Ultrasonic bonding device

Abstract

To provide an ultrasonic bonding device capable of efficiently performing high-quality ultrasonic crimping without wasting time by suppressing excessive temperature rise of a resin so as to intermittently apply ultrasonic vibrations to an ultrasonic horn.SOLUTION: There is provided an ultrasonic bonding device for performing ultrasonic crimping process using a resin boss by contacting a tip of an ultrasonic horn 40 into a head of a resin boss 31a, and applying ultrasonic vibration to the ultrasonic horn to melt the resin boss, the device comprises: a displacement meter 80 for detecting the displacement of the ultrasonic horn; and an ultrasonic oscillator 70 that stops application of ultrasonic vibration when an amount of displacement of the ultrasonic horn by the displacement meter reaches to an amount of a predetermined unit displacement, that starts application of ultrasonic vibration again when the displacement of the ultrasonic horn stops, and that repeats above control operation until completing the ultrasonic crimping process using the resin boss.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an ultrasonic joining device, and more particularly to an ultrasonic joining 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. [Background technology]

[0002] 2. Description of the Related Art Conventionally, an "ultrasonic bonding device" disclosed in Patent Document 1 is known as an ultrasonic bonding device that performs ultrasonic crimping using a resin boss.

[0003] The "ultrasonic joining device" disclosed in Patent Document 1 is configured to monitor the heat flow generated at the joining site using a heat flow sensor embedded in the anvil and to control the ultrasonic vibration applied to the ultrasonic horn based on the monitored heat flow. Figures 4 to 6 of the document show an example of ultrasonic crimping using a resin boss.

[0004] 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, making it difficult to control the ultrasonic vibrations. In addition, there are problems such as deterioration and discoloration of the resin due to excessive heating at the contact point with the ultrasonic horn, and erosion of the ultrasonic horn due to the cavitation phenomenon associated with liquefaction of the resin, shortening the life of the ultrasonic horn. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-1176 A Summary of the Invention [Problem to be solved by the invention]

[0006] Therefore, an object of the present invention is to provide an ultrasonic joining device that applies ultrasonic vibrations intermittently to an ultrasonic horn to suppress excessive heating of the resin, thereby enabling efficient, high-quality ultrasonic crimping processing without wasting time. [Means for solving the problem]

[0007] In order to achieve the above object, the invention of claim 1 provides an ultrasonic bonding device that brings a tip of an ultrasonic horn into contact with a head of a resin boss and applies ultrasonic vibration to the ultrasonic horn to melt the resin boss and perform ultrasonic crimping using the resin boss, the ultrasonic bonding device comprising: a displacement detection means for detecting a displacement of the ultrasonic horn accompanying the melting of the resin boss; and a displacement amount of the ultrasonic horn detected by the displacement detection means that corresponds to a predetermined unit displacement amount. The application of the ultrasonic vibration is continued until the displacement amount reaches the unit displacement amount. and an ultrasonic control means for stopping application of the ultrasonic vibration when the displacement of the ultrasonic horn reaches a plateau, and for restarting application of the ultrasonic vibration when the displacement of the ultrasonic horn reaches a plateau, and for repeating this control until the ultrasonic crimping process using the resin boss is completed.

[0008] The invention of claim 2 is characterized in that, in the invention of claim 1, 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 predetermined target displacement amount.

[0009] The invention of claim 3 is characterized in that, in the invention of claim 1, the ultrasonic control means determines that the ultrasonic crimping process is completed when the ultrasonic vibration applied to the ultrasonic horn reaches a peak power.

[0010] The invention of claim 4 is an ultrasonic bonding device that brings a tip of an ultrasonic horn into contact with a head of a resin boss and applies ultrasonic vibration to the ultrasonic horn to melt the resin boss and perform ultrasonic crimping using the resin boss, the ultrasonic bonding device comprising a displacement detection means for detecting the displacement of the ultrasonic horn, and a displacement detection means for detecting the displacement of the ultrasonic horn when the displacement amount of the ultrasonic horn detected by the displacement detection means is equal to a predetermined unit displacement amount. The application of the ultrasonic vibration is continued until the displacement amount reaches the unit displacement amount.and an ultrasonic control means for stopping the application of the ultrasonic vibration when the resin boss is pressed against the workpiece, and for restarting the application of the ultrasonic vibration after a certain time has elapsed, and for repeating this control until the ultrasonic crimping process using the resin boss is completed.

