JP7678709B2 - Ultrasonic bonding equipment - Google Patents

Description

The present invention relates to an ultrasonic bonding device, and more specifically, to an ultrasonic bonding device that brings the tip of a pressurized ultrasonic horn into contact with the head of a resin boss and applies ultrasonic vibrations to the ultrasonic horn to melt the resin boss and perform ultrasonic crimping.

Conventionally, the "ultrasonic bonding device" disclosed in Patent Document 1 is known as an ultrasonic bonding device that performs ultrasonic crimping using a resin boss.

The "ultrasonic bonding device" disclosed in this patent document is configured to monitor the heat flow generated at the bonding site using a heat flow sensor embedded in the anvil and control the ultrasonic vibration applied to the ultrasonic horn based on this monitored heat flow, and Figures 4 to 6 of the document show an example of ultrasonic crimping using a resin boss.

However, the ultrasonic crimping process using a resin boss disclosed in Patent Document 1 is configured to continuously apply ultrasonic vibrations to the ultrasonic horn, which makes it difficult to control the ultrasonic vibrations. In addition, there are problems with the resin deteriorating and discoloring due to excessive heating of the resin at the contact point with the ultrasonic horn, and with the cavitation phenomenon caused by liquefaction of the resin, which causes erosion of the ultrasonic horn and shortens the lifespan of the ultrasonic horn.

JP 2018-1176 A

The present invention aims to provide an ultrasonic bonding device that applies ultrasonic vibrations to an ultrasonic horn intermittently, thereby preventing the resin from overheating and enabling efficient, high-quality ultrasonic crimping without wasting time.

In order to achieve the above object, the invention of claim 1 is an ultrasonic joining device that abuts the tip of an ultrasonic horn against the head of a resin boss and applies ultrasonic vibrations to the ultrasonic horn to melt the resin boss and perform ultrasonic crimping using the resin boss, and is characterized in having a displacement detection means for detecting the displacement of the ultrasonic horn accompanying the melting of the resin boss, and ultrasonic control means for continuing to apply the ultrasonic vibrations until the displacement amount of the ultrasonic horn detected by the displacement detection means reaches a predetermined unit displacement amount , stopping the application of the ultrasonic vibrations when the displacement amount reaches the unit displacement amount, and starting the application of the ultrasonic vibrations again when the displacement of the ultrasonic horn stagnates, and repeating this control until the ultrasonic crimping using the resin boss is completed.

The invention of claim 2 is the invention of claim 1, characterized in that the ultrasonic control means determines that the ultrasonic crimping process using the resin boss is completed when the displacement of the ultrasonic horn detected by the displacement detection means reaches a preset target displacement amount.

The invention of claim 3 is the invention of claim 1, characterized in that the ultrasonic control means determines that the ultrasonic crimping process is complete when the ultrasonic vibration applied to the ultrasonic horn reaches a peak power.

The invention of claim 4 is an ultrasonic joining device that abuts the tip of an ultrasonic horn against the head of a resin boss and applies ultrasonic vibrations to the ultrasonic horn to melt the resin boss and perform ultrasonic crimping using the resin boss, and is characterized in having a displacement detection means for detecting the displacement of the ultrasonic horn, and ultrasonic control means for continuing to apply the ultrasonic vibrations until the displacement amount of the ultrasonic horn detected by the displacement detection means reaches a predetermined unit displacement amount, stopping the application of the ultrasonic vibrations when the displacement amount becomes the unit displacement amount , and starting the application of the ultrasonic vibrations again after a certain time has elapsed, and repeating this control until the ultrasonic crimping using the resin boss is completed.

The invention of claim 5 is characterized in that, in the invention of claim 4, the ultrasonic control means determines that the ultrasonic crimping process using the resin boss is completed when the displacement of the ultrasonic horn detected by the displacement detection means reaches a preset target displacement amount.

The invention of claim 6 is the invention of claim 4, characterized in that the ultrasonic control means determines that the ultrasonic crimping process is complete when the ultrasonic vibration applied to the ultrasonic horn reaches a peak power.

