JPH09225939A - Method and device for manufacturing prepreg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sense objectively and accurately such defects as feathering, cracks and foreign matters in compliance with respective defect reference standards by emitting the beam and sensing and judging the defects based on the comparison between signals of irregular reflection beam emitted out of a prepreg and the preset threshold level. SOLUTION: A one-dimensional CCD camera 2 having its field of view 7 in the width direction of a prepreg 1 is set on the position facing the surface of the prepreg 1 moving forward at the given speed and scattering irregular reflection beam from the surface is sensed by the camera in an inspection device for inspecting defects of the prepreg such as feathering, cracks and foreign matters. The threshold level is set preliminarily to a signal output from a scanning signal processing unit 3 to a defect judging unit 6 by a signal processing unit 9. The signal processed into binary on the set threshold level in the signal processing unit 9 is transferred to a judging unit 10 in the direction forming 90 deg. to the traveling direction and another judging unit 11 in the time axis direction, and whether respective defects are or not, the position and the level are judged.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the production of prepregs by a hot melt method or a wet method, for example, immediately after the step of impregnating reinforcing fibers with a resin.
The present invention relates to a prepreg manufacturing method and apparatus capable of detecting a defective portion of the prepreg.

[0002]

2. Description of the Related Art In recent years, many composite materials using reinforcing fibers have been adopted for sports and leisure equipment such as fishing rods and golf shafts. For these moldings, a molding material called a prepreg in which reinforcing fibers are aligned and impregnated with a thermosetting resin is used, and these are laminated in multiple layers and then cured. When producing a sheet-shaped prepreg among these molding materials, usually, the reinforcing fibers are aligned in a sheet shape and sandwiched between resin-supporting sheets, and heated and / or pressed to spread the reinforcing fibers to spread the resin. Impregnated.

However, in the process of producing reinforcing fibers or the process of impregnating the reinforcing fibers with a resin, the reinforcing fibers are rubbed with a roll or the like, and some of the filaments constituting the reinforcing fibers are cut and become fluffy. There is. In addition, broken filaments may be aggregated to form a lump on the surface of the prepreg. Such a defective portion of the reinforcing fiber or a lump of filaments is a defect called “fluff”, and a defect standard is determined by its size, and the defect is determined based on the standard and is corrected or excluded from the product. There is.

Further, in the step of impregnating the reinforcing fibers with the resin, when the reinforcing fiber bundles are not sufficiently spread, a gap is generated in the prepreg, or a part of the aligned reinforcing fibers is cut off, and the prepreg is cut. There may be a gap inside. Such a gap in the prepreg is a defect called “cracking”, and a defect standard is determined by its size, and the defect is judged based on the standard and is corrected or excluded from the product.

Further, in the step of impregnating the reinforcing fibers with the resin or the step of producing the resin-carrying sheet sandwiching the reinforcing fibers, there is a defect called "foreign matter" in which a cured product of the resin or a piece of release paper is mixed in the prepreg. , They need to be excluded based on the defect criteria.

The drawbacks of these prepregs are important factors that affect the physical properties of the above-mentioned molded product. In addition, since the demand for quality improvement of prepreg has increased in recent years,
There is an urgent need to objectively distinguish and reliably detect the above-mentioned fluff defect, cracking defect, and foreign matter defect based on the respective criteria, correct them, or exclude them from the product.

However, conventionally, there has been no method using an inspection device or the like for objectively and easily and surely detecting the defects of these prepregs according to the standards of the respective defects. For this reason, the operator has made a pass / fail judgment by visually inspecting the defects of the prepreg.

[0008]

However, visually inspecting the prepreg for defects is a work that requires a great deal of skill because it is difficult to find the defects due to the following problems.

In the case of the fluff defect, for example, the carbon fiber as the reinforcing fiber is black, and the hues of the defect portion and the formation portion of the prepreg are substantially the same, which makes it very difficult to see.

Regarding the cracking defect, since the release paper is usually present on one surface of the prepreg and the defect portion looks white, it is easy to detect carbon fiber having a large width or length, It is difficult to distinguish the small size from the reflection on the surface of the prepreg.

Regarding the foreign matter defect, in the case of carbon fiber, the cured prepreg and the debris of the release paper are light-colored with respect to the black formation of the prepreg, but those of small size are very small. It is hard to see and difficult to distinguish from the reflection on the surface of the prepreg.

From the above, in the inspection of the prepreg visually by the operator, there is a problem that the inspection speed is limited and the inspection cannot be continuously performed for a long time.

In the defect inspection of the above-mentioned prepreg, the defect criteria differ due to fluff, cracks, and foreign matter.
In the pass / fail judgment by visual inspection, there is a problem that the judgment criteria are slightly different for each worker and are not objective.

Further, the occurrence of the fluff defect and the crack defect can be suppressed by changing the production conditions. However, if the discovery of these defects is delayed during the prepreg production in the step of impregnating the reinforcing fiber with the resin, There is a problem that the product yield is significantly reduced.

