JPH046899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is aimed at removing colored stains present on the linear bodies, and even removing the linear particles during the process of continuously running a plurality of linear bodies such as artificial fibers in the manufacturing process of artificial fibers. The present invention relates to a defect detection method for a plurality of linear bodies for detecting defects such as uneven body thickness.

In recent years, the manufacturing technology of artificial fibers has greatly improved, and as a result, their quality has improved significantly, and as a result, they have come to be used for medical purposes such as artificial kidneys, such as Bemberg hollow fibers.

The Bemberg thread used for this artificial kidney is
Since it is used for medical purposes, it is naturally required to be of higher quality than those used for ordinary clothing, and not only does it have uneven thickness, but also in the manufacturing process of Bemberg yarn. Colored stains called blue stains due to the residual copper sulfate used are also a problem that must be avoided at all costs. The presence of blue stains on Bemberg yarns used for clothing also causes uneven dyeing, which is undesirable.

However, the conventional method for detecting defects in threads is generally performed offline by visual inspection by a worker, but this method has the disadvantage that there are differences depending on the worker, and it is difficult to grasp quantitatively. . In the online case, a method has been put into practical use in which electrodes are installed at positions that sandwich the running yarn, and changes in capacitance between these two electrodes are converted into electrical signals to measure yarn thickness unevenness. The above-mentioned colored dirt cannot be detected with this method, and if you try to carry out this method when multiple threads are running in parallel, the threads in parallel may become entangled, so the spacing between the electrodes must be widened. This has disadvantages in that accuracy is poor, and unfavorable manufacturing conditions such as changing the thread path have to be set because the thread spacing must be widened to attach the electrodes.

The present inventors have conducted various studies to develop a new defect detection method that eliminates the drawbacks of the conventional yarn defect detection method, which is performed by running multiple yarns in parallel. At the same time, by selecting the wavelength, we use a laser beam that is easy to obtain light that is easily absorbed by areas where colored dirt exists, and the property of transmitting the laser beam (hereinafter referred to as laser beam transmittance) is used. This laser beam is irradiated on a linear body such as a thread having a thread (as described above) that is continuously traveling in parallel, and the size of the laser beam to be irradiated is within a predetermined range greater than or equal to the thickness of the linear body. The diameter of By distinguishing the changes in the amount of light up to the end of each linear object and continuously determining them using a fast-responsive light-receiving element such as a photomultiplier tube, converting the changes in the amount of light into electrical signals and calculating them, each linear object can be detected with good response. The present invention was completed by discovering that defects could be detected for each object.

That is, the present invention provides a plurality of linear bodies that are transparent to laser beams and are continuously running in parallel at intervals, and from one side of the running road surface, a beam of at least the thickness of the linear bodies and not more than 5 times the thickness of the linear bodies is provided. A laser beam with a diameter of Reflection of the amount of light from before the beam crosses each linear body to after the beam crosses the linear body by providing parallel areas on the other side of the running road surface that do not reflect the laser beam, corresponding to each interval between the linear bodies. This invention provides a method for detecting defects in a plurality of linear objects, which is characterized in that defects are detected for each linear object based on changes in light intensity by sequentially reflecting the light onto a mirror and measuring it continuously with a light-receiving element. .

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for detecting defects in a plurality of linear bodies according to the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows one of the apparatuses for carrying out the method of the present invention.
An explanatory diagram showing an example, FIG. 2 is a diagram showing the relationship between the electric signal obtained by the method of the present invention and various properties of the linear body, and FIG. 3 is a diagram showing the relationship between the linear body and a moving laser beam. Figure 4 shows changes in the amount of light received in each positional relationship in Figure 3 when the laser beam is irradiated while moving, and the amount of light received in the area of the reflecting mirror that does not reflect the laser beam. FIG. 5, which is a diagram showing the changes, is a diagram showing the structure of the reflecting mirror.

