JPS6379061A - Apparatus for detecting adhesion-inferior laminated plate - Google Patents

Abstract

PURPOSE:To exclude an adhesion-inferior product, by applying bending load to the laminated plate on the way of feed and detecting an adhesion-inferior place by an ultrasonic inspection apparatus. CONSTITUTION:This adhesion-inferior product detection apparatus is constituted a feed apparats 1, a bending apparatus 3 and an ultrasonic inspection apparatus 4. A laminated plate 2 is fed by the feed pinch rollers 5 of the feed apparatus 1 and bent by a press roller 6 in the bending apparatus 3. The apparatus 3 is constituted so that a spacer 9 having a proper thickness is interposed between a load cell 10 and a pillow block 8, and bending load is applied to the laminated plate 2 from below and measured by the cell 10. In this case, the spacer 9 having a proper thickness capable of applying proper bending load is selected on the basis of the measured value. Next, the laminated plate 2 wherein an adhesion-inferior place is actualized is fed to the apparatus 4 by the apparatus 3. The apparatus 4 has transmitting and receiving parts and the ultrasonic pulse emitted from a transmitter 11 transmits through the laminated plate 2 to be received by a receiver 12 and the propagation time of said pulse is detected by a level discrimination circuit and the laminated plate imparting the propation time equal to or more than a set value is detected as an adhesion-inferior product.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a device for detecting poor adhesion of laminated plates.

In this light 1m, the term "latent" refers to adhesion defects that exist in a state where the adhesion defects cannot be detected unless inspected with an ultrasonic inspection device, regardless of whether there are any adhesion defects, and "overt." ” means that even if the defective adhesion part is not obvious from the outside, it can be detected by inspection using an ultrasonic inspection device.

Conventional technology and its problems Plywood, which is used in large quantities for construction and furniture, has
There is a problem of poor adhesion between laminated veneers, which is unavoidable in manufacturing. Conventionally, to detect defective adhesive products, generally,
! An appropriate number of plywood pieces were selected from a large number of lj-built plywood sheets and subjected to strength tests.

In this sampling test method, if any defective adhesion is found in the plywood samples tested, 10 of them are considered to have failed, and if no defective adhesion is found, the 10 are considered to be acceptable. Since the handling test is conducted even for lots that are judged to have passed, there is a problem in that there may be defective adhesives among the large number of remaining plywood boards that were not sampled and tested even for lots that were judged to be passed. According to test results, poor adhesion was found in plywood that was considered to be a good product after use, causing various problems. The reason lies in the following fact.

That is, during the manufacture of plywood, there are some places where adhesion defects are already present to the extent that air spaces are created between the laminated veneers, but these are discovered in the above tests and their number is small. However, at the stage of obtaining flooring and wall materials from plywood by applying heat pressure, chemical coating, cutting, drying, etc. to plywood after manufacturing, the adhesive strength is weak and air spaces are not formed during plywood manufacturing. As a result of the above-mentioned processing, potential adhesion defects that were not detected due to the process described above may be discovered as the plywood surface lifts or delamination occurs, causing adhesion defects to become apparent, or even after being used as flooring or wall materials. After a few months, potential adhesion failure points become apparent and discovered due to the influence of the weather, the absorption of moisture from the concrete, and the addition of loads from furniture and foot traffic in the case of flooring materials. be. In this way, even poor adhesion is a latent condition ff3 during plywood manufacturing, and most of the problems become apparent due to external shadows VW after plywood manufacturing. In addition to the above-mentioned sampling test method, there is also a proposal to use ultrasonic waves to detect defective bonding of plywood (Japanese Patent Publication No. 45
-18635, JP 49-5186 Oyohi JP On 5
1-19105), these are all tests to see if there is an air layer caused by poor adhesion in the plywood after WA construction, so such intrinsic adhesion defects can be detected. , it was impossible to detect potential adhesion defects.

It is an object of the present invention to provide an apparatus which can detect the presence of adhesion failures, whether intrinsic or latent, immediately after the laminate has been manufactured.

Means for Solving the Problems In order to achieve the above object, the device for detecting defective adhesion of laminated plates according to the present invention applies a bending load to the conveying device and the laminated plates in the process of being conveyed to detect potential defective adhesion points. This system consists of a bending device that makes the bonding defects obvious, and an ultrasonic inspection device that detects the bonding defects that have become obvious and the bonding defects that originally existed.

Specific examples of the laminate to which the detection device according to the present invention can be used are mainly plywood, but there are also m-fibers in some veneers of the so-called LVLlLVL structure in which the veneers are laminated with their fiber directions parallel to each other. Examples include those in which the direction is perpendicular to other materials, those in which bare roots and plywood are glued together, and those in which medium-density fiberboard and plywood are glued together.

