Abstract:
A setup for assembling, by brazing, a composite panel including at least two parts separated by a filler material and joined together by brazing. The setup includes a furnace to achieve a brazing temperature for brazing the panel, and an assembly device which has a form having a shape similar to the final shape of the panel to be brazed. In particular, the assembly device further includes a pressing device to apply mechanical pressure to at least part of the surface of the panel in a direction allowing the panel to be permanently deformed into a shape which matches that of the form. The pressing device is moved under the action of a spring, and the forces applied by the spring being determined so that, at the brazing temperature, the spring applies the force necessary for deforming the panel against the form.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/FR2012/052583, filed on Nov. 9, 2012, which claims the benefit of FR 11/60277, filed on Nov. 10, 2011. The disclosures of the above applications are incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to the manufacture of cellular core panels, and more particularly, to a device allowing the implementation of a method for brazing such panels. 
       BACKGROUND 
       [0003]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0004]    The use of acoustic attenuation panels, for example in the nacelles of aircraft engines and nacelle elements equipped with such a panel to reduce noise emissions of turbojet engines, is known from the prior art. 
         [0005]    In the case of an exhaust cone (plug), these acoustic attenuation panels generally have a sandwich structure comprising:
       a perforated skin which is permeable to air, external (oriented towards the noise source), called “resistive” or “acoustic” skin, the role of which is to dissipate the acoustic energy,   a cellular core structure of the honeycomb type and,   an inner skin formed by a solid skin (opposite to the noise source), called structuring skin.       
 
         [0009]    In some cases, the acoustic attenuation panels are designed to be installed in a hot area of the nacelle of the aircraft turbojet engine, and particularly in the downstream part of this nacelle through which exhaust gases are expelled. 
         [0010]    The use of acoustic attenuation panels in this exhaust area allows for significantly reducing the sound emissions situated in the range of high frequencies. 
         [0011]    For these particular applications at high temperature, acoustic attenuation panels whereof the outer skin is formed by a perforated metal sheet are generally used, the cellular core structure is metallic, and the inner skin is a solid metal sheet. 
         [0012]    The cellular core structure can then be joined by brazing the solid metal sheet and the perforated metal sheet. 
         [0013]    By definition, brazing is a method for assembling two elements using a filler metal having a melting temperature lower than that of the base metal of the elements. By bringing the filler metal to its melting temperature, the filler metal melts and wets the base metal with which it is in contact and then diffuses within the latter. Then, by cooling the assembly, the filler metal solidifies and provides bonding between the different elements in contact. 
         [0014]    Such assembling operations of acoustic attenuation panels are delicate operations insofar as there is a risk that the acoustic and structural qualities of the panel are affected by these operations such as affecting the mechanical strength of the panel or even a loss of panel acoustic absorption. 
         [0015]    A bad relative positioning of the constitutive elements of the panel after brazing can have an impact on the acoustic and structural qualities of the panel. 
         [0016]    It is thus desirable to be able to best control the relative positioning of the pieces involved during brazing and the braze joint, namely the contact between the brazed elements. 
         [0017]    Moreover, the assembling operations can affect metallurgical properties of the treated panel and have an impact on the surface properties of the latter, which can reduce the aerodynamic performances thereof. 
         [0018]    Devices for assembling pieces to be brazed, in which stress forces are exerted on the pieces to be brazed in order to provide a sufficient contact pressure between the pieces and compensate for the expansions of the latter, are already known. 
         [0019]    These forces tend to avoid deformations of pieces during brazing and to maintain them in their relative shape and positioning. 
         [0020]    These deformations, if not controlled, generate brazing defects such as a poor quality of the braze joints or a local lack of the joint. 
         [0021]    A known device provides for the use of tie rods to apply a mechanical pressure on the elements to be brazed, during brazing. The mechanical pressure may be insufficient during the brazing cycle, particularly during melting of the filler material. The defects of the braze joint may persist. 
         [0022]    Another known device can provide for using means providing a gas pressure on the elements to be brazed, a more easily adjustable pressure to compensate for a decrease in the pressure applied on the pieces and prevent deformations and defects of the braze joints. 
         [0023]    Moreover, such a device can further be used to stretch a piece if necessary while it is brazed, such as, for example, bending it such that it takes the shape of a matrix. 