According to the present invention, an ultrasonic joining device that brings the tip of an ultrasonic horn into contact with the head of a resin boss and applies ultrasonic vibrations to the ultrasonic horn to melt the resin boss and perform ultrasonic crimping using the resin boss is provided with a displacement detection means that detects the displacement of the ultrasonic horn accompanying the melting of the resin boss, and an ultrasonic control means that stops applying the ultrasonic vibrations when the displacement of the ultrasonic horn detected by the displacement detection means reaches a predetermined unit displacement amount, and starts applying the ultrasonic vibrations again when the displacement of the ultrasonic horn stagnates, and repeats this control until the ultrasonic crimping using the resin boss is completed. This has the effect of suppressing excessive heating of the resin and efficiently performing ultrasonic crimping without wasting time.

FIG. 1 is a side view showing an outline of an ultrasonic bonding apparatus according to the present invention. FIG. 2 is a diagram for explaining the operation of ultrasonic crimping by the ultrasonic bonding apparatus shown in FIG. FIG. 3 is a graph illustrating the operation of ultrasonic crimping by the ultrasonic bonding apparatus shown in FIG. FIG. 4 is a flow chart for explaining the operation of the ultrasonic crimping process by the ultrasonic bonding apparatus shown in FIG. FIG. 5 is a flow chart for explaining another operation of the ultrasonic crimping process by the ultrasonic bonding apparatus shown in FIG.

The following describes in detail an embodiment of the present invention with reference to the attached drawings.

Figure 1 is a side view showing an outline of the ultrasonic bonding device according to the present invention.

In FIG. 1, the ultrasonic joining device 100 according to the present invention places a workpiece 30 including a resin boss 31a on an anvil 20 fixed to a base 10, applies pressure to the resin boss 31 of the workpiece 30 from a pressure device (not shown), and applies ultrasonic vibrations from the tip of an ultrasonic horn (hereinafter simply referred to as the horn) 40, thereby melting and crimping the resin boss 31a of the workpiece 30.

The horn 40 is connected to an ultrasonic vibrator (hereinafter simply referred to as the vibrator) 60 via a cone 50, and the ultrasonic vibration of the vibrator 60 is controlled by an ultrasonic generator 70. Here, the ultrasonic vibration applied from the tip of the horn 40 to the part to be joined of the workpiece 30 is a vibration in the vertical direction Y perpendicular to the part to be joined, and the vibration in the vertical direction Y is suitable for melt joining of resin, etc. The part including the horn 40, the cone 50, and the vibrator 60 is held by an ultrasonic vibrator holder (hereinafter simply referred to as the vibrator holder) 61 attached to the cone 50, and a load is applied to the workpiece 30 from a load device (not shown) via the vibrator holder 61, and the displacement of the cone is detected by a displacement meter 80 that detects the movement of the vibrator holder 61.

As shown in detail in FIG. 2(A), the workpiece 30 used in the ultrasonic bonding device 100 is constructed by overlapping a resin plate 31 and a metal plate 32, and exposing a resin boss 31a embedded in the resin plate 31 on the metal plate 32 through a hole 32a in the metal plate 32. In the ultrasonic bonding device 100, the horn 40 is brought into contact with the resin boss 31a exposed on the metal plate 32, ultrasonic vibration is applied, and weight is applied to melt the resin boss 31a, thereby bonding the resin plate 31 and the metal plate 32. Here, a resin plate may be used instead of the metal plate 32.

A typical example of the workpiece 30 to be joined by fusion crimping is the door trim of an automobile interior.

In general, in the ultrasonic crimping process described above, as the temperature of the workpiece 30 rises, the temperature of the tip of the horn 40 rises due to thermal conduction, and the resin boss 31a in contact with the tip of the horn 40 becomes overheated, which can cause deterioration and discoloration of the resin, and erosion of the tip of the horn 40 due to the cavitation phenomenon caused by the resin liquefaction. As a result, proper ultrasonic crimping cannot be performed, and the life of the horn 40 is shortened.

Therefore, in the ultrasonic bonding device 100 according to the present invention, ultrasonic vibrations are applied intermittently to the horn 40 to prevent the resin boss 31a from overheating, thereby enabling efficient, high-quality ultrasonic crimping to be performed without wasting time.

Figures 2(A) to (E) are diagrams explaining the operation of the ultrasonic crimping process by the ultrasonic bonding device 100 shown in Figure 1, and Figure 3 is a graph explaining the operation of the ultrasonic crimping process by the ultrasonic bonding device shown in Figure 1.