[0011] 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 predetermined target displacement amount.

[0012] The invention of claim 6 is characterized in that, in the invention of claim 4, the ultrasonic control means determines that the ultrasonic crimping process is completed when the ultrasonic vibration applied to the ultrasonic horn reaches a peak power. Effect of the Invention

[0013] According to the present invention, there is provided an ultrasonic joining device in which the tip of an ultrasonic horn is brought into contact with the head of a resin boss and ultrasonic vibrations are applied to the ultrasonic horn to melt the resin boss and perform ultrasonic crimping using the resin boss. The ultrasonic joining device is configured to include a displacement detection means for detecting the displacement of the ultrasonic horn accompanying the melting of the resin boss, and an ultrasonic control means for stopping the application of the ultrasonic vibrations when the displacement of the ultrasonic horn detected by the displacement detection means reaches a predetermined unit displacement amount, and for starting the application of the ultrasonic vibrations again when the displacement of the ultrasonic horn stagnates, and for repeating this control until the ultrasonic crimping using the resin boss is completed. This has the effect of suppressing excessive heating of the resin and enabling efficient ultrasonic crimping without wasting time. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a side view showing an outline of an ultrasonic bonding device according to the present invention. [Diagram 2] FIG. 2 is a diagram for explaining the operation of ultrasonic crimping by the ultrasonic bonding apparatus shown in FIG. [Diagram 3] FIG. 3 is a graph illustrating the operation of ultrasonic crimping by the ultrasonic bonding apparatus shown in FIG. [Figure 4] FIG. 4 is a flow chart for explaining the operation of the ultrasonic crimping process by the ultrasonic bonding apparatus shown in FIG. [Diagram 5] FIG. 5 is a flow chart for explaining another operation of the ultrasonic crimping process by the ultrasonic bonding apparatus shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

[0016] FIG. 1 is a side view showing an outline of an ultrasonic bonding device according to the present invention.

[0017] 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, and applies a load to the resin boss 31 of the workpiece 30 from a pressure device (not shown) while applying ultrasonic vibrations from the tip of an ultrasonic horn (hereinafter simply referred to as the horn) 40, thereby melt-crimping the resin boss 31a of the workpiece 30.

[0018] The horn 40 is connected to an ultrasonic transducer (hereinafter simply referred to as transducer) 60 via a cone 50, and the ultrasonic vibration of the transducer 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 vibration in a 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, cone 50, and transducer 60 is held by an ultrasonic transducer holder (hereinafter simply referred to as the transducer holder) 61 attached to the cone 50, and weight is applied to the workpiece 30 from a loading device (not shown) via this transducer holder 61, and the displacement of the cone is detected by a displacement meter 80 which detects the movement of the transducer holder 61.

[0019] 2(A), the workpiece 30 used in the ultrasonic bonding device 100 is configured by overlapping a resin plate 31 and a metal plate 32, and exposing a resin boss 31a implanted 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.

[0020] A representative example of the workpiece 30 to be joined by fusion caulking is a door trim of an automobile interior.

[0021] Generally, in the ultrasonic crimping process as 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 associated with liquefaction of the resin. As a result, there are problems in that proper ultrasonic crimping cannot be performed and the life of the horn 40 is shortened.

[0022] Therefore, in the ultrasonic bonding device 100 of 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 processing to be performed without wasting time.

[0023] 2(A) to (E) are diagrams for explaining the operation of the ultrasonic crimping process by the ultrasonic bonding device 100 shown in FIG. 1, and FIG. 3 is a graph for explaining the operation of the ultrasonic crimping process by the ultrasonic bonding device shown in FIG. 1.

[0024] 2 and 3, as shown in FIG. 2(A), when the tip of horn 40 comes into contact with the head of resin boss 31a, ultrasonic oscillation of transducer 60 is started under the control of ultrasonic oscillator 70 (time t0 in FIG. 3), and the ultrasonic vibration oscillated by transducer 60 is transmitted from the tip of horn 40 to the head of resin boss 31a via cone 50 and horn 40.

