FR2587273A1 - METHOD AND AUTOCLAVE PRESSURE FOR LAMINATING MULTI-LAYER PRINTED CIRCUITS AND / OR PLASTIFICATION OF FLAT ELEMENTS, AND DEVICE FOR CONVERTING INTO AUTOCLAVE PRESS OF THIS TYPE - Google Patents

Abstract

A gap between platens (3) of a press-autoclave is subdivided by an envelope comprised of a rigid frame (18) and deformable bladders (15a, 15b) into an internal sealed chamber (22) connected to a vacuum pump and into at least one external pressure chamber (23). The bladders (15a, 15b) are applied against products to be treated (9) optionally mounted on toolings (14), thereby providing for their compression. The heating and cooling may be effected by the platens (3) or by the pressurization fluid of the external chamber or chambers (23). Application to the plastification and lamination of multilayer printed circuits.

Description

 The present invention relates to the technical field of the layering of flexible, rigid, or flexo-rigid multilayer printed circuits, that is to say each comprising at least one flexible part and at least one rigid part, as well as the technical field of the plasticization of flat elements, such as documents or cards, in particular credit or payment, with memory and / or with microprocessor, between two plastic films.

 The invention relates more precisely to a method of laminating such printed circuits and of plasticizing such flat elements, as well as to an autoclave press for the implementation of this method.

 The installations currently used for laminating multilayer printed circuits include laminate presses which are generally used in the following manner: the circuits to be laminated are stacked between tools made up of thick metal plates, and then transferred these tools loaded in the compartments of a press with multiple plates being able to be moved towards and away from each other using a jack, the tools are put in compression by bringing the plates towards each other while ensuring the heating of the tools using a heating circuit incorporated at least partially in the platens and comprising for example electrical resistances embedded in the platens of the press where a network of channels extending in the platens is traversed by a fluid heat transfer medium, such as superheated steam, then a natural or forced cooling phase is provided, for example e by circulation of a coolant in channels provided in the trays> and which may possibly be the same channels as those of the heating circuit, the cooling phase continuing while the trays are kept under pressure, and finally the tools carrying the stratified multilayer circuits are removed from the press. It can therefore be seen that there are essentially two stages in the treatment of the tools, and therefore the laminate circuits which they contain, namely a compression-heating phase and a compression phase - cooling. These two phases can be carried out in the same station, and we then have to do with a mixed press, or they can be carried out separately, and we then have to do with a press with separate stations. It should be noted that such a press with separate stations makes it possible to obtain, in specific applications, a better production rate, especially when it is equipped with an automatic installation for loading and unloading of tools. installation of this type is the subject of the French patent application filed on August 7, 1981 under NO 81 15 420 for "automatic installation of loading and unloading of tools for a multi-stage press, in particular a press for laminating multilayer printed circuits "in the name of the plaintiff. It should also be noted that certain mixed laminating presses are also equipped with an automatic loading and unloading installation.

 The various laminating presses for multilayer printed circuits which are currently used have the drawbacks that, despite the care which can be taken in the manufacture of their components, and in particular the plates, as well as in their assembly, which leads to high manufacturing costs, the inevitable flatness and parallelism defects of the plates are transmitted, via the tools, to the multilayer printed circuit, which affects the quality of the latter. In addition, for the stratification of printed circuits flexible, a high number of layers of a felted material, similar to blotting paper, are consumed which are stacked above and below the flexible multilayer printed circuits to be laminated, in order to constitute a compression mattress making it possible to marry the reliefs of printed circuits. In addition, known presses only allow a single multilayer printed circuit to be laminated in the interval between two press plates, because compression is directly ensured by bringing the plates together. Finally, the latter are bulky and heavy elements, machined in the mass, and made of expensive materials (generally stainless steel) and their heating is expensive. In general, the efficiency of the heating and cooling installation is low.

 By the invention, it is proposed to remedy these drawbacks, and the object of the invention is a method and a laminating press making it possible to increase the productivity of the operation by the simultaneous treatment, in a single interval between two plates. , of several multilayer printed circuits, some of which may be rigid, and previously arranged in tools, while others may be flexible and installed without tools.

 Another object of the invention is to propose a method and a laminating press making it possible to overcome the flatness and parallelism defects of the plates, and to ensure the compression of the circuits to be laminated by the application of pressure uniform on them.

 Yet another object of the invention is to propose a method and a laminating press making it possible to save on compression mattresses and other "blotters" for the laminating of flexible multilayer printed circuits.

 The invention further aims to provide a method and a laminating press for the use of lighter trays, less complex, and therefore more economical.

 Another object of the invention is to propose a method and a laminating press using heating means more efficient than those of the prior art laminating presses, and making it possible to obtain better homogeneity of the temperature during the heating and cooling cycle.

 Yet another object of the invention is to provide a method and a laminating press for laminating flexible circuits in several stages in a single interval between two plates, in order to provide excellent productivity.

 Another object of the invention is to propose a method and a press for laminating multilayer printed circuits which can also be implemented as a method and press for laminating documents or flat elements such as memory cards and / or microprocessor.

 A final object, finally, of the invention is to propose a device made up of a set of components making it possible to transform or modify a laminating press of the state of the art into an autoclave press providing the advantages mentioned above, such a transformation being particularly advantageous if the press that is transformed is a press with one or two stations with automatic loading and unloading.