In the drawing, 1 is a laser transmitting tube that transmits through a plurality of linear bodies Y whose defects are to be detected.
A laser beam B having a wavelength that is absorbed by colored stains generated on the surface is projected. This laser transmitting tube 1 emits a red laser beam B of a He-Ne laser whose amount of transmitted light is significantly reduced due to blue contamination when the linear body Y is a hollow or solid Bemberg thread. is preferred. Reference numeral 2 denotes a lens system, which functions to condense the laser beam B projected from the laser tube 1 and convert it into a light beam having a diameter of 1 to 5 times the thickness of the linear body Y. This lens system 2
The purpose of using is that when the linear body Y is irradiated with the laser beam B, the amount of light received changes as shown in Fig. 4 as the state changes from A to D in Fig. 3. When a laser beam B with a diameter less than one time the thickness is irradiated onto a linear body Y, when the laser beam B is exactly aligned with the center of the linear body Y, the linear body Y
The amount of light transmitted through the wire becomes very small, and the amount of light received in the vicinity becomes constant, making it difficult to determine whether the linear object Y is defective. This is because when the beam B is irradiated onto the linear body Y, most of the laser beam B becomes light that does not pass through the linear body Y and reaches the light receiving element directly, making it difficult to judge whether the linear body Y is defective. . 3 is a vibrating mirror, and a plurality of linear bodies Y are continuously traveling along the laser beam B that has passed through the lens system 2.
This is for moving the vehicle in a direction having a movement component perpendicular to the traveling direction of the vehicle. This mirror 3 has a structure that can be swung at high speed by vibration, and can irradiate the laser beam B while moving it in the above direction. When such a mirror 3 is used, the above-mentioned irradiation can be performed with one laser beam B projected from one laser transmitting tube 1. 4 is a reflecting mirror, and mirror 3
The laser beam B, which has been sequentially transmitted through the side surfaces of each of the plurality of linear bodies Y and the linear body Y while being moved in the irradiation direction by the linear body Y, is reflected in the direction of the light receiving element. This reflecting mirror 4 has a structure shown in FIG. 5 so that defects can be detected for each of the plurality of linear bodies Y running in parallel. That is, in order to determine which linear object Y in parallel is being detected, the laser beam B irradiated to a certain linear object Y is reflected and reaches the light receiving element 6, and then the next one is detected. The laser beam B irradiated onto the linear body Y adjacent to is reflected and reaches the light receiving element 6, until the reflected light of the laser beam B reaches the light receiving element 6.
Make sure to clearly distinguish between the two. In order to do this, areas 4a that do not reflect the laser beam B are provided in the mirror 4 in parallel corresponding to the respective intervals of the plurality of linear bodies Y. As a result, the linear body Y
In addition to measuring the number of linear bodies Y, defects can be detected for each linear body Y, and the amount of dark current and external light can also be measured. Reference numeral 5 denotes a condensing lens, which condenses the laser beam B irradiated onto the linear body Y and reflected by the reflection mirror 4 onto the light receiving element 6 . This light receiving element 6
As such, a photomultiplier tube that can detect changes in the amount of light with a quick response is preferable because it can efficiently detect defects in a large number of linear bodies Y. 7 is a differentiator that differentiates the electrical signal corresponding to the amount of light received by the light receiving element 6 with respect to time; and 8 is a differentiator that compares the differential value differentiated with respect to time by the differentiator 7 with a preset value and sets the value. This is a comparator that sends a defect signal to the defect signal processor 9 when it is larger than the value. 10 compares the electric signal corresponding to the amount of light received by the light receiving element 6 with a preset setting value as shown in FIG. It is a comparator that sends to the counter 11 for counting,
The electrical signal from this counter 11 is also sent to the defect signal processor 9. The defect signal processor 9 feeds back the signal to the manufacturing process of the linear body Y in which the defect was detected and sends the signal to equipment (not shown) that adjusts the manufacturing process so that the defect does not occur.

As shown in FIG.
A red laser beam B with a wavelength of 0.63 μm is irradiated from a He-Ne laser tube 1 with a diameter of about 0.8 mm to a plurality of linear bodies Y made of Bemberg hollow fibers with a diameter of 0.8 mm. The light is focused by the condenser lens 5, received by the photomultiplier tube 6, converted into an electrical signal corresponding to the amount of received light, and the electrical signal is differentiated with respect to time by the differentiator 7. As a result, as shown in Fig. 2, it is normal. There are defective yarns, usually called slub yarns, in which there is a lump-like part with a diameter that is about 1.2 times the diameter of the yarn, and defective yarns, usually called loop yarns, in which the yarns are intertwined two to three times or more. Since the waveform of each differential signal of the defective yarn, which is usually called blue stain, in which there is a blue colored part due to the residual copper sulfate, which is a peculiar defect of Bemberg yarn, is significantly large, the preset value and the comparator 8 are By comparing the results, it is possible to detect each filament as a defective filament. In addition, the present inventors used a device having the same configuration as the above-mentioned device to conduct a He-Ne wire with a diameter of about 0.3 mm against a plurality of linear bodies Y made of Bemberg threads with an outer diameter of about 0.08 mm running at 120 m/min. A red laser beam with a wavelength of 0.63 μm is irradiated from the laser transmitting tube 1, and the irradiated light is focused by the condenser lens 5 and sent to the photomultiplier tube 6.
As a result of receiving light and converting it into an electrical signal corresponding to the amount of received light, and differentiating the electrical signal with respect to time using a differentiator 7, each differential signal is obtained for the yarn with a bump-like defect, which is usually called a ball, and for the blue-stained yarn. The waveform of the yarn was significantly larger than that of the normal yarn, and a simple comparator 8 could detect each linear body Y as a defective yarn.

