WO2010142610A1

WO2010142610A1 - Template and template set for use in the repair of composite materials

Info

Publication number: WO2010142610A1
Application number: PCT/EP2010/057835
Authority: WO
Inventors: Jörg-Ulrich ZOWALLA
Original assignee: Zowalla Joerg-Ulrich
Priority date: 2009-06-11
Filing date: 2010-06-04
Publication date: 2010-12-16
Also published as: CH701247A1

Abstract

The invention relates to a template (1) and a template set (0), comprising the template (1) and at least one corresponding additional template (1'), and the use of said template to prepare flat and curved surfaces (3), preferably from several layers of composite material. In addition to preparing surfaces (3), the template (1) and the at least one additional template (1') can also be used to mark the cutting lines on patches made of repair material in the form of fiber-reinforced composite material.

Description

Stencil and stencil are used in the repair of composite materials

Technical area

The present invention describes a stencil set comprising a plurality of n separated stencils each having a peripheral contour and a central recess surrounding a recess contour, in particular as an aid for the repair of damaged areas in surfaces.

The state of the art in the field of mechanical stability and low weight makes it interesting for a range of application fields. Fiber reinforced composites, including multi / unidirectional woven fabrics of glass, carbon or aramid fibers, are used in aerospace, boatbuilding, automotive, but also in modeling and sports equipment.

Systems of composites are usually in the multilayer laminate structure, or in the so-called "SandwicrT structure. The laminate structure comprises a plurality of different fiber-reinforced composite layers, which are bonded together with different fiber orientations oriented relative to one another, whereby an extreme strength can be achieved.

If damage occurs, for example, by impacts of objects on the surface, individual layers of the laminate structure may be damaged. For the repair of such defects, for example in model making, there are instructions which provide the most careful possible preparation of the surface recommend. This is accomplished by abrading the various laminate layers at different depths with different sanding surfaces using different techniques. After grinding, patches of fiber reinforced composites in different orientations of the fibers are glued into the grinding surfaces by means of adhesives and firmly bonded to the workpiece, for example, by creating a vacuum. The patches are usually soaked in synthetic resins or painted before they are placed in the impregnated state on the pretreated surface and optionally coated with additional adhesive.

Even a skilled model-maker achieves only unsatisfactory repair results with the previously available instructions and tools, due to lack of precision of the surface preparation and inaccurate creation of the patches. Special tools to facilitate repair are unknown.

For example, as known from EP1782942 comes in aviation, the time pressure for repairs, for example of

Defects in wings added, since the aircraft operators demand the lowest possible downtime of their machines, so for

Exterior repairs only very little time remains. EP178294 discloses a method for easy and quick repair of damaged areas, but no tool which simplifies the preparation of the surface.

In order to ensure that the aordynamic properties are unchanged after the repair and the same loads can be absorbed, as well as voltages can be forwarded by the repair site, a device was disclosed in US6206067, which allows a virtually invisible repair of a damaged area in a surface. This is achievable with the construction of a shell under which patches can be fixed under vacuum on a previously prepared surface. Although aviation professionals are only specialists, repair is often not optimal, often due to poor surface preparation and the need to make repairs.

In order to reproducibly and exactly prepare the often curved surface to be repaired, a device according to US5207541 was proposed. This device allows the exact exposure of different fiber reinforced

Composite layers, into which corresponding fl eels can be glued. The complexity and size of the device make it difficult to use such a device in the exterior repair of aircraft. Not every repair mechanic will be able to acquire such a device for his daily mending work, and for semi-professional or home users, the device is prohibitively expensive. The use of such a device is useful for particularly serious damage sites, especially on strongly curved surfaces and to lead by trained professionals. For small defects, the great expense of transport and use of this device is undesirable.

For example, many aircraft manufacturers offer so-called "Structure Repair Manuals" (SRMs), which provide binding instructions for repair, but there is no reproducible and traceable guide to the individual steps to be taken, so that the repair technicians carry out the practical implementation differently can.

As the use of fiber reinforced composites will continue to increase in the future, there is a need for simple repair of defects in fiber reinforced composites reproducible, fast and even by non-professionals.

SUMMARY OF THE INVENTION The object of the present invention is to provide a template which permits simple and reproducible grinding surface marking in the area of damaged areas in surfaces, in particular of composites, and an exact and reproducible cutting definition of corresponding patches, in particular of composite materials, which are connected to material the prepared surface can be used.

Another object of the invention is to provide a stencil set of a plurality of stencils which achieves the abrasive surface marking in different sizes corresponding to each other on the surface to be prepared.

In an advantageous embodiment of the stencil set, the individual stencils are designed such that they can be stowed and transported into one another.

