U.S. patent application number 16/574795 was filed with the patent office on 2020-01-23 for method for manufacturing a rivet connection of a fiber composite component.
The applicant listed for this patent is AIRBUS OPERATIONS GMBH. Invention is credited to Paul JORN, Peter LINDE.
Application Number | 20200023590 16/574795 |
Document ID | / |
Family ID | 60420168 |
Filed Date | 2020-01-23 |
United States Patent
Application |
20200023590 |
Kind Code |
A1 |
JORN; Paul ; et al. |
January 23, 2020 |
METHOD FOR MANUFACTURING A RIVET CONNECTION OF A FIBER COMPOSITE
COMPONENT
Abstract
A method for manufacturing a rivet connection of a fiber
composite component. The method includes positioning a first
component which contains a fiber composite material in an overlap
joint with a second component, laser-drilling a shared through-hole
at least through the fiber composite material of the first
component, inserting a rivet into the through-hole and fixing the
rivet to the first and to the second component.
Inventors: |
JORN; Paul; (Hamburg,
DE) ; LINDE; Peter; (Hamburg, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AIRBUS OPERATIONS GMBH |
Hamburg |
|
DE |
|
|
Family ID: |
60420168 |
Appl. No.: |
16/574795 |
Filed: |
September 18, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15604277 |
May 24, 2017 |
10427358 |
|
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16574795 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29L 2031/3082 20130101;
B32B 2605/00 20130101; B29C 66/73921 20130101; B29K 2307/04
20130101; B32B 5/10 20130101; B29C 66/1142 20130101; B29C 35/0805
20130101; B32B 2262/106 20130101; B29C 66/54 20130101; B29C 66/1122
20130101; B29C 66/7212 20130101; B32B 7/08 20130101; B29C 65/601
20130101; B29C 66/0246 20130101; B29C 66/21 20130101; B29C
2035/0838 20130101; B29L 2031/30 20130101; B29C 66/73941 20130101;
B32B 27/08 20130101; B29C 65/60 20130101; B29K 2105/06 20130101;
B29K 2105/256 20130101; B29C 66/7212 20130101; B29K 2307/04
20130101 |
International
Class: |
B29C 65/60 20060101
B29C065/60; B29C 65/00 20060101 B29C065/00; B29C 35/08 20060101
B29C035/08; B32B 5/10 20060101 B32B005/10; B32B 7/08 20060101
B32B007/08; B32B 27/08 20060101 B32B027/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 8, 2016 |
DE |
10 2016 210 115.3 |
Claims
1. A method for manufacturing a rivet connection of a fiber
composite component, comprising: positioning a first component
which contains a fiber composite material in an overlap joint with
a second component; laser-drilling a shared through-hole at least
through the fiber composite material of the first component by at
least one of single-pulse drilling, percussion drilling, trepanning
or spiral drilling; inserting a rivet into the through-hole; and
fixing the rivet to the first component and to the second
component.
2. The method of claim 1, wherein the laser-drilling is carried out
using a high-energy laser beam.
3. The method of claim 2, wherein the high-energy laser beam has a
laser power in a kilowatt range.
4. The method of claim 1, wherein the second component likewise
contains a fiber composite material which is drilled through during
the laser-drilling.
5. The method of claim 1, wherein the fiber composite material
contains carbon fibers, some of which are partially drilled through
by the laser-drilling.
6. The method of claim 1, wherein a laser beam is widened or
defocused for laser-drilling to produce a desired hole
diameter.
7. The method of claim 6, wherein the laser beam is initially more
heavily widened or defocussed, and subsequently less and less so
down to the desired hole diameter, to form a conical entry to the
through-hole which is formed for countersinking a rivet head.
8. The method of claim 1, wherein at least the first component is
provided in planar form.
9. The method of claim 8, wherein a plurality of parallel joint
lines are provided along an edge of the first component.
10. The method of claim 1, wherein a plurality of shared
through-holes are formed in the first component and in the second
component in a line extending along an edge of the first component
by laser-drilling, a rivet being inserted into each of the
through-holes and fixed to the first component and to the second
component to form a uniformly continuous joint line.
11. The method of claim 10, wherein a plurality of parallel joint
lines are provided along an edge of the first component.