To this end, the subject of the invention is a method for laminating multilayer printed circuits and / or for laminating documents, comprising the steps which consist of:
- to have at least one product to be treated, such as a multilayer printed circuit to be laminated or a document to be laminated between two plastic films, in an interval delimited between two plates substantially parallel to each other and mounted movable , in a direction substantially perpenicular to their plans, on a press stand,
- to move the plates towards one another and to lock them in a position of approach,
- subject each product to be treated to hot compression,
- to cool and decompress each product to be treated, then
- to spread the trays to evacuate each treated product, and it is characterized in that it consists:
- sealingly enclosing each product to be treated in an envelope arranged in the meantime and the parts of which are located on either side of the product or products to be treated are flexible and deformable,
of
- to block a rigid lateral part / the envelope in position between the two locked plates in the approximation position, so as to delimit at the outside of the envelope and inside the interval at least one sealed chamber extending on either side of each product to be treated,
connecting the sealed chamber delimited inside the envelope to a source of vacuum by at least one passage passing through the envelope, and
- to connect each sealed outer chamber to the envelope to a source of pressurized fluid, in order to apply deformable parts of the envelope against each product to be treated with a uniform pressure ensuring the necessary compression, then
- relieve the pressure in each outer chamber and return the inner chamber to ambient pressure, in order to decompress each product to be treated. This gives the combined effects of putting the inner chamber under vacuum and the pressurization of the chamber or chambers external to the envelope force the flexible and deformable parts of the latter to closely match the external shape of the flexible circuits and of the flexible parts of the flexo-rigid circuits or of the tools loaded with rigid circuits or rigid parts . flexo-rigid circuits, which gives the certainty of a good application of uniform pressure on the circuits to be compressed.

 By analogy with the presses of the prior artjet in order to be able to transform them at the lowest cost, the heating of the products to be treated can be ensured by conduction from the heating of the trays, but, preferably, according to a characteristic specific to 1 the invention, the method consists in heating and / or cooling the pressurization fluid of at least one of the chambers external to the envelope, and in ensuring by conduction the heating of the product or products to be treated. This allows significant savings in heating and possibly the use of insulating and / or cell trays. Advantageously, in order to maintain good temperature uniformity, the process also consists in maintaining a mixing of the hot and then cold fluid. in the corresponding external chamber or chambers, during the pressurization cycle of this or these chambers. In order to facilitate the implementation of the process, a neutral gas such as nitrogen is advantageously used as the pressurization fluid.

 Advantageously, the method according to the invention consists in controlling the pressurization of each chamber outside the envelope only after a certain time interval following the start of the depressurization of the chamber inside the envelope, and preferably , also after the start of heating of the product (s) to be treated. In this way, the evacuation of the internal chamber purges the stack of the various layers of the printed circuit of air bubbles, water vapor and other impurities which are thus extracted. Likewise, the layers of fabrics of mineral or organic fibers, for example glass, which are pre-impregnated with a heat-polymerizable resin, and which are stacked with conductive layers and insulating layers, are thus purified to form a printed circuit. multilayer to laminate.

 To laminate documents or flat elements, the method consists in having at least one product to be treated in an interval between two plates only after having mounted it in tools, by placing each product to be treated between two non-stick coatings, by placing the subassembly thus obtained between two metal sheets, and by centering the different layers of the stack thus produced before enclosing the latter in the envelope. The non-stick coatings thus used make it possible to ensure protection against the creep of the resin of the prepreg layers of the multilayer circuits, so that this resin does not adhere to the tools. By analogy with the currently used layering process, for layering rigid circuits that can have up to twenty superimposed layers, the mounting of at least one product to be treated in tools also consists of placing the stack of the product or products to be treated, the two non-stick coatings and the two metal plates to be treated, between two thick metal plates and also to center the latter with the other layers of the stack thus produced before enclosing the latter in the envelope. In the latter case, the method advantageously also consists in protecting the flexible and deformable parts of the envelope from the metal plates of the tools by sticking pieces of adhesive tape on the corners of said metal plates. easily ensures centering - of the tools and products to be treated that they contain with respect to the casing / sgvant of compressing the product (s) to be treated and mounted in the tools, these are placed on support and centering shims tools in the envelope.

The subject of the invention is also urepresseautoclave for implementing the method according to the invention and comprising:
- a column frame,
- at least two plates substantially parallel to one another and mounted to slide on the frame in a direction substantially perpendicular to their planes,
- at least one device for operating the plates, controlling their approach and spacing as well as the locking of the plates enpeSi-iOn - :: n approach,
- at least one heating circuit for at least one product to be treated, such as a multilayer printed circuit to be laminated or a document or flat element to> tastifier2r between two plastic films, which is arranged in a delimited interval between two neighboring plateaus and possibly
at least one cooling circuit for each product to be treated, and the autoclave press according to the invention is characterized in that it further comprises, for at least one interval between two plates, but preferably for each interval,
- at least one rigid frame pierced with at least one suction channel and intended to be disposed between the two plates or between a plate and a rigid auxiliary frame, pierced with at least one pressurization channel and arranged in the meantime , or between two auxiliary frames, and around at least one product to be treated,
- At least one pair of watertight, flexible and deformable bladders, the two bladders of which are intended to be arranged each between one face of a frame and the opposite face of a plate or an auxiliary frame, so as to be extended one above and the other below at least one product to be treated and surrounded by this frame, and
- bladder protection members, comprising, for each frame, at least two layers of a coating
each non-stick, intended to be deposited / between one of the two bladders, corresponding to this frame and the product or products to be treated in this frame, and in that each of the two plates is pierced with at least one channel pressurization which opens in the meantime and inside the adjacent frame, so that after locking the plates in the approaching position, each bladder is tightly sealed between a corresponding frame and a corresponding plate or auxiliary frame, and each frame and the two corresponding bladders define around the product or products to be treated in this frame, a vacuum chamber intended to be connected by each suction channel to a source of vacuum, while each of the two corresponding bladders delimits, with the facing a plate adjoining the corresponding frame and inside it or with another bladder clamped against an auxiliary frame adjoining the corresponding frame, a pressurized chamber it is necessary to be connected, by each pressurization channel of this plate or of this adjoining auxiliary frame, to a source of pressurized fluid, in order to compress the product or products to be treated between portions of the two corresponding bladders.