         [0024]    However, such devices face sealing problems that affect the quality of the pressure during brazing, and the properties of the braze joints that result from the brazing cycle. 
         [0025]    Moreover, these problems multiply the maintenances of devices and the associated costs. 
         [0026]    Furthermore, a risk of telegraphing is encountered, which is a phenomenon wherein, under gas pressure, an acoustic panel skin, for example, would be unintentionally deformed upon its installation on the device. 
       SUMMARY 
       [0027]    The present disclosure provides an assembly device by brazing of a composite panel comprising at least two parts separated by a filler material and intended to be joined together by a braze joint characterized in that it comprises: 
         [0028]    a furnace allowing to reach a temperature for brazing the panel, 
         [0029]    an assembly device comprising a form having a shape similar to the final shape of the panel to be brazed, 
         [0030]    pressing means designed to exert a mechanical pressure on at least part of the surface of said panel along a direction allowing to permanently deform the panel into a shape, the configuration of which complies with that of a form, 
         [0031]    these pressing means being designed to move under the action of elastic forcing means, the forces exerted by said elastic forcing means being determined so that, at the brazing temperature, they exert the forces necessary for deforming the panel against the form. 
         [0032]    Thanks to the present disclosure, there is provided a mechanical assembly device by brazing a panel, easy to implement, which allows for controlling the thermal deformations and expansions of the elements constituting the panel and the braze joint. 
         [0033]    Indeed, such a mechanical device allows to control the stress forces exerted on the panel in order to, on the one hand, provide a proper relative position of the different parts to be brazed, in spite of their respective expansions, throughout brazing, providing therefore a good quality braze joint while allowing to perform, during these expansions, a controlled deformation of the panel into a predetermined final shape. 
         [0034]    According to particular forms of the present disclosure, a device according to the present disclosure can comprise one or several of the following technically feasible features, taken separately or in combination. 
         [0035]    Advantageously, the forces exerted by said elastic forcing means are determined so that, throughout the thermal cycle, they exert the forces necessary to the deformation of the panel against the form. 
         [0036]    Advantageously, the pressing means are movably mounted in translation on a support structure by means of a sliding connection. 
         [0037]    In one form, such pressing means comprise at least one ring formed of a plurality of bearing pads distributed over the surface of the panel on which a mechanical pressure is exerted. 
         [0038]    In another form, the pressing means are provided with at least one travel stop. 
         [0039]    Advantageously, the pressing means are indexed on the support structure. 
         [0040]    In one form, the elastic forcing means comprise leaf springs and/or springs. 
         [0041]    Advantageously, the mechanical pressure exerted by each pressing means is defined independently from the other pressing means. 
         [0042]    In another form, the elastic forcing means are each associated to a locking system defining the tensioning of elastic forcing means. 
         [0043]    As one form, the locking system comprises a wedge system. 
         [0044]    In still another form, the elastic forcing means are designed to become deformed in the direction of the slide. 
         [0045]    In one form according to the present disclosure, the device is made of carbon-carbon material—and in one form is the Sepcarb® brand material, which allows to overcome the effects of flow and deformations generated by the thermal cycles of brazing. 
         [0046]    In one form, the panel is a metal sandwich panel. 
         [0047]    As another form, the panel is a sandwich panel of a cellular core structure. 
         [0048]    The present disclosure also relates to an assembly method by brazing of a composite panel comprising at least two parts separated by a filler material and intended to be joined together by a braze joint implemented by the setup according to the present disclosure wherein: 
         [0049]    the panel is docked on the tooling device; 
         [0050]    the assembly device is placed in the heating means allowing to achieve a brazing temperature of the panel, 
         [0051]    during the thermal cycle and at the brazing temperature, a pressure is exerted by the pressing means on at least part of the surface of said panel in a direction allowing to permanently deform the panel into a shape whereof the configuration conforms to that of the form, these pressing means being designed to move under the action of elastic forcing means, the forces exerted by said elastic forcing means being determined so that, at the brazing temperature, they exert the necessary forces for the deformation of the panel against the form. 
         [0052]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0053]    In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
           [0054]      FIG. 1  is a schematic vertical cross-sectional representation of an assembly device by brazing of an acoustic panel according to the present disclosure, in a position in which the panel is brazed and deformed against a form; and 
           [0055]      FIG. 2  is a schematic cross-sectional representation of the assembly device by brazing of an acoustic panel of  FIG. 1 , seen from above. 