12. A method for manufacturing a vehicle skin, the method
comprising: providing a first component in a form of a first skin
portion which contains a fiber composite material; providing a
second component; and connecting the first component to the second
component using a rivet connection manufactured by a method
comprising: positioning a first component which contains a fiber
composite material in an overlap joint with a second component;
laser-drilling a shared through-hole at least through the fiber
composite material of the first component by at least one of
single-pulse drilling, percussion drilling, trepanning or spiral
drilling; inserting a rivet into the through-hole; and fixing the
rivet to the first component and to the second component.
13. The method of claim 12, wherein the second component is
provided in a form of a second skin portion or a connecting portion
for connecting the first skin portion to a second skin portion in a
butt joint.
14. A method of using laser-drilling to manufacture a rivet
connection of a fiber composite component, the method comprising:
positioning a first component which contains a fiber composite
material in an overlap joint with a second component;
laser-drilling a shared through-hole at least through the fiber
composite material of the first component by at least one of
single-pulse drilling, percussion drilling, trepanning or spiral
drilling; inserting a rivet into the through-hole; and fixing the
rivet to the first component and to the second component.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of and claims priority to
U.S. patent application Ser. No. 15/604,277 filed May 24, 2017,
which claims the benefit of and priority to German Patent
Application DE 10 2016 210 115.3 filed Jun. 8, 2016, the entire
disclosures of which are herein incorporated by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to a method for manufacturing
a rivet connection of a fiber composite component, to a use of a
laser-drilling process to manufacture a rivet connection of a fiber
composite component, to a structural arrangement comprising a rivet
connection of this type, to a method for manufacturing a vehicle
skin and to a vehicle skin.
[0003] Although they are applicable to any structural arrangements,
the present disclosure and the set of problems on which it is based
are described in greater detail in relation to an airplane
fuselage.
BACKGROUND
[0004] Modern airplane fuselages are often constructed using fiber
composite materials, generally carbon-fiber-reinforced plastics
materials. An airplane fuselage conventionally comprises a
plurality of skin portions which are interconnected to assemble the
airplane fuselage. To fix the skin portions together, riveting
methods are conventionally used, this often being required for
certification or authorisation.
[0005] To manufacture a rivet connection for connecting two
carbon-fiber-reinforced plastics material skin portions, in a
method known to the applicant through-holes are introduced to the
skin portions using a manually positioned drilling template and a
hand-operated power drill.
SUMMARY
[0006] Against this background, it is an idea of the present
disclosure to provide an improved method for manufacturing a rivet
connection of a fiber composite component.
[0007] Accordingly, the following are provided: [0008] A method for
manufacturing a rivet connection of a fiber composite component,
comprising steps of: positioning a first component which contains a
fiber composite material in an overlap joint with a second
component; laser-drilling a shared through-hole at least through
the fiber composite material of the first component; inserting a
rivet into the through-hole; and fixing the rivet to the first and
to the second component. [0009] A structural arrangement comprising
a first component which contains a fiber composite material and a
second component, the first and the second component being
connected using a rivet connection manufactured by a method
according to the disclosure herein. [0010] A method for
manufacturing a vehicle skin, in particular for an aircraft or
spacecraft, comprising the steps of: providing a first component in
the form of a first skin portion which contains a fiber composite
material; providing a second component, in particular in the form
of a second skin portion or a connecting portion for connecting the
first skin portion to a second skin portion in a butt joint; and
connecting the first component to the second component using a
rivet connection manufactured by a method according to the
disclosure herein. [0011] A vehicle skin, in particular of an
aircraft or spacecraft, manufactured by a method according to the
disclosure herein. [0012] A use of a laser-drilling process to
manufacture a rivet connection of a fiber composite component, in
particular by a method according to the disclosure herein.
[0013] An idea behind the present disclosure is to use a
laser-drilling process to manufacture a rivet connection of a fiber
composite component.
[0014] In this way, the very fine, very easily accumulating
drilling dust which occurs during conventional drilling of fiber
composite components can be prevented, since the fiber composite
material is evaporated rather than cut during laser-drilling.
[0015] For this purpose, the light energy of the laser beam
focussed on the material is absorbed by the fiber composite
material, in other words converted into heat, in such a way that
the material evaporates without dust occurring. During the
evaporation, the material volume in the drill hole expands, in such
a way that high vapor pressure occurs locally. This vapor pressure
subsequently also drives any molten material out of the drill
hole.
