JPS59196452A - Method of detecting bonding defective part in plaster board - Google Patents

Abstract

PURPOSE:To nondestructively detect bonding defective part in plaster boards running through a plaster board manufacturing machine by a method wherein temperature distribution on the plaster board surface is measured. CONSTITUTION:The surface temperature of a running plaster board 2 is measured using an infrared radiation thermometer 1 mounted above the shaping line in a manufacturing machine for the plaster board 2. The infrared radiation thermometer has a measurable temperature range of 10 deg.C-50 deg.C with accuracy of about 0.1 deg.C, and it may be arranged to transversely run perpendicular to the direction of running of the plaster board or may be previously fixed over the width of the plaster board 2. The board surface has a tendency to exhibit such widthwise temperature profile in the normal state that the temperature is high at the center and gradually lowered toward both side ends. If the central part includes bonding defect, a temperture distribution characteristic that the temperature is the same or relatively low at the center and raised up and then again lowered toward both side ends is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for non-destructively detecting defective adhesion of gypsum board running in a gypsum board facing machine. The adhesion between the two ends deteriorates, and both ends peel off.
Particularly in recent years, this problem has become conspicuous when the use of hard cores has been promoted for the sake of cost reduction, or when poor raw material conditions have forced the use of low-quality stone raw materials.

In addition, many of the recent adhesion failures are characterized by the fact that, although the gypsum ports adhere well immediately after coming out of the dryer, they peel off due to moisture absorption over time.
Adhesion tests are conducted after being submerged in water once every hour.

However, this method requires about two hours after the plasterboard is formed before the judgment results are available, so if poor adhesion occurs,
100 times in the history of O, which resulted in a huge amount of product loss.
Since the inspection is performed at a rate of 1 sheet per 0 to 2000 sheets,
Due to the above circumstances, there has been a strong desire to establish a method for testing the degree of adhesion of gypsum board online, in as short a time as possible, without omissions. Based on the results of microscopic inspection of defective boards, we observed that small pores were continuously arranged on the core surface of the defective area, and in the case of severely defective gypsum boards, we recognized the fact that the base paper swelled from the core due to moisture absorption, and FCO agreed. From the results, it is found that the board with poor adhesion has an inhomogeneous part (sparse shape M) of the core structure near the boundary layer due to some reason. He completed the present invention by discovering that during the hydration state and the heat dissipation from the board surface to the outside air, a difference occurs in the temperature of the board surface between relatively dense and relatively sparse areas of the core composite fibers. In other words, the present invention measures the temperature of the surface of a running gypsum board using an infrared radiation thermometer installed on the forming line of a gypsum board manufacturing machine, and detects poor adhesion based on changes in the temperature distribution obtained. ◎ The present invention will be explained in detail below along with examples.
It is sufficient to have an accuracy of about 0.1°C, and the suitable installation location is near the end of the gypsum hoard molding conveyor, just in front of the target cutting machine.

When measuring the temperature, the infrared rays input to the detector include radiant infrared rays from the object to be measured, infrared rays from the environment, infrared rays from inclusions, and infrared rays from the background.

Of these, the temperature of the surface of the gypsum board includes slight fluctuations in the infrared radiation radiated from the object to be measured even in areas with good adhesion, but other infrared rays can be stabilized by providing a measuring field MK hood or the like. However, even in the case of radiated infrared rays from the object to be measured, minute fluctuations in the surface temperature of the gypsum board will appear in the same way even if the detector passes through a defective part, so there is no practical problem in use. It is also possible to run the gypsum board perpendicular to the width direction with respect to the traveling direction of the gypsum board as shown in Fig. You can leave it in place.

Next, the temperature distribution on the surface in the width direction of the board shows that under standard conditions, the temperature is high in the center, and the temperature gradually decreases as it approaches both ends.On the contrary, if there is an adhesive failure in the center, It exhibits a temperature distribution characteristic in which the temperature is the same or low in the opposite regions, and as it goes to both sides, it increases higher and then decreases again. At this time, the difference between the minimum temperature and the maximum temperature of the bonded part is at most 1
℃, but in the case of a narrow adhesion failure (width of 10 m or less), the temperature will be about 4℃.

