JPH03176658A - Ultrasonic welding state inspection device - Google Patents

Abstract

PURPOSE:To enable accurate and efficient inspection even if a body to be inspected shifts in welding position by employing the minimum value among the numbers of defects corresponding to width-directional measurement points obtained by inspecting a weld zone as evaluation data on an article to be inspected. CONSTITUTION:A data processor 1 has the external memory 7 of a microprocessor 6, etc., internally and the memory 7 is stored with a defect detection processing program 8a and a quality decision processing program 8b. The defect detection processing program 8a makes a scan in a welding direction with an ultrasonic probe, and then moves the ultrasonic probe by specific pitch in the width direction of the weld zone; and data on echo levels of respective measurement points obtained by further movement in the welding direction are compared with a reference value to detect and count defects. The number of the defects is stored in the memory 7. The quality decision processing program 8b selects the minimum value among the numbers of defects corresponding to the respective width-directional measurement points stored in the memory 7 to obtain the evaluation data, which is compared with the criterion value to decide whether a work 1 is normal or not. Consequently, even if the body to be inspected shifts in welding position, the accurate inspection is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an ultrasonic welding condition inspection device, and more specifically, it is used to inspect welding of an inspection article made by overlapping plates and welding over a certain length. The present invention relates to an ultrasonic welding condition inspection device that inspects the condition and determines its pass/fail, and is capable of efficient and accurate inspection even if the welding position of the inspected article is slightly shifted.

[Prior Art] Conventionally, there are various methods for welding, but for example, products and parts (in this specification, these are collectively referred to as inspection items) are formed by stacking plates and using electron beam welding, laser beam welding, etc. When the weld is manufactured, the fusion width of the welded part is relatively small.

FIGS. 3 and 4 are cross-sectional explanatory views of a conventional apparatus for inspecting a workpiece (@inspected article) welded by this type of welding using an ultrasonic welding condition a inspection apparatus.

In FIG. 3, 11 is a workpiece, which is a cylindrical pedestal member 1.
2 and a bowl-shaped member 13 are welded circumferentially at a welding portion 14 and are integrated. This is the rotary table 15
The ultrasonic probe (the positioning mechanism is not shown) is placed on the top and is positioned (the positioning mechanism is not shown) and fixed to the rotary table 15.
The welding state is inspected by circumferential scanning (rotational scanning) by the probe 16 (hereinafter referred to as probe).

The workpiece 11 in FIG. 4 also has a substantially similar configuration.

However, in FIG. 3, the welded portion 14 is the bottom surface of the bowl-shaped member 13, but in FIG. 4, it is the peripheral surface.

Also, in Figure 3, is the probe 16 welded? It is located at the top of FJ14 and collects reflected echoes,
In FIG. 4, the probe lea is located inside the pedestal member 12 corresponding to the welded portion 14, and the method is such that the transmitted ultrasonic waves are collected. Note that 16a is a transmitting probe, and 16b is a receiving probe.

When inspecting the welding condition of a workpiece using ultrasonic waves to determine whether the welding is acceptable or not, the workpiece is irradiated with ultrasonic waves and the level of the reflected echo or transmitted sound m is set to a certain value (threshold P value). ), and detect the defect (non-welded state or incompletely welded state, hereinafter the same in this specification a) based on whether or not it exceeds it, and obtain the number of defects. It is.

As shown in Figures 3 and 4, when welding this type of workpiece, two members are overlapped and welded continuously or intermittently around the entire circumference, and the welding position is φD (see Figure 3). , H(
Even if the dimensions of φ1) and H differ slightly, there is little problem in terms of strength, so the dimensions of φ1) and H do not require much precision.

[Problem to be Solved] However, in the above-mentioned workpieces where high accuracy is not required in the welding position, it is not possible to inspect all the workpieces at the same probe position. That is, suppose that the workpiece 11 is first positioned on the rotary table 16, the probe 16 is set corresponding to the welding part position of one workpiece, and the echo level is sampled around the entire circumference for the welding boundary position to be inspected. However, if subsequent workpieces are inspected at the same probe position, some of the subsequent workpieces may sample echoes from a portion other than the welding position due to a shift in the welding position. Therefore,
A positioning process is required to match the probe to the welding position in accordance with the welded part of the workpiece, which results in poor inspection efficiency.

