JPH09229639A - Automatic hole diameter measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a hole diameter quickly with a practical time. SOLUTION: A laser beam is deflected by a laser scan system 15 furnished on a measuring head 1 to scan a hole provided in an subject to be inspected 30 and the areas around the hole, and the reflected light is passed through a lens 9 and half mirror 11 and received by a CCD 12, and an image of reflected light which represents the shape of the hole is produced. From the produced image, the diameter of a hole in the image is determined through a image processing, and the distance between the CCD 12 and the hole to be measured in the subject 30 is determined by capturing the reflected laser beam using a laser displacement meter 10 furnished on the measuring head 1, and on the basis of the distance obtained, the diameter of the hole in the image is corrected into the actual hole diameter of the subject.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic hole diameter measuring device suitable for measuring the diameter of a large number of small holes such as cooling holes in a gas turbine combustor liner.

[0002]

2. Description of the Related Art Conventionally, for example, a diameter of 0.8 to 5 m formed on the gas turbine combustor liner in units of thousands is used.
A non-contact three-dimensional laser measuring device using laser light is used to automatically measure the diameter (diameter) of a cooling hole (through hole) in the range of m in a non-contact manner.

This non-contact three-dimensional laser measuring device is shown in FIG.
As shown in FIG. 4, the angle changing mechanism 41 that rotates along two axes
The laser displacement meter 42 is attached to the structure. The angle changing mechanism 41 is movable up and down (vertical axis movement) along the vertical axis guide 43. An object to be inspected (object to be inspected) 50 whose hole diameter is to be measured, such as a gas turbine combustor liner, is a turntable 4 provided on a bed 44.
5.

In the non-contact three-dimensional laser measuring apparatus having the structure shown in FIG. 6, a laser displacement meter 42 attached to the angle changing mechanism 41 applies a laser beam having a diameter of 2.5 μm to the object 50 to be inspected. One point is irradiated and the object 50 to be scanned is scanned. This laser light scanning is realized by rotating the angle changing mechanism 41 along two axes. Since the laser beam scanning is performed by the structure having a large inertia as described above, it takes a long time to irradiate the laser beam from one point to the next point, for example, about 0.04 to 0.08 sec. is there.

Now, in the non-contact three-dimensional laser measuring apparatus of FIG. 6, the laser beam emitted to the object 50 is scanned by the laser beam scanning as shown in FIG. (Not passing through the through-hole formed in), the light is reflected by the surface of the object 50, and the reflected light is reflected by the laser displacement meter 4
2, the end of the hole formed in the inspection object 50 is searched, and the information on the distance Li and the angle θi from the laser light irradiation position (reflection position) on the inspection object 50 is obtained by the laser. The displacement is measured by the displacement meter 42. Then, the shape of the end of the hole (hole diameter) is calculated from the collected information on the distance Li and the angle θi, as shown in FIG. 7.

Here, in order to measure the diameter of a hole having a diameter in the range of 0.8 to 5 mm with an accuracy of, for example, ± 0.01 mm, in the example where the diameter of the laser beam is 2.5 μm, there is one location. It is necessary to measure about 250,000 points for each hole.

[0007]

As described above, in the conventional non-contact three-dimensional laser measuring device used for measuring the diameter of a minute hole, a laser beam having a diameter of 2.5 μm is applied to an object to be inspected. Irradiate one point at a time and scan on the subject. Therefore, if you try to measure the diameter of a hole with a diameter of 0.8-5 mm with an accuracy of ± 0.01 mm,
Ten thousand data are required. However, in the conventional measuring device, since the laser beam scanning by the structure having a large inertia is applied, the time required to irradiate the laser beam from one point to the next point is about 0.04. ~ 0.
It took as long as 08 seconds to measure the above-mentioned 250,000 points, and it took about 20 minutes to measure one hole, which was not practical. Moreover, since the hole diameter is minute, the measurement itself is difficult with the method of calculating the hole diameter by detecting the hole end.

