JP3859945B2 - Isotropic pressure molding method and molding apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for forming an object to be pressed by heating and isostatic pressing by using a high-temperature liquid.
[0002]
[Prior art]
2. Description of the Related Art An apparatus is known in which an object to be pressurized is stored in a pressure vessel, a liquid is supplied in a state where the pressure vessel is sealed, and pressure is applied to the object to be pressurized via the liquid. In this case, isotropic pressurization can be realized by pressurizing via a liquid. Furthermore, if the liquid is a high-temperature liquid, it is possible to pressurize while heating. An apparatus for performing isotropic pressure while heating is described in, for example, Japanese Utility Model Publication No. 4-44358.
[0003]
A multilayer electronic component such as a multilayer capacitor is molded using such an apparatus. A multilayer capacitor is manufactured by alternately laminating a sheet of a conductor having a predetermined shape and a ceramic green sheet, pressurizing them, heating them simultaneously to cure the binder between the layers, and firing the ceramic. A conductor having a predetermined shape serves as an electrode, and the fired ceramic layer serves as an insulator. In practice, this is cut into a predetermined shape and used as a circuit element. In a state where the conductor sheet and the ceramic green sheet are laminated, the green sheet is soft and the shape is not constant. Therefore, the laminate of the conductor sheet and the green sheet is placed on the plate-like member, and heating and pressing are performed in this state.
[0004]
[Problems to be solved by the invention]
As described above, a workpiece having an indeterminate state before processing requires a holding means for holding it in a predetermined shape until the end of processing. In the case of the laminated body, a plate member is used as the holding means. The workpiece is stored in the pressure vessel together with the holding means, and the temperature is increased to a predetermined temperature during processing. At this time, it is necessary to raise the temperature of the holding means to a predetermined temperature during processing. For this reason, it takes time to raise the temperature before pressurization, and the time for using the pressure vessel becomes longer. Since the tact time is determined by the time during which the pressure vessel is used, there is a problem that the tact time cannot be shortened, that is, the productivity cannot be increased.
[0005]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a molding method and apparatus that can shorten the processing time.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the isotropic pressure molding method according to the present invention is a method in which the object to be pressurized is held in a holding means for holding it in a predetermined shape before being stored in the pressure vessel. It is heated by a high-temperature liquid stored in the preheating tank in advance. Since the holding means and the workpiece are warmed and stored in the pressure vessel, the time required for the temperature rise in the pressure vessel is shortened. Therefore, the time for using the pressure vessel can be shortened, and the tact time can be shortened. Specifically, when pressure forming is performed in the pressure vessel, in parallel with this, an object to be pressed next to be formed is preheated at a place different from the pressure vessel.
[0007]
Further, such isostatic pressing device in the present invention, the pre-Symbol to be pressurized 圧物, while being held in the holding means for holding a predetermined shape, prior to the pressing, pre preheater A preheating device for heating with a high-temperature liquid stored in is separately provided from the pressure vessel. By separately providing the preheating device, pressure molding and preheating can be performed in parallel, and the tact time can be shortened.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings. FIG. 1 is a plan view showing the arrangement of the apparatus according to the present embodiment. The apparatus places a workpiece before molding on a basket and takes out the workpiece after molding from the basket. A loading / unloading station 10 and a preheating station 12 that preheats the workpiece placed on the basket before pressure molding. The pressure forming station 14 pressurizes the preheated workpiece while heating. Between these stations, guide rails 16 and 18 are provided, and a basket on which a workpiece is placed moves along the guide rails.
[0009]
FIG. 2 is a front view showing the carry-in transfer station 10 and the preheating station 12 in more detail. The pressure forming station 14 is located in the depth direction of the drawing, but is not shown in the figure. Inside the basket 20, a shelf or receiver (hereinafter simply referred to as a shelf) 24 on which the workpiece 22 is placed is provided. After the workpiece 22 is mounted, the basket 20 moves on the guide rail 16 and is sent to the preheating station 12. A preheating case 26 is disposed in the preheating station 12, and the basket 20 that has been conveyed is sent into the case. Then, the opening of the preheating case is closed by the shut 28. In this state, warm air is sent from the warm air blower 32 through the duct 30 into the preheating case 26. The temperature of the hot air is determined in consideration of the heat-resistant temperature of the workpiece.
[0010]
FIG. 3 shows details of the workpiece 22. The laminated body 34 to be pressure-molded is a material for a multilayer capacitor, and is obtained by alternately laminating a sheet of a conductor having a predetermined shape and a ceramic green sheet. Since the laminated body 34 is soft, the shape of the laminated body 34 cannot be maintained alone and is placed on the plate 36 in advance. The plate 36 is made of stainless steel, but other materials may be used as long as the plate 36 has sufficient rigidity, good thermal conductivity, and corrosion resistance. Further, the laminate 34 and the plate 36 on which the laminate 34 is placed are sealed with a film 38.