Advantageously, each suction channel of the frame (s) is connected to a vacuum pump by leaktight pipes on which is mounted at least one valve controlling the isolation or the venting with possible adjustment of the vacuum in the depres chamber (s)
if we. In addition, each plate pressurization channel and
if necessary, the auxiliary frame (s) is connected to a
accumulator of a pressurized neutral gas, such as azo
te, by watertight pipes on which is mounted at
minus a valve controlling the supply and possibly
the feed speed of the pressurization chambers,
as well as their decompression.

As in the state of the art laminating presses
the technique, the heating circuit and / or the heating circuit
can be drowned in the trays, but
lon a characteristic of the invention, the circuit
heating and / or cooling system include
pressurization chambers and channels as well as conduits
your waterproof connection to a heating and / or re
cooling of the pressurizing fluid, which is heated and /
or cooled in passing in this group before entering the
pressurization chambers. Advantageously, the cir
cooked heating and / or cooling includes a pump
traffic, mounted on a tight pipe loop which
is closed on the pressurization chambers and which passes through
heating and / or cooling groups.

In addition, the layers of the non-stick coating
of bladder protection advantageously consist of
sheets of glass fiber fabrics agglomerated by a mate
low friction coefficient such as poly-tetra
fluoroethylene. This avoids undulations of the cir
cooked soft prints that could be caused by
pressure bladders because these coatings have excellent
sliding coefficient In addition, these coatings protect
also the bladders against possible leakage of the resin
pre-impregnated layers of printed circuits.

For laminating, the press includes
tools, in the form of at least one pair of metal sheets
liques, between which are intended to be arranged two
non-stick coatings to be spread on both sides of 0 minus / product to be treated, the opposite faces of the two metal sheets
that pair having a mirror polished surface condition, the product or products to be treated, the two coatings and the two metal sheets being intended to be assembled in a centered stack using at least two centering pins passing through the stack which is intended to be placed in an interval between the two layers of the non-stick protective coating of two bladders.

 For the stratification of a rigid circuit, or rigid parts of flexo-rigid circuits, the tools further comprise, for each pair of pairs of sheets, a pair of metal plates intended to be centered against the sheets and outside of these in a pinned stack containing at least one product to be treated.

 Preferably, the two non-stick coatings of the tools are sheets of aramid fiber fabrics, for example from Tedlar (registered trademark).

The subject of the invention is finally a device for converting into an autoclave press for laminating multilayer printed circuits and / or for laminating documents, a laminating press which comprises:
- a column frame,
- at least two plates substantially parallel to each other and mounted to slide on the b ti in a direction substantially perpendicular to their planes,
at least one member for operating the plates, controlling their spacing, their bringing together and their locking in the close position, and
a heating circuit and / or a cooling circuit which are at least partially integrated in the plates, the device according to the invention being characterized in that it comprises:
at least one rigid frame pierced with at least one suction channel and intended to be placed between two plates and around at least one product to be treated, and for each frame,
- At least one pair of bladders, waterproof, flexible and deformable, the two bladders of which are each intended to be tightly sealed against a face of the corresponding frame, on either side of the product or products to be treated and surrounded by the frame and
- At least two sheets of a non-stick coating, each intended to be deposited between a bladder and the product or products to be treated in this context.

 Preferably, this transformation device also comprises a vacuum pump, at least one pipe for connecting the vacuum pump to the suction channels of the frame or frames, and at least one control valve. Preferably, there is also provided at least one pipe for connecting an accumulator of a neutral pressurized fluid to at least one pressurization channel which is to be drilled in each of the press plates, as well as at least one control valve. to be mounted on this connection pipe.

 Advantageously, if one wishes to push the transformation to the heating and / or cooling circuit, the transformation device also comprises a heating and / or cooling group and a pump for circulation of the neutral fluid under pressure, which are intended to be mounted on at least one pipe for transporting the neutral fluid under pressure. In this case, the transformation device can also comprise / agoins two insulating plates, each pierced with at least one pressurization channel, and substitutable for the plates with a partially integrated heating and / or cooling circuit of the press to be transformed.

 Of course, this transformation device can also include tools as presented above for the stratification of circuits or parts of rigid circuits and for the plasticization of flat elements.

 Finally, to allow the stratification of flexible printed circuits in several stages in a single interval between two press plates, the transformation device advantageously comprises at least one rigid auxiliary frame, pierced with at least one pressurization channel, and intended to be , on the one hand, clamped between two frames arranged in this same interval, with interposition of bladders, and, on the other hand, connected to a source of pressurized fluid.

Other advantages and characteristics of the invention will emerge from the description given below, without implied limitation, with reference to the appended drawings in which:
FIG. 1 schematically represents, partly in section and partly in side elevation, an autoclave press to be laminated at two intervals or stages in the layering configuration of rigid multilayer printed circuits,
FIG. 2 schematically shows in section the centered stacking of a rigid multilayer printed circuit in tooling and which is prepared before installation in an interval of the autoclave press of FIG. 1,
- Figures 3 and 4 show schematically in section a single interval or stage of the autoclave press of Figure 1, respectively before and after the locking of the two plates, for the stratification of one or more rigid multilayer printed circuits mounted in tools, as shown in Figure 2,
FIG. 5 schematically represents, in section, the stratification of a flexible multilayer printed circuit in a single interval of an autoclave press,
FIG. 6 represents in a similar manner the stratification in stages of several flexible multilayer printed circuits in a single interval of the autoclave press; and
- Figure 7 schematically shows the stratification of a rigid multilayer printed circuit in a single interval of an autoclave press equipped with a vacuum circuit whose pipes are represented by a single solid line and a circuit pressurization whose pipelines are represented by a double continuous line.