The present invention has been made in consideration of the above points, and an object thereof is to provide an automatic hole diameter measuring device capable of measuring the hole diameter at high speed in a practical time. Another object of the present invention is to provide a laser drilling machine capable of measuring the diameter of each hole drilled by laser light at high speed in a practical time.

[0009]

An automatic hole diameter measuring apparatus of the present invention scans a hole formed in an object and its vicinity by deflecting a laser beam by a laser scanning means provided in a measuring head. Then, the reflected light is received by the image forming means such as a CCD to obtain an image of the reflected light in which the shape of the hole is reflected, and the hole diameter is obtained from the image by image processing of the image processing means. It is characterized by However, the size of the image differs depending on the distance between the object to be inspected and the position of the image forming means (image forming position) and does not represent the original size.

Therefore, in the present invention, a laser displacement meter for receiving the above-mentioned laser reflected light and measuring the distance to the reflection position on the object to be measured is provided in the above-mentioned measuring head, and an image obtained by the image forming means is used. The image processing means is characterized in that the hole diameter on the obtained image is corrected to the actual hole diameter on the test object based on the distance measured by the laser displacement meter.

That is, in the present invention, the hole of the object to be measured and the vicinity of the hole are scanned by deflecting the laser light by the laser scanning means, and the image of the reflected light is read by a CCD or the like. It is acquired by the image forming means. By thus deflecting and scanning the laser light, it is possible to significantly reduce the time required for laser light scanning for the number of points required for hole diameter measurement.

The image acquired by the image forming means represents the shape of the hole irradiated with the laser beam, and the diameter of the hole on the image is obtained by image processing for that image. Further, the distance between the image forming means and the hole to be measured is measured by capturing the laser reflected light during scanning with a laser displacement meter, and based on this distance, the hole on the image obtained by the image processing described above. The diameter of is corrected to the diameter of the actual hole on the specimen.

Further, according to the present invention, the above automatic hole diameter measuring device is provided in a laser drilling machine equipped with a working laser head for drilling with a laser beam, and the measuring head of the measuring device is provided with the working laser. It is also characterized in that it is provided as a pair with the head.

In the laser boring machine having such a structure, immediately after laser boring, the machined hole can be measured (inspected) at high speed in a practical time. Therefore, when a problem occurs in the processing machine, it is possible to limit the influence on the product to only one hole.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows the overall structure of an automatic hole diameter measuring device according to a first embodiment of the present invention.

In the figure, the measuring head 1 irradiates the object 30 to be inspected placed on the turntable 6 with a laser beam and catches the reflected light to measure the measuring head 1 and the object 30 to be inspected. The distance between them is detected, and the holes (circular through holes) formed on the object 30 are imaged on the CCD 12 (see FIG. 3) described later. Here, a gas turbine combustor liner is used as the inspection object 30.

The distance and image data (analog data) detected by the measuring head 1 are transmitted to the measuring / driving computer 4 via a cable 5. The measuring / driving computer 4 analog-digital converts the distance data (distance signal) from the measuring head 1 into digital distance data. Further, the measuring / driving computer 4 performs image processing on the image data from the measuring head 1 to perform C processing.
The area of the image portion of the hole (hole) on the CD 12 is obtained, the hole diameter (hole diameter on the image) is calculated, and corrected by the distance indicated by the analog / digital converted distance data to obtain the object 30 to be inspected.
Get the hole diameter of the actual hole above.

Here, a large number of holes (holes) on the test object 30.
Is, for example, NC (numerical control) by laser drilling machine
It is formed according to the data. This NC data specifies the hole position, the diameter, etc. of the hole formed on the test object 30. Therefore, in this embodiment, this NC data is measured and
The measurement head 1 is stored in a hard disk 20 (see FIG. 4), which will be described later, connected to the driving computer 4, and the positioning of the measuring head 1 is controlled according to the hole position indicated by the NC data.

