Producing composite fiber/metal workpieces

Abstract

Methods, systems and apparatus for producing composite fiber/metal workpieces. In one aspect, a method includes locating a metal workpiece on a workpiece support of a machine tool, processing the metal workpiece located on the workpiece support to produce one or more shaped features on the metal workpiece, fitting a fiber fabric to the metal workpiece in a region of the shaped features, and connecting the fiber fabric to the metal workpiece in at least one of a non-positive-locking connection or a positive-locking connection to produce a composite fiber/metal workpiece.

Claims

1. A method of producing a composite fiber/metal workpiece, the method comprising: locating a metal workpiece on a workpiece support of a machine tool; processing the located metal workpiece using a processing device of the machine tool to shape at least one region of the metal workpiece; fitting a fiber fabric to the shaped region of the metal workpiece; and using the processing device of the machine tool, connecting the fitted fiber fabric to the metal workpiece to produce the composite fiber/metal workpiece, wherein processing the metal workpiece to shape the region of the metal workpiece comprises punching the metal workpiece, wherein fitting the fiber fabric comprises supplying at least a portion of the fiber fabric in the form of a fiber mat to the workpiece while the workpiece is located on the workpiece support, and wherein the shaped region comprises a feature extending from a surrounding region of the metal workpiece, and wherein fitting the fiber fabric to the metal workpiece comprises positioning the fiber mat on the metal workpiece such that the feature of the metal workpiece is received into a hole defined in the fiber mat.

2. The method of claim 1, wherein punching the workpiece raises a rim of material of the workpiece in the shaped region about a hole formed by the punching.

3. The method of claim 1, wherein the fiber fabric is connected to the metal workpiece by deforming the shaped region of the metal workpiece.

4. The method of claim 1, further comprising: applying at least one cover over the fiber fabric fitted to the metal workpiece, and wherein connecting the fiber fabric to the metal workpiece comprises clamping the fiber fabric between the metal workpiece and the cover.

5. The method of claim 1, further comprising separating the composite fiber/metal workpiece from a remainder of the metal workpiece by cutting the metal workpiece.

6. A method of producing a composite fiber/metal workpiece, the method comprising: locating a metal workpiece on a workpiece support of a machine tool; processing the located metal workpiece using a processing device of the machine tool to shape at least one region of the metal workpiece; fitting a fiber fabric to the shaped region of the metal workpiece; and using the processing device of the machine tool, connecting the fitted fiber fabric to the metal workpiece to produce the composite fiber/metal workpiece, wherein fitting the fiber fabric comprises producing at least a portion of the fiber fabric by winding fiber strands around raised regions of the metal workpiece formed by processing the metal workpiece.

7. The method of claim 6, wherein the fiber strands are supplied to the metal workpiece from a magazine.

8. The method of claim 6, wherein the fiber strands are wound around shaped portions of the metal workpiece while the metal workpiece is moved relative to the processing device.

9. The method of claim 6, wherein the fiber fabric is connected to the metal workpiece by deforming the shaped region of the metal workpiece.

10. The method of claim 6, further comprising: applying at least one cover over the fiber fabric fitted to the metal workpiece, and wherein connecting the fiber fabric to the metal workpiece comprises clamping the fiber fabric between the metal workpiece and the cover.

11. The method of claim 6, further comprising separating the composite fiber/metal workpiece from a remainder of the metal workpiece by cutting the metal workpiece.

12. A non-transitory computer readable storage medium storing instructions executable by one or more computers and upon such execution causing the one or more computers to perform operations to produce a composite fiber/metal workpiece, the operations comprising: locating a metal workpiece on a workpiece support of a machine tool; processing the metal workpiece located on the workpiece support to produce one or more shaped features of the metal workpiece; fitting a fiber fabric to the features of the metal workpiece; and connecting the fiber fabric to the metal workpiece to produce the composite fiber/metal workpiece, wherein processing the metal workpiece to shape the region of the metal workpiece comprises punching the metal workpiece, wherein fitting the fiber fabric comprises supplying at least a portion of the fiber fabric in the form of a fiber mat to the workpiece while the workpiece is located on the workpiece support, and wherein the shaped region comprises a feature extending from a surrounding region of the metal workpiece, and wherein fitting the fiber fabric to the metal workpiece comprises positioning the fiber mat on the metal workpiece such that the feature of the metal workpiece is received into a hole defined in the fiber mat.

Description

DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic illustration of an example of a machine tool having a device for applying fiber mats to a workpiece and a device for supplying fiber strands to the workpiece.

(2) FIG. 2 is a perspective view of a workpiece having shaped portions for further processing to form a composite fiber/metal workpiece.