In Figures 2 and 3, as shown in Figure 2 (A), when the tip of the horn 40 comes into contact with the head of the resin boss 31a, the ultrasonic oscillation operation of the transducer 60 is started under the control of the ultrasonic oscillator 70 (time t0 in Figure 3), and the ultrasonic vibration oscillated by the transducer 60 is transmitted from the tip of the horn 40 via the cone 50 and the horn 40 to the head of the resin boss 31a.

At the tip of the horn 40, a crimping die 41 is formed for crimping the resin boss 31a. The resin boss 31a melts from its head along the crimping die 41, and the displacement of the horn 40 decreases by a predetermined unit displacement amount ΔZ (from time t0 to time t1 in FIG. 3). This state is shown in FIG. 2(B).

Here, the unit displacement amount ΔZ is preset according to the oscillation frequency of the vibrator 60, the speed of the ultrasonic crimping process using the resin boss 31a, etc.

When the horn 40 descends by a predetermined unit displacement amount ΔZ, the ultrasonic oscillation operation of the vibrator 60 is temporarily stopped in order to prevent the resin boss 31a from overheating (time t1 in FIG. 3). This slows down the melting operation of the resin boss 31a, and the displacement of the horn 40 stagnates (from time t1 to time t2 in FIG. 3).

When the displacement of the horn 40 stagnates, the ultrasonic oscillation of the vibrator 60 starts again (time t2 in FIG. 3). This causes the resin boss 31a to start melting again, and the displacement of the horn 40 further decreases by a predetermined unit displacement amount ΔZ (from time t2 to time t3 in FIG. 3). This state is shown in FIG. 2(C).

When the horn 40 further descends by a predetermined unit displacement amount ΔZ, the ultrasonic oscillation operation of the vibrator 60 is temporarily stopped again to prevent the resin boss 31a from overheating (time t3 in FIG. 3). This slows down the melting operation of the resin boss 31a, and the displacement of the horn 40 stagnates (from time t3 to time t4 in FIG. 3).

When the displacement of the horn 40 stagnates, the ultrasonic oscillation of the vibrator 60 is resumed (time t4 in FIG. 3). This causes the resin boss 31a to melt, and the displacement of the horn 40 further decreases by a predetermined unit displacement amount ΔZ (from time t4 to time t5 in FIG. 3). This state is shown in FIG. 2 (D).

When the horn 40 further descends by a predetermined unit displacement amount ΔZ, the ultrasonic oscillation operation of the vibrator 60 is temporarily stopped again to prevent the resin boss 31a from overheating (time t5 in FIG. 3). This slows down the melting operation of the resin boss 31a, and the displacement of the horn 40 stagnates (from time t5 to time t6 in FIG. 3).

When the displacement of the horn 40 stagnates, the ultrasonic oscillation of the vibrator 60 is resumed (time t6 in FIG. 3). This causes the resin boss 31a to melt, and the horn 40 further descends (from time t6 to time t7 in FIG. 3). As shown in FIG. 2(E), when the displacement of the horn 40 reaches GD, a process of holding the resin by pressure alone for a predetermined time to cool the resin is performed, and then the ultrasonic crimping process is completed.

Figure 4 is a flow chart explaining the operation of ultrasonic crimping using the ultrasonic joining device shown in Figure 1.

When the ultrasonic crimping process is started, first, the horn 40 is controlled to descend (step 401). Then, it is checked whether the tip of the horn 40 has come into contact with the head of the resin boss 31a (step 402). Whether the tip of the horn 40 has come into contact with the head of the resin boss 31a can be detected by a well-known technique using the output of the displacement meter 82, etc.

If it is determined in step 402 that the tip of the horn 40 is not in contact with the head of the resin boss 31a (NO in step 402), the process returns to step 402 and waits for the tip of the horn 40 to come into contact with the head of the resin boss 31a. However, if it is determined that the tip of the horn 40 has come into contact with the head of the resin boss 31a (YES in step 402), ultrasonic oscillation is applied to the horn 40 and is started (step 403).

Next, it is checked whether the displacement of the horn has reached the unit displacement amount ΔZ (step 404). If the displacement of the horn has not reached the unit displacement amount ΔZ (NO in step 404), the process returns to step 404 and waits for the displacement of the horn to reach the unit displacement amount ΔZ. If the displacement of the horn reaches the unit displacement amount ΔZ (YES in step 404), the ultrasonic oscillation applied to the horn 40 is stopped (step 405).