The measuring head 1 is attached to the measuring head drive unit 2. FIG. 2 shows a detailed configuration around the measuring head drive unit 2. The measurement head drive unit 2 is movable in the vertical direction (vertical axis direction) along the vertical axis guide 3 according to an instruction from the measurement / drive computer 4. Further, the measurement head drive unit 2 is provided with an angle changing mechanism 16 for changing the angle of (the measurement head 1 attached to) the measurement head drive unit 2. Further, an air source 17 to an air bearing used for the measuring head 1 is also provided.

In the measuring head 1, however, the measuring head drive unit 2 is moved to the vertical axis guide 3 in accordance with the instruction of the measuring / driving computer 4 based on the hole position data on the NC data stored in the hard disk 20 in FIG. By moving along, it is moved in the vertical axis direction and the angle changing mechanism 1
6 is moved to the axis of the hole on the test object 30 in response to the angle change by 6, and the axis of the measuring head 1 is aligned with the hole axis.
The phase of the holes is determined by the turntable drive mechanism 7 provided on the bed 8 of the automatic hole diameter measuring device.
It is adjusted by rotating.

FIG. 3 shows a detailed structure of the measuring head 1 whose positioning is controlled as described above. In the figure, a semiconductor laser oscillator 14 for outputting a laser beam is provided on the measuring head 1 positioned on the hole axis on the object to be inspected 30. The semiconductor laser oscillator 14 oscillates and outputs laser light according to an instruction from the measurement / drive computer 4. The laser beam oscillated and output from the semiconductor laser oscillator 14 is a laser scanning system 1 for scanning the laser beam.
It is deflected by 5 and enters the half mirror 11. The laser light incident on the half mirror 11 is reflected by the half mirror 11 and guided to the optical lens 9, and is irradiated onto the test object 30 via the optical lens 9. Here, under the control of the measurement / driving computer 4, the laser scanning system 15 realizes laser light scanning (laser light scanning) by changing the deflection amount and direction with respect to the laser light. You can Since the laser beam scanning by the laser scanning system 15 is realized by the deflection operation, it is realized by using the angle change by the angle changing mechanism 41 as in the conventional measuring device shown in FIG. 6 and has a large inertia. Unlike the laser light scanning by the structure, the speed can be increased. That is, by controlling the deflection of the laser beam by the laser scanning system 15, the hole on the object to be inspected 30 and the vicinity thereof (via the half mirror 11 and the optical lens 9) are scanned at high speed by the laser beam (scanning laser beam). Can be trained. Here, the time from the irradiation of one point with the laser light to the irradiation of the next point, that is, the measurement time of one point (laser light scanning cycle) is 0.04 to 0.08 s as compared with the conventional one.
It can be shortened from ec to about 0.1 to 0.6 μsec.

Now, of the laser light (scanning laser light) that scans the object 30 to be inspected, the laser light applied to the hole (through hole) on the object 30 passes through the hole, but the hole The laser light emitted in the vicinity is reflected on the test object 30. The reflected light (laser reflected light) is guided to a laser displacement meter 10 provided at a position corresponding to the optical lens 9, detected by the laser displacement meter 10, and reflected by the object 30 to be measured and the optical lens 9. The distance between and is measured. Further, the reflected light passes through the optical lens 9 and the half mirror 11, and a CCD (charge coupled device) 12 provided behind the half mirror 11 for image formation (image acquisition).
The image of the reflected light is also formed (stored) at the corresponding position of the CCD 12.

When the measurement / driving computer 4 executes the first laser beam scanning for one hole, it inputs the image signal formed (acquired) by the CCD 12, and based on the image signal, the optical signal is output. By driving the focusing drive mechanism 13 that changes the position of the lens 9, the image is corrected to be focused on the CCD 12.
This technique can be realized by utilizing the autofocus function of a well-known camera.