[0016] It is also possible to laser-drill by way of laser-machining
using ultrashort pulse lasers, in such a way that the material
evaporates directly from the solid state, in particular without
melting, and is thus removed. This process is also referred to as
laser ablation.
[0017] Thus, according to the disclosure herein, it is possible to
omit the cleaning step which has thus far been required for
manufacturing a rivet connection of a fiber composite component
because of the drilling dust which occurs. Further, the machining
time for manufacturing a rivet connection is greatly reduced.
[0018] According to the disclosure herein, different types of
laser-drilling processes may be used.
[0019] The simplest type of laser-drilling is single-pulse
drilling, in which the material is drilled through using a single,
sufficiently temporally long laser pulse.
[0020] In percussion drilling, the material is removed by the
impingement of a plurality of pulses in succession on the same
point.
[0021] By contrast, in laser-drilling by trepanning, the laser beam
is passed around the centre of the drill hole, and thus
successively widens the diameter. A smaller through-hole can be
produced beforehand by percussion drilling.
[0022] In spiral drilling, a laser beam is directed onto the
workpiece whilst rotating in a circle. After a few circuits, the
circular material removal forms a through-hole.
[0023] In laser-drilling, each of these options is a very rapid
process by comparison with conventional drilling, and takes only a
fraction of the time, in particular just fractions of a second. In
addition, the energy consumption per hole drilled can also be
reduced in this way.
[0024] Further, laser-drilling is can also be automated or at least
partially automated better, since the through-holes can be
positioned and reproduced with a very high accuracy of
repetition.
[0025] In the case of complete automation, the step of positioning
a drilling template can be omitted.
[0026] In the case of partial automation, in other words if the
laser tool or laser optics are positioned under the control of an
operator, a drilling template may further be provided as a
positioning aid. For example, by a search laser, the laser optics
can be oriented onto the hole provided in the drilling template and
thus positioned for the laser-drilling.
[0027] Alternatively or additionally, the drilling template may be
arranged stationary, in such a way that the components to be
connected can be oriented on the drilling template in the desired
position. In this case, a plurality of adjacent holes can be
drilled in an automated manner after the orientation.
[0028] In one embodiment, it is conceivable to provide the second
component with pre-drilled holes, in such a way that the shared
through-hole can only be produced through the fiber composite
material of the first component by laser-drilling. In particular
holes pre-drilled in this manner in the second component may
comprise depressions for receiving a rivet head in a flush
manner.
[0029] In further embodiments, both the first component and the
second component are drilled through during laser-drilling. In this
case, a shared through-hole is laser-drilled through the fiber
composite material of the first component and through the second
component.
[0030] Laser beam optics are generally guided using a robot, in
particular an industrial robot. In this way, the laser beam can be
oriented.
[0031] Further, there are also movable laser beam optics known as
scanners which make it possible to orientate and guide the laser
beam by beam deflection. In particular, this also makes
laser-machining possible "on the fly", in other words without
halting the robot carrying the optics, and this can further reduce
the machining time.
[0032] By the increased level of automation, according to the
disclosure herein the (human) working time required for manufacture
can be massively reduced, as well as the manufacturing time. This
effect may have enormous potential for example in airplane
manufacture, in which millions of rivets are placed every year.
[0033] The high reproducibility according to the disclosure herein
is because unlike a drill the laser beam can operate without wear.
Thus, in laser-drilling, even for large numbers of holes, no
deviation in the hole geometry and no worsening of the hole wall,
in particular no increase in roughness, are observed.
[0034] Further, the method according to the disclosure herein may
also be used flexibly for different types of composite materials.
In particular, it may equally be used both for components
containing composite materials having a thermoplastic matrix and
for components containing composite materials having a thermoset
matrix.
[0035] The method according to the disclosure herein can therefore
be used for manufacturing a wide range of structural arrangements
comprising rivet connections, for example both for a wide range of
skin portions of an airplane, such as on the fuselage, the wings or
the like, and for example for fiber composite material skin
portions on land vehicles or boats. Further, use of the method
according to the disclosure herein to connect a skin portion to
other types of structural parts, for example to connecting or
stabilizing elements, known as clips or cleats, or directly to
stringers and/or formers is also conceivable.
[0036] The second component, as a joining partner of the first
component which contains a fiber composite material, may comprise
an identical or different material.
