JPH0558501B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic measurement method in which a specimen is automatically scanned and measured by immersing it in a liquid bath, and in particular, it concerns whether or not the automatic measurement can be started at the time of starting the automatic measurement. This is a suitable method for determining.

[Conventional technology]

An example of a conventional ultrasonic measuring device that automatically scans and measures a subject immersed in a liquid bath will be described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram illustrating the configuration of the apparatus, in which 1 is a subject and 2 is a probe. In this example, the object 1 is a rotating member,
It is detachably held by the chuck 3. Check 3
is connected to a rotating device 4 and rotated at a predetermined pitch angle. The probe 2 is attached to a holder 5, and a scanning device 6 as shown in FIG.
It scans in the axial direction and inputs the reflected wave signal obtained by scanning into the ultrasonic measuring device 8. The input signal is sent to the CPU 9 via the A/D converter. The rotating device 4 and the scanning device 6 each have a respective control device 7 connected to the CPU 9, and each operation, that is, the liquid tank ( Usually, a water tank filled with water is often used (explained below with reference to the water tank), attaching the subject 1 to the chuck 3 outside, immersing the subject 1 in water, and the probe 2 attached to the holder 5. movement to place the test object 1 at a fixed distance from the immersed measurement surface of the test object 1, start scanning, rotate the test object 1 to change the measurement position, and release the chuck 3 of the test object 1 at the end of the measurement. A series of operations such as removal are performed. Each of these operations is almost automatically performed via the CPU 9 based on a measurement software program depending on the type of the subject 1. Therefore, when automatic scanning starts, unless the measurement value displayed on the display shows an extreme abnormality, even if the measurement conditions at the start of the measurement are poor, in most cases the defects will be on the circumference. The reality is that it is not possible to confirm abnormal values caused by poor measurement conditions until measurements at all measurement positions are completed and abnormal values are found from the measurement results. Measurement conditions at the start of measurement that affect measured values include the degree of water contamination,
The main factors include the grip state of the chuck 3 of the subject 1 (for example, when chucked at an angle), the roughness of the measurement surface of the subject 1, etc.
Contaminated water has traditionally been replaced based on the judgment of workers based on their visual inspection, and this judgment inevitably varies from person to person. Similarly, the effect on measured values is not constant, and the effect may exceed the permissible limit. In some cases. The grip state of the specimen 1 is normally not checked again because once the specimen 1 is gripped by the chuck 3, it is chucked correctly, and even if the chuck is chucked slightly diagonally, the measurement is still accurate. As the process progresses, in most cases, measurement begins without you noticing. There are various cases regarding the roughness of the measurement surface, such as cases where it is not machined to the specified roughness, cases of machining omissions, cases where the measurement surface has scratches exceeding the specified roughness, and cases where dust is attached. In these cases, the measurement proceeds in the same way as in the gripping state of the object 1, so the abnormality may not be noticed at the start of the measurement, but only discovered from the results after the measurement is completed. It was on. Further, even if an abnormal value is found from the measurement results, it is impossible to determine which measurement condition at the start of the measurement is the cause.

[Problem that the invention seeks to solve]

In the conventional method, even if the measurement conditions at the start of the measurement are poor, the defect cannot be confirmed until an abnormal value is found in the measurement results after the measurement is completed, and even if an abnormal value is found, the fault cannot be confirmed. There was a problem in which it was not possible to determine which measurement condition was the cause of the defect.

The present invention solves the above-mentioned problems of the prior art, and is an ultra-high technology capable of determining whether automatic measurement of a subject can be started at the time of starting automatic measurement, and also easily determining the cause when automatic measurement of a subject cannot be started. The purpose is to provide a method for measuring sound waves.

[Means for solving problems]

The present invention provides a reference test in an ultrasonic measurement method in which a measurement surface of a specimen immersed in a liquid is automatically scanned and measured by a probe that is opposed to the measurement surface at a fixed distance through the liquid. Under standard measurement conditions, a certain range is set around the position where the peak level of the echo of the surface reflected wave reflected from the measurement surface is allowed to shift. The range is compared with the appearance position of each peak level of the surface echo at a plurality of measurement points distant from each other on the subject, and it is determined whether or not to start automatic measurement based on whether each appearance position is within the range. This ultrasonic measurement method makes it possible to easily and accurately determine whether or not a start is possible in a short period of time, as well as quickly determine the cause in the case where a start is not possible.