Embodiments Examples of the present invention will be described below with reference to the drawings. Note that "front and rear" refers to the forward moving side as the front, and the opposite side as the rear, with the transport direction of the laminate as a reference.

The illustrated device for detecting defective adhesion of laminated plates is a conveyor device (1).
and a bending device (m) that applies a bending load to the laminate (2), which is plywood, while it is being transported to expose potential adhesion defects.
(3), and an ultrasonic inspection device (4) for detecting areas with apparent adhesion failure and areas with inherent adhesion failure.

The conveying device (1) consists of several sets of driven pinch rollers (5) arranged at predetermined intervals in the front-rear direction. The bending device (3) comprises an upward pressure roller (6) arranged approximately in the middle of the length of the conveying device (1) between each lower roller of adjacent pinch rollers (5), and a roller @( 7)
A pillow block (8) receiving both ends of the pillow block (8), and a stand (1) for arranging a spacer (9) and a spacer (9) which are replaceably arranged under the pillow block (8).
3) and a load cell (10) on a pedestal (14) installed via a mount (14). The ultrasonic inspection device (4) transmits an FB sonic pulse through the laminate (2) and uses the fact that the propagation time of the sound wave changes depending on the internal state of the laminate (2) to detect the presence or absence of defective adhesion. The transmitter (11) and receiver (12) that make up this are placed one above the other, and the laminated plate (2) passes between them without contact. being done. The ultrasonic inspection device (4) has a transmitting/receiving section (not shown), and the transmitting section consists of a generating circuit that generates a transmitting pulse and a timing circuit that generates a control pulse. The power is amplified and emitted as an ultrasonic pulse from a transmitter (11). The receiving section transmits the ultrasonic pulses that have passed through the laminated plate (2) to the receiver (1).
The signal received in step 2) is passed through an RF amplifier circuit, a detection amplifier circuit, and a level discrimination circuit to detect the propagation time, and convert the propagation time into an analog voltage output. Then, a signal exceeding the set value of the propagation time is extracted as an output signal. A pair of a transmitter (11) and a receiver (12) is
They are arranged at predetermined intervals in the width direction of the laminate (2). Of course, the inspection accuracy improves as the number of pairs increases. When the laminate (2) is a plywood with a width of 30Qmm, the above-mentioned interval may be 80 to 100mm. The measurement cycle is for laminated plates (2)
It is determined based on the transport speed and required measurement accuracy.

For example, if the conveyance speed is 5Qm/min and the inspection range is a circle with a diameter of 5Qmm, the measurement period is 6Qm5ec.
If so, it is possible to continuously inspect the laminate (2) as it is transported. If the measurement period is set to 30 m5ec, the inspection accuracy will be improved because the inspection will be carried out sequentially overlapping each other in half.

In the bending device (3), when the spacer (9) is removed, the upper end of the pressure roller (6) is at the same level as the upper end of the lower roller of the pinch roller (5).

By interposing a spacer (9) of an appropriate thickness between the load cell (10) and the pillow block (8), a bending load is applied to the laminate (2) from below. The load is measured by the load rail (10), and a spacer (9) with an appropriate thickness is selected based on the measured value so that an appropriate bending load can be applied. The appropriate amount of bending load is determined based on the material, thickness, width, etc. of the laminate, but adding a bending force increases the physical strength such as the bending strength of the laminate itself. Therefore, the stress generated in the laminate due to the bending load should be kept below the bending proportional limit stress. For example, the height is 12mm and the width is 30Qmm.
For 5-ply plywood, the bending stress is 150-250 k
q/cI112 is suitable.

In this example, the bending device (3) is equipped with a load cell (10
) is incorporated, but this may be omitted, and although the bending device (3) is arranged on the underside of the laminate (2), it could alternatively be arranged on the upper side. Additionally, bending load adjustment can be accomplished by hydraulic cylinders, pinion and rack mechanisms with handles, and the like.

In this embodiment, the ultrasonic inspection device (4) is placed in front of the conveyance device δ (1) for convenience of maintenance, but it may also be placed just before or after the bending device (3). . This is preferable in that a state in which potential adhesion failure becomes apparent is ensured. In the same sense, the bending device (
It is preferable to arrange one more bending device outside of 3). In this case, the magnitude of the latter bending load may be much smaller than the former.

The conveyance device is not limited to one consisting of a group of pinch rollers, but may also be a conveyor in a belt, a chain φ conveyor, etc.
It is necessary to be able to apply a bending load to the 4174 board being conveyed and to hold down the laminate to prevent it from floating off the conveyor.

