JPH1110362A - Method for judging joined quality in piling ultrasonic welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and accurately discriminate the joined quality by collating a displacing quantity of the displacing part of a work detected at a prescribed point of the time in the initial stage of a welding with a reference value and judging as the abnormality at the time of being the reference value or larger and as the normal welding at the time of being smaller than the reference value. SOLUTION: A displacing quantity sensor 9 is arranged at the lower side part of a horn supporting part 8 for welding to enable the detection of the displacing quantity of the displacing part 13 containing the joined part 12 of the works 6, 7. At the same time of starting the welding, the measurements of the displacing quantity of the displacing part 13 and the welding time are started. In a welding condition deciding instrument 10, it is judged whether the welding time reaches a prescribed time (e.g. 0.4 sec) at the initial stage of the welding or not, and in the case of judging to reach the prescribed time, it is judged whether the displacing quantity at the point of time is the reference value or larger in the good quality reference value or not. In the case of being the reference value or larger to the displacing quantity, it is judged that this part is the abnormal welding or defective joined quality and this judgement is displayed on a displaying device 11 and also, this welded product is ejected. On the other hand, in the case of being less than the reference value to the displacing quantity, it is judged that this part is the normal welding, and the welding is continued and at the point of time when the displacing quantity reaches the reference value, the welding is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joining quality discrimination method in lap ultrasonic welding.

[0002]

2. Description of the Related Art In superposition ultrasonic welding, as shown in FIG. 4, an anvil (also called a work table) 5 and a horn (also called an ultrasonic tool) 4 between a slip preventing knurl 4a. This is an ultrasonic welding in which a plurality of works 6 and 7 are superposed and set, and the horn 4 is ultrasonically vibrated to join the plurality of works 6 and 7 together.

In such superposition ultrasonic welding, the grip force of the horn 4 on the work 6 is
In the case where ultrasonic vibration is not sufficiently transmitted from the horn 4 to the work 6, for example,
Is not sufficiently cleaned and the bonding strength is reduced, and the bonding quality is poor.

Conventionally, when judging the joining quality,
Usually, a method of estimating a change in the vibration transmissibility according to the welding time has been adopted.

[0005]

However, in the method of determining the joining quality based on the welding time, it is often difficult to easily and accurately determine the quality of the joining quality.

The inventors of the present invention have conducted intensive studies on a method for easily and accurately determining the joining quality, and have obtained the following findings.

According to the superposition ultrasonic welding, FIG.
The displacement part 13 including the work joining part 12 is displaced
You. The displacement amount L of the displacement portion 13 is
Knurl 4a bite amount L_e1And the other work 7
Infeed amount L of anvil 5 with respect to _e2And substantially to the joint strength
Deformation amount L of joint 12 between involved works 6 and 7_W Sum with
And L = L_e1+ L_e2+ L_W It is represented by

In the case of normal welding, as shown in FIG. 5A, the work 6 can sufficiently follow the ultrasonic vibration of the horn 4 during welding, and the amplitude of the horn 4 and the amplitude of the work 6 are reduced. Almost match. In this case, the biting amount L _e1 knurl 4a is small, approximately 0.05mm when for example the amount of displacement L of about 0.3 mm. Note that in FIG.
V _P is the direction and magnitude of the vibration of the horn 4, V _W is
The direction and magnitude of the vibration of the work 6 are shown for convenience (the same applies to FIG. 5B described later).

On the other hand, in the case of abnormal welding performed in a state where the serration of the horn 4 is worn or the pressing force is reduced, as shown in FIG.
The work 6 cannot follow the ultrasonic vibration of the horn 4 due to insufficient gripping force of the knurl 4a, causing a slip, and the horn 4
And the amplitude of the work 6 are different. In this case, the workpiece 6 is long plastically deformed by knurling 4a, biting amount L _e1 knurl 4a is increased, for example, about when the displacement amount L is approximately 0.3 mm .15 to 0.
2 mm.

[0010] The welding process in the case of normal welding and the welding process in the case of abnormal welding are represented by a displacement L with respect to time t.
As a result, graphs as shown by a and b in FIG. 6 were obtained.

A comparison between the graphs a and b shown in FIG.
In the early stage of welding, changes in abnormal welding
The position L is larger than the displacement L for normal welding
I understand. For example, an aluminum plate for a rectifier fin for a generator
(T = 2 to 3 mm) and a copper plate (t = 0.5 to 1 mm)
When welding, 0.4 seconds after the start of welding, t
₀ The displacement L during normal welding is about 0.15 mm.
On the other hand, the displacement L during abnormal welding is about 0.25 mm.
Yes, displacement L at the initial stage of welding during abnormal welding is large
It has been found.

Further, the welding process in the case of normal welding and the welding process in the case of abnormal welding are represented as a change in the displacement change amount K (= ΔL / Δt) with respect to time t based on the graph of FIG. 7 were obtained as graphs indicated by a and b in FIG. 7, respectively.