[0037] The shared through-hole through the first and second
components may be manufactured in a shared manufacturing step by
laser-drilling. In this way, the complexity of positioning is kept
to a minimum.
[0038] However, it is also conceivable to manufacture the shared
through-hole in two separate steps or in a two-step process by
laser-drilling. This may for example be advantageous if the
components comprise different materials and the laser-drilling thus
requires different process parameters. In this case, the components
may therefore be positioned in an overlap joint either before or
only after the shared through-hole is laser-drilled, naturally
coincidently with the shared through-hole.
[0039] In another development, the laser-drilling is carried out
using a high-energy laser beam. In this case, the intensity of the
laser beam is in a range which makes it possible to evaporate both
the matrix material and the fibers of the fiber composite
material.
[0040] In particular, this is a laser beam having a laser power in
the kilowatt range. For this purpose, in particular solid-state
lasers, for example a disc laser (for example Nd:YAG:
neodymium-doped yttrium aluminium garnet) or fiber laser (for
example an ytterbium fiber laser), are conceivable. Use of a
high-power gas laser, in particular a CO.sub.2 laser, would also be
conceivable.
[0041] In particular, this may be a high-brilliance laser beam. The
brilliance is generally the characteristic value for the beam
quality. At high brilliance, high beam intensities are possible, in
other words beams having particularly high energy per area, and
this advantageously leads to a high proportion of sublimated
material. Further, this is possible in a comparatively large region
of the beam path around the focal position of the laser beam. For
example, a high brilliance can be achieved using an ytterbium fiber
laser.
[0042] In one embodiment, the second component likewise contains a
fiber composite material. This is also drilled through during the
laser-drilling. Thus, the two fiber composite components are
provided with a shared through-hole. In particular, this is carried
out in a shared step in the overlap joint. In this way, in
particular a fiber composite construction of a structural
arrangement comprising a rivet connection can be manufactured
rapidly and without dust.
[0043] In one embodiment, the fiber composite material comprises
carbon fibers, some of which are drilled through by the
laser-drilling. Advantageously, according to the disclosure herein
this is implemented without the occurrence of carbon dust or
without carbon dust. In particular, the fiber composite material is
carbon-fiber-reinforced plastics material. Both thermoplastic and
thermosetting plastics materials are conceivable as matrix
materials.
[0044] In one embodiment, a laser beam for laser-drilling is
widened or defocussed in a manner adapted to a desired hole
diameter. In particular, the widening or defocussing is also
adapted during laser-drilling as a function of the hole depth
reached. Thus, different diameters and hole shapes of the
through-hole can be implemented, in particular diameters of a few
millimetres typically provided for rivets. The intensity of the
laser beam remains in a range which makes it possible to evaporate
both the matrix material and the fibers of the fiber composite
material.
[0045] In another development, the laser beam is initially more
heavily widened or defocussed, and subsequently less and less so
down to the desired hole diameter, to form a conical entry to the
through-hole which is formed for countersinking a rivet head. In
particular, this is adapted to the geometry of the rivet in a
predetermined manner as a function of the achieved hole depth.
Thus, advantageously, no post-processing for counter-sinking a
rivet head is required at the entry to the through-hole.
[0046] In one embodiment, at least the first component is provided
in planar form. Optionally or additionally, a multiplicity of
shared through-holes of the first component and second component
are formed by laser-drilling in a line extending along an edge of
the first component. To form a joint line, subsequently a rivet is
inserted into each of the through-holes and fixed to the first and
the second component. In particular, the holes are placed at
uniform distances, in such a way that a uniformly continuous joint
line is manufactured. In this way, advantageously, planar
components, for example skin portions, can be joined in a
comparatively simple and rapid manner using a rivet connection.
[0047] In another development, a plurality of parallel joint lines
are provided along the edge of the first component. In this way,
redundancy in the rivet connection is provided, in such a way that
a higher support loading capacity and a higher strength are
achieved. In addition, as a result of the multiple connection, the
rigidity of the structural arrangement created by the rivet
connections is also increased. In particular, a structural
arrangement for example of an aircraft or spacecraft is typically a
rivet connection comprising three joint lines, as is conventional
for aviation.