The present invention solves the problems of the prior art, and provides an ultrasonic welding condition inspection device that can efficiently perform accurate inspection even if the welding position of the inspection article is shifted. With the goal.

[Means for Solving the Problems] The configuration of the ultrasonic welding condition inspection device of the present invention to achieve such an object is to scan in the welding direction with an ultrasonic probe and then scan in the width direction of the welded part. It scans in the welding direction by moving at a predetermined pitch and repeats it, and scans in the welding direction plus scanning in the welding width direction, and corresponds to the measurement points in the 6 width directions obtained by detecting flaws in the welded part. The minimum value of the number of defects determined is taken as the evaluation data of the inspected article.

[Function] Normally, when welding is performed by electron beam or laser beam welding, the center part of the welding area is the thickest in the width direction, so the reflected echo of the ultrasonic wave obtained there. will have the lowest level (in the case of transmission, the ultrasound level will have the highest). Similarly, if the weld is firmly welded, the weld will be relatively thick, and the level of Moe echo will be low (in the case of transmission, the ultrasonic level will be high). On the contrary, in peripheral areas where welding is insufficient or in tubes that are not welded, the echo level will be correspondingly high (in the case of transmission, the ultrasonic level will be low).

Therefore, even if there is some misalignment in the welding position of the workpiece or the set position of the workpiece, or even if there is eccentricity during the rotation scan, the center of the weld or the firmly welded area around it will be scanned. The number of defects obtained by scanning at that time will be the lowest unless the scan is outside the weld area or in the periphery of the weld.

For this reason, it is necessary to scan the weld in the width direction, detect defects in the welding direction corresponding to each measurement position, count the number of defects in the scan in the welding direction, and select the minimum value. It is possible to obtain defect data for the weld center position and the tightly welded area in the vicinity without having to position the probe at the weld location. Therefore, it can be used as evaluation data.

As a result, accurate measurement is possible without having to set the probe to the appropriate measurement position of the weld each time with respect to the workpiece, especially when welding workpieces with overlap welding, where the welding position differs depending on the workpiece. Pass/fail judgments can be made in a short time.
Moreover, it can be performed accurately and efficiently.

[Embodiment] An embodiment of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an ultra-RF welding condition inspection apparatus to which the present invention is applied, and FIG. 2 is an explanatory diagram of the relationship between the echo level obtained as a result of the inspection and the welding condition.

Components that are equivalent to those in FIG. 3 are indicated by the same reference numerals.

FIG. 1 shows an example of inspecting a workpiece 11 using the method shown in FIG. Reference numeral 10 denotes a super-wave welding condition inspection device, which includes a co-rotating table 15 and a probe 16 shown in FIG.

The rotary table 15 is connected to the rotating device 5 and is driven to rotate at a predetermined rotational speed via its shaft. Further, the probe 16 is attached to the X-Z moving mechanism 4, and scans in the X direction corresponding to the width direction of the welding part 14, and also scans in two directions (height direction), which are the up and down directions with respect to the workpiece 11. The position can be set.

The X-Z moving mechanism 4 is controlled by the scanner 3, and positioning in the height direction and pitch movement in the X direction are controlled.

2 is an ultrasonic flaw detector, and this ultrasonic flaw detector 2 is
Consists of a pulser/receiver, etc., which sends a pulse signal from the transmission terminal to the probe 16, receives and amplifies the echo reception signal at the reception terminal, and converts the analog signal obtained by detecting it into a digital signal using an A/D conversion circuit. A microprocessor (MPU) 6 built in the data processing device 1 converts it into a value.
The input data is sent to the data processing device 1 as an input data value that can be processed.

The data processing device 1 includes a microprocessor 6 as well as a memory 7 and the like, and the memory 7 stores a defect detection processing program 8a, a pass/fail determination processing program 8b, and the like. The defect detection processing program 8a detects defects and counts the number of defects by comparing the echo level data of each measurement point obtained in response to one simultaneous scan in the rotational direction, which is the welding direction, with a reference value. . Then, processing is performed to store the number of defects in the memory 7. The pass/fail judgment processing program 8b selects the minimum value of the number of defects stored in the memory 7, compares it with a judgment reference value, and judges whether the work 11 is pass/fail.