After the focus correction described above, the measuring / driving computer 4 executes the second laser beam scanning in order to actually measure the hole diameter. By the way, 1
In laser light scanning for one hole, the diameter of the hole in the range of 0.8-5 mm is ± 0.01 mm.
When trying to measure with the accuracy of, the diameter of the laser beam is 2.5μ
If m, as described in the section of the prior art, 1
It is necessary to measure 250,000 points (holes) for each hole. However, in this embodiment, the measurement time for one point is 0.1
Since about 0.5 μsec is required, it is possible to measure 250,000 points (points) in 30 seconds or less (conventionally about 20 minutes), and it is possible to perform automatic measurement in a practical time.

FIG. 4 is a block diagram showing the system configuration of this device (hole diameter automatic measuring device). In the figure, the measurement / driving computer 4 processes the input signal from the laser displacement meter 10, the CCD 12, etc., the focusing driving mechanism 13, the semiconductor laser oscillator 14, as already described with reference to FIGS. 1 to 3. It controls the output of instructions to the laser scanning system 15, the measuring head drive unit 2, the angle changing mechanism 16 and the like.

The measuring / driving computer 4 executes the above-described second laser beam scanning, and the CCD 12
When the image of the hole on the object 30 to be scanned by the laser beam and its vicinity are acquired, the image signal is input from the CCD 12.

The measuring / driving computer 4 also inputs a signal of the distance La between the optical lens 9 and the reflection position on the object 30 measured by the laser displacement meter 10 in the second laser light scanning. To do. The signal of the distance La is analog / digital converted in the measuring / driving computer 4 and used for the hole diameter calculation (hole diameter correction) described below.

The measuring / driving computer 4 is a CCD 1
By processing the image signal input from 2 by the built-in image processing processor, the area of the hole is obtained from the image of the hole formed on the CCD 12, and its diameter (the diameter of the hole on the image of the CCD 12) db Ask for. This hole diameter db is CC
It is the diameter of the hole image on D12 and does not represent the actual diameter of the hole on the test object 30.

Then, the measuring / driving computer 4 sets the actual hole diameter on the object 30 as da, and the hole diameter db obtained by image processing and the object 30 measured by the laser displacement meter 10. Distance L between (at reflection position) and optical lens 9
From a and the distance Lb between the optical lens 9 and the CCD 12 which is determined by the driving amount of the focusing drive mechanism 13, the actual hole diameter da is obtained by the calculation of da = (La / Lb) × db. As described above, the measuring / driving computer 4 sets the diameter db of the hole image on the CCD 12 to La and Lb.
The actual hole diameter da is calculated by using

The laser displacement meter 10 is provided at a position corresponding to the CCD 12, the distance Lc between the object 30 (at the reflection position) and the CCD 12 is calculated, and the distance Lc and the distance Lb (focusing) are obtained. From the distance between the optical lens 9 and the CCD 12 which is determined by the driving amount of the driving mechanism 13), the distance La between the object 30 (at the reflection position) and the optical lens 9 is calculated by the calculation of Lc-Lb. The above calculation da = (La / Lb) × db may be performed.

The measuring / driving computer 4 repeatedly executes the driving control of the measuring head 1 and the like for the hole diameter measurement and the hole diameter calculation processing described above while switching the hole to be measured on the object 30 to be measured. .

A CRT (CRT display) 18 as a display unit, a printer 19 as a printing unit, and the hard disk (hard disk device) 20 as a large-capacity external storage device are connected to the measuring / driving computer 4. . When the measurement / driving computer 4 acquires the hole diameter measurement result for the test object 30, the measurement / drive computer 4 outputs the measurement result to the CRT 18 for display. Further, the measurement / drive computer 4 prints out the hole diameter measurement result by the printer 19 when a print output is requested by the operator. The hole diameter measurement result is stored in the hard disk 20. [Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 5 shows the overall construction of a laser drilling machine equipped with an automatic hole diameter measuring device according to a second embodiment of the present invention. The feature of the present embodiment is that the measurement head 1 of the automatic hole diameter measuring device shown in FIG. 1 is arranged in parallel with the processing laser head 21 of the laser drilling machine as shown in FIG. The point is that the structure attached to is applied. In the present embodiment, the computer for controlling the punching machine is the measuring / driving computer 4 shown in FIG.
It is also possible to combine the two.