The stencil according to the invention as well as the stencil set can be used for repairing damaged areas in a surface of multilayer composite materials which have a laminate structure. In addition, the use of the

Stencil or stencil set for repair of

Work piece surfaces possible, which can also be covered with one or more patches. Brief description of the drawings

A preferred embodiment of a template, as well as two embodiments of template sets, will now be described in conjunction with the accompanying drawings, in which the illustrated surface to be repaired consists of multiple layers of fiber reinforced composite materials.

FIG. 1 shows a first template and a first template set, comprising template-like configured templates in a perspective view.

Figure 2 shows a sectional view of a surface with an applied template on the outer contour of a marking means is guided along.

FIG. 3 a shows a sectional side view of a five-layered laminate structure of composite materials with a damaged area, while FIG

FIG. 3 b shows a sectional side view according to FIG. 3 a with a blister set, which is a flat panel

Includes templates and is used for marking the grinding surface.

FIG. 3c shows a sectional side view of the ground surface according to FIG. 3a, with a total of five grinding surfaces being applied.

FIG. 3d shows a sectioned side view of the prepared surface, as well as patches already to be positioned already cut by means of a template set, while FIG

FIG. 3e shows a sectioned side view of the repaired surface after a material connection of the patches. FIG. 4a shows a perspective view of a second stencil set, wherein the first stencil is disc-shaped and the plurality of second stencils are annular. FIG. 4b shows the second stencil set according to FIG. 4a folded together in a plan view.

Figure 5 shows a sectional view of a surface with an applied second template in the central recess a grinding device is moved.

Figures 6a to 6c show the Schleifflächenkennzeichnung, as well as the Absch leifprozess in nerha lb egg ner four-ply surface of fiber-reinforced composite material in a sectional side view shown.

description

In the following, a template 1, as well as a stencil set 0, comprising the template 1 and at least one corresponding additional template 1 'and the use for the preparation of flat and curved surfaces 3 are disclosed. In addition to the preparation of the surfaces 3, a marking of the cut lines on patches 2 made of repair material, preferably in the form of fiber-reinforced composite material, can additionally be carried out with the template 1 and the at least one additional template 1 '.

The surfaces 3 shown in the figures represent multilayer surfaces 3 of fiber-reinforced composite materials, which have a so-called laminate structure and are used primarily in aircraft, boat and automobile construction. Although the egg sentence of the templates 1, 1 'presented here is explained using the example of fiber-reinforced composite materials, their use for solid single-layer surfaces 3 is also possible.

By way of illustration, the blade 1 is a plate having a peripheral contour 11 and a central recess 10

The recess contour 12 delimits the central recess 10, wherein the contact between the recess and the recess is limited to the central recess 10

Circumferential contour 11 forms a covering surface 13 of the template 1.

Preferably, the template 1 is formed as a rotationally symmetrical disc with a circular peripheral contour 11. In embodiment of the template 1 as a disc and in forming the base of the

Recess 10 as a circular area, the cover surface 13 is annular. It is depending on the purpose but also possible to make the template 1 with a polygonal circumferential contour 11 and a polygonal base of the recess 10.

If damaged areas 4 have to be repaired with larger dimensions, it is advantageous to have at least one additional template 1 '. to use, which match in design with the template 1 and form with the template 1, the stencil set 0. The diameter Di of a template 1 and the diameter Dr of an additional template 1 'are shown in FIG. 4b by way of example for all possible embodiments.

The at least one additional template 1 'has compared to the template 1 different sized outer circumferential contours 11 and different stepped diameters Di. The diameter Dr of successive additional templates 1 'is gradually increased. As template 1, the template 1 with the smallest diameter Di of the entire template set 0 is always referred to here. All additional templates 1 'have correspondingly stepwise larger diameter D _r . A minimum overlap of successive templates 1 or additional templates 1 'of at least half an inch is preferred.

As can be seen in FIG. 2, the template 1 has a thickness and thereby an edge surrounding the peripheral contour 11 so that a marking means 7, for example a pin 7, can be guided along the edge around the peripheral contour 11 and along the recess contour 12, whereby grinding surface delimiting lines 55 can be produced on the surface 3.

In Fig. 3, the stepwise repair of a damaged area 4 in a surface 3 of a fiber reinforced composite comprising five different layers of material 30, 31, 32, 33, 34 is shown. The first template 1, as well as four additional ones Stencils 1 'are positioned approximately centrally on the damaged area 4 and the circumferential contours 11 are marked by means of a marking means 7. The orientation of the additional templates 1 'takes place on the basis of the central recess 10 of the additional templates 1' relative to the recess 10 of the template 1 and the damaged area 4. This is a simple, reproducible and correspondingly known repair instructions requirements

Abrasive area marking in the area of the damaged area 4 possible.