By comparing the graphs a and b shown in FIG. 7, it can be seen that the displacement change K in the case of abnormal welding is larger than the displacement change K in the case of normal welding at the initial stage of welding. I understand. For example, at time t ₀ when 0.2 seconds have passed from the start of welding, the displacement change amount K during normal welding was about 0.2 mm / sec, whereas the displacement change amount K during abnormal welding was about 0 mm. 0.4 mm / sec, and it was found that the displacement change amount K in the initial stage of welding during abnormal welding was large.

According to the present invention, it is possible to easily and accurately determine the joining quality based on the large difference in the displacement amount and the displacement change amount at the initial stage of welding between normal welding and abnormal welding as described above. It is an object of the present invention to provide a joining quality discriminating method in lap ultrasonic welding that can be performed.

[0015]

According to the method for judging joint quality in lap ultrasonic welding according to the present invention, as described in claim 1, based on the displacement amount of the displacement portion detected at a predetermined time point at the beginning of welding. When the displacement amount is large, it is determined that the welding is abnormal, while when the displacement amount is small, it is determined that the welding is normal, so that the joining quality can be easily and accurately determined.

Further, according to the method for judging the joining quality in lap ultrasonic welding of the present invention, the displacement change based on the displacement change amount of the displacement portion obtained at a predetermined point in time in the initial stage of welding. When the amount is large, it is determined that the welding is abnormal, while when the amount of change in displacement is small, it is determined that the welding is normal, so that the joining quality can be easily and accurately determined.

Here, the time point at which the amount of change in displacement is obtained is not limited to one time point, and a plurality of time points may be set.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of an ultrasonic welding apparatus for performing a joining quality determining method in lap ultrasonic welding according to the present embodiment.

The ultrasonic welding apparatus shown in FIG. 1 comprises a stabilizing power supply 1, an oscillator 2, a vibrator 3, a horn (ultrasonic tool) 4, a horn holding portion 8, a displacement sensor 9, a pass / fail judgment device 10, and a display device. 11 is provided.

An AC power source (for example, A
C200V) is connected. The stabilized power supply 1 includes an oscillator 2
Is applied with a constant voltage.

The oscillator 2 drives the vibrator 3.

The vibrator 3 outputs an ultrasonic wave.

The horn 4 amplifies the ultrasonic output of the vibrator 3.

The displacement sensor 9 detects the amount of displacement (the amount of displacement) of the horn holding unit 8 in order to detect the displacement L of the displacement unit 13 including the joint 12 between the works 6 and 7.

The pass / fail determination device 10 receives the detection signal from the displacement sensor 9 and determines the quality of the joining quality. The pass / fail determination device 10 stops the stabilized power supply 1 at the end of welding.

The display device 11 displays the judgment result of the pass / fail judgment device 10.

Next, the first of the joining quality discriminating methods in superposition ultrasonic welding using the ultrasonic welding apparatus having the above-described configuration.
An embodiment will be described with reference to FIG.

First, the works 6 and 7 are set between the anvil 5 and the knurl 4a of the horn 4, and a constant pressure P is applied to the works 6 and 7 by a pressing means (not shown) (step 101). ). The pressurizing means pressurizes the pressure P so that the pressure P is always constant during welding.

Next, the stabilizing power supply 1 is turned on, and the horn 4 is ultrasonically vibrated to start welding the works 6 and 7 (step 102).

Next, in the pass / fail determination device 10, the detection signal from the displacement sensor 9 is input, and measurement of the displacement L of the displacement unit 13 is started (step 103).

In the pass / fail judgment device 10, measurement of the welding time t is started (step 104).

In the pass / fail judgment device 10, the welding time t
Is determined to have reached a predetermined time t ₀ in the initial stage of welding (for example, a time 0.4 seconds has elapsed from the start of welding) (step 105), and it is determined that the welding time t has reached the predetermined time t _0. Then, it is determined whether or not the displacement amount L at the time point t ₀ is equal to or greater than a reference value L ₀ for determining the quality of the joining quality (step 106).

When it is determined that the displacement L is equal to or greater than the reference value L _0, it is determined that the joining quality is poor due to abnormal welding, and the display device 11 displays a message indicating that the joined product is defective. The joined product is discharged as a defective product (step 107).

On the other hand, if it is determined that the displacement L is less than the reference value L _0, it is determined that the welding is normal and the joining quality is good, and the displacement L reaches the reference value L ₁ for determining the end of welding. whether the judged (step 108), the displacement amount L is when it is determined to have reached the reference value L _1, and ends the welding and the like to stop the stabilized power source 1 (step 109).

As described above, according to the method of judging the joining quality in the superposition ultrasonic welding of the first embodiment, the displacement amount L of the displacement portion 13 detected at the predetermined time t ₀ at the beginning of welding is determined.
When the displacement L is large, it is determined that the welding is abnormal, while when the displacement L is small, it is determined that the welding is normal. Therefore, it is possible to easily and accurately determine the joining quality.

