Laying die, laying device and method for manufacturing a laying die

Abstract

A laying die, for picking up and laying of substrates, comprising an elastically deformable substrate receiving structure providing an engagement surface for releasable receiving of substrates, an attaching element comprising a gas channel for providing positively or negatively pressurized gas for picking up and blowing off the substrates, and a carrier body made from elastically deformable material and sandwiched between the substrate receiving structure and the attaching element which is arranged to distribute the positively or negatively pressurized gas over the carrier body. The carrier body comprises breakthroughs to transfer the pressurized gas from the attaching element to the substrate receiving structure that comprises an elastically deformable distribution plate to distribute the positively or negatively pressurized gas over the engagement surface. Also, a laying device which changes the position and/or orientation of substrates to predetermined values can comprise the laying die and a method for manufacturing the laying die.

Claims

1. A method for manufacturing a laying die, comprising: providing an elastically deformable substrate receiving structure with an elastically deformable distribution plate; providing a carrier body made from an elastically deformable material; providing an attaching element comprising a gas channel; distributing a plurality of breakthroughs into the carrier body; sandwiching the carrier body between the substrate receiving structure and the attaching element; and providing a cambering device including a rope attached to the substrate receiving structure, wherein the cambering device configured to pull at least one of the carrier body and the substrate receiving structure into a predetermined deformation.

2. The method according to claim 1, wherein the providing the elastically deformable structure comprises: providing two elastically deformable films; arranging a heating element between the two elastically deformable films to provide a stack; and distributing a plurality of holes into the stack.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention will be described in more detail by way of the attached drawings, in which:

(2) FIG. 1 illustrates a laying device comprising a laying die for picking up and laying of substrates;

(3) FIG. 2 is an exploded view of the laying die of FIG. 1, comprising an attaching element, a carrier body and a substrate receiving structure;

(4) FIG. 3 shows the carrier body of FIG. 2 together with a stiffness distribution over the surface of the carrier body;

(5) FIG. 4 illustrates a gas flow through the laying die of FIG. 1;

(6) FIG. 5 shows the laying die of FIG. 1 being cambered around a curved surface;

(7) FIG. 6 shows the laying die of FIG. 1 being flexed over an angled surface;

(8) FIG. 7 shows the assembly of the attaching element and the carrier body of the laying die of FIG. 1 together with the resulting stiffness distribution according to FIG. 3;

(9) FIG. 8 illustrates breakthroughs in the carrier body formed as slits;

(10) FIG. 9 illustrates breakthroughs in the carrier body formed as a hole matrix;

(11) FIG. 10 shows the assembly of the substrate receiving structure out of two films and a sandwiched heating element;

(12) FIG. 11 shows a backside view of the substrate receiving structure;

(13) FIG. 12 shows a front side view of the substrate receiving structure;

(14) FIG. 13 illustrates a contact assembly to provide the coating as the heating element with a voltage;

(15) FIG. 14 shows an assembly of the carrier body and the substrate receiving structure viewed from above;

(16) FIG. 15 shows the assembly of FIG. 14 viewed from below;

(17) FIG. 16 shows an embodiment of the laying die comprising an attaching element with a first embodiment of a vacuum distribution system;

(18) FIG. 17 illustrates an embodiment of the laying die comprising an attaching element with a second embodiment of a vacuum distribution system;

(19) FIG. 18 shows the laying die of FIG. 1 comprising a cambering device and being in a non-deformed state;

(20) FIG. 19 shows the laying die of FIG. 18 in a cambered condition;

(21) FIG. 20 shows a perspective view to the cambering device of FIG. 18;

(22) FIG. 21 illustrates a view from above on the cambering device of FIG. 18;

(23) FIG. 22 shows a view to the cambered substrate receiving structure according to FIG. 19;

(24) FIG. 23 shows an exploded view of a laying die according to the state of the art comprising an attaching element, a carrier body and a substrate receiving structure;

(25) FIG. 24 illustrates the carrier body of FIG. 23 with a corresponding stiffness distribution; and

(26) FIG. 25 shows a gas flow through the laying die of FIG. 23.

DETAILED DESCRIPTION OF EMBODIMENTS

(27) FIG. 1 shows a laying device 10 for laying of fiber pieces, the device 10 comprising a laying die 12, the laying device 10 being able to moving the laying die 12 in two spatial directions x, y and to rotate the laying die 12 around axis y. Further, the laying device 10 is able to pivot the laying die 12 around axis z.

