LU87191A1 - METHOD FOR MANUFACTURING A HONEYCOMB CORE FOR A COMPOSITE PLATE FOR LIGHTWEIGHT CONSTRUCTION OR ANY OTHER SANDWICH CONSTRUCTION - Google Patents

Description

S 7 Λ — Û, \. BL-4099 / ETF / vdw I $ - - GRAND-DUCHE DE LUXEMBOURG _ __

Patent jn ° ________________________ ’~ *

Monsieur le Minister "of April 6, 1988 of the Economy and the Middle Classes" Department of Intellectual Property

Title delivers ___________ - · ......-¾¾

. _ LUXEMBOURG

G.jo.U j) eman <je <| e Patent of invention

Otj <£ "____________ ^ I. Request EURO-COMPOSITES S.A., Zone Industriellef____________________ (2) L - 6401 Echternach _____________________________ 1 __________________________________________- ygp-réfiP, nl-éP- by Messrs. FREYLINGER Ernest T. & MEYERS Ernest, înq.

nons.en propr.ind .. 46 rue du Cimetière, b.p. 1153, _____ (3) embonrg, acting as agents_____ file) this ...... six ...... Aprilmil nine hundred eighty-eight ________________________ (4) at hours, at the Ministry of Economy and of the Middle Classes, in Luxembourg: 1. this request for obtaining a patent for an invention concerning: ------------------------- ---------------------------------------------------------- ------------------- (5) ............... iBrocêdê ...... de ..... ..fabrication ...... dl.un ... no.Yau ...... en ... Jiid. „. d.! ._ ab.e.il.lds._p.Q_ur ____ --- --pTatjue Gomposifee — pouE — Light Gonstr-uctions — or, ...... any — other— -------- eeô.s.feJ? ^ 0% i0 ^ s.andwi <3li-- ---------------------------------------------------------- ----------------------—------- 2. the description in language_________ .. ._e French ___________________________ of the invention in triplicate; 3. ________3L____________________________________ drawing sheets, in triplicate; · 4. receipt of the fees paid to the Registration Office in Luxembourg, on April 6 - 15 .8.8 ._____; 5. the delegation of power, dated_____Echternach_______________________________ on __________ 3.1 ..... inar.s ._. 15..8.8 __________; 6. the successor document (authorization); declare) by assuming responsibility for this declaration, that the inventor (s) is (are): (6) HUBER ... Dietrich, Speersort 126, D - 2161 Hnl lern / RF A__ claims (s) for the above patent application the priority of one (or more) application (s) of (7) ____________________ LL __________________-______________________________________________ filed in (8) ___ /. / .............. .......................

on (9) .........: .................................... .................................................. .......................: .......................... ..........................................: --- under the N ° (10) _______________________ L L ______________________________________________________________________________________________________________________________________________________; ---------- on behalf of (11) ............................ .................................................. .................................................. .................................................. .............. J__________________________________ elect (elect) domicile for him (her) and, if designated, for his proxy, in Luxembourg ________________ ... 4..6 ...... xue .... du._C.ime.tiè.re ___________________________________________________________________________________________________________________: _ (12) seeks (s) the grant of a patent for the invention for the object described and represented in s the abovementioned annexes, with the date of this issue to ............................ s i.x ... month ____________________________ „_______________________________________________________________ Imois. (13)! / Λ / [ff IMa / saSI Π. Deposit Minutes

The above / patent application / invention was filed with the Ministry of Economy and Middle Classes, Service dejfa Property Inteüëc ^ igjl ^ J & ujcembourg, dated: April 6, 1988 χβ * e 'v \ - // ......% \ / ί '' 1 ”, Pr. the Minister of Economy and the Middle Classes,”. ./fM V Cu: X, \ Lj Le chef du sera ^ oek ^ intellectual property, 'A 68097_' _'l / X ~ _ ~ _ ~

f f) û [EXPLANATION OF THE DEPOSIT FORM. y 1: H

- V- v Q / (1) if applicable "Request for certificate of addition to the main patent, to main patent application No ........ f ... of .... ........ ”- (2) enter the surname, first name, profession,! Address of the applicant, when the applicant is an individual or corporate name, legal form, address of head office, when the applicant is a legal person - (3) register- / the surname, first name, address of the professional representative, industrial property attorney, with special powers, if applicable; "represented by ........ .... acting as agent's inquiry "- D - (4) date 'of filing in full - (5) ritride the invention - (ô) mscribe the names, first names, addresses of the inventors or the indication" (see ) separate designation (to follow) ", when a designation is made or will be made in a separate document, or the indication" not to mention ", when the inventor signs or signs a non-mention document to be attached to a separate designation * Ç · / / 2 present or future- (7) br evet, certificate of addition, utility model, European patent (EPC), international protection (PCT) - (8) State in which the first filing was made I BL-4099 / vdw * <

INVENTION PATENT APPLICATION FILED IN LUXEMBOURG

on behalf of EURO-COMPOSITES S.A.