 Referring to Figure 1, the autoclave press includes a rigid frame 1 supporting vertical columns 2 along which horizontal plates 3, relatively thick and made of stainless steel, are slidably mounted. In this example, the autoclave press comprises three plates, which delimit two by two, between them two intervals or stages in which the multilayer printed circuits to be laminated are arranged. The lower plate 3 rests on a piston 4 supported at the upper end of the rod 6 of an actuating and closing cylinder 5, the cylinder 7 of which is secured to the lower cross members of the frame 1. The cylinder 5 can be a cylinder of any known suitable type, for example hydraulic, mechanical, electromechanical or electric, and it is equipped with a locking device, also of any known suitable type, for example hydraulic, mechanical, electromechanical or electric, in order to be able to block the rod 6 relative to the cylinder 7 in any desired position and in particular in -ds: ition ^ of closing the autoclave press, in a position of approaching the plates 3, in which the upper plate 3 is in abutment against upper cross members of the frame 1. In each of the plates 3 are partially integrated a heating device and a ~~ reroidasseSent device identified as a whole by the reference 8. These devices are for example constructed killed from a network of shielded electrical resistances which are embedded in the plates 3 alternating with pipes of an internal network to the plates 3 and which is connected to an external source of a refrigerant, the regulations of the current passages respectively electric in the resistors and refrigerant in the pipes allowing to control the heating PU: i Cooling of the plates 3 according to desired laws as a function of time. These heating and cooling devices 8 can also include networks of pipes internal to the plates 3 and successively traversed by a heat transfer fluid, such as a thermofluid or steam, then / Rrfluid refrigerant, such as water, air, a mixture of water and air or a thermofluid.

At this point in the description, the autoclave press described above is no different from the prior art laminating presses. By analogy raya implementation of the latter for laminating rigid multilayer printed circuits or the rigid parts of flexo-rigid multilayer printed circuits, which are laminated in two operations (one for the rigid parts and one for the flexible parts), these circuits or parts of rigid printed circuits are mounted in tools before being loaded into the intervals of the autoclave press. This preliminary preparation is described with reference to FIG. 2: it consists in placing a plate on a support. steel 10a, then cover it with a stainless steel sheet 11a, one face of which, having a mirror-polished surface, faces upwards. Then spread on this face of the sheet 11a a non-stick coating, for example a sheet
from Tedlar 12a. The stack of layers of the multilayer printed circuit (s) 9 is then placed on this sheet 12a, which is covered with a second non-stick coating (sheet of Kevlar fabrics) 12b. On the latter, we place a sheet 11b, identical to sheet 11a but whose mirror polished side is facing down, then we have a second steel plate 10b, identical to plate 10a, on the second sheet 11b .The different layers of the stack thus produced are centered by centering pins 13, which pass through holes drilled opposite one another in the different layers. The pinned and centered assembly constitutes a tool 14 loaded with one or more rigid circuits or rigid part of multilayer integrated circuits to be laminated.

 Such loaded tooling 14 is then placed in an interval, between two plates 3, in the manner described below with reference to FIGS. 3 and 4.

A flexible, deformable and waterproof membrane or bladder 15a is placed on the lower plate 3 of two plates spaced apart in the open position. To make this bladder 15a, for example, the material sold in France under the name of oMOSI-TE by the Company is used.
SCEI, 2 Avenue Kléber Paris. The property of such a bladder is to be vacuum and nitrogen tight under pressure, to have good mechanical and heat resistance, to have great flexibility and a good coefficient of elongation. in a first reference, this material has an elongation coefficient of 300% and withstands a temperature of 2000C and in a second reference, its aionic coefficient k5 is yu Qe 100%, but it resists a maximum temperature of 2500C. Then deposited on the central part of this bladder 15a, a non-stick coating, consisting of a sheet 16a of a fabric of glass fibers impregnated with a polytetrafluoroethylene, then the loaded tooling 14 is positioned on the sheet 16a , after taking care to cover the corners and angles of the tool 14 with protective elements 17, produced for example by gluing pieces of adhesive tape. Then the tool 14 is covered with a second non-stick coating, namely a second sheet 16b identical to sheet 16a, and a rigid frame 18, made of steel or Duralumin, is positioned around the stack thus obtained, which follows the periphery of the lower plate 3 and rests on the peripheral edge of the bladder 15a . This frame 18 is pierced laterally, on each side, with a vacuum channel 19. In order to facilitate centering of the tool 14 in the frame 18, it is possible, as shown in FIG. 4, to use shims of support and centering 20 which is then placed first on the lower plate 3, before placing the bladder 15a. After the setting up of the frame 18, there is a second bladder 15b, identical to the bladder 15a, on the upper face of the frame 18 and by covering the stack surrounded by the latter, then the press is closed using the jack 5 (see FIG. 1), which causes the frame 18 to be blocked between the two plates 3 , with pinching of the peripheral edges of the bladders 15a and 15b between this frame 18 and the plates 3 (see FIG. 4).

 An essential characteristic of the plates 3 of the autoclave press with respect to the plates of the prior art laminating presses is that they each have at least one bent channel 21, one end of which opens out towards the plate 3, in a lateral face of the latter, and the other end of which opens towards the interior of the gap between the two plates 3, and at a sufficient distance from the edge of the plates for this channel 21 to open inside the frame 18. These channels 21 have been shown in FIGS. 3 and 4, but not in FIG. 1, so as not to overload the latter, but it should be understood that the plates 3 of FIG. 1 are also pierced with such canals.

 By the cooperation of the bladders 15a and 15b with the frame 18, there is defined, after closing the press, an internal sealed chamber 22 which contains the tool 14 and which does not communicate with the outside of the interval defined between the two plates 3 as through the channels 19 of the frame 18. Simultaneously, the bladders 15a and 15b delimit with the parts of the opposite faces of the plates 3 which are located inside the frame 18, two sealed external chambers 23, located one at above and the other below the internal chamber 22, and which communicate with the outside of the interval only through the channels 21 of the plates 3.

