JP2007160337A - Ultrasonic welding device and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ultrasonic welding device where sticking can be prevented only by itself without inserting an inclusion, and, even if sticking is not eliminated, the production line is swiftly stopped, and the occurrence of the failure in joining on and after the following production, can be prevented, and to provide a control method therefor. <P>SOLUTION: In the control method for the ultrasonic welding device where two planar works are held between a horn and an anvil applying ultrasonic vibration so as to be pressurized, ultrasonic vibration is applied in parallel to the contact face between the two planar works, so as to cause solid phase joining, and post-vibration is applied upon the release of the horn after the joining, whether sticking is caused or not is monitored during the post-vibration upon the release of the horn, and, when it is judged that sticking is caused, the post-vibration is continued, and the works are shaken off, thus the joining amplitude of the horn on and after the following time is reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultrasonic bonding apparatus that superimposes bonding surfaces of two plate-like workpieces and applies ultrasonic vibration while applying pressure, and performs ultrasonic bonding, and a control method thereof.

  An ultrasonic bonding apparatus pressurizes two metal plates sandwiched between a horn and an anvil that gives ultrasonic vibrations, and applies ultrasonic vibrations parallel to the contact surfaces of the two metal plates, thereby solid phase. It is an apparatus for performing bonding. It is known that adhesion occurs between a metal plate having low hardness and a horn or the like.

  Patent Document 1 discloses that as an anti-adhesion measure, an ultrasonic wave is applied by inserting a carbonaceous sheet between a tip and a bonding base material and / or an anvil and a bonding base material. However, according to this measure, since a carbon sheet must be inserted, extra equipment such as an insertion device for inclusions is required.

Therefore, there is a demand for a measure for preventing adhesion by the ultrasonic bonding apparatus alone without inserting inclusions. For example, in the production of lithium-ion secondary batteries for automobiles, a large number of positive electrode tabs and negative electrode tabs of a flat unit cell are connected in series by ultrasonic bonding to increase the capacity as an assembled battery. Yes. In this ultrasonic bonding of electrode tabs, adhesion is suppressed by performing “post-vibration”, which is an operation of vibrating the horn when the horn is lifted after the end of bonding to shake off the workpiece.
JP 2004-268069 A

  By the way, in the ultrasonic bonding of the electrode tab described above, 1. The work contacting the horn is an aluminum material, 2. The amplitude, time, and pressurizing force are large compared to appropriate bonding conditions. If the condition that the friction is large is satisfied, the workpiece (aluminum material) adheres to the horn after the joining is completed even if the post-vibration operation is performed. When such adhesion occurs, there is a problem that the next joining cannot be performed and the production line is stopped.

  That is, when the occurrence of adhesion cannot be detected, the work is taken out while the work is fixed to the horn, so that the work is peeled off and cracked, resulting in a defective product. In addition, if the next production is performed with aluminum attached to the horn surface, the joining state changes, resulting in joining failure.

  On the other hand, even if the occurrence of adhesion can be detected, an operation of manually peeling the workpiece from the horn is necessary, and as a result of the operation, the workpiece may crack and become a defective product. Moreover, since aluminum adheres to the horn surface, it is necessary to remove the aluminum.

  The present invention can prevent adhesion with an ultrasonic bonding device alone without inserting inclusions, and even if the adhesion cannot be eliminated, the production line is quickly stopped and the subsequent production An object of the present invention is to provide an ultrasonic bonding apparatus capable of preventing the occurrence of bonding failure and a control method thereof.

  In order to achieve the above object, a method for controlling an ultrasonic bonding apparatus according to the present invention includes two plate-like workpieces pressed by sandwiching two plate-like workpieces between a horn that imparts ultrasonic vibration and an anvil. In the control method of an ultrasonic bonding device that applies solid vibration by applying ultrasonic vibration in parallel to the contact surface of the solder and applies post vibration when the horn is opened after bonding, whether or not adhesion occurs during post vibration when the horn is opened When monitoring and judging that there is adhesion, the workpiece is shaken off by continuing the post-vibration, and the joining amplitude after the next time is reduced.

