Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The i~vention relates to light-weight construction
material and to a process for manufacturing honeycomb structures
from such light-weight construction material.
Plates of honeycomb structure, that are preferably
manufactured from a high-strength polyamide paper and coated with
a phenolic resin unaffected by high changes of temperature, are
used as core material fox sandwich boards with covering layers of
carbon or glass fibre reinforced plastics or of aluminium. Such
sandwich boards are structural members with a very high strength
1~ and stiffness, a high specific energy absorption cap~city and good
elasticity at the lowest weight. Sandwich boards with honeycomb
cores are used in the fields of aeronautics and space travel,
mechanical engineering and in -the construction of rail vehicles
and watercraft as well as of sports and recreational equipment.
Light-weight building boards with a honeycomb structure
are manufactured according to the "expansion process" or the "pro-
filing process".
During the expansion process strip material, for ex-
ample polyamide paper drawn from a reel is severed into sheets,
an adhesive is dotted onto the sheets in straight lines running in
the direction of travel of the strip, the sheets are stacked and
the lines of adhesive are hardened. Finally the layers of paper
stacked on top of one another are pulled or spread apart into
honeycomb blocks Erom which plates with the desired thickness
can be cut. Furthermore, it is possible ko cut discs of the
desired thickness from the stack of sheets and to then spread
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26636-28
these discs apart into plates o~ honeycomb structure.
The profiling process is used to manufacture honeycomb
structures having greater strength. In this process the strip
material, for example o~ aluminium, running off a reel, is rolled
by means of profile reels into, for e~ample, a trapezoidal profile
strip, the profiled strip is severed into trapezoidal profile
plates, an adhesive is applied to the raised parts of the trape-
zoidal profile plates and the plates are stacked on top of one
another and glued together to form a honeycomb block from which
paneling of desired thickness is cut.
It is the object of the present invention to develop a
light-weight construction material as well as a process and in-
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stallation for manufacturing honeycomb structures from this mate-
- rial which, in comparison to the known honeycomb structures, areI characterized by a higher strength and stiffness, improved energyj absorption as well as improved behaviour in fire.
The light-weight construction material according to the
present invention which meets these objectives consists of a
fibrous thermoplastic composite foil which contains carbon, sili-
con carbide, whisker or the like fibres in the form of woven
fabric, nests or mats, the ibres being embedded in a matrix of a
high temperature thermoplastic such as polyether ether ketone,
polyether sulfone or polysulfone.
Three processes are proposed in accordance with the
present invention for manufacturing honeycomb structures from
fibrous thermoplastic composite foil described above, these
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26636-28
processes using -the known "profiling pxocess" and being distin-
yuished by the production of fibrous thermoplastic composite foil
as the base material for the honeycomb structures.
In the first process an upper and a lower heated thermo-
plastic foil strip and a fibrous material guided between the two
foil strips are joined together by rolling.
The second process is characterized in that the thermo-
plastic foil strip is extruded and subsequently joined to a fi-
brous material by rolling.
The third process is characterized therein that
thermoplastic granules are melted and in the melted state rolled
with a fibrous material to a fibrous thermoplastic composite foil.
The latter process avoids the disadvantages occurring
in the first two processes of poor fibre wetting and fibre damage
caused by the high viscosi~y of the thermoplastic composite foil
used.
In all three processes the fibrous thermoplastic com-
posite ~oil is compressed following rolling by subsequently heat-
ing and rolling it once or several times and is brought to the
desired thickness.
Three installations operating according to the processes
described abo~e are explained herebelow on the basis of the accom-
panying schematic drawings, which show in
Figure 1: a side view of a complete installation for
manufacturing honeycomb structures,
Figures 2 and 3: side ~iews of two modified parts I
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26636-28
of an installation for manufac-turing the fibrous thermoplastic
composite foil,
Figure 4: part of a longitudinal section of a profiled
plate for manufacturing a honeycomb structure, and
Figure 5: a modification of part II of an installation
for manufacturing a honeycomb structure from the fibrous thermo-
plastic composite foil.
The installation according to Figure 1 comprises a part
I for manufacturing the fibrous thermoplastic composite foil 1 in
the form of strips and a part II for further processing the com-
; posite foil to a block 2 of honeycomb structure, from which honey-
comb plates are cut, these plates being used as core material
for sandwich boards with covering layers of carbon or glass fibre
reinforced plastics or of aluminium.