 The channels 19 are then placed in communication with an external vacuum source, for example a vacuum pump, the start of the heating cycle of the plates 3 is controlled, then, after a certain time interval, the channels 21 are put in communication with an external source of a neutral pressurized fluid, for example a pressurized nitrogen accumulator. This evacuation of the internal chamber 22 containing the loaded tooling 14 makes it possible to purify the prepreg layers of resin not yet polymerized from the rigid printed circuits or rigid parts of flexorigid printed circuits 9 and to purge the stack of air bubbles , water vapor and sde2E impurities it may contain.The heating of the trays 3 is carried out according to a law allowing to reach a maximum temperature of 2500C at the circuits 9, and the pressurization of the external chambers 23 s 'also performs according to a progressive law until a maximum pressure of approximately 2 MPa. The combined effects of placing the chamber 22 under vacuum (arrow V) and the pressurization of the chambers 23 (arrow P) cause deformation of the bladders' = a e; ui épvas ^ nv t-itement-the external form of the tool 14 and exert on it a compression, with a uniform application of pressure. This leads to good compression of the rigid circuits or rigid parts of printed circuits 9. The elements 17 for protecting the corners and angles of the tool 14 and the sheets 16a and 16b of a non-stick coating prevent deterioration of the bladders 15a and 15b during their deformation. In addition, the sheets 16a and 16b prevent wrinkling or the formation of undulations on the printed circuits 9 which could be caused by the deformation under pressure of the bladders, due to the excellent sliding coefficient of these sheets 16a and 16b, which , moreover, protect the bladders 15a and 15b against possible spillage of the resin outside the printed circuits, just as, in the loaded tool 14, the sheets 11a and llb and the plates 10a, 10b are protected against creep of the resin by the sheets 12a and 12b of Kevlar fabric.

 In FIG. 1, the autoclave press comprises three plates 3, therefore two intervals or stages, in each of which a tool loaded 14 has been mounted in the manner described with reference to FIGS. 2 to 4. In addition, there are shown by double continuous lines the pipes 24 supplying the chambers 23 with nitrogen under pressure, these pipes 24 being connected to the channels 21 drilled in the plates 3. If the plates 3 lower and upper can be satisfied with the channels 21 opening respectively in their upper faces and lower, the intermediate plate 3 has channels 21 opening into its upper face and into its lower face. In fact, all the plates can have channels 21 opening into their upper and lower faces, but these channels can be selectively connected to 1 pressurized nitrogen accumulator, according to the needs and the position of each tray.

 After the heating phase of the plates 3, their cooling phase is controlled, while maintaining the evacuation of the internal chambers 22 and the pressurization of the external chambers 23. Then, at the end of the cooling phase, the depressurization of the chambers 23, and finally the gradual bringing to room pressure of the chambers 22. The pressautoclave is then opened by spreading the plates 3 using the jack 5, the tools 14 are unloaded and the printed circuits are removed from the latter laminates.

In Figure 5, there is shown a presseautoclave stage similar to that of Figure 5, so that the same components have been identified by the same references. However, this autoclave press stage is used in this case for the stratification of a flexible multilayer printed circuit 9 ′. This flexible circuit 9 ′ is not mounted in a tool, but simply placed between the two sheets 16a and 16 b of glass fiber fabric impregnated with polytetrafluoroethylene (PTFE), and the bladders 15a and 15b directly compress these sheets 16a and 16b as well as the circuit 9 ', when the internal chamber 22 is put under vacuum by the connection of the channels 19 of the frame 18 to the vacuum pump, and when the external chambers 23 are pressurized by the connection of the channels 21 of the plates 3 to an accumulator of neutral gas under pressure
In this example, the sheets 16a and 16b not only protect the bladders 15a and 15b against the flow of resin from the flexible printed circuit 9 'to be laminated, but they prevent undulations which could form on this flexible circuit 9' come from the deformation under pressure of the bladders 15a and 15b, this advantageous result being obtained due to the good sliding coefficient of the glass fabric impregnated with PTFE.

 In FIG. 6, there is shown an assembly allowing, in a single interval between two plates 3, to laminate several flexible multilayer printed circuits 9 ′ in several stages. In this arrangement, the constituent elements similar to those of the preceding figures have been identified by the same references. This assembly comprises three identical frames 18, each pierced with these suction channels 49, and arranged vertically one above the other, being separated in pairs by a rigid auxiliary frame 25, also made of steel or duralumin, also pierced with lateral channels 26 on each side, and which differs from a frame 18 only in its height, which is lower than that of the latter. This assembly therefore comprises two auxiliary frames 25 separated from each other and each of the tray 3 closest by a frame 18. To each frame 18 is associated, as before, a pair of bladders 1Sa and 15b. Between the two bladders of each pair is disposed a multilayer printed circuit 9 'sandwiched between two sheets of glass fabric impregnated with PTFE 16a and 16b. The assembly is mounted so that when the autoclave press is closed, by bringing the plates 3 closer together, the lower bladder 15a of the lower frame 18 is pinched between the latter and the lower plate 3, and the upper bladder 15b of this - lower frame is pinched between the latter and the lower auxiliary frame 25. The lower bladders 15a and upper 15b of the middle frame 18 are pinched between this frame 18 and the auxiliary lower and upper frames 25 respectively, and the lower bladders 15a and upper 15b of the upper frame 18 are pinched between this frame and the auxiliary frame respectively 25 upper and the upper plate 3. Three internal chambers 22 are thus formed, each delimited between a frame 18 and the two corresponding bladders 15a and 15b. Between the lower plate 3 and the lower bladder 15a of the lower frame 18, and between the upper plate 3 and the upper bladder 15b of the upper frame 18, two external chambers 23 are defined. Finally, between the upper bladder 15b of the lower frame 18 and the lower bladder 15a of the middle frame 18, on the one hand, and, on the other hand, between the upper bladder 15b of the middle frame 18 and the lower bladder 15a of the upper frame 18, two auxiliary sealed chambers 23 'are formed , each of which communicates with the outside only through the channels 26 of the auxiliary frames 25. By connecting all the channels 19 of the frames 18 to a vacuum pump, the three chambers 22 are placed under vacuum, then, by connecting the channels 21 of the two plates 3 and all the channels 26 of the auxiliary frames 25 to a pressurized neutral gas accumulator, the two chambers 23 and the two chambers 23 ′ are pressurized, as shown in FIG. 6. the bladders 15a and 15b, and therefore the compression of the three flexible printed circuits 9 '. In this example, the heating, pressurization, cooling, depressurization and venting vacuum cycle is carried out as in the previous example, the plates 3 also being in this case heating plates and coolers.