  In addition, an ultrasonic bonding apparatus according to the present invention for achieving the above object presses and sandwiches two plate-like workpieces between a horn and an anvil that apply ultrasonic vibration, and pressurizes the two plate-like workpieces. An apparatus for solid-phase bonding by applying ultrasonic vibration parallel to the contact surface, and comprising a control device that applies post-vibration when the horn is opened after bonding, the command power is supplied to the vibrator of the horn. Control circuit, power monitor for monitoring the command power, storage circuit for storing the initial amplitude and power threshold level of the post-vibration, and the presence or absence of adhesion by comparing the monitor value and threshold level storage value of the power monitor An anti-adhesion circuit that determines whether or not the monitor value exceeds the threshold level stored value. Characterized in that so as to reduce the junction amplitude of the next and subsequent horn gives amplitude command.

  According to the control method of the ultrasonic bonding apparatus according to the present invention as described above, the presence or absence of adhesion is monitored during the post-vibration when the horn is opened. Since the workpiece was shaken down and the welding amplitude from the next time on was reduced, the welding amplitude from the next time onward was optimized to the extent that adhesion did not occur, and the ultrasonic bonding device alone was used without any inclusions. Wearing can be prevented. In addition, even if the workpiece cannot be shaken off, the presence of adhesion is monitored during post-vibration when the horn is opened, so the production line is quickly stopped and joint failures occur after the next production. Can be prevented.

  In addition, according to the ultrasonic bonding apparatus according to the present invention as described above, the presence or absence of adhesion is monitored during the post-vibration when the horn is opened. The joint amplitude after the next time is reduced, so that the joint amplitude after the next time is optimized to the extent that adhesion does not occur, and the ultrasonic bonding device alone is attached without inserting inclusions. Can be prevented. In addition, even if the workpiece cannot be shaken off, the presence of adhesion is monitored during post-vibration when the horn is opened, so the production line is quickly stopped and joint failures occur after the next production. Can be prevented.

  Hereinafter, an ultrasonic bonding apparatus and a control method thereof according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram illustrating an example of an ultrasonic bonding apparatus. FIG. 2 is a block diagram showing the configuration of the ultrasonic bonding apparatus according to the present embodiment.

  As shown in FIG. 1, the ultrasonic bonding apparatus 1 includes a bonding tool called an anvil 2 and a horn 3 that sandwich two plate-shaped members (plate-shaped workpieces). For example, when joining the electrode tab of a lithium ion secondary battery, the material of the negative electrode tab 11 is aluminum (Al), and the material of the positive electrode tab 12 is copper (Cu). Become.

  The anvil 2 is a pedestal on which two plate-like members to be joined (for example, the positive electrode tab 12 and the negative electrode tab 11) are placed, and a plurality of protrusions 4 are formed on the holding surface. The horn 3 can adjust the relative position with respect to the anvil 2 as appropriate, and a plurality of protrusions 5 are formed on the holding surface. The horn 3 is provided with a pressurizing means 6 that presses the horn 3 from the rear in the clamping direction. At the time of ultrasonic bonding, ultrasonic vibration is generated while the horn 3 pressurizes the two plate-like members placed on the anvil 2 with a constant pressure.

  That is, the ultrasonic bonding apparatus 1 causes the two plate-like members to reciprocate linearly by ultrasonic vibrations from the horn 3 and the contact surfaces of the plate-like members are rubbed together, so that an oxide film or the like on the surface of the member can be obtained. Impurities are removed to expose and contact a beautiful metal surface, and two plate-like members are solid-phase bonded by frictional heat generated at that time.

  As shown in FIG. 2, the ultrasonic bonding apparatus 1 of the present embodiment is mainly composed of an ultrasonic bonding apparatus main body 31 and an ultrasonic bonding control apparatus 41 that controls the vibrator 32 of the ultrasonic bonding apparatus main body 31. The ultrasonic bonding control device 41 is electrically connected to a production line control device 61 for transferring a workpiece to the ultrasonic bonding device main body 31.

  As described above, the ultrasonic bonding apparatus main body 31 includes the horn 3 and the anvil 2 that apply ultrasonic vibration as main components, but in this embodiment, the ultrasonic bonding control apparatus 41 controls the horn side. Therefore, only the elements on the horn side are shown. That is, the horn side element of the ultrasonic bonding apparatus main body 31 includes the vibrator 32, the booster 33, and the horn 3. The vibrator 32 is formed of, for example, a piezoelectric element, and converts command power output from a power module 43 described later into physical vibration. The booster 33 amplifies the vibration of the vibrator 32 and transmits it to the horn 3.