Industrial Zone L - 6401 Echternach for

PROCESS FOR MANUFACTURING A HONEYCOMB CORE FOR A COMPOSITE PLATE FOR LIGHTWEIGHT CONSTRUCTIONS OR ANY OTHER SANDWICH CONSTRUCTION

BL-4099 PROCESS FOR MANUFACTURING A HONEYCOMB CORE FOR A COMPOSITE PLATE FOR LIGHTWEIGHT CONSTRUCTIONS OR ANY OTHER SANDWICH CONSTRUCTION The present invention relates to a method for manufacturing a honeycomb core in fibrous material pre-impregnated with thermoplastic and / or thermosetting resins for a composite sheet of light construction.

Honeycombs for making composite plates for light constructions (sandwich plates) are produced by assembling a stack of sheets of unimpregnated paper, by gluing at predetermined locations in strip-shaped zones, then deploying them. to form a honeycomb block and finally impregnating this block with a thermosetting synthetic resin. After the synthetic resin has hardened, a block of this kind can then be cut perpendicular to the orientation of the honeycombs, in order to obtain plates of any thickness which are then used as cores for the sandwich plates. In a plate of this kind, the honeycomb core is located between two covering layers with high tensile strength, generally arranged in parallel planes, while the direction of orientation of the honeycombs 25 is perpendicular to these overlapping layers.

This arrangement of a sandwich plate makes it possible to obtain optimum lightness characteristics.

When manufacturing the honeycomb in question, certain essential operations, such as deployment and impregnation, are carried out by hand, which has an unfavorable effect on the costs of production of the light plates, consequently the relatively high proportion of salary costs. As the impregnation medium, a phenolic resin is used, which presents a danger in the event of fire because of its toxicity. This aspect is of particular importance if the plates in question are used to build passenger aircraft.

Therefore, the object of the present invention is to provide a process of this kind, in which the essential manufacturing operations can be carried out fully automatically, while the material used does not produce, or at least little, toxic gases. in the event of a fire, while the structure of the sandwich plates described above remains unchanged.

The object of the invention is achieved by a process for manufacturing a honeycomb-shaped core of fibrous material pre-impregnated with thermoplastic and / or thermosetting resins for a composite plate of light construction which is characterized by the following operations: a) alternating stacking of a prepeg prepreg layer and a mesh, a prepeg layer and a mesh, etc., until the predetermined thickness of the stack has been reached, while the gratings consist of parallel bars located at predetermined intervals and the bars of a screen are offset from the bars of a neighboring screen, so as to fall in the interval; b) compression of the pile perpendicular to the axis of the bars; c) hardening and / or heat treatment of the pile with pressure and heat, as well as d) extraction of the bars from the pile.

The invention is shown in the figures and will be described in more detail below. The figures represent respectively: Figure 1, the principle of the device for manufacturing a honeycomb core for a sandwich plate and Figure 2, a device with a vertical arrangement of the layers.

ri -Βία figure 1 represents a device for manufacturing a core in nest. of bees for sandwich plate, consisting of a base plate 2 with a profiling 3 and a large number of compression gratings 4. Each mesh 5 4 consists of a number of prismatic bars 5, made of alloy aluminum, which preferably have a hexagonal section. The upper face of the base plate 2, as well as the bars 5, are coated with a release agent. The different bars 5 of a grid 4 are arranged at predetermined intervals from one another and are placed in a grid 4, so that the bars 5 of a determined grid 4 are offset with respect to the bars 5 of the mesh 4 neighbor above and below, to fall into the inter-valley.