The present invention has been made in view of the above points, and an object of the present invention is to manufacture a prepreg capable of objectively and accurately detecting a fluff defect, a crack defect, and a foreign matter defect of the prepreg according to respective defect criteria. A method and apparatus are provided.

[0016]

The present inventors have arrived at the present invention as a result of extensive studies to solve the above problems.
That is, the method for producing a prepreg according to the present invention, the prepreg containing the reinforcing fiber and the matrix resin is irradiated with light, the scattered reflected light from the prepreg is detected by the light receiving means, and the scattered reflected light detected by the light receiving means. The method is characterized by detecting and judging a defect of the prepreg by comparing the signal with a preset threshold level.

The light receiving means is not particularly limited as long as it is provided with a sensor capable of detecting scattered reflected light from the prepreg and emitting a signal corresponding to the level of the detected reflected light. A CCD camera can be used as the one. When a CCD camera is used, for example, the threshold level for fluff defects of the prepreg can be set on the dark signal side, and the threshold levels for cracking defects and foreign matter defects of the prepreg can be set on the bright signal side.

Although it is possible to perform the defect inspection with the prepreg stationary, the inspection of a large area can be performed efficiently in a short time by performing the inspection while the prepreg is running. In this case, it is preferable to detect a defect of the prepreg in the traveling direction of the prepreg and / or the direction substantially orthogonal to the traveling direction. When inspecting the prepreg in a stationary state, the illumination means and the light receiving means may be moved relatively.

The prepreg defect inspection apparatus according to the present invention comprises an illuminating means for irradiating the prepreg containing reinforcing fibers and a matrix resin with light, a light receiving means for detecting scattered reflected light from the prepreg, and the light receiving means. And a signal processing means for detecting and determining the defect of the prepreg by comparing the signal of the scattered reflected light detected by the above with the preset threshold level.

It is preferable that this apparatus has a traveling speed detecting means for the prepreg, and a signal from the traveling speed detecting means is inputted to the signal processing means. With such a configuration, as described above, it becomes possible to continuously and automatically detect the defects of the prepreg in the traveling direction of the prepreg and / or the direction substantially orthogonal to the traveling direction.

By providing the apparatus as described above during the prepreg manufacturing process, for example, immediately after the resin impregnation step,
Continuously manufactured running prepregs can be automatically inspected.

In the present invention, for example, for a fluff defect having the same hue as that of the prepreg, a threshold level is set in the dark signal, and the threshold level is set to 9 in the running direction of the prepreg.
At least one kind of judgment is made among the input changes in the 0 ° direction and the time axis direction (prepreg running direction), and the defect is detected. For foreign matter defects and cracking defects whose hue is brighter than that of the prepreg, the threshold level is set in the bright signal, and at least one of the input changes in the 90 ° direction and the time axis direction with respect to the running direction of the prepreg is judged. Is done and defects are detected. And fluff defects, foreign matter defects,
Since the cracking defect is detected based on different defect criteria, the set value for judging the 90 ° direction with respect to the traveling direction of the prepreg and the set value for judging the time axis direction of each threshold level are The above-mentioned problems can be solved by setting each of them individually. Further, since the defect is detected and judged by the signal processing based on the optical detection, it is possible to perform an objective, accurate and accurate inspection as compared with the conventional visual inspection.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a prepreg defect inspection apparatus according to an embodiment of the present invention. Fuzz defects of the prepreg of this example,
The inspection device for cracking defects and foreign matter has a one-dimensional CCD camera 2 having a field of view 7 in the width direction of the prepreg 1 at a position facing the surface of the prepreg 1 which advances to the right in the figure at a predetermined speed.
Is installed to detect scattered reflected light from the prepreg surface. Here, it is preferable that the one-dimensional CCD camera 2 is installed at an angle of 3 to 15 ° with respect to a vertical line from the prepreg surface, and a more preferable range is 5 to 11 °. If the signal is installed at an angle outside the above range, the signal-to-noise ratio of the defective portion cannot be sufficiently obtained, which makes detection difficult. A high-frequency fluorescent lamp, for example, is used as the light source 8 as an illuminating means for irradiating light toward the prepreg, but other than this, a laser light source and other generally commercially available ones can be used and are not particularly limited. Not something.
A pulse generator 5 that emits a pulse corresponding to the traveling speed of the traveling prepreg 1 is installed, and a periodic signal can be output to the timing controller 4. The scanning signal processing unit 3 is connected to the CCD camera 2, and the prepreg 1 is sent from the CCD camera 2 at a predetermined cycle by a periodic signal from the timing controller 4.
Scanning signal from the surface of the vehicle, that is, 90 with respect to the traveling direction
Outputs the change in input in the ° direction.