Next, a description will be given of a second embodiment of the method for judging the joining quality in superposition ultrasonic welding with reference to FIG.

First, the works 6 and 7 are set between the anvil 5 and the knurl 4a of the horn 4, and a constant pressure P is applied to the works 6 and 7 by a pressing means (not shown) (step 201). ). The pressurizing means pressurizes the pressure P so that the pressure P is always constant during welding.

Next, the stabilizing power supply 1 is turned on, and the horn 4 is ultrasonically vibrated to start welding the works 6 and 7 (step 202).

Next, the detection signal from the displacement sensor 9 is input to the pass / fail determination device 10, and measurement of the displacement L of the displacement section 13 is started (step 203).

In the pass / fail judgment device 10, the measurement of the welding time t is started (step 204).

Further, in the pass / fail determination device 10, the displacement change amount K (= K) is determined based on the displacement amount L and the welding time t.
ΔL / Δt) is started (step 205).

In the pass / fail judgment device 10, the welding time t
Is determined to have reached a predetermined time point t ₀ in the initial stage of welding (for example, a point in time after 0.2 seconds have elapsed from the start of welding) (step 206), and it is determined that the welding time t has reached the predetermined time point t _0. Then, it is determined whether or not the displacement change amount K at the time point t ₀ is larger than a reference value K ₀ for determining the quality of the joining quality (step 207).

If it is determined that the displacement change amount K is larger than the reference value K ₀ , it is determined that the joining quality is poor due to abnormal welding, and the display device 11 displays that the joined product is defective. Then, the bonded product is discharged as a defective product (step 208).

On the other hand, if it is determined that the displacement change amount K is equal to or less than the reference value K _0, it is determined that the welding is normal and the joining quality is good, and the displacement amount L reaches the reference value L ₁ for determining the end of welding. determining whether the not (step 209), the displacement amount L is when it is determined to have reached the reference value L _1, and ends the welding and the like to stop the stabilized power source 1 (step 210).

[0046] As described above, according to the bond quality determination method in the superimposition ultrasonic welding of the second embodiment, based on the displacement deviation K of the displacement unit 13 obtained at a given time t ₀ of the welding early, this displacement When the change amount K is large, it is determined that the welding is abnormal. On the other hand, when the displacement change amount is small, it is determined that the welding is normal, so that the joining quality can be easily and accurately determined.

As a point of time when the displacement change amount K is obtained,
As shown in FIG. 7, a plurality of time points t ₀ , t ₀₁ , and t ₀₂ may be set, and the quality of the joining quality may be determined based on the entire shape of the displacement change amount.

The present invention is not limited to the application of only two workpieces. For example, an aluminum plate (t = 2 to 3 mm) and a copper plate (t = 0.5 to 1m
m) can be applied to a case where an iron plate (t = 2 to 3 mm) is inserted and three sheets are simultaneously joined. In such a case, the joining quality can be easily and accurately determined. is there.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an ultrasonic welding apparatus for performing a joining quality determination method in superposition ultrasonic welding according to one embodiment.

FIG. 2 is a flowchart illustrating a joining quality determination method in superposition ultrasonic welding according to the first embodiment.

FIG. 3 is a flowchart illustrating a joining quality determination method in superposition ultrasonic welding according to a second embodiment.

FIG. 4 is an explanatory diagram for explaining a displacement amount of a displacement unit.

FIG. 5 is an explanatory diagram for explaining a difference between normal welding and abnormal welding.

FIG. 6 is a graph for explaining the difference between the displacement during normal welding and the displacement during abnormal welding.

FIG. 7 is a graph for explaining a difference between a displacement change amount during normal welding and a displacement change amount during abnormal welding.

[Explanation of symbols]

6, 7 Work 8 Horn holding part 9 Displacement amount sensor 10 Pass / fail judgment device 12 Joining part 13 Displacement part L Displacement K Displacement change t ₀ Predetermined time

Claims (4)

[Claims] 1. The method according to claim 1, further comprising detecting a displacement amount of a displacement portion including a joint portion between the workpieces, and judging quality of the joining quality based on the displacement amount of the displacement portion detected at a predetermined point in time of initial welding. Quality judgment method in lap ultrasonic welding. 2. The method according to claim 1, further comprising: obtaining a displacement change amount of said displacement portion based on a displacement amount of said displacement portion including a joint portion between the workpieces; and joining quality based on a displacement change amount of said displacement portion obtained at a predetermined point in time of initial welding. A method for judging the joining quality in superposition ultrasonic welding, characterized by judging pass / fail of the joint. 3. The method according to claim 2, wherein a plurality of time points are set as the predetermined time points. 4. The displacement sensor according to claim 1, wherein the displacement of the displacement unit is detected based on a signal of a displacement sensor for detecting a displacement of the horn holding unit. A joining quality discrimination method in lap ultrasonic welding characterized by the following.