JPH01313739A - Method and device for inspecting peripheral surface of cylindrical body - Google Patents

Abstract

PURPOSE:To completely scan the overall length of the outside peripheral surface to be inspected of a cylindrical body without excess and shortage by giving an incident angle to the peripheral surface to be inspected and projecting a flat beam whose width is wider than length of the peripheral surface to be inspected in parallel to the rotation axis. CONSTITUTION:A cylindrical body W to be inspected is rotated by a rotation supporting device 1. The peripheral surface to be inspected is irradiated by a flat beam whose width is longer than length of the peripheral surface to be inspected at an incident angle in parallel to the rotation axis from a projecting part 2, and the whole surface of the peripheral surface is scanned. The irradiating light is reflected by the peripheral surface to be inspected, but both an irregularly reflected light from a flaw part and an irregularly reflected light from the outside of the peripheral surface to be inspected are received by a light receiving part 3, and a regularly reflected light is received by a light receiving part 4. A signal from the light receiving part 3 is brought to gate by AND with a signal from the flight receiving part 4, inputted to a width measuring part 11 after an irregularly reflected light signal from the outside of the outside peripheral surface to be inspected has been eliminated, and compared with a prescribed width value. When that which exceeds the prescribed width exists, its width is integrated successively by an integrator 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method and apparatus for inspecting the circumferential surface of a cylindrical body, for example, the outer circumferential surface of a micropipe.

[Conventional technology]

In conventional technology, the outer circumferential surface of a cylindrical body is inspected by rotating the cylindrical body, irradiating and scanning a convergent light onto the generatrix of the outer circumferential surface, and detecting the diffusely reflected light.

[Problem to be solved by the invention]

Inspection of the outer circumferential surface of a cylindrical body by conventional techniques cannot completely scan the entire outer circumferential surface to be inspected without noise. This is because it is difficult for the scanning light to scan the entire length of the outer circumferential surface of the cylindrical body to be inspected without too much or too little, that is, it is difficult to make the width of the scanning light completely match the length of the outer circumferential surface to be inspected. .

[Means to solve the problem]

The method for inspecting the circumferential surface of a cylindrical body according to the present invention provides an incident angle to the circumferential surface of the cylindrical body to be inspected while rotating the cylindrical body to be inspected, so that the cylindrical body to be inspected is parallel to the axis of rotation of the cylindrical body to be inspected. A flat beam with a width wider than the length of the circumferential surface is projected, and the diffusely reflected light is reflected on a plane with a reflection angle different from the incident angle of the incident flat beam, and in a range wider than the length of the circumferential surface to be inspected.
The light receiving section receives the light, and the second light receiving section receives the specularly reflected light from the peripheral surface to be inspected on a plane with a reflection angle equal to the incident angle of the incident flat beam, and the light receiving signal of the first light receiving section is transmitted to the second light receiving section. Gate with the light reception signal of The condition of the circumferential surface of the cylindrical body to be inspected is determined. For example, the state of the circumferential surface of the cylindrical body to be inspected is determined based on the number of received light signals exceeding a predetermined value and the integral value of the magnitude of the received light signals exceeding a predetermined value.

The cylindrical body circumferential surface inspection device of the present invention includes a rotary support device that supports a cylindrical body to be inspected so as to rotate the cylindrical body to be inspected; a light projecting unit that projects a flat beam parallel to the axis and having a width wider than the length of the circumferential surface to be inspected; a reflection angle different from the incident angle;
and a first light receiving section that receives diffusely reflected light in a wider range than the length of the circumferential surface to be inspected, a second light receiving section that receives specularly reflected light on the circumferential surface to be inspected with a reflection angle equal to the incident angle, and both of the light receiving sections. a gate that gates the light reception signal of the first light receiving section with an AND condition of the light reception signal of the second light receiving section, and the judgment control device makes the judgment based on the output signal from the gate. The system is equipped with a determination unit that performs the determination.

The judgment control device is provided with a counter for counting the number of received light signals exceeding a predetermined value and/or an integrator for integrating the magnitude of signals exceeding the predetermined value; is the above number and the above integral value,
The condition of the circumferential surface of the cylindrical body to be inspected is determined by comparing either one of them with a predetermined determination value.