 In Figure 7, there is shown the assembly of a laminating installation comprising a single autoclave press stage which is identical to that of Figure 4, for the stratification of one or more rigid multilayer printed circuits or rigid parts of flexo-rigid printed circuits 9 mounted in tools 14. The constituent elements of this autoclave press stage are therefore identified by the same references as in FIG. 4, and they are not described again.

 In this installation, the channels 19 of the frame 18 are connected by conduits 27 which meet, to a vacuum pump 29 of a motor pump group 28 whose electric motor 30 drives the vacuum pump 29. From upstream to downstream on the pipe connecting to the pump 29, and from the junction point of the two pipes 27, a control pressure gauge 31, a blocking electro-valve 32 and a filter 33 are mounted on this pipe liaison. On this one is also connected, in bypass, between the junction of the two pipes 27 and the blocking electro-valve 32, a vent pipe 34, on which they are mounted, from upstream downstream, an electro-vent valve 35 and a vacuum adjustment valve 36. The channels 21 of the two plates 3 are connected to a pressurized nitrogen bottle 37 by lines 38 which meet and are connected to a regulator and pressure gauge assembly 39 mounted at the outlet of the bottle 37. A nitrogen supply solenoid valve 40, a feed speed adjustment valve 41 and a pressure gauge control 42 are mounted on the common part of the pipes 38, from upstream to downstream. Between the valve 41 and the pressure gauge 42, a decompression line 43 is connected in bypass and an electro-decompression valve 44 is mounted on this line 43.

In addition, a loop pipe 45 connects the two branches of the pipes 38 which supply the channels 21 situated on the two opposite sides of the plates 3, in order to constitute a closed loop on the two chambers 23, and a motor-pump group 46 with pump. circulation 47 driven by an electric motor 48, is mounted on this loop pipe 45, in order to ensure, after pressurization of the chambers 23, a continuous circulation of nitrogen, and therefore a mixing favoring the homogeneity of the stratification temperature.

 In this example, heating and cooling can be provided, as in the previous examples, by conduction from the heating and cooling plates 3. However, preferably, a heating and cooling group 49 is mounted on the supply lines 38 and on the loop line 45 in order to be able to heat and cool successively the nitrogen which is used as pressurizing agent for the chambers. 23. The use of nitrogen or another neutral, gaseous or liquid fluid, simultaneously as a pressurizing fluid and as a heating and cooling fluid makes it possible to achieve significant savings.

It is also possible to use trays 3 devoid of heating and cooling devices, these trays then being able to be thinner and, for example, dimpled, and even thermally insulating.

 The control of the operation of the valves 36 and 41 and of the solenoid valves 32, 35, 40 and 44, the control of the supply of the motors 30 and 48 to drive the pumps 29 and 47, as well as the control of the operation of the group of heating and cooling 49 are ensured according to a programming by microprocessor setpoint generator, so that the heating, cooling, depressurization and pressurization are carried out according to predetermined laws.

To laminate documents or flat objects, using the Aitscidessus ~ autoclave press examples ountilise tools limited, for example, to two sheets of stainless steel or chrome-plated brass, having a mirror-polished face and a thickness about 1 mm, such as the two sheets îîa and llb of Figure 2, and there is between them the document or documents or flat objects to be laminated and previously sandwiched between the two sheets
12a and 12b of Kevlar fabric for the rest, the procedure is the same.

 Note that in the autoclave presses described above, it is possible to have between two bladders several multilayer printed circuits, some of which are housed in tools and others of which are not.

Finally, by the use of a set of components comprising frames and auxiliary frames, bladders, non-stick coatings and tools as described above, as well as a vacuum pump, an accumulator
/ of a neutral pressurized fluid and of the corresponding regulation valves and solenoid valves, it is possible to transform a laminating press of the state of the art into a self-clave press according to the invention. If, in addition, it is desired not to use the heating and cooling devices which are fitted with the plates of the transformer press, one can also provide, in the transformation device, a heating and cooling unit and a grouI: in: ot, continuous circulation pump for pressurizing fluid.