After the marking and the removal of the stencil set 0, the first layer 30 according to the grinding surface marking of the largest, with respect to the diameter, additional template 1 'by means of a grinding device 8 ground. According to the grinding surface marking, a first grinding surface 50 is abraded according to the marked grinding surface delimiting lines 55. In a further step, the second layer 31 is ground according to a marked second grinding surface 51 corresponding to the second largest additional template 1 '. This process is repeated accordingly until the third layer 32, the fourth layer 33 and the fifth layer 34 have been graded with different diameters, according to a third grinding surface 52, a fourth grinding surface 53, and a fourth grinding surface 54 have been ground.

The template 1, as well as the additional templates 1 'are likewise used for the reproducible cutting definition of corresponding patches 2, in particular made of composite materials which are suitable for material-bonding connection with the prepared surface 3. The blank definition is carried out on the patches 2 by a marking agent 7 is guided around the peripheral contour 11 of the template 1 and the additional templates 1 ', while the template 1 and the additional templates 1' are held fixed by hand.

After the blank definition, a cut of the patches 2 according to the prior art. After the preparation of the surface and the cutting of the patches 2, the patches 2 are secured in a coherent manner with an adhesive, for example synthetic resin, on the abraded surfaces of the surface 3. The patches 2 can either be impregnated with synthetic resin, or be coated on both sides with synthetic resin, before they are placed on the surface and pressed. Under certain circumstances, a repainting with adhesive, especially with synthetic resin is necessary after the positioning of the patches 2. In order to support the fixation of the patches 2 on thin surfaces 3, the use of a support pad 6 below the surface 3 is helpful.

In order to achieve the highest possible mechanical stability and strength, the two composite materials are impregnated with adhesive and glued in different fiber orientations over the ground grinding surfaces. After the bonding of the different patches 2, known standard methods for pressing, drying and curing, for example by generating a vacuum in the region of the patches 2, can be carried out. This known Vakuumiermethode uses the outer air pressure for a uniform pressing of the patches 2 on the surface. 3

Another embodiment of the stencil set 0 is shown in FIGS. 4a and 4b. The additional templates 1 'are at least approximately annular, wherein the central recess 10 is designed to be correspondingly large. Also, the template 1 is annular and has such a large diameter that the template 1 in the recess contour 12 of the following additional annular second template 1 'is flush inserted. Each additional additional template 1 'can be inserted into the recess contour 12 of the respectively next larger additional template 1'. Each subsequent next larger additional template 1 'completely surrounds the smaller template 1 or additional template 1'. That's the way it is it is possible to put together the template 1 and the plurality of additional templates 1 'in a plane stencil set 0. It is also possible to make the template 1 as in the first embodiment according to FIG.

With a fixed template 1 or additional template 1 ', a grinding device 8 can be inserted directly into the recess 10, the recess 10 transversely and operated there. To fix the templates 1, 1 ', the user can either hold them by hand or, for example, fix them releasably on the surface 3 with an adhesive tape.

FIG. 5 shows an additional template 1 'which is placed on the surface 3 or on the first layer 30 and fixed. The central recess 10 marks the grinding surface without the need for marking with marking means. Within the recess 10 of the additional template 1 ', the first layer 30 can be removed directly with the grinding device 8. The grinding head 80 of the grinding device 8 is moved within the recess 10 on the first layer 30, wherein a region around the damaged area 4 to the second layer 31 in the z-direction is removed.

FIGS. 6a to 6c show the further steps of the stencil support and thus for the grinding surface marking and the individual abrading processes. By flush fit the different sized template 1 or additional template 1 ', the grinding process directly in the recess 10 of the templates 1, 1' take place. Again, the patches 2 are cut with the template 1 and the plurality of additional templates 1 ', so that on the grinding surfaces adapted patches 2 can be produced. The template 1, as well as the additional templates 1 'have a defined edge, so that the circumferential contour 11 of the templates 1, 1' defined with the marking means 7 is reversible. In order for a grinding process to take place directly in the recess 10 of the templates 1, 1 ', the thickness of the templates 1, 1' must be such that the templates 1, 1 'can be fixed stably on the surface 3 or on the patches 2.

In all embodiments, the first template 1 can optionally be embodied as an annular template 1 or disc-shaped template 1, with the outer circumferential contour 11 of the template 1 corresponding to the recess contour 12 of the following additional template 1 'corresponding to the template blone 1 is completely enveloped by the following additional template 1 'in a plane.

As can be seen in FIGS. 1 and 4a, the diameters and the outer circumferential contours 1 1 of the first and second corresponding templates 1 'are made larger than the diameter and the outer circumferential contour 11 of the template 1. The diameters of successive additional templates 1 'are made enlarged in an ascending manner and also the recess 10 of the additional templates 1' has a circular area.