  The ultrasonic bonding control device 41 mainly includes a control circuit 42, an adhesion prevention circuit 45, an input / output circuit 46, and a storage circuit 51. The control circuit 42 is electrically connected to the vibrator 32 via the power module 43. The output side of the power module 43 is electrically connected to the control circuit 42 and the anti-adhesion circuit 45 via the power monitor 44. A storage circuit 51 and an input / output circuit 46 are electrically connected to the anti-adhesion circuit 45, and the input / output circuit 46 is further electrically connected to a production line control circuit 61.

  The control circuit 42 transmits a power command value to the power module 43, and the command power is output from the power module 43 to the vibrator 32 based on the command value. The command power is monitored by the power monitor 44, and the power monitor 44 feeds back the monitor value to the control circuit 42. Further, the power monitor 44 also inputs the monitor value to the anti-adhesion circuit 45.

  The storage circuit 51 performs initial amplitude storage 52 of the post-vibration operation, and also performs power threshold level storage 53 to transmit the power threshold level to the anti-adhesion circuit 45.

  The anti-adhesion circuit 45 receives the monitor value of the command power from the power monitor 44 to determine the presence or absence of adhesion, and transmits an amplitude command to the control circuit 42. That is, the adhesion prevention circuit 45 compares the monitor value of the command power with the power threshold level, and determines that there is no adhesion when the monitor value is smaller than the power threshold level. On the other hand, if the monitor value is equal to or higher than the power threshold level, it is determined that there is adhesion, and the work is shaken off by continuing the post-vibration. In this operation of shaking the workpiece, the post-vibration may be continued with the same amplitude, or the amplitude command may be transmitted from the adhesion prevention circuit 45 to the control circuit 42 to increase the amplitude to the maximum value.

  Then, after the workpiece has been shaken off, an amplitude command is transmitted from the adhesion preventing circuit 45 to the control circuit 42 to reduce the joining amplitude from the next time. That is, the occurrence of adhesion means that the ultrasonic vibration energy is too high, and therefore, the ultrasonic vibration energy is to be optimized by reducing the bonding amplitude from the next time. As a reduction width of the junction amplitude, for example, a reduction width of 5% of the original amplitude can be considered. However, if adhesion still occurs, it is adjusted stepwise so as to further reduce it by 5%.

  If the workpiece is not shaken out even after the post-vibration is continued, an abnormal signal is transmitted from the adhesion preventing circuit 45 to the input / output circuit 46, and the input / output circuit 46 causes the production line control device 61 to stop the production line. Send an adhesion abnormality signal for.

  Further, the anti-adhesion operation by the anti-adhesion circuit 45 will be specifically described with reference to the time chart shown in FIG. 3A is a time chart showing the operation of the horn, and FIG. 3B is a time chart showing the change in amplitude when adhesion is detected in the post-vibration when the horn is opened.

  As shown in FIG. 3 (A), after changing the tool of at least one of the horn and the anvil, when the horn descends from the original position and reaches the joining position, squeeze is started (not shown), When a predetermined squeeze time elapses, horn ultrasonic vibration is performed and the first point is joined. In order to cool the workpieces after the end of joining, the horn is raised (opened) after being held for a predetermined time (not shown).

  After a predetermined delay time from the start of the hold, when the horn is opened, it shifts to the rear vibration. Thereafter, the horn rises from the joining position to the original position while vibrating, but if there is no adhesion, the operation proceeds to the second joining process through the same operation as described above, and such an operation is repeated. . In the case of no adhesion, the amplitude does not change with the initial amplitude of the post-vibration operation, and the monitor value of the command power does not substantially change with a value smaller than the threshold level.