By integrating the measuring head 1 (including the automatic hole diameter measuring device) with the processing machine as described above, the diameter of the corresponding hole can be measured immediately after drilling. Therefore, even if a problem occurs in the laser drilling machine,
It is possible to limit the impact on the product to only one hole.

The case where the gas turbine combustor liner is used as the test object 30 and the diameter (diameter) of the cooling hole (through hole) formed on the liner is measured has been described above. It can be applied to the measurement of the hole diameter of various members such as the measurement of the hole diameter of a plate. It is also possible to compare the required shape and size by measuring the two-dimensional shape by applying the image forming technology and the image processing technology applied in the present invention.

[0036]

As described above in detail, according to the present invention, the hole on the object to be measured and the vicinity of the hole are scanned by deflecting the laser beam by the laser scanning means and reflecting the laser beam. Since the image of light is acquired by the image forming means such as CCD, the time required for laser light scanning for the number of points required for hole diameter measurement can be greatly shortened. Further, the diameter of the hole on the image acquired by the image forming means is based on the distance measured by capturing the laser reflected light during scanning by the laser displacement meter, and the diameter of the actual hole on the test object. Corrected to the diameter. From the above, according to the present invention, it is possible to measure the diameters of a large number of holes on a test object with high precision and at high speed in a practical time.

Further, according to the present invention, the measuring head portion of the above-mentioned device having the automatic measuring function of the hole diameter is provided in the laser drilling machine in pair with the processing laser head, so that the drilling is performed once. It becomes possible to measure the diameter of the processed hole for each processing, and even if a processing machine malfunctions, the effect on the product can be limited to one hole.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an automatic hole diameter measuring device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a detailed configuration around a measurement head drive unit 2 in FIG.

FIG. 3 is a diagram showing a detailed configuration of a measuring head 1 in FIG.

FIG. 4 is a block diagram showing a system configuration of the same embodiment.

FIG. 5 is a diagram showing an overall configuration of a laser drilling machine equipped with an automatic hole diameter measuring device according to a second embodiment of the present invention.

FIG. 6 is an overall configuration diagram of a conventional device capable of measuring a hole diameter.

FIG. 7 is a diagram for explaining a hole diameter measuring method applied to the conventional device of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Measuring head, 4 ... Measuring / driving computer (processing means), 9 ... Optical lens, 10 ... Laser displacement meter, 12 ... CCD (electrically coupled device, image forming means), 13 ... Focusing drive mechanism, 14 ... Semiconductor Laser oscillator, 15 ... Laser scanning system, 21 ... Processing laser head, 30 ... Test object.

Claims (2)

[Claims] 1. A laser scanning means for scanning a hole which is a hole diameter measurement target formed in a test object by deflecting the laser light and a vicinity of the hole, and a result of the laser light scanning by the laser scanning means. An image forming means for receiving a laser beam reflected by the test object and forming an image of the laser reflected light, and a distance between the laser reflected light and a reflection position on the test object. With a laser displacement meter for measuring, a measuring head that can be positioned in any hole on the object to be measured, and obtain the diameter of the hole on the image acquired by the image forming means, and determine the hole diameter on the image. And an image processing unit for performing a correction calculation to an actual hole diameter on the object based on the distance measured by the laser displacement meter. 2. A laser boring machine having a processing laser head for boring with a laser beam, comprising the automatic hole diameter measuring device according to claim 1, wherein the measuring head of the measuring device is provided. Is provided in a pair with the processing laser head.