Therefore, the indicated temperature is room temperature, temperature distribution gradient in the width direction,
Since the change is due to changes in the heat melt generated by the curing reaction, the detection method is not the absolute value of the indicated temperature, but the rate of temperature change (for example, the deceleration average temperature α4℃ or more per α2 seconds).
It is reasonable to consider the thickness of the board as the detection limit. There are so-called all-party foam attachment failures, which show significant adhesion failures such as bulges, and cases where adhesion failures occur due to the extremely weak adhesive force even though the adhesive appears to be attached from the outside.〇Normal standard condition Even on this board, the surface temperature is up to about 1°C due to paper unevenness and the influence of the atmosphere (there is some fluctuation, but it is periodic). On the other hand, in the former all-party foam entry section, even the same IC changes rapidly, and there is a clear difference between the foam entry section and the area before and after it. Defective part detection is 6M- for bubbling defects with a width of 6- or more, assuming a sensor temporary constant of 30 m5ec and a line speed of 42-.

Regarding the detection of the latter defective adhesion, although the absolute temperature difference is not so remarkable, there is a clear difference in temperature distribution, so we use a computer etc. to process the sensor signal at high speed and (Detection by turn comparison is necessary.) Data processing may be performed, for example, by the method shown in FIG. 3. In FIG. The data is sent to the operation unit 13 via the O operation unit 13, which integrates the time and calculates the average value.Next, calculate the difference between this average value and the previous average 1st shift, and if the value exceeds a certain value Defective adhesion is determined based on whether or not the adhesion is defective.For example, it is determined as follows: 0 7T>, xo, and when 2 defective animals ≦α, it is good.ΔT Δt Here, ΔT is the difference between the previous average value and the current average value. The absolute value of the subtraction, Δt is the cumulative time, and α is the set value.If an adhesion failure is detected, a discharge command is sent to the production line.

According to the present invention, M pieces of gypsum board can be inspected using non-destructive transverse strain in a short period of time without leaking VC. Therefore, production losses can be significantly reduced in the production of gypsum boards.

Next, examples of the present invention will be described.Example 1 A stone f board forming line with standard forming conditions of 9 x 3 x 6 squares was used to produce gypsum board with gold bubbles near the end of the board forming line. , an external radiation thermometer installed just before the cutting machine detected a temperature of 05°C (at 40°C),
Accuracy 1%, temperature measurement surface let 2.5 mm (at 25
cyn), the response time is 02 seconds, and the surface temperature was measured as shown in Figure 1 (a). !
11) and the central part, but in the case of a plasterboard with air bubbles in the central part of the board, the first
〇Example 2 showing a concave temperature distribution pattern as shown in the figure (rylK) After filling all the air bubbles on the long side of the gypsum board and artificially creating a non-bonded part, temperature was detected in the direction of movement of the gypsum board. Figures 4 (a) and (b) show the results of zero measurements obtained by scanning the device in the width direction and continuously measuring the surface temperature from the artificial non-bonded area to other areas. The position was installed approximately 5 m before the cut point of the board while the plasterboard was being cut.The movement range of the gypsum board was perpendicular to the direction of the plasterboard's progress, and the range was larger than the width of the plasterboard. did.

As is clear from the measurement curve in Figure 4 (b), a clear change in temperature distribution was observed in the poorly bonded area.
(Figure 1 (4) (b) is a pattern diagram showing the temperature distribution of gypsum board, Figure 1 (b) is a pattern with good adhesion,
Figure (B) indicates a defective bond. Figure 2 (H) and (B) are explanatory diagrams showing the setting positions of the temperature detector. Figure 3 is a block diagram showing the determination mechanism based on the temperature detection signal. Figure 4 (
B) is related to the theory BAIIc of Example 2, FIG. 4B is a schematic plan view showing the fixed position of the gypsum hoard, and FIG. 4B is a temperature change diagram showing the detection results. In the figure.

l-temperature detector 2-Gypsum board 2a-back side 2b-Front side 11-Detector 12-Converter 13- It’s a performance club◎ patent applicant Onoda Cement Co., Ltd. Japan I.T.Nis Co., Ltd. People Patent Attorney Hikari Ishibe (1 other person) 311

Claims (1)

[Claims] The temperature of the surface of the running stone board is measured using an infrared radiation thermometer installed on the paper line of the gypsum hoard manufacturing machine.
A method for detecting adhesion defects in gypsum hoard, characterized by detecting adhesion defects based on changes in the obtained temperature component 4b.