       
    
    
       [0056]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
       DETAILED DESCRIPTION 
       [0057]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
         [0058]      FIG. 1  schematically illustrates an assembly device  1  in accordance with the present disclosure for the implementation of a method of brazing. 
         [0059]    Such a device  1  is arranged inside a brazing furnace, not shown. 
         [0060]    The following examples will be described with respect to an operator requiring to assemble by brazing an acoustic attenuation panel  100 . 
         [0061]    The present disclosure is obviously neither limited to this field of application nor to the types of associated materials. 
         [0062]    An acoustic attenuation panel, designated by the reference  100  on  FIG. 1 , includes, on the opposite side to the origin of the acoustic excitement, an inner skin consisting of a structuring skin formed in a sheet. 
         [0063]    On this structuring skin, a structure of acoustic absorption material is brought, which, in a non-limiting manner, is a structure of honeycomb type. 
         [0064]    An external acoustic skin formed, in a non-limiting manner by a perforated sheet can be brought onto the honeycomb structure. 
         [0065]    This acoustic attenuation panel  100  is designed to be used in high temperature areas, in particular on an aircraft nacelle (in particular the area of expulsion of turbojet exhaust gas). 
         [0066]    Thus, the structuring skin and the acoustic skin may be formed from metallic materials. 
         [0067]    These materials can be selected from metals and/or metal alloys such as titanium, Inconel and all their grades. 
         [0068]    The cellular structure may be formed, for its part, of metallic, polymer, ceramic or composite materials, available on the market. 
         [0069]    The cellular structure can be fixed on the acoustic skin and on the inner skin by a brazing method, with an assembly device according to the present disclosure. 
         [0070]    For this, a filler material interposed between the sheets and the cellular core structure is provided. It can be formed by a strip of braze joint or any other filler material of brazing, such as for example, a powder. 
         [0071]    The melting point of this filler material should be lower than the melting temperature of the base metal of the skins and of the acoustic structure. 
         [0072]    The device is designed to apply to this panel  100 , during brazing, forces which tend to permanently deform from an initial shape of preform to a final shape after brazing. 
         [0073]    More particularly, according to the present disclosure, the device  1  comprises pressing means  30  designed to exert mechanical pressure on at least part of the surface of said panel  100  in a direction allowing to permanently deform the panel  100  into a shape the configuration of which conforms to that of a form  20  during brazing. 
         [0074]    These pressing means  30  are designed to move under the action of elastic forcing means  210 , the forces exerted by said elastic forcing means  210  being determined so that throughout the assembly (of the brazing cycle(s) in particular), and more particularly at brazing temperature, they exert the necessary forces to the deformation of the panel  100  against the form  20 . 
         [0075]    More specifically, with reference to  FIGS. 1 and 2 , the assembly device  1  includes a frame  10  having a basic base  11  and a lid  12 , the base  11  and the lid  12  being connected by a support structure  13 . 
         [0076]    This support structure  13  perpendicular to the base  11  and to the lid  12  is exhibited, according to a non-limiting example a conical framework with a double wall  13   a ,  13   b.    
         [0077]    The base  11  and the lid  12  are designed to allow a docking of the panel  100  to be brazed using clamping means (not shown). 
         [0078]    These clamping means may include, but are not limited to, clamping screws. 
         [0079]    The device  1  further comprises several deformation units  200  of the treated panel, in one example by the number of 96, designed to apply forces to the treated panel  100 , still in the preform phase, during brazing, which tend to deform the panel  100  against the form  20  thus, so that the panel  100  espouses the mark of said form  20 . 
         [0080]    The number 96 of units is given for illustrative purposes and is in no way limiting. 
         [0081]    Each unit  200  is implemented within the brazing furnace facing the form  20  the shape and dimensions of which are complementary to the final shape of the brazed panel  100 . 
         [0082]    This form  20  is a rigid external shell, stationary, integral with the frame  10  and, more particularly, the base  11   
         [0083]    In one form, it consists of two upper and lower parts, this in order to facilitate the unmolding of the panel  100  at the end of the brazing cycle(s). 