When the ultrasonic oscillation applied to the horn 40 is stopped in step 405, it is then checked whether the displacement of the horn 40 has stagnated (step 406). Here, the determination of whether the displacement of the horn 40 has stagnated is made by checking the amount of displacement of the horn 40 within a certain period of time, and if this amount of displacement becomes equal to or less than a predetermined value, it is determined that the displacement of the horn 40 has stagnated.

If it is determined in step 406 that the horn 40 is not stagnating (NO in step 406), the process returns to step 406 and waits for the displacement of the horn 40 to stagnate. However, if it is determined that the displacement of the horn 40 is stagnating (YES in step 406), then it is checked whether the displacement of the horn 40 has reached the target displacement GD (step 407).

If it is determined that the displacement of the horn 40 has not reached the target displacement GD (NO in step 407), the process returns to step 403, and the processing from step 403 to step 407 is repeated until it is determined in step 407 that the displacement of the horn 40 has reached the target displacement GD.

When it is determined in step 407 that the displacement of the horn 40 has reached the target displacement GD (YES in step 407), a process of maintaining the horn 40 by applying pressure only for a predetermined time is completed, and then the horn 40 is controlled to rise (step 408), thereby completing the ultrasonic crimping process.

Figure 5 is a flowchart that explains other operations of ultrasonic crimping using the ultrasonic joining device shown in Figure 1.

In this ultrasonic crimping process, the determination of "Has the displacement stagnated?" shown in step 406 of FIG. 4 is replaced with a determination of "Has a certain amount of time passed?" as shown in step 506 of FIG. 5, and the determination of "Has the target displacement GD been reached?" shown in step 407 of FIG. 4 is replaced with a determination of "Has a predetermined target peak power been reached?" as shown in step 507 of FIG. 5. The other processes are the same as those in the flowchart shown in FIG. 4.

In other words, the determination of "Has the displacement stagnated?" in step 406 in FIG. 4 is a determination of whether excessive heating of the resin boss 31a has been suppressed, so this determination has been replaced with a determination of "Has a certain amount of time passed?" to suppress excessive heating of the resin boss 31a.

In addition, the determination in step 407 in FIG. 4 of "Has the target displacement GD been reached?" is a determination of whether the ultrasonic crimping process is complete, so this determination has been replaced with a determination of whether the power (W) of the ultrasonic vibration has "reached a predetermined target peak power."

In other words, in general ultrasonic crimping, when the resin boss is crushed, the load increases and the ultrasonic power increases sharply. This is because the ultrasonic vibration continues even though the resin boss cannot be crushed any further, and this causes a large amount of power to be consumed by the ultrasonic generator. Therefore, when the power (W) increases sharply, it can be assumed that the resin boss has been completely crushed, and by monitoring the power (W), it is possible to determine whether the resin boss has been completely crushed.

In this case, the drive current increases to keep the ultrasonic vibration amplitude constant, so in the flowchart in Figure 5, the power (W) is calculated (the product of current A and voltage V) and monitored inside the ultrasonic oscillator, and when the peak power (W) reaches the target peak power GP, it is determined that the resin boss has been completely crushed.

In FIG. 5, first, the horn 40 is controlled to descend (step 501). Then, it is checked whether the tip of the horn 40 has contacted the head of the resin boss 31a (step 502). If it is determined that the tip of the horn 40 has not contacted the head of the resin boss 31a (NO in step 502), the process returns to step 502 and waits for the tip of the horn 40 to contact the head of the resin boss 31a. If it is determined that the tip of the horn 40 has contacted the head of the resin boss 31a (YES in step 502), ultrasonic oscillation to be applied to the horn 40 is started (step 503).

Next, it is checked whether the displacement of the horn has reached the unit displacement amount ΔZ (step 504). If the displacement of the horn has not reached the unit displacement amount ΔZ (NO in step 504), the process returns to step 504 and waits for the displacement of the horn to reach the unit displacement amount ΔZ. If the displacement of the horn reaches the unit displacement amount ΔZ (YES in step 504), the ultrasonic oscillation applied to the horn 40 is stopped (step 505).

When the ultrasonic oscillation applied to the horn 40 is stopped, it is then checked whether a certain amount of time has passed since the ultrasonic oscillation was stopped (step 506). Here, the certain amount of time determined in step 505 is a certain amount of time that is set in advance to prevent the resin boss 31a from overheating, and a value that gradually increases or decreases as the horn 40 is processed may be used.