(28) To be able to move, rotate and pivot the laying die 12 the laying device 10 comprises a robot arm 14. Further, a control device 16 is provided to control the robot arm 14. The control device 16 comprises a storage device 18 in which predetermined values of the position, orientation and/or camber of the fiber pieces to be attained are stored. The storage device 18 is communicating with an activation device 20 which activates the robot arm 14 according to the values to be attained.

(29) FIG. 23 to FIG. 25 show a laying die 12 according to the state of the art. The conventional laying die 312 comprises an attaching element 322, a carrier body 324 and a substrate receiving structure 326 as shown in the exploded view of FIG. 23. The attaching element 322 comprises a gas channel 328 through which a negatively or positively pressurized gas can be provided to the substrate receiving structure 326. The gas channel 328 communicates with a silicon gas channel 330 provided by a pipe 332 which is embedded in a central breakthrough 334 formed in the carrier body 324. At its lower end the silicon gas channel 330 comprises a silicon distribution plate 336 being integrally formed with the pipe 332. The substrate receiving structure 326 is formed by a silicon mat 338 with an integrated heating element 340 made from carbon fiber.

(30) When substrates have to be picked up by the laying die 312, i.e. by using negatively pressurized gas flow, a vacuum is attached to gas channel 328 and supplied via pipe 332 and the silicon distribution plate 336 over the inner surface 342 of the substrate receiving structure 326. As the substrate receiving structure 326 comprises evenly distributed holes 344, the vacuum is also distributed over the engagement surface 346 of the substrate receiving structure 326. Due to this vacuum at the engagement surface 346 a substrate which is located nearby the outer surface 346 will be attached to the substrate receiving structure 326 and can be transported via the laying device 10 to a predetermined position.

(31) FIG. 24 shows that due to the central breakthrough 334 in the carrier body 324 the stiffness is not evenly distributed over the carrier body 324, but has higher values in the area of the central breakthrough 334. FIG. 25 shows how the vacuum attached to the gas channel 328 transports gas 347 from outside the laying die 312 through the substrate receiving structure 326, the silicon gas channel 330 and the gas channel 328.

(32) FIGS. 2 to 22 show embodiments of the laying die 12 according to the invention. In FIG. 2 is shown that the laying die 12 comprises an attaching element 22, a carrier body 24 and a substrate receiving structure 26. The attaching element 22 comprises a pipe element 28 and a base plate 30 integrally formed with the pipe element 28. The carrier body 24 comprises breakthroughs 34 in the form of slits 36 which are distributed over a longitudinal extension direction 38 of the carrier body 24. The substrate receiving structure 26 comprises separate films 40, 42 and a heating element 44 being sandwiched between the two films 40, 42.

(33) FIG. 3 shows the stiffness distribution over the carrier body 24 resulting from the slits 36 being evenly distributed over the longitudinal extension direction 38 of the carrier body 24. As can be seen, different to the carrier body 324 of the state of the art, the stiffness of the carrier body 24 is evenly distributed over its overall extension direction 38.

(34) FIG. 4 shows a gas flow through the laying device 12, wherein a gas 45 is not only transported through a central breakthrough 334 as shown in FIG. 25 in the state of the art, but is divided over all breakthroughs 34 and therefore evenly distributed in the carrier body 24. As further can be seen the pipe element 28 is formed to provide a gas channel 46, wherein the base plate 30 is only in contact with the outer edges 48 of the carrier body 24 thereby providing a hollow space 50 between the attaching element 22 and the carrier body 24. When providing a positively pressurized gas flow through the gas channel 46 to the substrate receiving structure 26 the gas 45 is evenly distributed over the breakthroughs 34 due to this hollow space 50.

(35) The carrier body 24 and the substrate receiving structure 26 are formed from an elastically deformable material 51 and are therefore elastically deformable. Due to the even stiffness distribution over the whole longitudinal extension direction 38 the laying die 12 can more excessive be deformed around bent surfaces. For example, in FIG. 5 is shown that the laying die 12 can be cambered around a cambered surface with a diameter of 50 millimetres. Further, as shown in FIG. 6 the laying die 12 can be flexed over an angled surface with an angle of 90°.

(36) To provide an effective gas flow through the laying die 12, wall surfaces 52 of the breakthroughs 34 comprise at least partially air-tight seals 54. Also, the carrier body surfaces 56 can be provided with these air-tight seals 54. The air-tight seals 54 can be formed by a glue-film 58 or by a silicon film 60.