         [0084]    Each deformation unit  200  is mounted permanently on the support structure  13  in order to cooperate with the pressing means  30 , themselves indexed, in part, by suitable means on the support structure  13 . 
         [0085]    This support structure  13  is associated, along the panel  100  to be brazed, to one or several superposed rings, each provided with several pressing means  30  providing forces that tend to apply the panel against the form  20 . 
         [0086]    These pressing means  30  may be distributed over the surface of the panel  100  on which each pressing means  30  exerts a local mechanical pressure. 
         [0087]    Specifically, each pressing means  30  comprises at least one pressing sector  32  designed to contact the panel  100 , this pressing sector  32  being slidably mounted relatively to the support structure  13  by means of a sliding connection. 
         [0088]    Each pressing means  30  can move to apply a pressure to the panel  100  to be brazed, this movement being defined as cited above, by the elastic forcing means  210  to which they are associated. 
         [0089]    Each of these is associated with end-of-travel stops limiting their movement and that, as a result, of the panel  100  to be brazed. 
         [0090]    Thus, in one form mode of the present disclosure, illustrated in  FIGS. 1 and 2 , the rings of the pressing sector  32  are superposed by a suitable system, for example of a basket type, along the panel  100  and independently from the conical framework  13 . 
         [0091]    The pressing means  30  may come in the form of a pad  32  driven by a retainer rod  33  provided at its end opposite to the pad  32 , with a supporting head  31 , in simple contact on the corresponding pad  32  and, at the opposite end, a head forming an end-of-travel stop  34  of the rod  33 . 
         [0092]    This retainer rod  33  is mounted permanently in the support structure  13  crossing both walls  13   a ,  13   b.    
         [0093]    As for the heads forming end-of-travel stop  34 , they allow to prevent any exit of the retainer rod  33  from its housing in the support structure  13 . 
         [0094]    They further participate in the locking/unlocking of the corresponding pressing means  30 , as will be described later in the description. 
         [0095]    In one form, the pressing means  30  have an axial stroke, radially with respect to the support structure  13 , of the order of 3 mm in radius. 
         [0096]    It is also to be considered to vary the stroke in an interval of 3 to 10 mm in radius. 
         [0097]    Pertaining to the units of deformation  200 , they include thrust systems of the pressing means  30  of the panel  100 , namely the elastic forcing means  210  but also the locking means  220  providing the tensioning of the elastic forcing means  210  and used to support the latter. 
         [0098]    The elastic forcing means  210  are fixed on the support structure  13  and more particularly, each in a particular concavity formed between the double wall  13   a ,  13   b  by a suitable maintenance system. 
         [0099]    It may be mentioned, as non-limiting example of maintenance system, a ring providing the maintenance of the corresponding elastic forcing means  210  in the framework  13 . 
         [0100]    Furthermore, each elastic forcing means  210  is mounted on the circumference of the retainer rod  33  of the corresponding pressing means  30 , between the supporting head  31  and the locking means  220 . 
         [0101]    The elastic forcing means  210  may come in a non-limiting manner, in the form of a leaf spring or a spring. 
         [0102]    The locking means  220  are also supported by this support structure  13  and arranged in the axis of the sliding connection, opposite the corresponding support pad  32 , between the elastic forcing means  210  and the head forming an end-of-travel stop  34  of the retainer rod  33 . 
         [0103]    The locking means or tapered wedges  220  as will be seen below allow the withdrawal of elastic forcing means  210  so as to provide the placing of the cone of the support structure  13 . 
         [0104]    The tapered wedges  220  are removed after locking the expansion plug on the frame  13  so that the elastic forcing means  210  exert a force on each pad  32 , throughout the assembly and the thermal cycle of the panel  100  and particularly at brazing temperature. 
         [0105]    This force is such that it provides the maintenance of the relative position of the constitutive elements of the panel  100  during their dilatation, while directing the deformation of the panel  100  so that it espouses the shape of the form  20 , resulting in a plastic deformation of the panel  100  into its final shape. 
         [0106]    Experiments, tests, routines, or calculations allow finding the calibration of the elastic forcing means  210 , compared with their relative position on the panel  100  to be heat conformed. 