[For production]

The cylindrical body to be inspected is supported by a rotary support device and rotated. At the same time, a flat beam with a width longer than the length of the circumferential surface to be inspected is irradiated from the light projector to the circumferential surface to be inspected at an incident angle parallel to the axis of rotation of the cylindrical body to be inspected. is scanned over. The irradiated light is reflected by the circumferential surface of the cylindrical body to be inspected, but if there is a flaw, pinhole, etc. on the circumferential surface of the cylindrical body to be inspected, diffuse reflection may occur at that part. , the reflected light is received by the first light receiving part of the cylinder together with the diffusely reflected light outside the circumferential surface to be inspected, and the specularly reflected light from the circumferential surface to be inspected is received by the second light receiving section.
The light is received by the light receiving section. The light receiving signal of the first light receiving section is gated with the light receiving signal of the second light receiving section at the gate, and the light receiving signal of diffusely reflected light from other than the circumferential surface to be inspected is removed before being output.

If the received light signal is larger than a specified value, the integrator sequentially integrates the received light signal to obtain an integrated value, and the counter counts the number. The integral value and/or number of signals obtained in this way are:
is input to the determination unit and compared with a predetermined determination value in the determination unit, thus.

Based on the comparison result, a determination signal is output from the determination section.

〔Example〕

An apparatus according to an embodiment of the invention will be explained with reference to FIG.

As shown in Fig. 1, a micropipe W which is a cylindrical body to be inspected
A light emitter 2 and a first light receiver are provided above a rotary support device 1 (for example, a support center at both ends equipped with a stepping motor for rotational drive, or parallel rotating rollers on a lower support) that supports the 3 and a second light receiving section 4 are installed.

The light projecting unit 2 projects a laser flat beam onto the outer peripheral surface of the micro pipe W over the entire length of the micro pipe W and parallel to the axis of the micro pipe W when the micro pipe W is supported by the rotation support device 1. In order to completely irradiate the outer circumferential surface of the micropipe W to be inspected, it is longer than the entire length of the outer circumferential surface to be inspected.

The first light receiving section 3 and the second light receiving section 4 receive the laser flat beam from the light projecting section 2 that is reflected on the outer circumferential surface of the micropipe W over the entire length, and their length also depends on the light emitting section. This is the same as part 2.

Then, the relative positions of the light projecting section 2, the first light receiving section 3, and the second light receiving section 4 with respect to the micropipe W are determined such that the winner is the micropipe W.
The planes PL, P2. They are installed separately on P3 and parallel to the axis of the micropipe W. Moreover, the plane P1 of the light projecting section 2 and the plane P3 of the second light receiving section 4 are symmetrical with respect to the plane PO including the generatrix G and the axis (the angles that the plane P1 and the plane P3 make with the plane PO are both θ), the plane P2 of the first light receiving section 3 is
It is located between plane P1 and plane P3. The plane P2 is
Although it is preferable that it is on the same plane as the plane PO, it is not necessarily limited thereto.

The first light receiving section 3 and the second light receiving section 4 are connected to the illustrated control circuit. The first light receiving section 3 and the second light receiving section 4 include amplifiers 5, 6, filters 7.8, and binarization circuits 9, 10, respectively.
The binarization circuit 10 is connected to the binarization circuit 9, and the binarization circuit 9 is connected to the width measurement section ratio and the integrator 1.
2, counter 13, 'connected to determination section 14;
4, a test signal is output.

The inspection operation using the above-mentioned surface inspection device and the operation of the surface inspection device will be explained.

First, the micropipe W is supported by the rotary support device 1 and rotated. At the same time, a laser flat beam is irradiated from the light projection unit 2 over the entire length of the outer peripheral surface of the micropipe W to be inspected. Since the length of the laser flat beam is longer than the length of the outer peripheral surface to be inspected, the entire outer peripheral surface of the micropipe W is completely scanned. The scan is actually done every 1/2 degree. The irradiated light is reflected by the outer peripheral surface of the micropipe W, but if there are no flaws, pinholes, etc. on the outer peripheral surface of the micropipe W, the reflected light is received only by the second light receiving section 4. be done. However, if there is a flaw, pinhole, etc. on the outer circumferential surface of the micropipe W, diffuse reflection occurs at that portion, and the reflected light is received by the first light receiving section 3.

The light is received by each of the first light receiving section 3 and the second light receiving section 4, and the CC
The signal obtained by the D image sensor is transmitted through an amplifier 5,
6 is amplified and scaled, and then the high frequency noise superimposed on the waveform of the amplified signal is cut by a low-pass filter 7.8 (second
Figure C9d).