Further, a signal is output from the scanning signal processing unit 3 to the defect judgment unit 6, and a threshold level is set in advance for the signal by the signal processing unit 9. The threshold level signal may be a signal that is differentiated with respect to the running direction of the prepreg by 90 °, that is, the scanning direction of the one-dimensional CCD camera, or a signal obtained by subtracting the signal with respect to the time axis direction. preferable. Here, as the signal for setting the threshold level, either one of the above signals may be used for all the defects, or either signal may be selected and used depending on the type of the defect. In the signal processing unit 9, the signal binarized by the set threshold level is sent to the determination unit 10 in the 90 ° direction and the determination unit 11 in the time axis direction with respect to the traveling direction, and Presence / absence and its position and level are determined.

FIG. 2 shows an output signal from the video controller 3 (scanning signal processing unit 3) when there is a fluff defect, a cracking defect, or a foreign matter defect in one scanning line of the one-dimensional CCD camera 2. The fluff defect is a dark signal, a crack defect, and a foreign substance is a bright signal. Since defects are detected individually, it is possible to detect each defect by setting threshold levels on the dark and bright sides of these signals. The threshold level is preferably set for at least two types of defects.

FIG. 3 is a block diagram for explaining the defect detection logic of the defect determination unit 6 which constitutes the prepreg inspection device of FIG. Threshold level 21 (P1,
With respect to P2 and P3), the fluff defect is set on the dark signal side, and the foreign matter defect is set on the bright signal side.

The signal exceeding the threshold level 21 is the input change 22 (X1, X) in the direction of 90 ° with respect to the running direction of the prepreg for each of the fluff defect, the crack defect, and the foreign matter defect.
2, X3) and the input change 23 (Y1, Y2,
It is determined by Y3). The determination is preferably performed using at least one of the input change 22 in the 90 ° direction with respect to the traveling direction of the prepreg and the input change 23 in the time axis direction. Further, since it is necessary to detect the fluff defect, the crack defect, and the foreign matter defect according to different defect standards, it is preferable that the threshold level can be set and the above determination can be performed individually. In the present embodiment, the fluff defect is judged in parallel based on either the input change in the 90 ° direction or the time axis change, because the defect criterion of the fluff defect is based on the major axis evaluation. Foreign matter defects and cracking defects can be determined in series because defects are detected by determining both width and length. For the foreign matter defect, the area determination may be performed instead of the width / length determination.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments.

[0029]

As is clear from the above description, according to the prepreg manufacturing method and apparatus of the present invention, when the prepreg is produced, the drawbacks of each of the prepregs, such as the step of impregnating the reinforcing fiber with the resin, are caused. Part easily and reliably,
It can be detected automatically by objective judgment based on each defect criterion, and it is possible to deal with the defect substantially immediately at the same time as the defect occurrence, so that the product yield is remarkably improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a prepreg defect inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a characteristic diagram of an output signal from a scanning signal processing unit when a scan line of a one-dimensional CCD camera has a fluff defect, a crack defect, or a foreign matter defect.

FIG. 3 is a block diagram for explaining detection logic in the detection device of FIG.

[Explanation of symbols]

 1 prepreg 2 CCD camera 3 scanning signal processing unit 4 timing controller 5 pulse generator 6 defect determination unit 7 field of view 8 light source 9 signal processing unit 10 90 ° direction determination unit 11 time axis direction determination unit 21 threshold level 22 input in 90 ° direction Change 23 Change in input along the time axis

Claims (8)

[Claims] 1. A prepreg containing reinforcing fibers and a matrix resin is irradiated with light, scattered reflected light from the prepreg is detected by a light receiving means, and a signal of the scattered reflected light detected by the light receiving means and a preset threshold are set. A method of manufacturing a prepreg, which comprises detecting and determining a defect of the prepreg by comparing with a level. 2. The method for producing a prepreg according to claim 1, wherein the threshold level for the fluff defects of the prepreg is set on the dark signal side, and the threshold levels for the prepreg cracking defects and foreign matter defects are set on the bright signal side. 3. The method for producing a prepreg according to claim 1, wherein the defect is detected while the prepreg is running. 4. The method of manufacturing a prepreg according to claim 3, wherein defects in the prepreg are detected in a running direction of the prepreg and / or a direction substantially orthogonal to the running direction. 5. An illuminating means for irradiating a prepreg containing reinforcing fibers and a matrix resin with light, a light receiving means for detecting scattered reflected light from the prepreg, and a signal of the scattered reflected light detected by the light receiving means in advance. A prepreg defect inspection device, comprising: signal processing means for detecting and determining a defect of the prepreg by comparing with a set threshold level. 6. The defect inspection device for a prepreg according to claim 5, wherein the light receiving means is a CCD camera. 7. A prepreg running speed detecting means is provided,
7. The prepreg defect inspection apparatus according to claim 5, wherein a signal from the traveling speed detection means is input to the signal processing means. 8. A prepreg manufacturing apparatus, comprising the prepreg defect inspection apparatus according to any one of claims 5 to 7.