Experimental example Ultrasonic frequency: 40KHz, detection hole diameter of transmitter and receiver: 5Qmm, distance between them = 601, measurement cycle:
Experiments were conducted using an ultrasonic inspection device with an output of 20 to 60 m5ec (variable).

Thickness 12mm, width 31011111. length 1820vn
Prepare 10 pieces of normal plywood and 10 sheets of plywood with intrinsically poor adhesion of the same size that is clearly peeling due to poor adhesion.
When 75 locations per sheet were inspected, the results shown in Table 1 were obtained.

Based on the facts above in Table 1, in the case of plywood with a thickness of 12 mm, the propagation time is less than 1.20 m5ec;
．． It was determined that a box with a propagation time of 20 m5ec or more was an abnormal box, and a box with a propagation time longer than this was judged to be a poorly bonded plywood.

Now, using lauan veneer, the 1st layer and 5th layer are each 1.51
．． The 3rd and 4th layers are each 3.0IIIIIIl, 2 layers only, 3.0IIIIl 112.6IllIIl and 3
．． Three veneers of 01 were made into a layer with uneven thickness, and each layer was integrated by heat and pressure using a known plywood adhesive.
Six sheets of 5-brie plywood were obtained, each having a thickness of 12 mm, a width of 310 mm, a length of 18201611, and having an uneven thickness at the same point n.

No bending load was applied to one of the six sheets (sample No. 1).
), and sample No. 1 to which a predetermined bending load should be applied to the remaining five sheets.
2-6). Also, instead of using a veneer with uneven thickness for the second rib, apply plywood adhesive at 120o/+ to the second layer of veneer.
After applying 2, apply 200 mm x 200
A 1 am absorbent paper was placed on it to absorb some of the adhesive.

From calculations of the weight of the absorbent paper, etc., it was found that the remaining adhesive was 40 g/m2. The amount of adhesive applied to the other veneers was all 120 CI/IR2, and two plywood sheets of the same size as the above plywood were obtained. No bending load is applied to one of the two sheets (
Sample No. 7>, and a bending load was applied to the remaining one (sample No. 8).

The results of testing these using an ultrasonic testing device are shown in Table 2.

Table 2 (Note) O... Sufficient, Δ... Slightly insufficient, ×...
insufficient.

In FIGS. 2 to 7, * indicates a normal value, and X indicates an abnormal value.

As is clear from Table 2, the plywood (No. 1 and No. 2) for which the device of this invention was not used all showed normal values, and potential adhesion defects remained as they were and could not be detected at all during the inspection. . On the contrary, plywood (N) using the device of the invention.

, 2 to No. 6) showed abnormal values. As a result of cutting the part that showed the abnormal value and examining the inside, it was found that the part where the abnormal value was concentrated in two or more places was a clear adhesion failure part. Therefore, the plywood of No. 014 to No. 5 was exposed to potential adhesion failure due to the application of an appropriate bending load, and the plywood of No. 12 and No.
In case No. 3, the bending load was not sufficient, so it can be said that the latent adhesion failure was not manifested to a satisfactory extent.

When using the device of the present invention, it is possible to detect not only the actual adhesion failure points mentioned above but also internal adhesion points, as well as those with large gaps between the core materials and the joints between the core materials. Items with cracks, cracks, etc. on the board,
It is also possible to detect cases where the cutting surface is too rough.

The device of the present invention is not limited to detecting adhesion defects immediately after plywood is manufactured, but can also be used to process plywood into flooring materials, wall materials, etc., before shipping.

Effects of the Invention According to the device for detecting defective adhesion of laminated plates of the present invention, there is provided a conveyance device, a bending device that applies a bending load to the laminated plates during conveyance to reveal latent adhesion defects, and a method for detecting adhesive defects that have become apparent. Since it consists of an ultrasonic inspection device that detects defective areas and areas with inherent adhesion defects, it is possible to detect any adhesion defects, whether intrinsic or latent, immediately after the laminate is manufactured. This makes it possible to eliminate products with poor adhesion.

Therefore, there is no fear that latent adhesion defects will become apparent and cause trouble during the manufacture of the flooring and wall materials, or even after the flooring and wall materials are installed.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIGS. 2 to 6 are plane views of plywood, respectively, showing the results of inspection after exposing potential adhesion defects using the apparatus of the present invention. 7 are plan views of plywood showing a state in which latent adhesion defects remained and were not detected during inspection because the apparatus of the present invention was not used. (1)... Conveyance device, (2)... Laminate plate, (3)...
...Bending device, (4)...Ultrasonic inspection device. that's all

Claims (1)

[Claims] A conveying device (1), a bending device (3) that applies a bending load to the laminate (2) during transportation to expose potential adhesion defects, and a bending device (3) that A laminate board adhesion defect detection device consisting of an ultrasonic inspection device (4) for detecting locations.