JP2700543B2 - Thermal pressure control method for multi-stage press - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial application field" The present invention relates to a type of plywood material to be supplied in a multi-stage press in which a plurality of hot plates are arranged to be openable and closable in a vertical direction or a horizontal direction. In particular, the present invention relates to a method for controlling heat and pressure from the start of pressurization to the end of pressurization in accordance with the material thickness in addition to the vertical and horizontal sizes. "Prior art" Conventionally, after laminating a plurality of veneer veneers coated with adhesive on the upper and lower surfaces, temporarily press-pressed plywood material is heated and pressed between hot plates in each stage of a multi-stage press Has controlled the discharge pressure of the hydraulic cylinder in accordance with the area determined from the vertical and horizontal sizes of the plywood material. At this time, since the plywood material supplied between the hot plates has a plurality of types of vertical and horizontal sizes, the discharge pressure of the pump to the hydraulic cylinder is adjusted so that the pressing force per unit area of the plywood material becomes equal. Was changed each time. Usually, the unit pressure g of the plywood material and the discharge pressure P of the pump
The relationship is Required by In the above equation, W is the total compressive force (kg), A is the area of the plywood material (cm ² ), S is the area of the cylinder, d is the inner diameter of the cylinder, and n is the number of cylinders. The area S of the cylinder, the inner diameter d of the cylinder, and the number n of the cylinders are constant in the initially installed multi-stage press and are constant, so if the area of the plywood material changes, the pump By changing the discharge pressure, the pressurization control is performed by obtaining the optimum surface pressure of the plywood material. That is, based on the calculation result by the calculation unit in which the above equation is set, the pump supplies pressure oil to the hydraulic cylinder, and adjusts the discharge pressure of the pump via a relief valve in order to adjust the discharge pressure. And the pressurization of the plywood material is controlled at the optimum surface pressure. "Problems to be Solved by the Invention" However, the pressurization control of the hydraulic cylinder obtained by the calculation result from the above equation is determined only by a planar element based on the area of the plywood material. That is, when the plywood material is pressed between the hotplates, the hotplate temperature is allowed to reach deeper portions from above and below the plywood material, and the adhesive layer applied between the veneer veneers constituting the plywood material is heated. However, it is necessary to accurately regulate the curing time of the adhesive by heating while applying pressure, but the plywood material is three-dimensional, and its thickness is large and small. The pressure time was not precisely regulated. "Means for solving the problem" In view of the above, the present invention is openable and closable, and depends on the vertical and horizontal size and thickness of the plywood material which is heated and pressed between a plurality of hot plates adjacent to each other. Classify, pre-install the heating and pressurizing conditions specified for each type in the computer in advance, and determine the type that matches or is the closest to this from the vertical and horizontal sizes and thickness of the plywood material supplied between the hot plates. In the method of selecting and performing the heating and pressurizing work under the heating and pressurizing condition according to the selection, the detection from the detector which detects the heating and pressurizing condition, the hot plate temperature of the multi-stage press, the discharge pressure of the cylinder, and the heat and pressure time respectively The hot plate temperature, cylinder discharge pressure, and heat pressure time are controlled to match the values.Especially, for a thick plywood material, pressurization for an arbitrary set time, or upper and lower limits to the pressure By setting the pressure to the width When the pressure reaches the upper limit, the supply of the pressurizing force is stopped, and when the pressure reaches the lower limit, the pressurizing force is supplied again. After the pressure is adjusted within the set width (hereinafter referred to as pressure regulation), the pressure is reduced once. The heating and pressurizing condition is such that the pressure is maintained in a reduced pressure state or the pressure is adjusted again in the reduced pressure state. Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. First, the outline of the multi-stage press employed in the present invention will be described with reference to FIGS. That is, the vertical multi-stage press 1 shown in FIG.
The upper frame 3 and the lower frame 4 are opposed to each other at regular intervals vertically, and the movable plate 7 can be moved up and down by the ram 6 of the hydraulic cylinder 5 installed on the lower frame 4. A plurality of hot plates 8 are arranged at equal intervals between the upper frames 3, and a plywood material 9 is provided between the hot plates 8.
Then, the movable platen 7 is raised and the hot plate 8 located above the lowermost plate is sequentially pushed up through the plywood material 9 to close the press, and the plywood material 9 is heated. To press. The horizontal multi-stage press 10 shown in FIG.
A left frame 13 and a right frame 14 are provided on the right and left via a lower horizontal beam 12 and a hydraulic cylinder provided on the right frame 14.