(3) FIG. 3 is a perspective view of the workpiece of FIG. 2 having a fiber mat which is applied in the region of the shaped portions.

(4) FIG. 4 is a perspective view of the workpiece of FIG. 3 with the fiber mat and a metal covering sheet applied.

(5) FIGS. 5a and 5b are sectioned illustrations of a part-region of a workpiece with a fiber fabric and metal covering sheet applied before and after the joining operation, respectively.

(6) FIGS. 6a and 6b are sectioned illustrations of a part-region of a workpiece without a metal covering sheet before and after the joining operation, respectively.

(7) FIG. 7 is a perspective view of a composite fiber/metal workpiece after separation from a remainder of the workpiece.

(8) FIG. 8 shows a workpiece during the application of a fiber roving.

(9) FIGS. 9a-9d and FIGS. 9e-9h are lateral sectioned illustrations and corresponding plane views of a portion of an application device during various phases of the application operation of the fiber roving, respectively.

DETAILED DESCRIPTION

(10) FIG. 1 shows a machine tool 1 which is constructed as a laser/punching combination machine and which has, as processing tools for the shaping (and optionally separating) processing of a plate-like workpiece 2 in the form of a metal sheet, a conventional punching head 3 having a punching stamp 3a and a laser processing head 4 for the separating processing operation. The workpiece 2 to be processed is supported during the workpiece processing operation on a workpiece support 5 in the form of a processing table. Using a conventional retention device 6, which has clamps 7 for holding the workpiece 2 securely, the workpiece 2 can be moved with respect to the punching stamp 3a and the laser processing head 4 in the X direction of the workpiece plane (X-Y plane of an XYZ coordinate system) using a linear drive 8a which is indicated with a double-headed arrow. In the Y direction of the workpiece plane, the workpiece 2 can be moved by the workpiece support 5, together with the retention device 6, being moved by means of an additional conventional linear drive 8b which is indicated by a double-headed arrow.

(11) The workpiece 2 can be moved in this manner in the X and Y directions with respect to the punching stamp 3a and the laser processing head 4 so that the region of the workpiece 2 to be processed in each case can be positioned in a fixed processing region 10 of the punching stamp 3a or a fixed processing region 11 of the laser processing head 4. In the processing region 10 of the punching stamp 3a, there is positioned an (exchangeable) punching die 12 which has an opening 12a for engagement for the (also exchangeable) punching stamp 3a. Accordingly, there is arranged in the fixed processing region 11 of the laser processing head 4 a laser die 13 which acts as an opening delimitation for a substantially circular suction opening 13a in the workpiece support 5.

(12) On the machine tool 1 illustrated in FIG. 1, it is possible to produce composite fiber/metal workpieces, as described below with reference to FIGS. 2 to 6 by way of example for the production of a composite fiber/metal workpiece 23 in the form of a wheel, which is illustrated in FIG. 7. In order to control the linear drives 8a, 8b, or for the coordination thereof with the processing operation which is carried out at the processing position 10, 11 of the punching stamp 3a or the laser processing head 4, a control device 21 is provided in the machine tool 1. The control device 21 uses an NC control program (processing program) whose control commands are carried out during the processing operation. The NC control program (processing program) controls the machine tool 1 or the components thereof in such a manner that all the steps required for the production of a composite fiber/metal workpiece can be carried out. The processing program itself or a corresponding computer program product 21a is encoded on one or more computer storage media and has instructions which, when they are carried out by one or more computers, which are typically integrated in the control device 21 or are connected thereto in terms of signal technology, cause the one or more computers to carry out the steps or operations required to produce a composite fiber/metal workpiece.

(13) After the workpiece 2 has been supplied to the workpiece support 5 by means of a transport device (not shown) and the lateral clamping by means of the retention device 6, the workpiece 2 is first subjected to a cutting processing operation using the laser processing head 4 by three annular segments being cut from the workpiece 2, three webs remaining which form the spokes of the wheel (see, for example, FIG. 2). Using the laser processing head 4, there are also cut from the workpiece 2 holes 24, 25 which act as force introduction locations on the outer and inner periphery of the composite fiber/metal workpiece to be produced.

(14) In another processing step, the workpiece 2 is provided with shaped portions 15, that is to say, selected regions of the workpiece 2 are deformed using the punching head 3 or the punching stamp 3a so that the deformed regions protrude from the workpiece plane (three-dimensional plastic deformation) to form features extending out of a plane of the surrounding workpiece. In order to produce different types of shaped features, the punching stamp 3a can optionally be changed. In the example shown in FIG. 2, shaped features are produced in the form of collar-like rims about holes, which are suitable for producing a non-positive-locking and/or positive-locking connection with respect to a fiber fabric.