Claims (27)

 1. Method for laminating multilayer printed circuits and / or laminating documents and flat elements, comprising the steps consisting of:  - to have at least one product to be treated (9), such as a multilayer printed circuit to be laminated or a do cument to be laminated between two plastic films,  a in / interval delimited between two plates (3) substantially parallel to each other and mounted movable, in a direction substantially perpendicular to their plane, on a press frame (1),  - to move the plates (3) relative to each other and to lock them in a closer position,  - subject each product to be treated () to hot compression,  - to cool and decompress each product to be treated (9), then  - spreading the trays (3) to evacuate each treated product (9), characterized in that it consists of:  - sealingly enclosing each product to be treated (9) in an envelope (15a, 15b, 18) arranged in the meantime and the parts (15a, 15b) of which are located on either side of the product or products process (9) are flexible and deformable,  - to block a rigid lateral part (18) of the envelope in position between the two plates (3) locked in the approaching position, so as to delimit outside the envelope and inside the gap at least one sealed chamber (23) extending on either side of each product to be treated (9),  - connecting the sealed chamber (22) delimited inside the envelope to a vacuum source (29) by at least one passage (19) passing through the envelope, and  - connecting each sealed chamber (23) outside the envelope to a source of pressurized fluid (37), in order to apply deformable parts (15a, 15b) of the envelope against each product to be treated (9) with a uniform pressure ensuring the necessary compression, then  - releasing the pressure in each sorting chamber (23) and bringing the interior chamber (22) to ambient pressure, in order to decompress each product to be treated.  2. Method according to claim 1, characterized in that it consists in heating the plates (3) and in ensuring by conduction the heating of the product or products to be treated (9)  3. Method according to claim 1, characterized in that it consists in heating and / or cooling the pressurization fluid of at least one of the external chambers (23) to the envelope and in ensuring by conduction the heating of the or products to be treated (9).  4. Method according to claim 3, characterized in that it consists in maintaining a stirring (47, 45) of the hot then cold fluid in the external chamber or chambers (23) corresponding during the pressurization cycle of this or these chambers.  5. Method according to one of claims 1 to 4, characterized in that it consists in using a neutral gas, such as nitrogen, as pressurizing fluid.  6. Method according to one of claims 1 to 5, characterized in that it consists / control the pressurization of each outer chamber (23) to the envelope only after a certain interval & time following the start of the setting under pressure from the interior chamber (22) to the envelope and, preferably, also from the heating of the product or products to be treated (9)  7. Method according to one of claims 1 to 6, for the stratification of rigid circuits and rigid parts of flexo-rigid circuits, or for the plasticization of documents and flat elements, characterized in that it consists in having at least a product to be treated (9) in the interval between two plates (3) after having mounted it in the tools, by placing each product to be treated between two non-stick coatings (12a, 12b), by placing the sub- assembly thus obtained between two metal sheets (11a, 11b), and by centering the different layers of the stack thus produced before enclosing the latter in the envelope (15a, 15b, 18d.  8. Method according to claim 7, for the stratification of a rigid circuit and rigid parts of a flexo-rigid circuit, characterized in that the assembly of at least one product to be treated (9) in tools consists of more to place the stack of the product or products to be treated, the two non-stick coatings (12a, 12b) and the two metal sheets (1a, llb) between two metal plates (10a, 10b) and also to center the latter with the other layers of the stack thus produced in order to enclose the latter in the envelope.  9. Method according to claim 8, characterized in that it consists in protecting the flexible and deformable parts (15a, 15b) of the envelope against the metal plates (10a, 10b) of the tools by gluing pieces adhesive tape (17) on the corners of said metal plates.  10. Method according to one of claims 8 and 9, characterized in that it consists before compressing the product or products to be treated (9) and mounted in tools (14), to arrange the latter on support wedges and centering (20) of the tools in the envelope (15a, 15b, 18).  11. Autoclave press for laminating multilayer printed circuits and / or for laminating documents or flat elements, for implementing the method according to one of claims 1 to 10, comprising:  - a frame (1) with columns (2),  - at least two plates (3) substantially parallel to each other and mounted to slide on the frame (1) in a direction substantially perpendicular to their planes,  at least one operating member (5) of the plates (3) controlling their approach and their spacing as well as the locking of the plates in the approach position,  - at least one heating circuit (8) of at least one product to be treated (9), such as a multilayer printed circuit to be laminated or a document to be laminated between two plastic films, which is arranged in a defined interval between two neighboring trays (3), and, optionally, at least one cooling circuit (8) for each product to be treated, characterized in that it further comprises, for at least one interval between two trays (3), and preferably for each interval,  - at least one rigid frame (18) pierced with at least one suction channel (19), and intended to be disposed between the two plates (3) or between a plate (3) and a rigid auxiliary frame (25) pierced with at least one pressurization channel (26) and arranged in the interval, or even between two auxiliary frames (25) and around a product to be treated (9, 9 '),  - At least one pair of flexible and deformable waterproof bladders (15a, 15b), the two bladders of which are intended to be arranged each between one face of a frame (18) and the opposite face of a plate (3 ) 'or an auxiliary frame (25), so as to be extended, one above and the other below at least one product to be treated and surrounded by this frame, and  - bladder protection members (15a, 15b) comprising, for each frame (18) at least two layers of a non-stick coating (16a, 16b), intended to be deposited each between one of the two bladders ( 15a, 15b) corresponding to this frame (18) and the product or products to be treated in this frame, and in that, each of the two plates (3) is pierced with at least one pressurization channel (21) which opens into the interval and inside the adjacent frame (18), so that after the trays (3) have been locked in the approaching position, each bladder is tightly tightened between a corresponding frame and a tray or a frame corresponding auxiliary, and each frame (18) and the two corresponding bladders (15a, 15b) delimit, around the product or products to be treated in the frame (18), a vacuum chamber (22) intended to be connected by each suction channel (19) to a source of vacuum (29), while each of the two bladders (15a, 15b) delimits, with the fac e opposite a plate (3) contiguous to the corresponding frame and inside the latter or with another bladder clamped against an auxiliary frame (25) contiguous to the corresponding frame, a pressurization chamber (23, 23 ') intended to be connected, by each pressurization channel (21, 26) of this plate (3) or of this adjoining auxiliary frame (25), to a source of pressurized fluid G 7) in order to compress the product or products to be treated (9,9 ') between portions of the two corresponding bladders.  