The movable plate 17 can be reciprocated in the left-right direction by the ram 16 of 15; on the other hand, between the left frame 13 and the movable plate 17, a moving member 19 from both upper sides on a rail 18 installed on the upper cross beam 11. The protruding hot plates 20 are suspended in a plurality of stages, and at each corner of the hot plates 20 and the movable plate 17 at each stage, a bracket 21 and a regulating member 22 are respectively provided as a set by a transport conveyor 23, and a plywood material is provided. 9 is transported almost upright and inserted between the hot plates 20 of each stage,
With the forward movement of the movable platen 17, the hot plate 20 is sequentially contracted to the left to close the press, thereby preventing variations in the pressure applied to the plywood material 9 to be heated and pressed, thickness reduction, and the like. . The hydraulic cylinders 5, 15 of these vertical or horizontal multi-stage presses 1, 10 are usually supplied with pressurized oil by a variable discharge pump 26 driven from an oil tank 24 via a motor 25. In order to adjust the discharge pressure, a hydraulic pressure control circuit 28 is provided in which a relief 27 valve capable of adjusting the pressure is provided on the way of the piping. On the other hand, in the computer 29, types 30 are formed in accordance with the vertical and horizontal sizes and the material thickness of the plywood material 9, and a plurality of heating / pressing conditions respectively set for each type 30 are incorporated in advance. Pressing conditions, that is, formulas for determining the pressing force per unit area, and the temperature and time required to cure the adhesive in the deep layer by heating the veneer veneer, or based on the correlation between both Heat and pressure conditions
The program 31 is provided. That is, the plywood material 9 adjusts the optimal pressing force obtained by the above equation for the area, and adjusts the required time length based on the set hot plate temperature for the thickness of the plywood material. It is determined as in the time chart shown in the figure. According to this time chart, the pressure set in the program 31 is set to 7 kg / cm ² , the temperature is set to 115 ° C., and the pressurizing and regulating time is set to 60 seconds. Plywood material 9 having a specific thickness or more, for example,
As for the plywood material 9 having a thickness of 5 mm or more, as shown in the time chart of FIG. 3, the first-stage pressurizing pressure set in the program 31 is set to 7 kg / cm ² and the temperature is set to 120 ° C. for 60 seconds. After the pressure has been adjusted, the pressure is temporarily reduced, and the pressure is maintained for 40 seconds while the pressure is reduced. Further, as shown in the time chart of FIG. 4, the heating pressure is adjusted again for 40 seconds while the pressure is reduced. The pressure condition is also incorporated, and in order to prevent “swelling”, “puncture” and the like of the plywood material 9, the pressurized state is once reduced to release the moisture contained in the plywood material 9 to the atmosphere. Of the variables set in the program 31, the set pressure controls the discharge pressure to the hydraulic cylinders 5, 15 by sequentially converted signals, and at this time, the set temperature is set to the hot plate 8, The steam is supplied to the inlet side of 20, and the drain is discharged from the outlet side. The steam is controlled by a temperature controller 33 installed in each steam header 32. On the other hand, the vertical and horizontal multi-stage presses 1, 10 are equipped with detectors for grasping the hot plate temperature during operation, the discharge pressure of the cylinder, and the heat pressure time, and are incorporated in the program 31. Each variable of type 30 is compared. That is, the discharge pressure to the hydraulic cylinders 5, 15 is constantly detected by the pressure detector 34, and the detected value 35 of this pressure is fed back to the successive comparison unit 36. Similarly,
The drain temperature of the steam header 32 is constantly detected from the outlet sides of the hot plates 8 and 20 by the temperature detector 37, and the detected value 38 of this temperature is sequentially fed back to the comparison unit 36. Then
The respective detection values 35 and 38 are sequentially compared with each variable at the time point according to an arbitrary type 30 transmitted from the computer 29 in the comparison unit 36, and when the comparison results are different, the type 30 The hydraulic cylinders 5, 15 are controlled by the relief valve 27 so as to match or approximate each variable at the time of
And the flow rate of steam from the steam header 32 to the hot plates 8, 20 is controlled by the temperature controller 33. Then, the hot plate 8,10 of vertical or horizontal multi-stage press 1,10