[Effect]

The ultrasonic measurement method according to the present invention uses an ultrasonic measurement device that automatically scans and measures a test object using an immersion method, and before starting measurement of the test object, a reference test piece, such as a test piece of the test object, is prepared in advance. Among them, the dimensions, shape, processing accuracy, etc. must be correctly manufactured according to the drawings and have passed the test, or those manufactured specifically as standard test pieces should be used, and the standard measurement conditions must be met, such as when the liquid (water, etc.) is new and dirty. The measuring surface should be displayed on the CRT of the measuring device under conditions such as: the measuring surface is not properly attached to the chuck, the measuring surface and the probe are facing each other correctly, and there are no scratches or dirt on the measuring surface. A certain range is set around the peak level of the surface echo in the direction of the beam path and in the gain direction to allow deviation of the appearance position of the peak level depending on the type of object. , when starting the measurement of the object, at the start of each object, the appearance position of the peak level of each surface echo at multiple (preferably 3 or more) measurement points distant from each other on the object is within the set range. If it is within the range, measurement can be started; if it is outside the range, the cause is determined based on the processing float for elucidating the cause of the defect in the measurement conditions, and measurement is started until the cause of the defect is eliminated. This is a method that can easily and quickly determine whether the

〔Example〕

Embodiments of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram showing an example of a range in which a shift in the appearance position of the peak level is allowed, which is set around the peak level of the surface echo of the reference test specimen.
Figure 2 is an explanatory diagram of the comparison between the correct surface echo of the standard test piece and the surface echo when the measurement starting conditions are poor. Figure 2a is a diagram of the correct surface echo, and Figure 2b is the peak of the surface echo. The second diagram shows the level changing up and down (downward in this example) on the screen in the direction of gain.
Figure c similarly shows a diagram showing changes in the direction of the beam path and the gain direction (horizontal and vertical directions on the screen), and Figure 3 is an example of a flowchart for determining whether or not to start measurement of the object. In the figure 1
0 is the surface echo of the reference test specimen displayed on the CRT 15, and a range A surrounded by a dotted line around this position is set as the position where the peak level appears. Range A is predetermined according to the probe, ultrasonic measuring device, and type of object being used, and indicates a certain range that allows deviation in the appearance position of the peak level. circular without limitation,
Any shape and size such as oval, square, polygon, etc. can be determined. 2a is the same as the surface echo 10 shown in FIG. 1, and FIG. 2b shows the surface echo 10 with a chain line, and the surface echo 11 with a lower peak level and the same beam path than the surface echo 10 with a solid line. In the case of this figure, the peak level of the surface echo 11 is outside the range A indicated by the chain line, and it is determined that the measurement conditions are poor and it is not possible to start the measurement. The cause of the poor measurement conditions is determined to be water contamination in the water, since the peak level of the surface echo 11 appears at the same beam path path as the surface echo 10, and the gain simply decreases. Fig. 2c shows a case in which a surface echo 12 shown by a solid line and a surface echo 13 shown by a dotted line appear alternately with respect to a surface echo 10 shown by a chain line, where the beam path and gain change.In the case of this figure, the amount of change is within a range. Since it is within A, it is determined that it is possible to start measurement. However, the amount of change is large and the surface echo 1
If the peak levels of both 2 and 13 are outside range A, chuck the test object again and scan again. If the changes in the beam path and gain are almost eliminated, the cause of the failure is due to the mounting of the test object on the chuck. If it is determined that it is defective and the change is still not resolved, the cause of the defect is the roughness of the measurement surface,
It is determined that this is due to scratches, dirt, etc. Third
The figure is a flowchart for determining whether or not to start measurement and the cause of poor measurement conditions when the object to be examined is a rotating body.Based on this chart, the determination can be made automatically, easily, and in a short time.

In the above embodiments, the case where the object to be examined is a rotating member was explained, but it may be a flat member or a rod-shaped member by changing the chuck, and it is also possible to move either the object or the probe for scanning. You can also do this. Furthermore, although an example has been shown in which echoes displayed on a CRT are compared and discriminated, it is of course possible to compare other analog signals or digital signals.

〔Effect of the invention〕

As explained above, the present invention sets a certain range around the peak level position of the surface echo by the reference test piece, and compares this range with the peak level position of the surface echo when measuring the object. Since it is possible to determine whether or not automatic measurement can be started based on whether the position is within the set range, it is possible to easily and reliably determine whether or not automatic measurement can be started in a short time. This has a significant practical effect in that the cause can be quickly identified.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining one example of the measurement method according to the present invention, FIG. 2 is a diagram for explaining the comparison between the surface echo shown in FIG. 1 and the surface echo when the measurement starting conditions are poor, and FIG. Flowchart 1 for Figure 2
Give an example. FIG. 4 is a block diagram illustrating an example of the configuration of a conventional measuring device, and FIG. 5 is a diagram showing an example of the scanning device shown in FIG. 4.

Claims (1)

[Claims] 1. A reference test piece is used in an ultrasonic measurement method in which the measurement surface of a specimen immersed in a liquid is automatically scanned and measured by a probe that is opposed to the measurement surface at a certain distance through the liquid. and, under standard measurement conditions, a certain range is set at the peak level appearance position of the echo of the surface reflected wave reflected from the measurement surface, and a certain range is set around the position to allow deviation of the appearance position, and the range and It is characterized by comparing the appearance positions of each peak level of the surface echo at a plurality of measurement points separated from each other on the subject, and determining whether or not to start automatic measurement based on whether each appearance position is within the range. Ultrasonic measurement method.