Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1998-10-14
2001-01-30
Yao, Sam Chuan (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S229000, C156S273900, C156S288000
Reexamination Certificate
active
06179947
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a method for manufacturing laminates and an apparatus for performing the method and, more particularly, a laminate manufacturing method in which synthetic resin sheet members and metal sheets are stacked and are integrally thermoformed under a pressure into laminates including the metal sheets while electrically heating the metal sheets, as well as to an apparatus for performing such method.
DESCRIPTION OF RELATED ART
The laminates having the metal sheets on their surfaces have been obtained through an integral laminate molding of the metal sheets and synthetic resin sheet members. Copper foils or the like have been used as the metal sheet, and the laminate employing prepregs or the like as the synthetic resin sheet member has been employed in various ways such as printed circuit boards and the like. Such laminate is formed by stacking a set of the metal sheets and prepregs, of the metal sheets and inner layer members, or of the metal sheets and inner and outer layer members, melting synthetic resin which forming the prepregs by heating them under a pressure, and causing the resin to set through a heating or cooling. In heating under the pressure the laminated sheets and members, there may be employed such processes as a hot pressing, vacuum pressing and the like.
In the hot pressing process, an opposing pair of heating plates are heated, and the stacked metal sheets and such members as the prepregs and so on are pressurized by the heating plates from both of top and bottom sides. In the vacuum pressing process, on the other hand, the stacked sheets and members are covered hermetically by a packing member, its interior is drawn into a vacuum, and a highly heated and pressurized gas is led to its periphery. When the laminate molding is performed through such hot pressing or vacuum pressing process, generally one set of a plurality of such members as the prepregs which forming each laminate is made to form a laminate combination, a plurality of sets of such laminate combinations are stacked with interlayers interposed between them to form a laminate block, and this laminate block is thermoformed under a pressure so that a plurality of the laminates can be simultaneously obtained. The interlayers are employed for ensuring the flatness of the respective laminates produced, and normally stainless steel plates are employed as the interlayers.
In an event where the laminate combinations stacked into multiple layers are subjected to the thermoforming under a pressure through the hot pressing process as has been described, the laminate block is heated from the top and bottom sides by means of press plates of molding press. Therefore, there arises a difference in heated temperature between the laminate combinations facing the press plates and the laminate combination centrally positioned, due to a delay in heat transfer as well as heat radiation from side faces of the laminate block. Such non-uniformity of the heating temperature has resulted in a problem that the thus obtained products of the laminates involve a fluctuation in the quality, due to which an allowable stacking number of the sets of the laminate combinations is limited.
According to the vacuum pressing process, on the other hand, the laminate block is heated from its periphery so that the temperature of the respective laminate combinations in the block will rise substantially uniformly, whereas the temperature difference is still caused to arise due to the delay in the heat transfer between outer peripheral portions and core portion of the respective combinations. For this reason, the molding of the laminate having a larger surface area has been uneasy.
As one of measures for eliminating such problems, there has been a method in which the metal sheet is formed in a continuous sheet, the synthetic resin sheet members and insulating interlayers are alternately stacked with the continuous metal sheet interposed between them as sequentially folded back, so as to be multiple layers, the continuous metal sheet is connected at its both ends to an electric power source so as to function as an electric resistor which generates a required heat so that, when a proper pressure is applied to this laminate block by means of a cold pressing, the respective constituent members are adhered to each other, and a number of the laminates are simultaneously molded. According to such heating process, the heating temperature will be uniform both in stacking direction and planar direction of the constituent members of the laminate, and the quality is caused to less fluctuates. In the case when such manufacturing method is employed, it is necessary to form such laminate block as has been described.
In forming this laminate block, there has been adopted an arrangement in which a pair of continuous metal sheet rolls are constituted with a pair of the continuous metal sheets wound respectively on each of a pair of reels, the pair of continuous metal sheets are drawn out the reels through their outlets, and the laminate block is formed while moving the pair of continuous metal sheet rolls above the laminate block.
In forming such laminate block as has been described, however, there has been a problem that the pair of continuous metal sheets are caused to be excessively drawn out so that, when the pair of continuous metal sheets employed are thin, they may happen to be wrinkled as a result of being expanded or to be doubled. Further, when an excessive tensile force is applied to the continuous metal sheets and especially upon application of a tensile force non-uniform in axial direction of the pair of reels, there arises a problem that the pair of continuous metal sheets may happen to be torn off by edges or the like of the interlayers.
Since at this time the pair of continuous metal sheets are excessively drawn, an operator will have to wind up or draw out a required amount of the pair of continuous metal sheets, so that there arises a problem that the operation is time-consuming, and the production cannot be speeded up.
Arrangements of the kind as above for manufacturing the laminates have been disclosed, for example, in Japanese Patent Laid-Open Publications Nos. 4-192497 and 7-52354.
SUMMARY OF THE INVENTION
The present invention has been suggested in order to overcome the foregoing problems, and its object is to privide a method for manufacturing the laminates and an apparatus for performing the method, which are capable of restraining any slackening of the continuous metal sheets which can be a cause of the wrinkle, doubling or tear of the sheets during the formation of the laminate block, capable of shortening operation time to speed up the production, and capable of elevating production efficiency with the operation rendered to be easier for its automation.
The above object can be realized by means of a method for manufacturing the laminates in which continuous thin metal sheets
3
and
4
wound as rolls
5
and
6
on reels are sequentially folded back while alternately interposing synthetic resin sheet members
9
and insulating interlayers
10
to stack them into a laminate block
12
of multiple layers, and the laminate block
12
is thermoformed under a pressure while electrically heating the metal sheets
3
and
4
in the block
12
, characterized in that the continuous thin metal sheets
3
and
4
are folded back while keeping the sheets in tension between outlets
16
of the reels and an end edge of the stacked block
12
.
With such manufacturing method, it is enabled to prevent any slackening of the continuous metal sheets
3
and
4
, which being a cause of wrinkle, doubling or tear of the sheets even when the continuous metal sheets employed are thin, by keeping the continuous metal sheets
3
and
4
in tension while forming the laminate block
12
.
In this method for manufacturing the laminates, it is desirable that stacking work of the laminate block
12
while a pair of the continuous metal sheet rolls
5
and
6
consisting of a pair of the continuous metal sheets
3
and
Kawamura Kazushi
Maeda Hiroshi
Okamoto Takeshi
Lynn & Lynn
Matsushita Electric & Works Ltd.
Yao Sam Chuan
LandOfFree
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