         [0107]    More particularly, each elastic forcing means  210  is compressed to exert on the corresponding pressing means  30  a force in the direction of the slide, causing a radial displacement of the pressing means  30  which exert as such a compression force perpendicular to the panel surface  100  on the latter. 
         [0108]    In one form, these locking or withdrawal means  220  include wedge systems  221 , each of which defining the clamping force by biasing the corresponding elastic forcing means  210 . 
         [0109]    As illustrated in  FIG. 1 , in an alternative form, each wedge system  221  comprises two complementary beveled corner sections  222 ,  223 , mounted between the inner side (opposite the elastic forcing means  210 ) of the inner wall  13   a  of the support structure  13  and the stop  34  of the retainer rod  33 , on the circumference of the latter. 
         [0110]    The relative movement of these two corner sections  222 ,  223  along the inner side of the inner wall  13   a  of the support structure  13  defines the associated movement of the retainer rod  33 . 
         [0111]    Any other known withdrawal system  220  may be provided. 
         [0112]    During the temperature rise, the skins/sheets and the cellular core structure of the panel  100  are subjected to expansion forces and their relative position may change as they tend to become spaced apart from each other. 
         [0113]    The device  1  according to the present disclosure allows to apply evenly distributed forces of adapted intensity on the panel  100  to maintain the relative position of the parts to be assembled according to their expansions by the movement of the pressing means  30  along the corresponding slide, while allowing a permanent monitored plastic deformation of the panel  100  against the form  20 . 
         [0114]    In one form, the pressure exerted in a range in the order of 6 Mpa to 18 Mpa. 
         [0115]    Furthermore, the device  1  is at least partially of carbon-carbon material (in one for is the Sepcarb® brand material). 
         [0116]    In another form, the elastic forcing means  210  are made of carbon-carbon material. 
         [0117]    Such a material has low thermal inertia. 
         [0118]    It is resistant at high temperatures and light, and thus reduces the mass of the device and can extend the service life of the device to about 20 years. 
         [0119]    In a non-limiting example, the elastic forcing means  210  are formed by the methods described in French patent application FR 2 772 748, which is incorporated herein by reference in its entirety. 
         [0120]    Furthermore, the device  1  allows a significant economic gain on the service life of an aircraft program on the investment as well as on the production time. 
         [0121]    It also allows brazing several components at the same time as furnaces are limited in tonnage. 
         [0122]    Its low mass also allows reducing the brazing cycle owing to the low thermal inertia of the tooling. 
         [0123]    Furthermore, such a device may be placed in a brazing furnace provided with means designed to carry out a vacuum brazing. 
         [0124]    A method of assembly by brazing using a device  1  according to the present disclosure is now described. 
         [0125]    First, various points of attachment between the skins and acoustic structure of the panel  100 , are carried out, preferably at each end of the jointing of one of the skins. 
         [0126]    In a non-limiting example, these points may be welding points. 
         [0127]    Thereafter, the panel to be brazed  100  is docked on the base  11  provided with the lower part of the form  20  (cut at the apex to allow its implementation and unmolding). 
         [0128]    The panel  100  in place, it can then be installed the second part of the form  20  around the panel  100 . 
         [0129]    In a non-limiting example, six rings of 16 pads  32  are superimposed by a suitable system, facing the support structure  13  and independent from the latter. 
         [0130]    These pad rings  32  are distributed radially opposite to an internal side of the panel  100  to be brazed. 
         [0131]    Mounting of the expansion system  13  with the elastic forcing means  210  in the retracted position by the wedge systems  220  and  221 , is then performed. 
         [0132]    At this stage, the elastic forcing means  210  are compressed and biased by the withdrawal means  220  and  221 . Once the expansion system  13  is locked by screwing on the upper part of the base  12 , the wedge systems  220  to  223  may be removed to release the pressure from the pads  32 . 
         [0133]    At this stage, each deformation unit  200  exerts a pressure on the internal wall of the corresponding pad ring  32 . 
         [0134]    It is worth noting that the elastic forcing means  210  are in cold and hot compression throughout the brazing thermal cycle. 
         [0135]    This allows preventing a detachment of the panel  100  with the tooling during the cooling phase of the cycle. 
         [0136]    Furthermore, the compression of the panel  100  by the pressing means  30  is permanent, continuous and exerted before the beginning of the brazing cycle; during the whole brazing cycle until the withdrawal of the panel  100  from the form  20 . 