[0025] At the tip of horn 40, a crimping die 41 for crimping resin boss 31a is formed, and resin boss 31a melts from its head along crimping die 41, causing horn 40 to decrease in displacement by a predetermined unit displacement ΔZ (from time t0 to time t1 in FIG. 3). This state is shown in FIG. 2(B).

[0026] 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, and the like.

[0027] When horn 40 descends by a predetermined unit displacement ΔZ, the ultrasonic oscillation of transducer 60 is temporarily stopped in order to prevent excessive temperature rise in resin boss 31a (time t1 in FIG. 3). This slows down the melting operation of resin boss 31a, and the displacement of horn 40 stagnates (from time t1 to time t2 in FIG. 3).

[0028] When the displacement of horn 40 stagnates, ultrasonic oscillation of transducer 60 starts again (time t2 in FIG. 3). This causes resin boss 31a to start melting again, and the displacement of 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).

[0029] When horn 40 further descends by a predetermined unit displacement ΔZ, the ultrasonic oscillation of transducer 60 is temporarily stopped (time t3 in FIG. 3) again to prevent excessive heating of resin boss 31a. This slows down the melting of resin boss 31a, and the displacement of horn 40 stagnates (from time t3 to time t4 in FIG. 3).

[0030] When the displacement of horn 40 stagnates, the ultrasonic oscillation operation of transducer 60 is resumed (time t4 in FIG. 3). This causes resin boss 31a to melt, and the displacement of 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).

[0031] When horn 40 further descends by a predetermined unit displacement amount ΔZ, the ultrasonic oscillation operation of transducer 60 is temporarily stopped (time t5 in FIG. 3) again to prevent excessive temperature rise in resin boss 31a. This slows down the melting operation of resin boss 31a, and the displacement of horn 40 stagnates (from time t5 to time t6 in FIG. 3).

[0032] When the displacement of horn 40 stagnates, the ultrasonic oscillation operation of transducer 60 is resumed (time t6 in FIG. 3). This melts resin boss 31a, and horn 40 further descends (from time t6 to time t7 in FIG. 3). When the displacement of horn 40 reaches GD as shown in FIG. 2(E), a process of holding the resin by only applying pressure for a predetermined time to cool the resin is performed, and then the ultrasonic crimping process is completed.

[0033] FIG. 4 is a flow chart for explaining the operation of the ultrasonic crimping process by the ultrasonic bonding apparatus shown in FIG.

[0034] When the ultrasonic crimping process is started, first, horn 40 is controlled to descend (step 401). Then, it is checked whether the tip of horn 40 has come into contact with the head of resin boss 31a (step 402). Whether the tip of horn 40 has come into contact with the head of resin boss 31a can be detected by a well-known technique using the output of displacement meter 82, etc.

[0035] If it is determined in step 402 that the tip of horn 40 is not in contact with the head of resin boss 31a (NO in step 402), the process returns to step 402 and waits for the tip of horn 40 to come into contact with the head of resin boss 31a. However, if it is determined that the tip of horn 40 has come into contact with the head of resin boss 31a (YES in step 402), ultrasonic oscillation to be applied to horn 40 is started (step 403).

[0036] Next, it is checked whether the displacement amount of the horn has reached unit displacement amount ΔZ (step 404). If the displacement amount of the horn has not reached unit displacement amount ΔZ (NO in step 404), the process returns to step 404 and waits for the displacement amount of the horn to reach unit displacement amount ΔZ. If the displacement amount of the horn reaches unit displacement amount ΔZ (YES in step 404), the ultrasonic oscillation applied to horn 40 is stopped (step 405).

[0037] When the ultrasonic oscillation applied to horn 40 is stopped in step 405, it is then checked whether the displacement of horn 40 has stagnated (step 406). Here, to determine whether the displacement of horn 40 has stagnated, the amount of displacement of horn 40 within a certain period of time is checked, and when this amount of displacement becomes a predetermined value or less, it is determined that the displacement of horn 40 has stagnated.

[0038] 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).