In order to enable an arrangement of the template 1, as well as the at least one additional stencil 1 'in egg nem menagbaren together stencil set 0, the diameter of the template 1 must be at least approximately the diameter of the central recess 10 of the stencil 1 following additional template 1 'correspond. Thus, the peripheral contour 11 of the template 1 and / or the at least one additional template 1 'each flush in the central recess 10 on the template 1 and / or the at least one additional template 1' following additional template 1 'are introduced. The diameter of the successive additional templates 1 'is executed stepwise verg rosse rt.

Particularly preferably, the template 1, as well as the at least one additional template 1 'made of a transparent material, so that the damaged area and the surface 3 remain visible during the marking.

In order to enable accurate grinding surface marking on curved surfaces 3, the material of the template 1 and the additional templates 1 'should be chosen to be flexible. For a nestling of the template 1 and the additional templates 1 'on a curved surface 3 is possible.

With the aid of the template 1 according to the invention and the additional templates 1 ', it is even possible to mark damaged areas in a massive single-layered surface, to abrade them and to repair them with patches 2 of correspondingly solid repair material. It can be introduced with different depths using the template 1 and the additional templates 1 'size graded grinding surfaces. Subsequently, a plurality of patches 2 material and / or positively connected to be arranged on or in the grinding surfaces.

The template 1 and the additional templates 1 'are made of dimensionally stable and chemically neutral materials. Then it is possible to pass along the marking means and the grinding head and the templates 1, 1 'are not chemically attacked during the grinding process. In order to use the template 1 and the additional templates 1 'on curved surfaces for reproducible marking of grinding surfaces, should The material used can nevertheless be flexible within narrow limits, flexible and easily deformable according to the curved surfaces.

The different sized, stepped running diameter of the templates 1, 1 'are designed such that a minimum overlap of the next smaller grinding surface is achieved. For example, since the S RM of at least one well-known manufacturer (OEM) requires a minimum overlap of Vi inch, the gradual reduction of the diameter is carried out accordingly.

LIST OF REFERENCE NUMBERS

0 stencil set

1 template

1 'additional template

10 recess (centric)

11 peripheral contour (outer)

12 recess contour

13 cover surface

2 patches

3 surface (multilayer composite)

30 first location

31 second location

32 third location

33 fourth location

34 fifth position

4 damaged area

50 first grinding surface

51 second grinding surface

52 third grinding surface

53 fourth grinding surface

54 fifth grinding surface

55 grinding surface delimiting lines

6 support pad

7 markers

8 Grinder 80 Grinding head z-direction

Di, diameter template / additional template Dr

Claims

claims

A stencil set (0), comprising a plurality of n separated stencils (1) each with a peripheral contour (11) and a central recess (10) surrounding a recess contour (12), in particular as a tool for repairing damaged areas (4) in surfaces (3), characterized in that the diameter of the outer peripheral contour (11) of successive templates (1) is stepped from the diameter of the outer peripheral contour (11) of the first template (1) to the diameter of the outer peripheral contour (11) of the n stencil (1 ') is vergra rt, so that by the peripheral contour (11) and / or the recess contour (12) of each template (1, 1') each have a grinding surface (50) on the surface (3) and / or a marking of blank lines on patches (2) of repair material is definable.

2. stencil set (0) according to claim 1, characterized in that the diameter of the recess contour (12) of the n-th template (1,1 ') the diameter of the peripheral contour (11) of the adjacent (nl) -ten stencil (1, 1 ') corresponds.

3. stencil set (0) according to claim 2, characterized in that the peripheral contour (11) of the first template (1) to the (n-1) - th template (1 ') each flush in the central recess (10) of each following additional template (1 ') can be inserted and thus a just collapsible stencil set (0) from n templates (1, 1 ') can be formed.

4. stencil set (0) according to claim 2, characterized in that the thickness of the templates (1, 1 ') has a sufficiently stable edge for the defined operation of a grinding head (80) of a grinding device (8) within the central recess (10).

5. stencil set (0) according to claim 1, characterized in that by the step-like configuration of the circumferential contours (11) directly successive templates (1, 1 ') of the first template (1) to the n-th template (1') a cone-shaped collapsible n-layer stencil set (0) can be formed.

6. stencil set (0) according to one of the preceding claims, characterized in that the templates (1, 1 ') are made of a dimensionally stable and transparent plastic.

7. stencil set (0) according to any one of the preceding claims, characterized in that the templates (1, 1 ') of a slightly flexible

Plastic are made.

8. stencil set (0) according to one of the preceding claims, characterized in that the base surface of the recess (10) is a circular area with a circular recess contour (12), so that the definable first grinding surface (50) and / or the mark of cut lines on patches (2) of repair material is a circular area.

9. Use of a stencil set (0) according to one of the preceding claims, characterized in that a grinding head (80) of a grinding device (8) the central recess (10) of the n stencils (1, 1 ') crossing the surface (3) in the region of the recesses (10) can be placed and n grinding surfaces (50) in n layers (30) of the surface (3) are abradable.