12. Autoclave press according to claim 11, characterized in that each suction channel (19) of the frame or frames (18) is connected to a vacuum pump (29) by sealed pipes (27) on which is mounted at least one valve (32, 35, 36) controlling the isolation or the venting with possibly the adjustment of the vacuum in the vacuum chamber (s) (22).  13. Autoclave press according to one of claims 11 and 12, characterized in that each pressurization channel (21, 26) of the plates (3) and, if necessary, of the auxiliary frame or frames (25), is connected to an accumulator of a pressurized neutral gas (37), such as nitrogen, by sealed pipes (38) on which is mounted at least one valve (40, 41, 44) controlling the supply and, optionally , the supply speed of the pressurization chambers (23, 23 ') or their decompression.  14. Autoclave press according to one of claims 11 to 13, characterized in that the heating circuit and / or the cooling circuit (8) are embedded in the plates (3).  15. Autoclave press according to one of claims 11 to 13, characterized in that the heating circuit and / or the cooling circuit comprise the chambers (23, 23 ') and the pressurization channels (19, 26) as well that sealed pipes (38, 45) for connection to a heating and / or cooling group (49) of the pressurization fluid which is heated and / or cooled in the passage in said group (49).  16. Autoclave press according to claim 15, characterized in that the heating and / or cooling circuit comprises a pump (47) mounted on a sealed pipe loop (45) which is closed on the pressurization chambers (23, 23 ') and which passes through the heating and / or cooling group (49).  17. Autoclave press according to one of claims 11 to 16, characterized in that the non-stick coating layers for protecting the bladders (15a, 15b) consist of sheets (16a, 16b) of glass fiber fabric agglomerated by a material with a low coefficient of friction such as a polytetrafluoroethylene.  18. Autoclave press according to one of claims 11 to 17, for the stratification of rigid circuits or rigid parts of flexo-rigid circuits, and for the plasticization of documents or flat elements, characterized in that it also comprises tools, in the form of at least a pair of metal sheets (lla, llb) between which are intended to be arranged two non-stick coatings (12a, 12b) to be spread on either side of at least one product to be treated (9), the opposite faces of the two sheets of each pair having a mirror polished surface state, the product or products to be treated (9), the two coatings (I2a, 12b), and the two metal sheets (lla , la, llb) being intended to be assembled in a centered stack using at least two centering pins (13) passing through the stack which is intended to be placed in a gap, between the two layers of the anti-coating -adhesive (16a, 16b) for protecting two bladders (15a, 15b).  19. Autoclave press according to claim 18, for the stratification of rigid circuits or rigid parts of flexo-rigid circuits, characterized in that the tools further comprise, for each pair of sheets (lla, la, lob), a pair of metal plates (10a, 10b) intended to be centered against and outside the sheets in a pinned stack (13) containing at least one product to be treated (9).  20. Autoclave press according to one of claims 18 and 19, characterized in that the two non-stick coatings (12a, 12b) of the tools (14) are des.feuil- les of aramid fiber fabric.  21. A device for converting into an autoclave press for laminating multilayer printed circuits and / or for laminating documents or flat elements, a laminating press comprising:  - a frame (I) with columns (2),  - at least two plates (3) substantially parallel to each other and mounted to slide on the frame (1) in a direction substantially perpendicular to their planes,  - at least one operating member (5) of the plates (3), controlling their spacing, their bringing together and their locking in the close position,  - a heating circuit (8) and a cooling circuit (8) which are at least partially integrated in the plate (3),  - the device being characterized in that it comprises:  - at least one rigid frame (18) pierced with at least one suction channel (19) and intended to be disposed between two plates (3) and around at least one product to be treated (9), and for each frame (18),  - At least one pair of waterproof, flexible and deformable bladders (15a, 15b), the two bladders of which are each intended to be tightly sealed against one face of the corresponding frame (18), on either side of the products to be treated (9), and surrounded by the frame, and  - At least two sheets of a non-stick coating (16a, 16b) each intended to be deposited between a bladder (15a, 15b) and the product or products (9, 9 ') to be treated in this context (18).  22. Transformation device according to claim 21, characterized in that it comprises a vacuum pump (29), at least one connection pipe (27) of the vacuum pump to the suction channels (19) of the middle frames (18) and at least one control valve (32, 35, 36).  23. Transformation device according to one of claims 21 and 22, characterized in that it comprises at least one connection pipe (38) of a pressurized neutral fluid accumulator (37) to at least one pressurization channel (21) to be drilled in each of the plates (3) of the press and at least one control valve (40, 41, 44).  24. Transformation device according to claim 23, characterized in that it comprises a heating and / or cooling group (49) and a circulation pump (47) of the neutral pressurized fluid, which are intended to be mounted on at least one transport pipe (45, 38) for the neutral fluid under pressure.  25. Transformation device according to claim 24, characterized in that it further comprises at least two insulating plates, each pierced with at least one pressurization channel (21) and substitutable for the plates (3) with heating circuit and / or partially integrated cooling of the press.  26. Transformation device according to one of claims 21 to 25, characterized in that it comprises tools for the stratification of rigid circuits and rigid parts of. flexo-rigid circuit, and for the plasticization of documents or flat elements, said tools comprising:  - at least one pair of metal plates (10a, lOb),  - at least one pair of metal sheets (lia, llb), one face of which has a mirror-polished surface finish,  - at least one pair of non-stick coating sheets (12a, 12b), and  - centering pins (13) of the plates and / or sheets, sheets of coverings and at least one product to be treated (9), which are intended to be assembled in a stack.  27. Transformation device according to one of claims 21 to 26, characterized in that it comprises, for the stratification of flexible circuits (9 ') in several stages in an interval between two press plates (3), at least an auxiliary frame (25), rigid, pierced with at least one pressurization channel (26), and intended to be, on the one hand, clamped between two frames (18) disposed in this same interval, with interposition of bladders ( 15a, 15b), and, on the other hand, connected to a source of pressurized fluid (37).