[0048] In another embodiment of a structural arrangement, a
through-hole of the rivet connection comprises a hole wall which
comprises a surface manufactured without cutting. The hole wall
manufactured by laser-drilling is in particular free of grooves
normally brought about by cutting tools or conventional drills.
Further, the constitution of the hole wall is also different from
in etched holes, since in composite materials etching always brings
about a different surface structure on the different materials. In
particular, the hole wall manufactured by laser-drilling may
instead be covered with material directly solidified from a molten
liquid state. This is material melted by the laser beam which has
been left behind on the cavity wall when the melt was driven out or
has been melted on during the evaporation. Alternatively, the
surface may also be manufactured by direct evaporation. This
surface structure of the hole wall is therefore clearly
distinguishable by conventional analysis methods, for example under
a microscope, from a conventionally drilled hole wall, which
usually has machining traces and/or a certain roughness and/or
drilling dust.
[0049] In another embodiment of a use, the laser-drilling process
for manufacturing a rivet connection of a vehicle skin by a method
according to the disclosure herein is used. In particular, the
vehicle skin is the skin, for example the fuselage, of an aircraft
or spacecraft. However, the method according to the disclosure
herein is also usable in other skin portions of an aircraft or
spacecraft, for example the skin of a wing. Further, the method
according to the disclosure herein is also usable in the
manufacture of a vehicle skin for other types of vehicles, for
example motor vehicles or boats.
[0050] The above embodiments and developments can be combined with
one another as desired, within reason. In particular, all features
of the method for manufacturing the rivet connection are also
transferrable to a structural arrangement comprising a rivet
connection of this type and vice versa. The same applies to a
method for manufacturing a vehicle skin and to a vehicle skin.
[0051] Further possible embodiments, developments and
implementations of the disclosure herein also comprise combinations
not explicitly mentioned of features of the disclosure herein which
are disclosed above or in the following in relation to the
embodiments. In particular, in this context a person skilled in the
art will also add individual aspects to each basic form of the
present disclosure as improvements or supplements.
BRIEF DESCRIPTION OF THE DRAWINGS
[0052] In the following, the disclosure herein is described in
greater detail by way of embodiments with reference to the
accompanying example drawings.
[0053] In the drawings:
[0054] FIG. 1 is a perspective view of an example of manufacturing
through-holes for rivet connections;
[0055] FIG. 2A-2C are cross-sectional drawings of the typical steps
for manufacturing a rivet connection for connecting two skin
portions;
[0056] FIG. 3A shows an arrangement for laser-drilling a fiber
composite component;
[0057] FIG. 3B is a cross-sectional view of a fiber composite
material component drilled through by laser-drilling;
[0058] FIG. 4A shows an arrangement for drilling through two fiber
composite material components in an overlap joint;
[0059] FIG. 4B is a cross-sectional view of a structural
arrangement comprising a rivet connection of two fiber composite
material components;
[0060] FIG. 5 is a perspective drawing of a fuselage portion of an
aircraft or spacecraft; and
[0061] FIG. 6 is a perspective drawing of two fiber composite
material components connected in a butt joint by a connecting
portion.
[0062] In the drawings, unless stated otherwise, like reference
numerals denoted like or functionally equivalent components. The
drawings are not necessarily to scale with one another.
DETAILED DESCRIPTION
[0063] FIG. 1 is a perspective view of an example of manufacturing
through-holes 103 for rivet connections.
[0064] The components to be connected are two skin portions 101 and
102 of a fiber composite material airplane fuselage. To manufacture
the through-holes 103, a drilling template 106 is manually
positioned and fixed, for example by an adhesive strip 107 as
shown. Subsequently, a through-hole 103 is drilled in the skin
portions 101, 102 using a hand-operated power drill 105.
[0065] FIG. 2A-2C are cross-sectional drawings of the typical steps
for manufacturing a rivet connection for connecting two skin
portions 101, 102.
[0066] In a first step in accordance with FIG. 2A, through-holes
103 are drilled in an overlap region of the fiber composite
material skin portions 101, 102 in the manner described in FIG. 1,
by mechanical cutting using a hand-operated power drill at a
position specified using a drilling template 106.
[0067] In a second step in accordance with FIG. 2B, the
through-holes 103 are cleaned of drilling dust and residues. This
takes place for example by pressurised air from both sides, as is
indicated schematically using flow lines and directional arrows.