  In the post-vibration when the horn is opened, if adhesion is detected by the monitor value of the command power, the post-vibration is continued and the work is shaken off. Then, as shown in FIG. 3B, the amplitude after the next time is reduced by the detection of adhesion, and the subsequent joining process is performed in the reduced state. In the case of this adhesion, the command power exceeds the threshold level. When the amplitude is gradually increased until the maximum amplitude is reached in order to shake off the workpiece, the command power increases to the maximum command power as the amplitude increases. Normally, the workpiece is shaken off by this maximum amplitude. However, if the workpiece is still not shaken off, the maximum amplitude and the maximum command power continue. Therefore, an adhesion abnormality signal is transmitted to the production line control device 61.

  Thereafter, as shown in FIGS. 3A and 3B, when the tool change of the horn or / and the anvil is performed, the reduced amplitude is initialized and returned to the set initial amplitude.

  Next, based on FIG. 2 and FIG. 3, the control method of the ultrasonic bonding apparatus of this embodiment will be described.

  The control method of the ultrasonic bonding apparatus according to this embodiment relates to the control of the horn amplitude. That is, the presence or absence of adhesion is monitored during post-vibration when the horn is raised (when opened). If it is determined that adhesion is present, the post-vibration operation is continued to shake off the workpiece, and the next and subsequent joint amplitudes Decrease.

  Specifically, in post-vibration when the horn is opened, the command power output from the control circuit 42 to the vibrator 32 via the power module 43 is monitored by the power monitor 44, and the monitor value and the threshold level storage value are obtained. The presence or absence of adhesion is judged by comparison. If the monitored value of the command power exceeds the threshold level storage value, it is determined that there is adhesion, and an amplitude command is given from the adhesion prevention circuit 45 to the control circuit 42. Shake off.

  Then, after the shaking of the workpiece is completed, an amplitude command is given from the anti-adhesion circuit 45 to the control circuit 42, and the next and subsequent joining amplitudes are reduced.

  If it is determined that the workpiece cannot be shaken by monitoring the command power monitor value in spite of the workpiece shaking operation, the production line control device 61 from the adhesion prevention circuit 45 via the input / output circuit 46 is used. Outputs an adhesion abnormality signal.

  The control method of the ultrasonic bonding apparatus of the present embodiment in the automatic production line will be described more specifically with reference to the flowcharts of FIGS.

  First, after completing the tool change of at least one of the horn and the anvil, the joining process is started. The preset initial amplitude is defined as the joining amplitude (step 1; hereinafter referred to as “ST1”). To do.)

  A joining step is performed for one spot (ST2), and a post-vibration operation is started when the horn is opened after the joining is completed. Meanwhile, the monitor value of the command power of the power monitor 44 is input to the control circuit 42 and the anti-adhesion circuit 45, and the anti-adhesion circuit 45 determines whether or not there is adhesion depending on whether or not the monitor value is larger than the threshold level. (ST3).

  In ST3, when the monitored value of the command power by the power monitor 44 is equal to or lower than the threshold level, it can be determined that there is no adhesion, and the process proceeds to the next spot joining process. On the other hand, in ST3, when the monitor value of the power monitor is larger than the threshold level, it can be determined that there is adhesion, so the post-vibration operation is continued and the workpiece is shaken off.

  Then, it is determined whether or not the workpiece has been shaken off based on the monitor value of the command power by the power monitor 44 (ST4). In ST4, if it is determined that the monitor value of the command power has not decreased and the workpiece has not been shaken, manual correction is necessary, so that the production line control device from the anti-adhesion circuit 45 via the input / output circuit 46 An adhesion abnormality signal is transmitted to 61 (ST5), and the joining process is terminated. On the other hand, in ST4, when it is determined that the monitor value of the command power has decreased and the workpiece has been shaken, the amplitude of the next and subsequent joints is decreased to optimize the amplitude so as not to cause adhesion (ST6). .

  The following joining process is performed until the horn or / and anvil tool is changed manually with the welding amplitude reduced (ST7), and the series of joining processes is completed by the tool change.

  After the tool change, the joining amplitude is initialized in ST1, and the joining process is performed with a preset initial amplitude.