(37) FIG. 7 shows the assembly of the attaching element 22 and the carrier body 24 comprising the slits 36 to form an upper part 62 of the laying die 12, wherein this upper part 62 also comprises an evenly distributed stiffness. The evenly distributed breakthroughs 34 in the carrier body 24 can be provided by slits 36 as shown in FIG. 8 or by circles 64 which are arranged in a matrix 66, the matrix 66 comprising more than two rows and more than two columns as shown in FIG. 9. With a circle matrix the stiffness is not only distributed over the longitudinal extension direction 38 of the carrier body 24, but also over the extension direction in depth 68.

(38) The substrate receiving structure 26 is formed from a distribution plate 70 as shown in FIG. 10. The distribution plate 70 comprises the two elastically deformable films 40, 42, each comprising evenly distributed holes 72. The heating element 44 is sandwiched between the two films 40, 42 and arranged on bars 74 between the holes 72. The holes 72 of the films 40, 42 are arranged correspondingly, i.e. the holes 72 of the upper film 40 are laying exactly over the holes 72 of the lower film 42. In FIG. 10 those films 40, 42 are formed from silicon and the heating element 44 is formed by a steel fiber made of thin steel filaments.

(39) FIG. 12 shows a backside view onto the distribution plate 70 with the heating element 44 in between the two films 40, 42. FIG. 13 shows a front side view of this distribution plate 70. FIG. 13 shows an alternative possibility to provide one or both of the films 40, 42 with a heating element 44.

(40) Here, the heating element 44 is formed by a heatable coating 78, for example a graphite coating, which can be contacted via metal stripes. Therefore, one of the films 40, 42 is provided with those metal stripes and afterwards the coating 78 is provided on to film 40, 42 and metal stripes via rolling, spraying or brushing. Thereafter, the metal stripes can be provided with a voltage provided by contacting cables 82 to contact the metal stripes thereby heating up coating 78.

(41) FIG. 14 and FIG. 15 show an assembly of the distribution plate 70 and the carrier body 24, wherein FIG. 14 shows a view from above onto the slits 36 in the carrier body 24 and FIG. 17 shows a view from below onto the distribution plate 70. The lower surface 84 of the distribution plate 70 which is directed away from the carrier body 24 provides an engagement surface of the substrate receiving structure 26 where substrates can be picked up.

(42) FIG. 16 and FIG. 17 show embodiments of the laying die 12 having a larger scale. Both embodiments comprise vacuum distribution systems 88 comprising a plurality of gas pipes 90 branching from the pipe element 28 over an upper surface 91 of the attaching element 22. In the embodiment of FIG. 16 only two gas pipes 90 are branching from pipe element 28. In the embodiment of FIG. 17 four gas pipes 90 are branching from pipe element 28. In case of large scaled laying dies 12 it is preferred to provide an attaching element 22 formed from a composite construction e.g. a carbon fiber reinforce polymer skin together with a Nomex® honeycomb core.

(43) FIG. 18 shows the laying die 12 being provided with a cambering device 92 to actively camber the carrier body 24 and the substrate receiving structure 26. In FIG. 18 the engagement surface 86 of the laying die 12 is shown in a non-deformed condition relative to a predetermined camber 94, wherein in FIG. 19 the engagement surface 86 is in a cambered condition according to the predetermined camber 94. The cambering device 92 comprises a rope system 96 with a rope 98 and a bobbin 100. The rope 98 is arranged in the outermost breakthroughs 34 of the carrier body 24 and is attached to the substrate receiving structure 26.

(44) FIG. 20 shows that the rope system 96 also comprises a motor 102, in particular a linear motor, to drive the bobbin 100. The rope 98 is guided in a square-like manner over bobbin 100, the opposing edges 104 of the carrier body 24 and an idler pulley 106 on a bearing 108, the idler pulley 106 and the bearing 108 being located at the vicinal edge 109 of the attaching element 22 to the bobbin 100. In FIG. 20 two rope systems 98 are provided for pulling opposing edges 104 of the attaching element 22.

(45) FIG. 21 shows a top view onto the laying die 12 comprising the rope system 96. FIG. 22 shows a view onto the carrier body 24 after being cambered by the rope system 96.