If it is determined in step 506 that a certain amount of time has elapsed (NO in step 506), the process returns to step 506 and waits for the certain amount of time to elapse. If it is determined that the certain amount of time has elapsed (YES in step 506), the process next checks whether the power (W) of the ultrasonic vibration applied to the horn 40 has reached the target peak power GP (step 507).

If it is determined that the power (W) of the ultrasonic vibration has not reached the target peak power GP (NO in step 507), the process returns to step 503, and the processes from step 503 to step 507 are repeated until it is determined in step 507 that the power (W) of the ultrasonic vibration has reached the target peak power GP.

When it is determined in step 507 that the power (W) of the ultrasonic vibration applied to the horn 40 has reached the target peak power GP (YES in step 507), a process of maintaining the power by only applying pressure for a predetermined time is completed, after which the horn 40 is controlled to rise (step 508), and the ultrasonic crimping process is terminated.

The above is an explanation of one embodiment of the present invention, but the present invention is not limited to the above embodiment, and many modifications are possible using the ordinary creative abilities of a person skilled in the art, provided they fall within the scope of the technical concept of the present invention.

For example, in the ultrasonic crimping process shown in the flowchart of FIG. 4, the decision to stop the ultrasonic vibration applied to the horn to prevent the resin boss 31a from overheating was made in step 406 based on the decision of "has the displacement stagnated?", but this decision may also be made in step 506 in FIG. 5 based on the decision of "has a certain amount of time passed?".

In addition, in the flowchart of FIG. 5, the completion of ultrasonic crimping is determined by determining "whether a predetermined target peak power has been reached" in step 507, but this determination may also be made by determining "whether a target displacement GD has been reached" as shown in step 407 of FIG. 4.

REFERENCE SIGNS LIST 10: Base 20: Anvil 30: Workpiece 31: Resin plate 31a: Resin boss 32: Metal plate 40: Horn 41: Crimping mold 50: Cone 60: Transducer 61: Transducer holder 70: Ultrasonic oscillator 80: Displacement meter

Claims (6)

An ultrasonic bonding device that performs ultrasonic crimping using a resin boss by bringing a tip of an ultrasonic horn into contact with a head of the resin boss and applying ultrasonic vibration to the ultrasonic horn to melt the resin boss,
A displacement detection means for detecting a displacement of the ultrasonic horn;
an ultrasonic control means for continuing to apply the ultrasonic vibration until the displacement amount of the ultrasonic horn detected by the displacement detection means reaches a predetermined unit displacement amount, stopping the application of the ultrasonic vibration when the displacement amount reaches the unit displacement amount , and starting the application of the ultrasonic vibration again when the displacement of the ultrasonic horn stagnates, and repeating this control until the ultrasonic crimping process using the resin boss is completed;
An ultrasonic bonding apparatus comprising: The ultrasonic control means includes:
When the displacement amount of the ultrasonic horn detected by the displacement detection means reaches a preset target displacement amount, it is determined that the ultrasonic crimping process is completed.
2. The ultrasonic bonding apparatus according to claim 1 . The ultrasonic control means includes:
When the ultrasonic vibration applied to the ultrasonic horn reaches a peak power, the ultrasonic crimping process is determined to be completed.
2. The ultrasonic bonding apparatus according to claim 1 . An ultrasonic bonding device that performs ultrasonic crimping using a resin boss by bringing a tip of an ultrasonic horn into contact with a head of the resin boss and applying ultrasonic vibration to the ultrasonic horn to melt the resin boss,
A displacement detection means for detecting a displacement of the ultrasonic horn;
an ultrasonic control means for continuing to apply the ultrasonic vibration until the displacement amount of the ultrasonic horn detected by the displacement detection means reaches a predetermined unit displacement amount, stopping the application of the ultrasonic vibration when the displacement amount reaches the unit displacement amount , and starting the application of the ultrasonic vibration again after a certain period of time has elapsed, and repeating this control until the ultrasonic crimping process using the resin boss is completed;
An ultrasonic bonding apparatus comprising: The ultrasonic control means includes:
When the displacement of the ultrasonic horn detected by the displacement detection means reaches a preset target displacement amount, it is determined that the ultrasonic crimping process is completed.
5. The ultrasonic bonding apparatus according to claim 4. The ultrasonic control means includes:
When the ultrasonic vibration applied to the ultrasonic horn reaches a peak power, the ultrasonic crimping process is determined to be completed.
5. The ultrasonic bonding apparatus according to claim 4.

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