JPS5932124B2 - Fastener inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fastener inspection method, and more particularly to a fastener inspection method that uses laser light scanning and a photoelectric conversion system to determine the quality of a fastener.

As is generally known, fasteners include a retainer 1, a puller 2, a slider 3, and an element 4 shown in Figure 1.
, a bottom stopper 5, and a tape 6.

And when this zipper is completed,
whether it is attached to the specified position and whether the specified distance is maintained between it and the next element 4 (0)
Check whether the slider 3 and the pull handle 2 are in the specified positions (/→ whether the element 4 is missing 2
Check whether the bottom stopper is in place or bent. (H)
It is necessary to inspect the tape for fraying, uneven cuts, and uneven weaving.

Conventionally, when inspecting such fasteners, I
TVs (industrial television cameras) and photo detection arrays are used, but since these both use incoherent illumination, the cloth part of the zipper and part of the zipper (
There is a drawback that when the mold parts (infected areas) are of the same color, the contrast is low and it is difficult to determine defects.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fastener inspection method that can determine the difference in surface condition between cloth and worm parts even if they are of the same color when using light illumination.

According to the present invention, the pass/fail condition of the fastener is determined by combining one-dimensional scanning of coherent light and one-dimensional movement of the fastener, and converting reflected light and transmitted light of a portion of the fastener into electrical signals. A fastener inspection method is proposed.

The fastener inspection method according to the present invention will be explained in detail below with reference to the drawings.

The method according to the present invention scans a laser beam with a spot diameter corresponding to the resolution required for inspection at high speed in a direction across the fastener in one dimension, and measures the reflected light (transmission) characteristics at each part of the fastener using a spatial filter and a photoelectric conversion element. This method basically determines the stiffness that can be detected by using the method, and inspects each part of the fastener using a combination of the above-mentioned -dimensional optical scanning and movement of the fastener in the longitudinal direction.

Figure 2 shows the configuration of the optical system.

In Fig. 2, 10 is a conveyor 11 on which fasteners are placed.
is a He Ne laser, 12 is a lens thread, 13 is an optical scanner, 14 is a scanning lens, 15 is a transmitted light condensing lens, 16 is a photoelectric converter, 1γ is a reflected light condensing lens,
18 is a spatial filter, and 19 is a photoelectric conversion element.

In this embodiment, the laser 11 has a wavelength of 632
Eight people used a He-Ne laser with an output of about 2 mW, and the lens thread 12 had a structure of two concave and convex layers, thereby determining the inspection resolution.

Also, as the optical scanner 3, the mirror size is 5II.
Condensing optical system 1.4, 15. using a vibrating mirror type with t11Lφ and a light deflection angle of 12°. s and 16 are Fresnel lenses,
A spherical mirror or the like was used, a signal light detection area selection mask was used as the spatial filter 18, and photodiodes or the like were selected as the photoelectric conversion elements 16 and 19 by a signal light detection method.

As for the parameters of the optical scanning thread, as shown in Fig. 3, if the scanning width is 60 mm, the spot diameter is 200 μmφ, and the optical deflection angle is 12°, the distance l between the scanner 13 and the object is 0 11 knee = 285 mrn tan6'.

Also, the beam diameter d on the fastener is d- λ 440 2, 44-1 = -< 200 μm D becomes.

Therefore, the beam diameter on the scanner is D〉2,21n
1rLφ.

Therefore, a diameter of 5 mm is sufficient for the optical scanner 13.

Also, if the scanning pitch is 100 μm, the scanning frequency f is determined from the inspection speed: 70 mm f = −= 2700 Hz o, 1 mm In other words, the vibration frequency of the optical skinner 13 is 2
．． 8K) fz was used.

In the fastener inspection method configured as shown in FIGS. 2 and 3, it is possible to detect, with a high signal-to-noise ratio, leakage of some elements of the fastener using transmitted light.

FIG. 4 shows the transmitted light for each part of the fastener.

In Fig. 4, AJ and B are the signals obtained by converting the transmitted light into electrical signals when the fastener is scanned in the A and B directions. Figure 4 B' becomes noisy and the signal from the defective part is lost.

Therefore, defects can be easily determined by comparing the signal waveforms of these A and B with the reference signal.

Further, C, D, and E in FIG. 4 are the results obtained by converting the transmitted light into electrical signals when the fastener in FIG. 4 is scanned in the C, D, and E directions, respectively.
When the stopper is missing, the output signal is as shown in E' in the figure.

Therefore, defects can be easily determined by comparing the signal waveforms of C, D, and E with the reference signal.

Furthermore, the detection S/N ratio of painted elements and resin elements is expected to improve by converting the reflected light from the surface of each part of the fastener into electrical signals using the photoelectric conversion element 19 and capturing the reflection intensity and direction of the reflected light as electrical signals. be done.

FIG. 5 shows another embodiment of the system according to the present invention, which differs from the system in FIG. This is because linearly long elements are used as 20, and in this case, by arranging a large number of photoelectric elements in a linear manner, exactly the same effect as in FIG. 2 can be obtained.

In the present invention, the following inspection items for fasteners can be determined using the inspection method described above.

In other words, in determining the above inspection items, (() Transmitted light can be used to measure element shedding, the total length of zippers, etc., and (Cf) Specular reflection components of reflected light can be used to measure top stops, sliders, pulls, elements, bottom stops, etc. It is possible to inspect the tape for fraying, uneven cutting, and uneven weaving using the diffused reflection component of the reflected light, and it is also possible to perform these tests simultaneously, and the use of transmitted light and reflected light is limited to the above. It's not something you can do.

According to the present invention, the depth of focus of the inspection light is relatively deep due to the use of coherent laser light, which makes it possible to suppress signal fluctuations due to positioning errors of fasteners, and to reduce the lifespan of major components (for example, He-Ne laser - 20,000 yen). time,
The advantages of the method according to the present invention are wide-ranging, such as the long optical scanner (10,000 hours, etc.).

[Brief explanation of the drawing]

FIG. 1 is an external view of a fastener to be inspected by the method according to the present invention, FIG. 2 is an embodiment of the method according to the present invention, and FIG. 3 is a detailed view of the optical scanning thread according to the method according to the present invention. FIG. 4 is a waveform diagram of the test output signal in the method according to FIG. 2, and FIG. 5 is another embodiment of the method according to the present invention. In the figure, 11 is a laser, 12 is a lens thread, 13 is an optical scanner, 14 is a scanning lens, 15 is a transmitted light condensing lens, 16, 19 and 20 are photoelectric conversion elements, 1
7 is a reflected light condensing lens, and 18 is a spatial filter.

Claims (1)

[Claims] 1. A fastener inspection method characterized by scanning a fastener with a coherent light beam and converting reflected light or transmitted light from the fastener into an electrical signal to determine the quality of the fastener.