Furthermore, the present inventors have discovered that linear bodies Y other than Bemberg threads
As an example, the outer diameter is approximately 0.08 mm when traveling at 130 m/min.
Approximately 0.3 mm in diameter for multiple linear bodies Y made of 50 denier 24 filament polyester thread.
The wavelength is 0.63μm from the He-Ne laser transmitter tube 1.
The irradiated light is focused by a condenser lens 5, received by a photomultiplier tube 6, and converted into an electrical signal corresponding to the amount of received light.The electrical signal is converted to a time signal by a differentiator 7. As a result of the differentiation, the waveform of the differentiated signal of defective threads with fuzz was larger than that of normal threads, and it was possible to detect each linear body Y as a defective thread using a simple comparator 8.

As described in detail above, the method for detecting defects in a plurality of linear bodies according to the present invention is to detect defects in a plurality of linear bodies, such as threads, which are transparent to a laser beam, such as threads, which continuously run in parallel at intervals. The thickness is equal to or greater than the body thickness, and the thickness is 5
A laser beam with a diameter less than double the diameter is irradiated by a mirror that swings at high speed while moving in a direction having a movement component perpendicular to the running direction of the linear object, and the laser beam is The amount of light that crosses the body from before to after is reflected by a special reflecting mirror, and is continuously measured for each linear object using a light-receiving element such as a photomultiplier tube. Defects in the linear object are detected by changes in the amount of light. With this configuration, defects can be detected simultaneously while a plurality of linear bodies are running, and defects can be detected for each linear body. By selecting the wavelength range of the laser beam that irradiates the linear object, it is possible to effectively detect not only the outer shape of the linear object but also colored stains, and also to detect defects in the linear object. Since the linear objects can be left running continuously in a predetermined direction, defects in the linear objects can be detected immediately and efficiently in various manufacturing processes where multiple linear objects are running. , its industrial value is extremely large.

[Brief explanation of drawings]

FIG. 1 shows one of the apparatuses for carrying out the method of the present invention.
An explanatory diagram showing an example, FIG. 2 is a diagram showing the relationship between the electric signal obtained by the method of the present invention and various properties of the linear body, and FIG. 3 is a diagram showing the relationship between the linear body and a moving laser beam. Figure 4 shows changes in the amount of light received in each positional relationship in Figure 3 when the laser beam is irradiated while moving, and the amount of light received in the area of the reflecting mirror that does not reflect the laser beam. FIG. 5, which is a diagram showing the changes, is a diagram showing the structure of the reflecting mirror. In the drawings, 1... Laser transmitting tube, 2... Lens system, 3... Mirror, 4... Reflecting mirror, 4a...
Non-reflective area, 5...Condensing lens.

Claims (1)

[Scope of Claims] 1. A plurality of linear bodies that are transparent to laser beams and are continuously running in parallel at intervals, and from one side of the running road surface, a beam of at least the thickness of the linear bodies and 50% of the thickness of the linear bodies is A laser beam with a diameter less than double that is reflected by a mirror that swings at high speed due to vibration, and is irradiated while moving in a direction having a movement component perpendicular to the running direction of the linear body, The amount of light from before to after the laser beam crosses the linear body for each linear body is determined by providing areas in parallel on the other side of the running road surface that do not reflect the laser beam corresponding to each interval between the linear bodies. 1. A method for detecting defects in a plurality of linear bodies, characterized in that defects are detected for each linear body based on changes in the amount of light reflected by a reflecting mirror sequentially reflected by a light receiving element, and defects are detected for each linear body based on changes in the amount of light. 2. The linear body is a Bemberg thread, and the laser beam is a He-Ne laser beam with a wavelength of 0.63 μm, the amount of transmitted light being significantly reduced by blue stains generated on the Bemberg thread. A method for detecting defects in multiple linear bodies. 3. A method for detecting defects in a plurality of linear objects according to claim 1 or 2, wherein the amount of light continuously measured by a light receiving element is differentiated with respect to time and the differential value is detected as a change in the amount of light.