To manufacture a honeycomb core, a layer of fibrous material (Prepeg) impregnated with thermosetting plastic is first applied to the base plate 2. Next, a compression mesh 4 is applied to the Prepeg layer, so that these bars 5 are parallel to the profiling of the base plate. A Prepeg layer 6, a mesh 4, a Prepeg layer 6, a mesh 4, etc. is then superimposed successively, until the stack has reached the desired height. The stack is then compressed transversely to the bars 5. After hardening in an appropriate oven, the different Prepeg 6 layers have a coherent honeycomb structure, while each Prepeg 6 layer has a wavy shape and the 30 superimposed layers in the stack are glued to each other in strip-shaped areas. After the stack has cooled, the bars 5 are removed and the honeycomb block is, in principle, finished. A plaster based on poly-tetrafluoroethylene (PTFE) is used as a release agent. If one uses, in particular, Prepegs whose fibers are based on graphite, it has been surprisingly found that the removal of the bars 5 offers absolutely no difficulty.

-4- * * 0

FIG. 2 schematically represents a device for manufacturing a honeycomb core, with layers arranged vertically. In this case, the screens 4 are arranged with the bars 5 vertically, so that the Prepeg layers 6 can be introduced from above, between the screens 4. The bars 5 of a screen 4 are assembled to each other by one side, by means of a support 7 which ends in a traction element 8. The different traction elements 8 seen in the direction 10 "x" continue alternately towards + y and towards -y. This arrangement of the grid 4 makes it possible to manufacture, almost completely automatically, honeycomb cores by operating, for example, as follows: in a preparation station, the grids 4 are in the positions indicated. Layers

Prepeg 6 coming from a roll, are introduced from above, between screens 4, which can possibly be facilitated by grapples coming from below, which guide each end of Prepeg layer down and fix it, while the the upper end is also fixed, after it has been separated from the roll. When all the Prepeg layers 6 are introduced, the screens 4 are brought together in the "x" direction so that the Prepeg layers 6 take on a wavy shape and touch each other, in striped areas. The stack thus formed is introduced into a compression device, which also serves as a transport pallet.

The stack can thus be compressed as intended and then be brought into an appropriate oven to allow curing. During hardening, a new battery can be assembled at the preparation station. When the pile has undergone hardening, it is brought to a demolding station.

The gratings 4 are extracted therefrom from the stack by means of the traction elements 8. For this purpose, provision is made for extraction devices which act on the traction elements 8.

All the operations which take place in this way can be carried out by means of automatic devices, using the conventional methods of automation.

Μ; ! , · I 0 -5- Οη can use for this purpose either electrical controls, hydraulic controls, or pneumatic controls.

As far as the control of the various operations is concerned, all the principles which can be used can be applied, which opens, in the case of the use of digital control signals, the possibility of controlling the progress of the process described according to stored programs.

The choice of materials to be used is based on usual technical considerations and concerns both the honeycomb cores and the devices for their manufacture.

Claims (4)

1. A method for manufacturing a honeycomb core of fibrous material pre-impregnated with thermoplastic and / or thermosetting resins for a composite plate of light construction, characterized by the following operations: a. Alternating stacking of a Prepreg prepreg layer (6) and a mesh (4), of a Prepreg layer (6) 10 and a mesh (4), etc., until the predetermined thickness of the stack has been reached, while the gratings (4) consist of parallel bars (5) situated at predetermined intervals and the bars (5) of a grid (4) are offset with respect to the bars 15 (5) of a neighboring grid (4), so as to fall into 1 * .in tervalle? b. Compression of the stack perpendicular to the axis of the bars (5); vs. Hardening and / or heat treatment of the stack with pressure and heat, as well as d. Extraction of the bars (5) from the stack. 2. Method according to claim 1, characterized by a horizontal arrangement of the layers (fig. 1). 3. Method according to claim 1, characterized by a vertical arrangement of the layers (fig. 2). 4. Method according to claim 1, characterized by the following prepreg fibrous composite materials: while the thermosetting resins are polyesters, epoxy resins, phenolic resins, polyurethanes, melamine resins, polyimides (such as bis- maleimide), the thermoplastic materials are poly-sulfones, polyethersulfones, polyetherimides, polyimides, polyamides, polyetherimines, poly (ether-ether) ketones, polyarylsulfides, polybutylene terephthalate, polycarbonates , polyvinyl alcohols, vinyl, polyethylene and phenoxy resins and the fibrous materials are metallic and non-metallic fibers such as, for example, glass fibers, aramid fibers, fibers carbon (PAN 5 and Pitch), SIC fibers, cellulose fibers, boron fibers and aluminum coated glass fibers.