[0039] Here, if it is determined that the displacement of horn 40 has not reached the target displacement GD (NO in step 407), the process returns to step 403, and the processes from step 403 to step 407 are repeated until it is determined in step 407 that the displacement of horn 40 has reached the target displacement GD.

[0040] When it is determined in step 407 that the displacement of horn 40 has reached the target displacement GD (YES in step 407), after a process of maintaining the horn 40 by only applying pressure for a predetermined time, horn 40 is controlled to rise (step 408), and the ultrasonic crimping process is terminated.

[0041] FIG. 5 is a flow chart for explaining another operation of the ultrasonic crimping process by the ultrasonic bonding apparatus shown in FIG.

[0042] 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 time elapsed?" 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.

[0043] That is, 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 is replaced with a determination of "has a certain time elapsed?" in which excessive heating of the resin boss 31a is suppressed.

[0044] In addition, since 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 completed, this determination is replaced with a determination of “Has the power (W) of the ultrasonic vibration reached a predetermined target peak power?”

[0045] That is, 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 is caused by the large power consumption on the ultrasonic generator side. Therefore, when the power (W) increases sharply, it can be assumed that the resin boss has been completely crushed, so by monitoring the power (W), it is possible to determine whether the resin boss has been completely crushed.

[0046] 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) inside the ultrasonic oscillator and monitored, and when the peak power (W) reaches the target peak power GP, it is determined that the resin boss has been completely crushed.

[0047] 5, first, horn 40 is controlled to descend (step 501). Next, it is checked whether the tip of horn 40 has contacted the head of resin boss 31a (step 502). If it is determined that the tip of horn 40 has not contacted the head of resin boss 31a (NO in step 502), the process returns to step 502 and waits for the tip of horn 40 to contact the head of resin boss 31a. If it is determined that the tip of horn 40 has contacted the head of resin boss 31a (YES in step 502), ultrasonic oscillation to be applied to horn 40 is started (step 503).

[0048] Next, it is checked whether the displacement amount of the horn has reached unit displacement amount ΔZ (step 504). If the displacement amount of the horn has not reached unit displacement amount ΔZ (NO in step 504), the process returns to step 504 and waits for the displacement amount of the horn to reach unit displacement amount ΔZ. If the displacement amount of the horn reaches unit displacement amount ΔZ (YES in step 504), the ultrasonic oscillation applied to horn 40 is stopped (step 505).

[0049] When the ultrasonic oscillation applied to horn 40 is stopped, it is then checked whether a certain time has passed since the ultrasonic oscillation was stopped (step 506). Here, the certain time determined in step 505 is a certain time set in advance to prevent excessive temperature rise in resin boss 31a, and may be a value that gradually increases or decreases as horn 40 processes.

[0050] 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), then it is checked whether the power (W) of the ultrasonic vibration applied to the horn 40 has reached the target peak power GP (step 507).

[0051] Here, 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 processing from step 503 to step 507 is repeated until it is determined in step 507 that the power (W) of the ultrasonic vibration has reached the target peak power GP.

[0052] 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 pressure alone for a predetermined time is completed, after which the horn 40 is controlled to rise (step 508), and the ultrasonic crimping process is terminated.

[0053] The above is a description of one embodiment of the present invention, however, the present invention is not limited to the above embodiment, and many modifications are possible using the ordinary creative abilities of those skilled in the art within the scope of the technical concept of the present invention.

[0054] 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 in order to prevent excessive heating of the resin boss 31a 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 period of time elapsed?”.

[0055] In addition, in the flowchart of FIG. 5, the completion of the ultrasonic crimping process is determined by determining in step 507 whether “a predetermined target peak power has been reached?”, but this determination may also be made by determining whether “the target displacement GD has been reached?” shown in step 407 of FIG. 4. [Explanation of symbols]

[0056] 10…Pedestal 20…Anvil 30…Work 31…Resin plate 31a…Resin boss 32...Metal plate 40…Horn 41…Crimped type 50…Corn 60...Transducer 61...Transducer holder 70...Ultrasonic oscillator 80...Displacement gauge

Claims

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 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:

2. 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 .

3. 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 .

4. 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:

5. 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.

6. 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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