groove shape of the guide groove 7a, the linear work Wb substantially contacts the inner peripheral surface of the cylindrical work Wa at the joining position X. As shown in FIG.

Next, the front end portion 6b of the horn tip 6 is set above the joining position X (the outer peripheral surface of the cylindrical work Wa) (step S04). It is preferable that the horn chip 6 is reliably moved to the bonding position X by positioning using an XY table or the like.

Finally, the horn tip 6 is brought into contact and ultrasonic vibration is applied to join the workpieces (step S05). As a result, the worker can join the linear work Wb to the inner peripheral surface of the cylindrical work Wa, although the joining position X cannot be visually recognized from the outside.

[Second embodiment]
Next, a specific example of the second embodiment (second ultrasonic bonding method) of the present invention will be described with reference to FIGS. 4A and 4B.

First, FIG. 4A shows a cross-sectional view near the bonding position Y. FIG. The same cylindrical work Wa and linear work Wb as in the first embodiment are used. A linear work Wb and a guide block 20, which will be described later, are shown three-dimensionally.

In this embodiment, the horn tip 16 has a structure in which a protrusion 16c is provided at the tip 16b. As shown, the protrusion 16c has a cylindrical shape with a diameter e and a length f. The diameter e is approximately 1.5 to 3.0 [mm], and the length f is approximately 2.0 to 4.0 [mm]. Since the horn tip 16 is inserted from the end of the cylindrical work Wa to reach the joining position Y, it is preferable that the joining position Y is relatively close to the end.

When moving the tip of the linear work Wb to the joining position Y, the linear work Wb is set on the cylindrical guide block 20 and moved by a predetermined distance. The linear work Wb is preferably inserted from the opposite end of the cylindrical work Wa to the end into which the horn chip 16 is inserted.

During movement, the leading end of the linear work Wb is projected from the end of the guide block 20 by about 0.25 to 0.50 [mm]. The cylindrical work Wa may be moved, and the relative position between the cylindrical work Wa and the guide block 20 may be changed.

Then, the linear workpiece Wb is pressed from above by the protrusion 16c of the horn tip 16 and ultrasonic vibration is applied (with an amplitude of about 5.0 [μm] at maximum), thereby turning the linear workpiece Wb into a cylinder. can be joined to the inner peripheral surface of the shaped work Wa.

Further, in the present embodiment, the cylindrical work Wa is fixed by jigs 9a and 9b that sandwich the cylindrical work Wa from above and below. Since the lower jig 9a is located on the lower surface side of the bonding position Y, it also serves as an anvil during ultrasonic bonding.

At least one projecting portion 16c is provided on the tip portion 16b. Since the protrusion 16c is a very small component, it is preferably integrally molded with the horn tip 16. As shown in FIG.

On the other hand, as shown in FIG. 4B, the projecting portion 16c may be detachably attached to the distal end portion 16b. When attaching the protrusion 16c to the tip 16b of the horn tip 16, it is necessary to provide a screw hole in the tip 16b in advance. Moreover, it is necessary to provide a screw thread at one end of the protrusion 16c. With this method, an appropriate protrusion can be selected according to the joining application and the material of the workpiece.

Finally, a flowchart of the second ultrasonic bonding method will be described with reference to FIG.

First, the cylindrical work Wa is fixed (step S11). In this embodiment, the jigs 9a and 9b fix the cylindrical work Wa, but when the linear work Wb is moved to the bonding position Y, positional deviation does not occur, and rotation of the cylindrical work Wa is prevented during bonding. can do.

Next, the linear work Wb is moved to the joining position Y (step S12). Specifically, the guide block 20 to which the linear work Wb is fixed is moved to the bonding position Y using, for example, an xy stage device.

Next, the protrusion 16c of the horn tip 16 is inserted into the cylindrical work Wa and set so that the protrusion 16c is above the joining position Y (step S13).

Further, the horn tip 16 is brought into contact with the workpieces, and ultrasonic vibration is applied to join the workpieces (step S14). As a result, the worker can join the linear work Wb to the inner peripheral surface of the cylindrical work Wa, although the joining portion cannot be visually recognized from the outside.

In the above embodiment, it is important to reliably move the linear work Wb to the joining position X (joining position Y). For this reason, it is preferable to perform precise alignment using, for example, an xy stage device.

In the horn chip 16 of the second embodiment, the shape of the projection 16c does not have to be cylindrical, and for example, the horn chip 16 may have a planar bonding surface. Moreover, the bonding efficiency may be improved by forming convex portions and concave portions on the bonding surfaces.

DESCRIPTION OF SYMBOLS 1... Ultrasonic bonding apparatus, 2... Ultrasonic vibrator, 3... Ultrasonic expansion horn, 3a... Flange part, 4... Ultrasonic LT horn, 4a... Oblique slit, 6, 16... Horn tip, 6a... Base part, 6b, 16b... Tip part 6c... End face 7... Anvil 7a... Guide groove 7b... Shallowest part 8... Oscillator 9a, 9b... Jig 10... Pressure device 12... Sensor 13... Control device 14 Display device 16c Protrusion 20 Guide block Wa Cylindrical work Wb Linear work.

Claims (5)

By vibrating the bonding tip with ultrasonic vibration that combines a vibration component in a first direction perpendicular to the direction in which the bonding tip presses and a vibration component in a second direction perpendicular to the first direction, the workpiece is An ultrasonic bonding method for bonding
A step of inserting a columnar or cylindrical anvil having a diameter smaller than the inner diameter of the cylindrical work into the interior of the cylindrical work;
a step of inserting a linear work having a diameter smaller than the gap into the gap between the cylindrical work and the anvil, and moving the tip of the linear work to a joining position on the inner peripheral surface of the cylindrical work; ,
a step of bringing the joining tip into contact with a position on the outer peripheral surface of the cylindrical work corresponding to the joining position and applying the ultrasonic vibration;
An ultrasonic bonding method, wherein the outer peripheral surface of the anvil is provided with guide grooves in the longitudinal direction along which the linear workpiece is guided to the bonding position. 2. The ultrasonic bonding method according to claim 1, wherein the guide groove is formed so that the groove becomes shallower as it approaches the end of the anvil. 3. The ultrasonic bonding method according to claim 1, further comprising a step of pressing the cylindrical workpiece from both ends in the longitudinal direction. By vibrating the bonding tip with ultrasonic vibration that combines a vibration component in a first direction perpendicular to the direction in which the bonding tip presses and a vibration component in a second direction perpendicular to the first direction, the workpiece is An ultrasonic bonding method for bonding
a step of inserting a protrusion of the joining tip having a diameter smaller than that of the cylindrical work into the interior of the cylindrical work;
a step of inserting a linear work into the interior of the cylindrical work and moving the tip of the linear work to a joining position on the inner peripheral surface of the cylindrical work;
A step of moving the protrusion to the bonding position and applying the ultrasonic vibration,
An ultrasonic welding method, wherein in the step of inserting the linear work, the linear work is fixed to a guide block, and the relative position of the guide block with respect to the cylindrical work is changed. 5. The ultrasonic bonding method according to claim 4, wherein the protrusion is detachable from the bonding tip.

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