JPH0647600A - Pressing/heating plate for pressing machine - Google Patents

Abstract

PURPOSE:To provide a pressing/heating plate for a press whose thermal deformation is difficult to generate by using a graphite having the far smaller coefficient of thermal expansion compared with a steel and in addition having a good heat conductivity as the component material for the upper plate for functioning an upper plate serving also as a heating plate. CONSTITUTION:The upper plate 1 heated by a heating means and abutted on a work is formed with graphite as a base stock. On the surface of the upper plate 1, a covering layer 5 is provided which is constituted of a metal and other materials having a good smoothing finish property.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressurizing / heating plate for a press machine suitable for producing a press-processed product, such as a liquid crystal plate, which requires extremely high precision in its thickness dimension.

[0002]

2. Description of the Related Art In order to manufacture a liquid crystal plate having a structure in which a thin layer of liquid crystal is sandwiched between two glass plates, first, an uncured stock solution of a thermosetting epoxy resin is packed in a peripheral portion of a lower glass plate. Then, the upper glass plate is laid on top of it and placed on a hot / press machine to cure the stock solution, thereby forming a closed void with an extremely uniform thickness between the two glass plates. A method is adopted in which a plurality of glass plates are attached to each other and then liquid crystal is injected into the closed space. The conventional pressurizing / heating board attached to this heat / pressing machine has a multi-layer structure as shown in FIG. 3, and a copper plate 11 for heat equalization is provided on the back surface of the upper board 10 with which the workpiece is brought into contact. A heating plate 12 for heating the upper plate 10 is laminated through the above, and an inorganic heat insulating material layer 14 and a water-cooling corrugated pipe 15 are assembled between the back surface of the heating plate 12 and the mounting base 13 of the lowermost layer. The cooling board 16 attached thereto and the assembling spacer 17 also serving as a heat shield layer are sequentially interposed. In this case, the heating plate 12 made of a heat-resistant steel plate having a thickness of 6 cm or less is replaceably incorporated with the electric heater 18 for accelerating the curing reaction of the epoxy resin stock solution, and the water-cooling flexible pipe 19 for cooling the cured resin is also provided. Is buried. The pressurizing / heating plate is a pair of upper and lower platforms 20 of the press machine.
The upper and lower surfaces (only the lower one is shown in the figure) are bolted and fixed, respectively.

[0003]

If the thickness of the closed space into which the liquid crystal is injected is not extremely uniform over the entire surface, a clear high quality screen cannot be obtained. Ideally, this thickness error is desired to be ± 0.03 μmm or less. However, at present, it is only possible to secure the thickness accuracy within ± 0.1 μm. It is considered that the main reason why the thickness accuracy cannot be sufficiently improved is the high coefficient of thermal expansion of the steel material. That is, even if the entire surfaces of the upper plate 10 and the heating plate 12 are heated substantially evenly by the electric heater 18, the degree of heat dissipation is inevitably larger in the peripheral portion than in the central portion. Therefore, even if the arrangement of the electric heater 18 is taken into consideration in consideration of this fact, it is almost impossible to keep the temperature distributions of the upper plate 10 and the heating plate 12 strictly and uniformly over the entire surface. Nearly impossible. Therefore, the upper plate 10 and the heating plate 12 having a large coefficient of thermal expansion.
In this case, a large thermal deformation strain that cannot be ignored occurs, and it becomes impossible to finish the surface of the pressed product to ideal flatness or smoothness. Therefore, the purpose of the present invention is to
Focusing on graphite, which has a much smaller coefficient of thermal expansion than steel and also has good thermal conductivity, and used this graphite instead of conventional steel to make thermal deformation strain less likely to occur. It is to provide the pressurizing / heating board of.

[0004]

A pressurizing / heating plate for a pressing machine according to the present invention for achieving the above object comprises a top plate 1 which is heated by a heating means and is brought into contact with a workpiece. Is formed as a material. A coating layer 5 made of metal or other material having a good smooth finish may be provided on the surface of the upper plate 1.

[0005]

As the constituent material of the upper plate 1 which is heated by the heating means and directly abuts on the work, graphite having a much lower coefficient of thermal expansion than the conventional steel material and having good thermal conductivity is used. By this, the thermal deformation strain of the upper plate 1 due to heating / cooling is remarkably reduced, so that the thickness dimensional accuracy and flatness or smoothness of the pressed product are remarkably enhanced.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The pressurizing / heating board of this embodiment is different from the conventional pressurizing / heating board shown in FIG.
0 and the copper plate 11 are omitted, and those functions and the function of the heating plate 12 are combined with the upper plate 1 of the present invention. Therefore, the same members as those in the conventional example of FIG. 3 are designated by the same reference numerals.

In this embodiment, the material of the upper plate 1 which also serves as the conventional heating plate 12 is artificial graphite, unlike the conventional heat-resistant steel material. Commercially available artificial graphite has a wide range of characteristic values depending on its manufacturing method, and has a thermal expansion coefficient of 2
~ 6 × 10 ^-6 ℃, and the thermal expansion coefficient of iron is about 12 × 10 ^-6 ℃
It has a characteristic that it is much lower than that of, and deformation strain due to thermal expansion and contraction hardly occurs. The thermal conductivity is 90 ~ 130 at room temperature.
Since it is as good as Kcal / m · h · ° C, it is possible to uniformly heat the upper plate 1 over the entire surface in a short time. On the side surface of the upper board 1, there is horizontally provided a mounting groove 2 having a trapezoidal cross section that gradually narrows toward the inner depth.