         [0137]    It is worth noting that, at room temperature (20° C.), the panel  100  to be brazed is not pressing on the form  20 . Contact only occurs once the brazing temperature is reached. 
         [0138]    Thus, prior to the brazing cycle, the locking means  220  are unlocked, the biasing of the elastic forcing means  210  is released for compressing each pad  32  on the panel  100 . 
         [0139]    In a following step, at least one brazing cycle is started after having emptied the furnace chamber. 
         [0140]    The furnace temperature is thus raised to the brazing temperature. 
         [0141]    During the rise in temperature, differential expansions between the elements of the panel  100  to be brazed, the filler material and the device  1  are present. 
         [0142]    Each elastic forcing means  210  applied to the corresponding pressing means  30  causes the retainer rod  33  and the associated pad  32  in a displacement providing a pressure on the panel  100  such as to compensate the phenomena of differential expansion of the elements. 
         [0143]    At the brazing temperature at the same time higher than the melting temperature of the filler metal and lower than the melting temperature of each of the three materials, the mechanical pressure exerted by each elastic forcing means  210  on the corresponding pressing means  30  is calibrated to move by sufficient axial stroke the related pressing means  30  to stretch the panel  100 , so that it espouses the shape of the form  20 . 
         [0144]    The forces applied to the panel  100  extending beyond the forces related to the thermal expansion of the various elements thereof and providing to maintain these elements providing in contact throughout the brazing cycle, not only is the mechanical pressure applied adapted to form uniform braze joints for the brazed panel  100  but also to heat form the panel  100 . 
         [0145]    The following step consists in cooling the treated panel  100  by decreasing the temperature by suitable means, so as to solidify the filler metal which thus makes a connection between the two materials. 
         [0146]    It is worth noting that, in one form, the brazing operation is carried out under vacuum. 
         [0147]    At this stage, an acoustic panel  100  is obtained whereof the acoustic structure and the skins are brazed and the panel  100  conformed to its final shape. 
         [0148]    Hence, a panel  100  brazed and conformed in one single operation with good brazing quality is obtained. 
         [0149]    Thanks to the present disclosure, the differential expansions of the panel  100 , the tooling and the filler material are monitored throughout the brazing cycle in order not to change the relative position of the latter and in a precise manner, the deformation of the panel  100  to a particular shape of a form  20  is guided, by a simple and rapid to implement mechanical device. 
         [0150]    Such a device finds a non-limiting application in the brazing of panels  100  having to present one or several bends in their profile. 
         [0151]    Advantageously, the geometry of the parts to be brazed and to be conformed can be a geometry of revolution. 
         [0152]    Such a device allows reducing the brazing cycle time. In fact, the device  1  makes it possible to braze two pieces simultaneously since thanks to its low mass, it is possible to place two pieces in the same furnace. This can go as far as not needing to invest in a vacuum furnace. 
         [0153]    Furthermore, it avoids problems of sealing that may occur in the assembly devices of the prior art where gas pressure is required. 
         [0154]    It also reduces the phenomena of “telegraphing” resulting from a depression of the skins of the panels during their docking in the assembly devices of the prior art in which a gas pressure device is required 
         [0155]    Such a tooling has an improved service life (no flow) and the maintenance, due to the simplicity of the device, is lesser and cheap. 
         [0156]    Although the present disclosure has been described with specific form, it is obvious that it is in no way limiting and that it includes all technical equivalents of the means described as well as the combinations thereof if these fall within the scope of the present disclosure. 
         [0157]    Thus, it can be considered to exert different or not local stress forces according to their position on the panel to be treated. 
         [0158]    An alternative form may also provide to exert stress forces on either side of the panel  100  to be treated rather than on the same side of the latter. 
         [0159]    Furthermore, an alternative form may provide a brazing cycle under a monitored atmosphere. 
         [0160]    The present disclosure may also find a non-limiting application in brazing acoustic attenuation panels used in ejection cone/primary turbojet nozzle setups. 
         [0161]    In addition, each panel may be conformed and brazed by a device according to the present disclosure with the front and rear flanges thereof welded with finished lugs. This provides the hold of the eject section and performing a thermal releasing treatment after the brazing while enjoying a hold of the setup throughout the cycle.