This cleaning step is important when fiber composite materials are
machined using a conventional drill, since very fine carbon dust
occurs when the material is cut and easily accumulates in the hole
103.
[0068] In a third step in accordance with FIG. 2C, rivets 104 are
introduced into the through-holes 103 by a riveting tool (not
shown) and fixed to the two skin potions 101, 102 by deforming the
rivet.
[0069] FIG. 3A shows an arrangement for laser drilling a fiber
composite component.
[0070] By way of example, a first component 1 made of
carbon-fiber-reinforced plastics material is provided as the fiber
composite component.
[0071] The arrangement comprises laser optics 8, which are carried
and positioned by a robot 7. The robot 7 may for example be a
conventional industrial robot having a suitable mounting.
[0072] The laser optics 8 are supplied with laser radiation from a
laser source 9 via an optical fiber 15. For example, the laser
source 9 is a high-energy solid-state laser, in particular a disc
laser or fiber laser, having a laser power in the kilowatt
range.
[0073] Preferably, a laser beam 5 generated thereby has a high
brilliance. The brilliance B is defined as the quotient of the
laser power P.sub.L divided by the product of the beam quality
factor M.sup.2 and the wavelength .lamda. of the laser beam. The
beam quality factor M.sup.2 denotes the degree of divergence of the
beam path. It is known in principle to a person skilled in the art
how to derive the beam quality factor for transverse
electromagnetic modes (TEM.sub.mn), and so a theoretical
explanation is omitted herein. The brilliance which can be
calculated in this manner is a measure of the quality of the laser
beam. In practice, the beam parameter product (BPP), based on the
beam quality factor M.sup.2 in terms of calculation, is often given
in connection with the laser power P.sub.L so as to express the
beam quality.
[0074] The laser optics are positioned above a first fiber
composite material component 1 to be drilled through by a robot 7
in such a way that the focal position of the laser beam 5 is at the
level of the first component 1. In the theoretical ideal case, the
laser beam can be focussed to a minimum diameter corresponding to
the fiber diameter of the optical fiber 15.
[0075] To drill through the first component 1, a multiplicity of
laser pulses are emitted onto the first component, for example by
percussion drilling, in such a way that the material of the first
component 1 evaporates, the laser beam 5 digs further into the
first component 1, and material vapor 10 escapes from the resulting
hole. This is repeated until a through-hole is manufactured.
[0076] The laser beam 5 evaporates both the matrix material and the
fiber material of the fiber composite material equally. In
particular, in the case of carbon-fiber-reinforced plastics
materials, the laser beam evaporates both the plastics material
matrix and the carbon fibers in the region of the through-hole.
[0077] Because of the different thermophysical properties of the
fibers and the matrix material, particular constraints should be
adhered to when laser-drilling fiber composite materials. In
particular in carbon-fiber-reinforced plastics materials, care
should be taken that the temperatures within the component do not
exceed material-dependent thresholds in the environment of the
through-hole to be manufactured as a result of thermal conduction
along the carbon fibers. Thresholds of this type may for example be
the glass transition temperature and the evaporation temperature,
and in the case of thermoplastic systems the melting point of the
matrix.
[0078] It is therefore advantageous to aim for a high degree of
sublimation or ablation. The intensity of the laser beam is
selected to be appropriately high so as to be able to evaporate
both the matrix material and the fibers of the fiber composite
material.
[0079] So as to achieve a desired diameter of the through-hole, for
example a through-hole manufactured by percussive drilling can be
widened by trepanning, in other words moving the component or the
laser optics in a circle around the centre of the through-hole.
[0080] Alternatively or additionally, a spiral drilling process may
be used or carried out to drill through the first component 1. In
this process, depending on the type of construction, the laser beam
(for example using movable mirror optics, known as a scanner) or
the laser beam optics (by moving the robot accordingly) or the
first component (by moving a mounting accordingly) constantly
rotates around the centre of the through-hole to be manufactured,
in such a way that a hole having the desired diameter is produced
directly. Superposed movements are also conceivable, in particular
in the case of a scanner provided as laser optics and mounted on
the robot.
[0081] An alternative to laser-drilling involves directing a
high-energy laser beam having sufficiently high laser power, for
example a CO.sub.2 laser, a fiber laser or a disc laser, for
example having a power >3 kW, in particular >6 kW, onto the
first component 1 in a configuration in which a beam diameter
directly corresponds to the desired diameter of the through-hole.