[0011]
FIG. 4 is a side view showing the pressure forming station 14 in more detail. After the preheating is completed, the basket 20 is sent to the pressure forming station 14 by the guide rails 16 and 18. At the pressure forming station 14, the basket 20 is suspended from the lid 42 of the pressure vessel 40. On the other hand, the pressure vessel 40 is immersed in the warm water in the thermostat 44. Hot water in the thermostatic chamber 44 is sent into the pressure vessel 40 through the pipes 48 and 50 by the circulation pump 46. Hot water overflowing from the pressure vessel 40 is accommodated in a thermostatic chamber 44. The hot water is maintained at a temperature suitable for processing the laminated body 34 by a heating means (not shown). The basket 20 suspended from the lid 42 descends together with the lid 42 and is placed in and stored in the pressure vessel 40. When the lid 42 closes the opening of the pressure vessel 40, the pin 52 penetrates the lid 42, and the lid 42 and the pressure vessel 40 are connected as shown in FIG. 5.
[0012]
FIG. 5 is an explanatory diagram of the pressure molding process. The workpiece (not shown) placed on the basket 20 is stored in the pressure vessel 40. The temperature of the work 22 is increased by the preheating described above, and pressurization can be started at an early stage after the work 22 is immersed in warm water. The valve 54 is closed, the booster pump 56 is driven, and the hot water in the thermostatic chamber 44 is further fed into the pressure vessel 40 through the pipes 48 and 50 to increase the pressure in the vessel. When a predetermined pressure is reached, this pressure is maintained for a predetermined time. During this time, the ceramic green sheet is pressed and cured by heating and pressing with warm water. When a predetermined time elapses, the valves 54 and 58 are opened to release the pressure in the pressure vessel 40.
[0013]
After releasing the pressure, the pin 52 is removed, the lid 42 is raised, and the basket 20 is placed on the guide rail 18. Then, it is sent on the guide rails 18 and 16 and sent to the carry-in / carry-out station where the work 22 after pressure forming is taken out from the basket 20.
[0014]
FIG. 6 is a diagram illustrating the movement of the basket 20. This apparatus is provided with two baskets, which are denoted by reference numerals 20A and 20B in the figure. By providing two baskets, different processes can be executed in parallel, and the tact time can be reduced as a whole. In (a), the basket 20A is in a state of being recovered from the pressure vessel 40 after completion of the pressure molding. On the other hand, the basket 20B is in a state where the preheating is finished. As shown in (b), the basket 20A is first sent to the loading / unloading station 10, and then the basket 20B is sent to the pressure forming station 14 as shown in (c).
[0015]
The workpiece 22 is carried into the basket 20 </ b> A sent to the carry-in / carry-out station 10. As shown in (d), when the carry-in is completed, the basket 20A is sent to the preheating station 12, where the workpiece 22 is heated. On the other hand, in parallel with this, the basket 20B is put into the pressure vessel 40, and after the workpiece 22 is heated to a predetermined temperature, pressure molding is started. After the pressure is increased to a predetermined pressure, this pressure is maintained for a predetermined time, and then the pressure is released. When the basket 20B is recovered from the pressure vessel 40 and the heating of the work of the basket 20A is completed, the basket 20A and the basket 20B in (a) are switched.
[0016]
As described above, by performing preheating on the workpieces in the basket 20A while performing pressure molding on the workpieces mounted on the basket 20B, heating performed before pressurization in the pressure vessel is omitted or It can be shortened. Therefore, the tact time can be shortened.
[0017]
In the above-described embodiment, the preheating is performed by warm air. However, it is also possible to provide a tank storing a high-temperature liquid and immerse the entire basket in this liquid to perform the preheating. In this case, it is possible to easily reduce the temperature unevenness in the workpiece as compared with preheating with warm air. Moreover, the said high temperature liquid can utilize the warm water stored in the thermostat 44 of a pressure molding apparatus.
[0018]
Further, in the case of the present embodiment, the effect as described above can be achieved even with a preheating method in which the heat capacity of the plate 36 is larger than the stacked body 34 and only the plate 36 is heated. As such a heating method, it is conceivable that a heater by Joule heat, a heater by induction current, or the like is disposed in the preheating case 26 so as to face the lower surface of the plate 36, thereby heating. Furthermore, the object to be pressed and the member that holds the object to be pressed are not limited to a flat plate shape, and may have any shape.
[0019]
Moreover, you may make it provide more than two baskets. In this way, for example, in the above-described embodiment, the number of baskets is three, and each of them is disposed in the transfer-in station, the preheating station, and the pressure molding station, and the work can be performed in parallel at three locations. In this case, it is necessary to extend the guide rail toward the opposite side of the pressure forming station to provide a basket retreat position.