Furthermore, RO of memory 7 or microprocessor 6
In M, the ultrasonic flaw detector 2 and scanner 3 are controlled to scan the welded part 14 once with the probe 16, and then the probe 16 is moved at a predetermined pitch in the welding width direction of the welded part 14 for positioning. , a scan control program is provided that controls the scanning for one rotation again.

Now, in the data processing device 1, as a measurement condition in the rotational direction which is the welding direction, for example, if the cylindrical workpiece 11 is measured at 1000 measurement points per round, this number of measurement points is equal to the measurement period. The rotation speed is determined by selecting the rotation speed, and in accordance with this condition setting, the microprocessor 6 of the data processing device 1 executes each of the programs described above to obtain the echo levels at each of the 1000 measurement points. At the same time, when one rotation of measurement is completed, the position of the probe 16 is sequentially moved by a predetermined pitch in the X direction according to the completion of one rotation of measurement to obtain the number of defects corresponding to one rotation at each X direction measurement point. , are stored in the memory 7 corresponding to the measurement points.

An example of a graph of the envelope of each echo level obtained in this case is shown in FIG.
are each measurement point in the X direction, and here, for convenience of explanation, these five measurement points are assumed. The number of defects at each measurement point A to E in the X direction is shown at the top of the graph 9. In addition, in order to clarify the content of the invention, for convenience of explanation, the measurement target is a workpiece as shown in FIG.
shall be measured. The workpiece lla is not welded in a closed circumferential manner, but is partially welded in such a manner that the welded portion 17 is divided into four locations.

Therefore, there is a non-welded portion (non-welded portion 18) between the four welded portions. Note that the welded portion 17 is
Convenience of illustration and explanation-11 Here, explanation will be made assuming that there is a relatively wide range.

Graph 9 above is an envelope that continuously shows the echo level for one revolution in the welding direction (per round of the workpiece) obtained at each of the five measurement points by pitch-feeding the position of the probe 16 in the X direction four times. It is a route.

In addition, in the echo level data for each rotation, there are four high peaks in the middle of the workpiece (b).
This corresponds to the non-welded portion 18 of a.

The echo level in this part appears to be high. Therefore, this is detected as a defect. Further, TH is a thread or hold level for determining defects. In addition, the dot-dashed circle shown in the same figure (b) represents each measurement point A-E.
The locus of the rotational scan corresponds to , and the center of the measurement position of the probe 16 and the center of the workpiece lla are misaligned and are eccentric with respect to the workpiece lla.

Here, the number of defects at measurement points A and E is 818.956, which is much larger than the others, but this is because measurement point A
This means that the position of the probe 16 corresponding to , E is often removed from the welded part 17 of the workpiece lla during scanning.

In other words, this is because echoes from the bottom surface (mating surface) of the incident side member are sampled, and when compared with the threshold value (TH), the echo level that exceeds it increases, and that portion is considered as a defect. It's being counted.

The probe positions at measurement points B and D are also partially shifted from the workpiece welding position, or the flaw detection was performed in the peripheral area where the welding condition is not good, so these are counted as defects.

Therefore, the number of defects is increasing.

On the other hand, at the measurement point C, the probe position and welding position match, and most of the echoes are from the welded part 17, and the reflected echo from the joint surface is not captured, so the number of defects is 193. This is a low value. In other words, this is a result of the substantially welded part of the weld 18 being scanned during the one-quarter scan, and the scanning process does not deviate from the weld 17; This is the case when the surrounding area is not unstable.

Note that in this example, the number of defects does not become "0" because echoes from the joint surface of the non-welded portion are counted.

In this way, echo level data obtained by rotating the workpiece many times (for example, the measurement points A-E mentioned above)
The microprocessor 6 obtains the smallest number of defects by executing the defect detection processing program 8a, which becomes data obtained as a result of the probe 16 scanning the appropriate welding position on the workpiece 11. Then, the pass/fail judgment processing program 8b is executed using this minimum number of defects (data at measurement point "C" in the above case) as a representative value of the inspection workpiece, and the microprocessor 6 uses the representative value as a pass/fail judgment value (standard value). Pass/fail judgment is made by comparing with the value).