This is the case in FIG. 3A, and can be achieved by way of
appropriately configured laser optics 8 having an appropriate
imaging ratio, by optically defocussing the laser beam 5, by
adjusting a relevant distance from the focal position and/or by way
of an appropriately thick diameter of an optical fiber from the
laser source to the laser optics. Because of the high power, the
intensity of the laser beam 5 is still high enough to evaporate the
material both of the matrix and of the fibers of the fiber
composite material.
[0082] In this way, by single-pulse or percussive drilling, by
which the laser beam works into the fiber composite material, a
through-hole can be produced directly at the desired diameter.
[0083] Naturally, these drilling process are merely examples of a
possible implementation. Further drilling strategies or drilling
processes are also possible.
[0084] In particular, a continuous laser may be used as a laser
source. However, a pulsed laser would also be conceivable.
[0085] FIG. 3B is a cross-sectional view of a fiber composite
material component drilled through by laser-drilling.
[0086] This first component 1 accordingly comprises a through-hole
3. The hole wall 11, manufactured by laser-drilling, of the
through-hole 3 is a completely smooth and clean surface without
residues of the drilling dust. It is in particular a surface which
is covered with material directly solidified from the molten liquid
state or which is manufactured by direct evaporation.
[0087] The material melted on by the laser beam 5 has for example
been left behind on the hole wall 11 when the melt was driven out
or been melted on during the laser-drilling.
[0088] FIG. 4A shows an arrangement for drilling through two fiber
composite material components 1, 2 in an overlap joint.
[0089] The two components 1, 2 arranged in an overlap joint consist
of or comprise for example carbon-fiber reinforced plastics
material and are occupied by a drilling template 6, for positioning
or orientating the laser optics 8, on a face provided for the entry
of the laser beam 5.
[0090] As explained in relation to FIG. 3A, the laser optics 8 are
mounted on a robot 7. The associated laser source 9 and the optical
fiber 15, which supply the laser optics, are not shown here for
improved clarity.
[0091] The embodiment shown is in particular a semi-automatic
system. In other words, the laser optics 8 are oriented onto
recesses provided in the drilling template 6, in a robot-assisted
manner but under the control of a user. For this purpose, the laser
source 9 comprises a search laser which emits a visible light beam
through the fiber in such a way that a light point is projected
onto the targeted point by the laser optics.
[0092] Alternatively, the drilling template 6 may also be fixed in
position and be formed as a positioning means or stop for the first
and second components 1, 2. In this case, the approach towards the
positions for drilling may be programmed or saved (for example by
learning or teaching) into a control system of the robot 7.
[0093] Further, a laser machining pattern or a machining sequence
may be programmed into a control system of the laser source 9
and/or of the laser optics 8.
[0094] After the components 1, 2 and/or the drilling template 6
have been positioned, an automatic sequence of the drilling process
can be initiated.
[0095] As a further alternative, in the case of specified and/or
automatic positioning of the components 1, 2 an automatic sequence
of the drilling process could also be initiated without a
template.
[0096] By way of example, in the embodiment shown three
through-holes 3 uniformly spaced apart from one another are
provided in each cross-sectional plane.
[0097] The through-holes 3 are formed by laser-drilling in the
manner described in relation to the previous FIGS. 3A and B. To
form conical entries to the through-holes for countersinking a
rivet head, the laser beam is initially more heavily defocussed,
and subsequently less and less so down to the desired hole
diameter. The intensity of the laser beam always remains high
enough to evaporate both the matrix material and the fibers of the
fiber composite material.
[0098] Arrangements of this type for (semi-)automatically
laser-drilling fiber composite components may be adapted to
different desired hole diameters and to different component
thicknesses. Thus, by comparison with a method according to FIG. 1
or 2A, much higher production speeds are possible, merely requiring
a fraction of the time to manufacture the through-holes 3. Further,
arrangements of this type advantageously operate without any
variation in the quality of the laser-drilled through-holes 3. By
contrast, in mechanical drilling methods, as described in relation
to FIGS. 1 and 2A, a drill loses sharpness and thus precision with
continued use. This can be discerned in microscope images of the
drilled holes by way of increased occurrence of drilling dust and
unclean or rough surfaces.