If the plywood material 9 supplied between the spaces 20 is input into the computer 29 by a detector such as a phototube, a limit switch, or the like, whose length and width and thickness are arranged on the loader side, based on the input values, The optimum heating and pressing conditions are automatically selected as described above, and the heating and pressing are performed under the heating and pressing conditions. In addition, in the present embodiment, particularly in the time charts shown in FIGS. 3 and 4, when heating and pressurizing the plywood material 9 having a large thickness, it is assumed that the pressure is reduced only once after the pressure control for an arbitrary time. As described above, when the material thickness further increases, the number of times of depressurization is increased according to the material thickness as shown in FIG. 5, and each time the pressure is reduced, the pressure is reduced in a state as shown in FIG. Or the pressure is adjusted again in a state where the pressure is reduced as shown in FIG. 4, and the time is gradually reduced every time the pressure is reduced. [Effects] As described above, according to the present invention, the plywood material is made openable and closable, and heated and pressed between a plurality of hot plates adjacent to each other. The heating and pressurizing conditions determined for each case are incorporated in the computer in advance, and from the vertical and horizontal sizes and plate thicknesses of the plywood material supplied between the hot plates, a type that matches or is closest to this is selected, and accordingly In the method of performing the heating and pressurizing operation under the heating and pressurizing condition, the heating and pressurizing condition and the detection values from the detectors that detect the hot plate temperature of the multi-stage press, the discharge pressure of the cylinder, and the heat and pressure time are matched. As described above, since the hot plate temperature, the discharge pressure of the cylinder, and the heat pressure time are controlled, the pressurization control of the hydraulic cylinder is determined only by a planar element based on the area of the plywood material as in the above-described conventional method. Whereas plywood material An element based on the size of the material thickness, which can precisely control the time that the adhesive cures due to heating, and determine the heating temperature and pressurization time in a correlated manner, thus ensuring good press control. It is.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram schematically showing an embodiment of the present invention;
FIG. 2 is a time chart showing one embodiment of the type of program, FIGS. 3 to 5 are time charts showing another embodiment of FIG. 2, and FIG. 6 is used for control of the present invention. FIG. 7 is a schematic side view showing one embodiment of a vertical multi-stage press, and FIG. 7 is a partially cutaway side view showing one embodiment of a horizontal multi-stage press used for control of the present invention. Multi-stage press, 8,20 ... Hot plate, 9 ... Plywood material, 10 ... Horizontal multi-stage press, 29 ... Computer, 30 ... Type, 31 ... Program, 33 ... Temperature controller, 34 ... Pressure detector, 35, 38… Detected value, 36… Comparison part, 37… Temperature detector,

Claims (1)

(57) [Claims] The plywood material is openable and closable, and is heated and pressed between a plurality of adjacent hotplates. The plywood material is classified according to the vertical and horizontal sizes and the material thickness, and the heating and pressing conditions determined for each type are previously stored in a computer. A method of selecting a type that matches or is closest to the length and width of the plywood material and the thickness of the plywood material supplied between the hot plates, and performing the heating and pressing work under the heating and pressing conditions according to that The hot plate temperature, the discharge pressure of the cylinder, and the hot pressure so that the detection values from the detectors that detect the hot press temperature, the hot plate temperature of the multi-stage press, the discharge pressure of the cylinder, and the heat pressure time, respectively, match. A method for controlling heat and pressure of a multi-stage press, characterized by controlling time. 2. The pressurizing condition among the heating and pressurizing conditions respectively defined for each type is such that the plywood material is pressurized and regulated for a predetermined time and then temporarily depressurized, and the pressure is maintained in the depressurized state. 2. The method for controlling heat and pressure of a multi-stage press according to claim 1. 3. The pressurizing condition of the heating and pressurizing conditions respectively defined for each type is such that the plywood material is pressurized and regulated for a predetermined time, and then temporarily depressurized, and then re-pressurized in the depressurized state. 2. The method for controlling heat and pressure of a multi-stage press according to claim 1. 4. The pressurizing condition among the heating and pressurizing conditions determined for each type is as follows. After the plywood material is pressurized and regulated for a predetermined time, the pressure is temporarily reduced, and the pressure is maintained in the reduced pressure state. 2. The method according to claim 1, wherein the pressure is further reduced a plurality of times to maintain the pressure, and each time the pressure is reduced, the time is gradually reduced. 5. The pressurizing condition among the heating and pressurizing conditions defined for each type is as follows. After the plywood material is pressurized and regulated for a predetermined time, the pressure is temporarily reduced, and then the pressure is reduced again. 2. The hot-press control method for a multi-stage press according to claim 1, wherein the pressure is further reduced and adjusted a plurality of times in accordance with the pressure, and the time is gradually reduced each time the pressure is reduced.