Part I of the installation includes a two-hi~h rolling
stand with a pair of calender rollers 3, 4, an upper and a lower
strip guide 5, 6 for two thermoplastic foil strips 7, 8 running
; off reels (not illustrated), heating devices 9 in the area of the
strip guides 5, 6 and a centre guide 10 for a fibrous material 11
drawn off a reel (not illustrated).
Part II of the installation comprises three heating
devices 9 and two additional two-high rolling stands with pairs of
calender rollers 12, 13 arranged alternately in succession, a
profiling device 14 with two profile rollers 15, 16 with which the
fibrous thermoplastic composite foil strip 1 is rolled to a trape-
zoidal profile 17 with a pitch X, a device 1~ with a roller 19 for
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26636-28
applying an adhesive to the raised parts 20 of the trapezoidal
profile 17, a cutting device 21 Eor cutting profiled plates 22
from the fibrous thermoplastic composite foil and a press 23 for
gluing together the plates 22 stacked on top oE one another to
form a honeycomb block 2.
Instead of gluing, the profiled plates 22 can also be
join~d together by fusion welding or ultrasonic welding in that by
means of a welding head 24 two profiled plates 22 are respectively
held by a welding mandrel 25.
In part I of the installation the two thermoplastic
foil strips 7, 8 are heated by means o heating devices 9 in the
area of the upper 5 and the lower 6 strip guide and are rolled with ~ ;
; the fibrous material 11 (that runs in the centre guide 10 between
the two foil strips 7, 8) in the two-high rolling stand with the
pair of calender rollers 3, 4 to the fibrous thermoplastic com-
posite foil 1.
After being first heat~d by the heating devices 9, the
fibrous thermoplastic composite foil 1 is compressed in part II of
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the installation by two additional roll passes in two-high rolling
stands with pairs of calender rollers 12, 13 arranged after one
another and is rolled to the desired thickness. After being heat-
ed again in final heating device 9, the strip-like fibrous :~
thermoplastic composite foil 1 is rolled by the profiling device
14 into a foil strip with a trapezoidal pro.file 17 and the raised
parts 20 of the trapezoidal profile strip are subse~uently coated .
with an adhesive in the applicator 18. Plates 22 are continually
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cu-t from the profiled strip in the following cutting device 21,
the plate length L amounting to a rnultiple plus half of the pitch
X of the trapezoidal profile 17. Finally, the trapezoidal profile
; plates 22 are stacked and are gluecl together under pressure (and
possibly under renewed heating) in a press 23 to form a honeycomb
block 2 from which plates of desired measurements are cut follow-
ing hardening o~ the adhesive.
Part I of the installation illuistrated in Figure 2 for
manufacturing the fibrous thermoplastic composite foil l is char-
acterized by an extruder 26 with a slit nozzle 27, followed by a
foil strip mill 28 designed as a three-high mill with a centre
strip guide 29 for the foil strip 30 emerging from the extruder 26
as well as an upper guide 31 for a fibrous material ll.
Part I of the installation I according to Figure 3 for
manufacturing the fibrous thermoplastic composite foil l is equip-
ped with a horizontal lower conveyor belt 32 and arranged at a
distance above it a parallel, upper conveyor belt 33 which extends
over the rear area of the lower belt 32 and with it forms a longi-
tudinal gap 34. Heating devices 9 are installed in the area of
the longitudinal gap 34 between the carrying run and the empty
return ru~ of the two belts 32, 33. Two feed stations 35, 36,
designed as hoppers for a thermoplastic granule 37, are arranged
at different heights above the forward area of the lower conveyor
belt 32 and in front of the upper conveyor belt 33. A feed with
a deflection pulley 38 is provided between the two feed stations
35, 36 for introducing a fibrous material 11 below the second
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26636-28
feed station 36 throuyh into the longitudinal gap 34 between the
two conveyor belts 32, 33, whereby the plane of travel of the
fibrous material 11 through the longitudinal gap 34 lies in the
area of the centre plane of the gap5 A specific rolling force is
transferred to the two conveyor belts 32, 33 by the deflection
pulleys 32a, 32b and 33a, 33b and the plastic melt located in the
longitudinal gap 34 is thereby rolled with khe fibrous material
11 to the fibrous thermoplastic composite oil 1.
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