  As described above, according to the ultrasonic bonding apparatus and its control method of the present embodiment, the presence or absence of adhesion of the workpiece is monitored during post-vibration when the horn is opened, and it is determined that adhesion is present. Continue the post-vibration to shake the workpiece and reduce the joining amplitude from the next time. Therefore, it is possible to prevent the adhesion by the ultrasonic bonding apparatus alone without optimizing the bonding amplitude after the next time to such an extent that adhesion does not occur, and without inserting inclusions. Since the occurrence of adhesion can be prevented in this way, manual work peeling work is unnecessary, and it is possible to prevent the work from cracking and becoming defective due to the peeling work. Furthermore, the work of removing aluminum on the horn surface becomes unnecessary.

  Even if the workpiece cannot be shaken off, the presence of adhesion is monitored during post-vibration when the horn is opened, and production is performed by outputting an adhesion abnormality signal from the adhesion prevention circuit to the production line controller. It is possible to prevent the occurrence of joint failure after the next production by quickly stopping the line and manually handling it.

  Since the present invention can prevent adhesion with an ultrasonic bonding apparatus alone without inserting inclusions in the bonding between metals, for example, the electrode tab in the manufacture of a lithium ion secondary battery for automobiles. It can be applied to ultrasonic bonding between various metals such as bonding.

It is a schematic diagram which shows an example of an ultrasonic bonding apparatus. It is a block diagram which shows the structure of the ultrasonic bonding apparatus of this embodiment. It is a time chart of the ultrasonic bonding apparatus of this embodiment. It is a flowchart which shows operation | movement of the ultrasonic bonding apparatus of this embodiment.

Explanation of symbols

1 ultrasonic bonding equipment,
2 Anvil,
3 Horn,
11 Upper member,
12 Lower member,
31 Ultrasonic bonding device body,
32 vibrators,
41 ultrasonic bonding control device,
42 control circuit,
44 power monitor,
45 Anti-adhesion circuit,
51 memory circuit,
52 initial amplitude memory,
53 Power threshold level storage,
61 Production line control device.

Claims (6)

Two plate-like workpieces are sandwiched between a horn and anvil that apply ultrasonic vibration, and pressure is applied. By applying ultrasonic vibration parallel to the contact surface of the two plate-like workpieces, solid phase bonding is performed. In the method of controlling an ultrasonic bonding apparatus that applies post vibration when the horn is opened,
Monitor the presence or absence of adhesion between the horn and the workpiece during the post-vibration when the horn is open. A method of controlling an ultrasonic bonding apparatus, characterized in that it is configured as described above.   When the horn is opened, the post-vibration command power is monitored, and the monitor value is compared with the threshold level stored value to determine the presence or absence of adhesion. If the monitor value exceeds the threshold level stored value, it is determined that there is adhesion. 2. The method of controlling an ultrasonic bonding apparatus according to claim 1, wherein the post-vibration is continued and the workpiece is shaken off to reduce the bonding amplitude of the horn after the next time.   When it is determined that the workpiece cannot be shaken from the monitor value of the command power in spite of the workpiece shaking operation, an adhesion abnormality signal is output to the production line control device. The method for controlling an ultrasonic bonding apparatus according to claim 2.   4. The method for controlling an ultrasonic bonding apparatus according to claim 1, wherein the bonding amplitude is initialized when at least one of the horn and the anvil is replaced. It is a device for solid-phase bonding by sandwiching two plate-like workpieces between a horn that gives ultrasonic vibration and an anvil and applying pressure and applying ultrasonic vibration parallel to the contact surface of the two plate-like workpieces. In the ultrasonic bonding apparatus provided with a control device that applies post-vibration when the horn is opened after bonding,
A control circuit that gives command power to the vibrator of the horn;
A power monitor that monitors the command power;
A storage circuit for storing the initial amplitude and power threshold level of the post-vibration;
An adhesion prevention circuit that compares the monitor value of the power monitor and the threshold level storage value to determine whether the horn and the workpiece are adhered,
If the monitor value exceeds the threshold level stored value, it is determined that there is adhesion, and the workpiece is shaken off by continuing the post-vibration, and the amplitude command is given to the control circuit from the adhesion prevention circuit, and the horn is joined next time. An ultrasonic bonding apparatus characterized in that the amplitude is reduced.   If the anti-adhesion circuit determines that the work cannot be shaken off from the command power monitor value in spite of the workpiece shake-off operation, the anti-adhesion circuit sends an adhesion abnormality signal to the production line controller. The ultrasonic bonding apparatus according to claim 5, wherein:

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