Reference numeral 3 denotes an outer frame material of the pressurizing / heating board 1, which is fixed to the outer surface of each laminated material such as the mounting base 13 and the cooling board 16 by screwing. On the inner side surface of the outer frame member 3, a fitting member 4 to be fitted into the groove is screwed at a position facing the mounting groove 2 provided in the upper board 1. In this embodiment, the upper plate 1, which also serves as a heating plate, has a thickness of 6 cm inside and outside thereof, and a plurality of heater accommodation holes are horizontally formed at predetermined intervals in the upper layer portion thereof. The electric heater 18 such as a sheathed heater is replaceably incorporated. or,
The cooling spiral tube 19 is simultaneously embedded at the time of molding the upper board 1 by utilizing the good moldability of graphite.

Next, the operation of the above configuration will be described. The pressurizing / heating plate is attached to the press machine in the same manner as in the prior art. After energizing the electric heaters 18 of the upper and lower pair of upper plates 1 and 1 mounted on the upper and lower lifting platforms 20 and 20 so as to be opposed to each other, a work machine is sandwiched between the upper and lower plates 1 and 1, and a pressing device is installed. When operated, the upper plates 1 and 1 having good thermal conductivity are uniformly and quickly heated to the predetermined temperature by the electric heater 18. Next, when the pressurizing device of the press machine is operated, the work is subjected to a predetermined press pressure to be compressed to a predetermined thickness and heated to a predetermined temperature. When the work is a liquid crystal plate, it is heated to 120 to 220 ° C. depending on the type of the above-mentioned epoxy resin stock solution. When the resin is hardened, water is passed through the water-cooling flexible pipe 19 to cool the upper plate 1 for the next press molding. In this way, thermal expansion and contraction strain occurs in the upper plate 1 which is repeatedly heated and cooled in each press molding cycle,
The degree of strain is much smaller than that of the conventional heating plate 12 made of steel having a large coefficient of thermal expansion. Therefore, when the work is the above-mentioned liquid crystal plate, the thickness error of the sealing gap into which the liquid crystal is to be injected is reduced from ± 0.1 μmm in the past to the ideal ± 0.03 μmm. It was possible to remarkably enhance the sharpness of the LCD screen.

Further, by replacing the conventional upper plate 10 and heating plate 12 each made of steel with an upper plate 1 made of graphite, which has a much smaller specific gravity than steel, the weight of the pressurizing / heating plate is changed. Was reduced to about 1/4, and the handling was significantly easier, and at the same time, the effect of being able to perform efficiently was also obtained.

FIG. 2 shows another embodiment of the present invention. The difference from the above example is that the surface of the upper plate 1 is covered with a coating layer in consideration of the fact that it is not easy to finish the surface of graphite strictly flat and smooth and that the graphite is easily oxidized. It is in the place where 5 was provided. As the material of the coating layer 5, various metal plates or the like which can be easily mirror finished are used. In this embodiment, heat-resistant steel (SKD-) having a thickness of 10 mm is used.
61) is used.

In the above structure, the heating platen 1 may be made by blending with various ceramic materials having a small coefficient of thermal expansion, molding and firing, in addition to using graphite alone. The heating means of the heating platen 1 is not limited to the electric heater 18, and it is also possible to energize the graphite itself having electric resistance to heat it to a predetermined temperature. Further, the laminated structure of the entire pressurizing / heating plate is not limited to that shown in the drawing, and the object of the present invention can be achieved even if the design is changed appropriately.

[0013]

As is clear from the above description, the pressurizing / heating plate for a press of the present invention has various practical excellent effects as listed below. (A) As a constituent material of the upper board of the present invention, which has the roles of a conventional upper board and a heating board made of steel, respectively, the coefficient of thermal expansion is much smaller than that of steel, and the thermal conductivity is also high. By adopting good graphite, it is possible to significantly reduce the degree of occurrence of thermal deformation strain of the upper plate during press molding. (B) Therefore, for example, when this pressurizing / heating board is used in a press machine for producing a liquid crystal plate, the thickness dimensional accuracy of the closed space for liquid crystal injection formed between two glass plates is significantly increased. It is improved, and the sharpness of the LCD screen can be sufficiently enhanced. (C) Since graphite has a much lower specific gravity than steel, the weight of the pressurizing / heating plate can be remarkably reduced, and the handling labor thereof can be greatly reduced. (D) Since graphite has a low specific heat, it is possible to significantly reduce the time and cost required for heating and cooling the heating plate.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing another embodiment of the present invention.

FIG. 3 is a view corresponding to FIG. 1, showing a conventional example.

[Explanation of symbols]

 1 Upper Plate 2 Mounting Groove 3 Outer Frame Material 4 Fitting Member 5 Covering Layer 10 Upper Plate 11 Copper Plate 12 Heating Plate 13 Mounting Base 14 Heat Insulating Material Layer 15 Water Cooling Pipe 16 Cooling Board 17 Assembly Spacer 18 Electric Heater (Heating Means) ) 19 Water-cooled spiral pipe 20 Elevating platform

Claims (2)

[Claims] 1. A pressurizing / heating plate for a pressing machine, characterized in that an upper plate (1) heated by a heating means and brought into contact with a work is formed of graphite. 2. A pressurizing / heating plate for a press machine, wherein a coating layer 5 made of metal or other material having a good smooth finish is provided on the surface of the upper plate 1.