[0099] FIG. 4B is a cross-sectional view of a structural
arrangement 16 comprising a rivet connection 17 of two fiber
composite material components 1, 2.
[0100] The two components 1, 2 arranged in an overlap joint and
provided with through-holes 3 by laser-drilling are connected by
rivets 4, which are introduced into the through-holes 3 and
subsequently fixed to the first component 1 and to the second
component 2.
[0101] In this connection, it should in particular be noted that no
additional cleaning step is required before the rivets 4 are
introduced, since when the through-holes 3 are laser-drilled no
drilling dust, in particular no carbon dust, occurs.
[0102] The fixing takes place in the manner conventional to a
person skilled in the art, in particular by way of a positive
connection provided on the rivet 4 by way of a rivet head at the
entry face and a positive and non-positive connection provided by
shaping at the exit face.
[0103] FIG. 5 is a perspective view of a vehicle skin 20. In the
embodiment shown, this is a vehicle skin 20 in the form of a
fuselage portion of an aircraft or spacecraft.
[0104] The fuselage portion comprises a first skin portion 18 as
the first component 1 and a second skin portion 19 as the second
component 2. The two skin portions 18, 19 are arranged in an
overlap joint with one another in the region of a rivet connection
17. A plurality of joint lines 13, typically three parallel joint
lines, are provided parallel to an edge 14 of the first skin
portion 18 by through-holes, each having an inserted and fixed
rivet 4.
[0105] In total, the fuselage portion shown consists of or
comprises by way of example four skin portions, which are each
curved and which are arranged to form a tubular fuselage shape and
interconnected in the same manner as the first skin portion 18 and
the second skin portion 19.
[0106] FIG. 6 is a perspective view of two fiber composite material
components 1, 12 connected in a butt joint by a connecting portion
2'.
[0107] This is a structural arrangement 16 comprising two
components 1, 12 in a butt joint, which are connected via the
connecting portion 2' using a rivet connection 17.
[0108] For this purpose, the first component 1 and a further
component 12 are arranged with respect to one another and covered
with a connecting portion 2' formed as a doubler in the region of
the butt joint. The connecting portion 2' is arranged overlapping
with each of the components 1, 12 and in each case connected by at
least one joint line 13 of through holes 3, for example a plurality
as shown here, in particular three, each having an inserted and
fixed rivet 4.
[0109] Thus, in this embodiment, the connecting portion 2' formed
as a doubler forms the second component arranged in an overlap
joint with the first component 1 and connected by rivet
connection.
[0110] In this case too, the joint lines 13 accordingly extend
along an edge 14 of the first component 1.
[0111] Although the present disclosure has been described herein by
way of several embodiments, it is not limited thereto, but can be
modified in numerous ways.
[0112] For example, for different applications, a wide range of
different types of rivets may be used, for example including hollow
rivets, blind rivets, spread rivets or the like instead of solid
rivets.
[0113] In one embodiment, it is conceivable to provide one of the
components with pre-drilled holes, in such a way that the shared
through-hole can only be produced through the fiber composite
material of the other component by laser-drilling. Subsequently,
the components can be riveted. In particular, holes of the
pre-drilled component which are pre-drilled in this manner may be
provided with countersinks for receiving a rivet head in a flush
manner.
[0114] Instead of skin portions, the first and second components 1,
2 may be any type of structural component of a structural
arrangement.
[0115] As an alternative to a fuselage for an aircraft or
spacecraft, skin portions of other types of vehicle skins
containing fiber composite components may be provided with a rivet
connection 17 in the manner according to the disclosure herein, for
example body parts of a motor vehicle or fuselage parts of a boat
or ship.
[0116] While at least one exemplary embodiment of the present
invention(s) is disclosed herein, it should be understood that
modifications, substitutions and alternatives may be apparent to
one of ordinary skill in the art and can be made without departing
from the scope of this disclosure. This disclosure is intended to
cover any adaptations or variations of the exemplary embodiment(s).
In addition, in this disclosure, the terms "comprise" or
"comprising" do not exclude other elements or steps, the terms "a",
"an" or "one" do not exclude a plural number, and the term "or"
means either or both. Furthermore, characteristics or steps which
have been described may also be used in combination with other
characteristics or steps and in any order unless the disclosure or
context suggests otherwise. This disclosure hereby incorporates by
reference the complete disclosure of any patent or application from
which it claims benefit or priority.
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