[0020]
FIG. 7 shows another example of the arrangement of each station. (A) is a plan view and (b) is a front view. The pressure forming apparatus main body 100 includes a pressure forming station 114. The carry-in / carry-out station 110 is disposed at a position lower than a position (a position indicated by reference numeral 113 in the drawing) for loading into the pressure forming station 114. Further, the preheating station 112 is disposed at substantially the same height as the carry-in / carry-out station 110.
[0021]
In the loading / unloading station 110, the work is placed at a predetermined position of the basket. The basket is sent to the preheating station 112 along a guide rail or the like. In the preheating station 112, the workpiece is heated by the method described above. When the heating is completed, the basket is raised to the charging standby position 113 by a lift or the like, and is sent to the pressure forming station 114 from here. After the press molding is completed, the basket is returned again to the loading standby position 113 and is sent from here to the unloading standby position 111 along a guide rail and the like. The loading standby position 113 and the unloading standby position 111 are located at substantially the same height. The basket is lowered by the lift from the unloading standby position 111 and is sent to the loading / unloading station 110.
[0022]
According to this configuration, the height of the loading / unloading station can be set separately from the main body of the pressure molding apparatus, particularly the charging standby position 113, and workability can be improved. Further, the basket circulates in one direction among the carry-in / carry-out station 110, the preheating station 112, the input standby position 113, and the carry-out standby position 111. Therefore, it can be seen that when there are three baskets, it is not necessary to provide a new configuration as compared with the above-described embodiment in which a position for retraction must be provided.
[0023]
FIG. 8 shows another example of the arrangement of each station. (A) is a plan view and (b) is a front view. The pressure molding apparatus main body 200 includes a pressure molding station 214. The carry-in / carry-out station 210 is disposed at a position lower than a position (indicated by reference numeral 213 in the drawing) for loading into the pressure forming station 214.
[0024]
In the loading / unloading station 210, the work is placed at a predetermined position of the basket. After the basket is lifted by a lift or the like, it is sent to the preheating station 212 along a guide rail or the like. In the preheating station 212, the workpiece is heated by the method as described above. When the heating is completed, the basket is moved along the guide rail to the charging standby position 113 and sent from here to the pressure forming station 214. After completion of the pressure molding, the basket is returned again to the loading standby position 213 and is sent from here to the unloading standby position 211 along the guide rail and the like. The loading standby position 213 and the unloading standby position 211 are located at substantially the same height. The basket is lowered from the unloading standby position 211 by a lift and sent to the loading / unloading station 210.
[0025]
According to this configuration, the height of the loading / unloading station can be set separately from the pressure molding apparatus main body, particularly the charging standby position 213, and workability can be improved. Moreover, the installation area of the whole apparatus can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic arrangement of an apparatus according to an embodiment.
FIG. 2 is an explanatory diagram of a transfer-in station and a preheating station.
FIG. 3 is a diagram showing details of a workpiece.
FIG. 4 is an explanatory diagram of a pressure forming station.
FIG. 5 is an explanatory diagram of a pressure molding station and a pressure molding process.
FIG. 6 is an operation explanatory diagram of the apparatus according to the present embodiment.
FIG. 7 is a diagram illustrating another example of the arrangement of stations.
FIG. 8 is a diagram showing still another example of the arrangement of stations.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Loading / unloading station, 12 Preheating station, 14 Pressure forming station, 20 Basket, 22 Workpiece, 26 Preheating case, 32 Hot air blower, 34 Laminate (pressure object), 36 Plate (holding means), 40 Pressure vessel , 42 Lid, 46 Circulation pump, 56 Booster pump.

Claims (4)

A preheating step of preheating by immersing the object to be pressurized in a preheating tank in which a high-temperature liquid is stored in a state of being held by a holding means for holding the object in a predetermined shape;
After the preheating step, the object to be pressurized taken out from the preheating tank is stored in the pressure vessel while being held in the holding means, heated by injecting a high-temperature liquid into the pressure vessel, A molding step of applying isotropic pressure through the liquid;
Have
During the molding process, heating is performed by the preheating step on an object to be pressed to be molded next.
Isotropic pressure molding method. The isotropic pressure molding method according to claim 1, wherein the pressure vessel is immersed in warm water in a thermostatic bath, and hot water in the thermostatic bath is used as a high-temperature liquid in the preheating bath, etc. Method of pressure molding. In an isotropic pressure molding apparatus that injects a high-temperature liquid into a pressure vessel that houses the object to be pressed, heats the liquid with the liquid, and isotropically pressurizes the object to be pressed through the liquid. There,
The object to be pressurized is put into the pressure vessel in a state of being held by a holding means for holding it in a predetermined shape,
A preheating device that is provided separately from the pressure vessel and includes a preheating tank in which a high-temperature liquid is stored;
An isotropic pressure forming apparatus. The isotropic pressure molding apparatus according to claim 3, wherein the pressure vessel is immersed in warm water in a thermostatic bath, and the hot water in the thermostatic bath is used as a high-temperature liquid in the preheating bath, etc. One-way molding equipment.

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