(46) The above described robot head, i.e. laying die 12, enables the positioning of short fiber carbon patches of any position and orientation of the fibers during preforming. The head stamp, formed from the carrier body 24 and the substrate receiving structure 26, grabs a carbon patch, delivered by a feeder, using vacuum suction, place it on the tool according to the specified position/orientation and fixate it using thermally activated binder. The present invention enables to overcome the former deformability issues, as the head permits now the lay-up of complex 3D forms following the structure curvatures, radiuses and edges.

(47) Heads according to the prior art had however some limitations:

(48) Due to its design the head could not deform significantly and could just lay on slightly curved structures;

(49) The head was quite sensitive: the thermocouple and/or the carbon fiber used for heating were breaking quite often;

(50) The manufacturing required important effort;

(51) The heating temperature was limited to ca. 80° C.;

(52) It was difficult to adapt the concept for larger head sizes.

(53) The present laying die 12 enables to overcome these former limitations and especially the deformability issues, as the die 12 permits now the lay-up of complex 3D forms following the structure curvatures, radius and edges.

(54) In the following embodiment of the laying die 12 is described in comparison with the laying die 312 according to the prior art.

(55) In the prior art die 312 there was a silicon tube, pipe 332, inserted into the foam of carrier body 324 to guide the vacuum from the metallic attaching element 322 to the silicon mat 338. The vacuum was then distributed in the silicon mat 338 (featuring an air distribution chamber) and then to the holes 344. This system was efficient but the stiffness of the silicon tube 332 was strongly reducing the deformability of the foam and therefore the carrier body 324.

(56) In the embodiment of the laying die 12 there is a gas distribution chamber, hollow space 50, in the metallic inserts of the attaching element 22. The gas is then guided through the foam, i.e. through the tailored drilled breakthroughs 34 in the foam. The gas 45 is then coming out of the holes 72 of the heated sandwich structure 75.

(57) This laying die 12 is efficient and the foam is now fully flexible and can adapt itself to complex contours. The foam is slightly permeable and in order to improve the vacuum guiding, the contour or surfaces of the carrier body 24 or wall surfaces 52 of the breakthroughs 34 can be partially or completely sealed with silicon, e.g. by gluing a silicon film 60 or simply using some glue 58 or by melting a thermoplastic film 60.

(58) The breakthroughs 34 in the foam are not only for guiding vacuum but also for improving the deformability. Likewise the foam size and composition can be adapted to improve the flexibility. Specific breakthrough-design can improve the performance of the deformation, and the breakthrough-design can be adapted to specific requirements. The breakthroughs can be cutted (e.g. by knife, by laser, by water jet), drilled and/or burned.

(59) In the laying die 12 of the prior art a carbon fiber was integrated via multi-step silicon casting in complex forms in order to create an heated silicon mat 338 with a gas distribution system. In the laying die 12 the heated sandwich structure 75 does not require to realise the gas distribution. The design is therefore simple and the heating fiber is simply glued, e.g. by a silicon glue, between two silicon films 40, 42 before the holes 72 are punched into it.

(60) The asset of the preferred laying die 12 is that the manufacturing is much easier. The manufacturing does not require specific tool and can then be easily changed. Steel fibers are more efficient and can reach higher temperatures than carbon fibers. The steel yarns are made of thin filaments and are not as brittle as carbon fibers, that allows more flexibility and robustness of the die 12. Another heating system that can be used is a heatable coating 78, for example graphite coating, which can allow more efficiency for large surfaces.

(61) The laying die 12 can easily be upscaled to manufacture larger heads. In that case it is preferable to foresee some adapted vacuum distribution systems 88. Also the use of a lighter design is preferable for the attaching element 22, e.g. a composite sandwich construction, with CFRP (carbon fiber reinforced polymer) with a Nomex® honeycomb core. For the lay-up of fibers on a concave surface, it is preferred to curve the carbon fibers according to the surface geometry before the lay-up in order to avoid fiber damages. Therefore it is preferred to have a die 12 which deforms the carbon material before the lay-up.

(62) The laying die 12 preferably contains a rope system 96 integrated in the foam of the carrier body 24 and/or in the flexible layer of the substrate receiving structure 26. Deformation of the laying die 12 to a specific curvature can be realized using a bobin 100 connected to a rotating motor 102.

(63) Some linear motors could also be used in combination with a similar rope system 96 in order to enable the deformation of the die 12. For this system it might be preferred to adapt the gas guiding through the foam of the carrier body 24 to concentrate the vacuum grip at the end of the fibers to be deformed.