In this case, for example, if the number of non-welded portions 18 counted as defects is 1θO point in design and the number of other allowable defects is 40 points, a total of 200 points can be set as the pass/fail determination value. Further, in this case, the pass/fail judgment may be made by using the measured value of the workpiece whose welding state passes as the standard for the pass/fail judgment.

In addition, the scanning range 1 of scanning the welding part 14 (or the welding part 17) in the width direction is determined when there is a positional deviation in the width direction of the welding part 14 with respect to the inspection position when the workpiece 11 is placed on the table 7. Displacement: Work I considering lX
It is preferable that the range covers at least the central area of the welding part 14 (or welding part 17), which is determined according to the positional deviation in the width direction of the welding part I itself.

Furthermore, the relationship between the width of the welded part 14 (or the welded part 17) and the number of scans to be sent in the X direction may be set so that the central part of the welded part falls within the scanning range.

As described above, in the embodiment, a cylindrical workpiece has been described, but the same applies to a linear workpiece. Therefore, the scanning for sampling the number of defects is not limited to rotational scanning.

In the embodiment, the workpiece is rotated to perform rotational scanning, and the probe is moved for scanning in the X direction, but since these only need to be scanned, the movement only needs to be performed relatively.

In the example, the explanation focuses on an example in which reflected echoes are collected, the number of defects is detected, and pass/fail judgment processing is performed. Of course, it may be.

[Effects of the Invention] In this invention, defects are detected in the welding direction corresponding to each measurement position by scanning in the width direction of the welded part, and the number of defects in the scanning in the welding direction is counted. By selecting the minimum value, the welding center (1r) can be set without having to position the probe at the welding point.

Defect data can be obtained for the well-welded weld area at or near 1d. Therefore, it can be used as evaluation data.

As a result, accurate measurement is possible without having to set the probe to the appropriate measurement position of the weld each time with respect to the workpiece, especially when welding workpieces with overlap welding, where the welding position differs depending on the workpiece. Pass/fail judgments can be made in a short time.
Moreover, it can be performed accurately and efficiently.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a super-unilateral welding condition inspection device to which the present invention is applied, FIG. 2 is an explanatory diagram of the relationship between the echo level obtained as a result of the inspection and the welding condition, and FIGS. 4
Each figure is an explanatory diagram of the measurement state of a conventional ultrasonic weld shape inspection device. 1...Data processing device, 2...Ultrasonic flaw detector, 3.
... Scanner, 4... X-Z movement mechanism, 5... Rotating device, 6... Microprocessor, 7... Memory,
8a... Defect detection processing program, 8b... Pass/fail determination processing program, 9... Envelope of echo level, 10... Super body wave welding condition inspection device, 11... Workpiece, 16... probe.

Claims (3)

[Claims] (1) An inspection article welded over a predetermined length is scanned in the welding direction along the predetermined length to perform ultrasonic flaw detection on the welded part, and the number of defects detected is determined based on the number of defects detected. In an ultrasonic welding state inspection device for inspection, an ultrasonic probe scans in the welding direction, moves at a predetermined pitch in the width direction of the welding part, scans in the welding direction, and repeats the process. A scan is performed in which a scan in the welding direction is added to a scan in the weld width direction, and the minimum value of the number of defects corresponding to each measurement point in the width direction obtained by flaw detection of the welded part is determined as evaluation data of the inspection article. An ultrasonic welding condition inspection device characterized by: (2) A scanning range of the scan in the weld width direction is a range that covers at least a central area of the weld that changes due to a positional shift in the width direction of the weld of the inspection article itself. 1. The ultrasonic welding condition inspection device according to 1. (3) The scanning range of the scan in the weld width direction is determined by the amount of positional deviation in the width direction of the welded part with respect to the inspection position when the inspection article is placed on the table, and the position of the weld in the width direction of the inspection article itself. The range covers at least a central area of the welded portion determined according to the amount of deviation, and the evaluation data is compared with reference data to determine whether the inspection article passes or fails. 1. The ultrasonic welding condition inspection device according to 1.