However, since the length of the laser flat beam is longer than the length of the outer circumferential surface to be inspected, there is a risk that reflected light from areas outside both ends of the outer circumferential surface to be inspected will also be received by the first light receiving section 3 and may be misjudged as a defect. There is.

However, since the second light receiving section 4 receives only the specularly reflected light from the outer peripheral surface to be inspected, the signals from the first light receiving section 3 and the second light receiving section 4 are further transmitted to the binarization circuit 9, 10 (C9d in FIG. 2). When the signal from the first light receiving section 3 is binarized, it is gated with the signal from the second light receiving section 4 under an AND condition. After signals caused by diffusely reflected light from other than the outer circumferential surface to be inspected at the first light receiving section 3 are removed, the signal is input to the width measuring section 11 .

Therefore, only the outer circumferential surface of the micropipe W to be inspected and the entire surface can be accurately inspected, and the signal from the first light receiving section 3 is compared with the specified width value in the width measuring section 11. If the width exceeds the specified width, the integrator 12 will:
The width is sequentially integrated, an integral value S is obtained, and the counter 1
3, the number (number of flaws larger than the specified one) C
n is counted. The integral value S obtained in this way
and the number of signals Cn are input to the determination unit 15, and the determination unit 15
It is compared with the judgment value recorded in . The determination value in the determination unit 15 is input and recorded as a value obtained by measuring a master micropipe WO prepared in advance.

Thus, a pass/fail signal is output from the judging section 15 based on the result of comparing the integral value S and the number Cn with the judgment value.

In this determination, for example, even if there are a predetermined number or more of flaws that are larger than a predetermined width, or even if the cumulative width value of flaws that are larger than a predetermined width is greater than or equal to a predetermined value regardless of the number, the product will be rejected in any case.

In addition, various types of determination can be considered, such as determination based only on width or determination based only on number.

Furthermore, the material to be inspected is not limited to a small pipe, but may be any cylindrical body, and it is easy to imagine that the present invention may be applied not only to outer circumferential surface inspection but also to inner circumferential surface inspection in some cases.

〔Effect of the invention〕

According to this invention, the entire circumferential surface to be inspected can be easily completely scanned without making the light projecting means and the light receiving means completely coincident with the axial length of the circumferential surface to be inspected, and the diffused reflection from the entire circumferential surface to be inspected can be easily scanned. Only light can be inspected as a light reception signal, and thereby the circumferential surface of the cylindrical body can be accurately inspected without noise.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a cylindrical body circumferential surface inspection apparatus according to an embodiment of the present invention, and FIG. It is a graph of the output signal. 1: Rotating support device 2: Floodlight

Claims (2)

[Claims] (1) While rotating the cylindrical body to be inspected, give an incident angle to the circumferential surface of the cylindrical body to be inspected so that a width wider than the length of the circumferential surface is parallel to the axis of rotation of the cylindrical body to be inspected. A flat beam is emitted, and the first light receiving section receives the diffusely reflected light on a plane with a reflection angle different from the incident angle of the incident flat beam and in a range wider than the length of the circumferential surface to be inspected. The specularly reflected light is received by a second light receiving section on a plane with a reflection angle equal to the incident angle of the incident flat beam, and the light receiving signal of the first light receiving section is gated with an AND condition with the light receiving signal of the second light receiving section, The condition of the circumferential surface of the cylindrical body to be inspected is determined based on the received light signal from the first light receiving section after removing components due to diffusely reflected light from other than the circumferential surface to be inspected from the light receiving signal of the first light receiving section. Cylindrical body circumference inspection method to determine (2) A rotary support device that rotatably supports the cylindrical body to be inspected, and the circumferential surface to be inspected is parallel to the rotational axis of the cylindrical body to be inspected by giving an incident angle to the circumferential surface to be inspected of the cylindrical body to be inspected. a light projecting part that projects a flat beam with a width wider than the length; a first light receiving part that receives diffusely reflected light having a reflection angle different from the incident angle and in a range wider than the length of the circumferential surface to be inspected; It is composed of a second light receiving section that receives specularly reflected light from the circumferential surface to be inspected at the same reflection angle, and a judgment control device for the light reception signals of both the light receiving sections, and the judgment control device judges the light reception signal of the first light receiving section for the second light receiving section. A cylindrical body circumferential surface inspection device comprising a gate that performs an AND condition with the light reception signal of two light receiving sections, and a determination section that performs a determination based on the output signal from the gate.