(15) In another processing step, a fiber fabric is applied to the workpiece 2. The application is carried out in the present example by positioning a prefabricated fiber mat 16 on the workpiece 2, that is to say, the fiber mat 16 already has the shape and size required for the composite workpiece. The fiber mat 16 is in this instance supplied by means of a device 17 for automatically supplying fiber mats 16 to the workpiece 2 (FIG. 1) and positioned on the workpiece 2 in such a manner that the shaped portions 15 engage in recesses 9 (holes) in the fiber mat 16 (FIG. 3). Owing to the shaped portions 15 which are in engagement with the recesses 9, the fiber mat 16 is retained on the workpiece 2 in the processing plane (XY plane) so that the fiber mat 16 can be moved together with the workpiece 2 without sliding during a subsequent movement of the workpiece 2 in the processing plane. Sliding can also be prevented when there are produced on the workpiece 2 angular, for example, prong-like shaped features which protrude through the fiber mat 16 when it is placed in position and thus bring about fixing of the fiber mat 16 to the workpiece 2.

(16) In the present example, the supply device 17 includes a conveyor belt 17a which conveys the fiber mat 16 to the workpiece 2 located on the workpiece support 5, and another linear drive 8c for displacing the conveyor belt 17a in the X direction. A suitable positioning of the fiber mat 16 in the Y direction can be determined by the selection of the position of the fiber mat 16 on the conveyor belt 17a and/or the conveyor belt 17a can be moved in the Y direction by means of an additional linear drive (not shown). The depositing of the fiber mat 16 on the conveyor belt 17a can, for example, be carried out by means of a gripping device (not shown) or the like.

(17) Of course, the device 17 for automatically supplying fiber mats may also be constructed in a different manner to that shown in FIG. 1. For example, a direct depositing of the fiber mat 16 on the workpiece 2 can be carried out by means of one or more gripping devices, which can be fitted, for example, to an appropriately modified transport device 17b for positioning the workpiece 2 on the workpiece support 5. The gripping devices may, for example, be constructed as vacuum suction devices 17c which are suitable for gripping the flexible fiber mat 16. For example, it is possible to use as gripping devices for the fiber mat 16 (extensive) suction gripping devices 17c which, at the side thereof facing the fiber mat 16, may have an air-permeable component 17d, for example, in the form of a (planar) sieve or an air-permeable layer of an open-pore material, for example, of foam, through which the suction can be carried out. Of course, it is possible to dispense with the conveyor belt 17a, or the conveyor belt 17a can be used for supplying fiber mats 16 to a transfer position in the region of the transport device 17b, at which position the transport device receives a respective fiber mat 16.

(18) Regardless of the precise construction of the device 17, the fiber mat 16 or the recesses 9 in the fiber mat 16 is brought into the region of the workpiece 2 at which the shaped portions 15 are formed in order to prevent a sliding of the fiber mat 16 relative to the workpiece 2 during the subsequent shaping processing operation. The control device 21 serves to control the device 17 (of the conveyor belt 17a and the linear drive 8c and/or the transport device 17b) and to coordinate with a displacement of the workpiece 2 using the linear drives 8a, 8b, which displacement may be necessary for precise positional placement.

(19) As an alternative to supplying a fiber mat 16, the fiber fabric or portions thereof can also be produced directly on the workpiece located in the machine tool 1. To this end, a fiber strand 18a (also called fiber roving) is automatically supplied by means of an additional supply device 18 into the region of the punching head 3 or the processing region 10 which is associated therewith and wound around the shaped portions 15 previously produced at that location. In the present example, a fiber strand 18a is unwound from a magazine in the form of a coil 18b which is fitted to the C-shaped machine frame of the machine tool 1. The coil 18b may optionally be provided with a drive (not shown) in order to convey fiber strands 18a. Naturally, the transport or the storage of the fiber strands 18a can also be carried out at another location in the machine tool 1.

(20) The workpiece 2 is preferably moved using the machine axes of the machine tool 2 relative to the device 18 in such a manner that the winding action around the shaped features 15 of the workpiece 2 is carried out as a result of the relative movement of the workpiece 2 relative to the output-side end of the supply device 18 or an application device 18c which is provided at that location. The application device 18c also serves to fix a respective fiber strand 18a to the workpiece 2 before and after the shaped portions 15 have been subjected to winding. To this end, it is possible to form on the workpiece 2 by means of the punching head 3 and/or by means of the laser processing head 4 a narrow gap in which the fiber strand 18a is introduced and securely clamped with the (free) end thereof.

(21) FIG. 8 shows such an application operation. The fiber strand 18a is supplied to the workpiece 2 by means of the inner side of a tubular thread guide 18d. There is provided in the workpiece 2 a V-shaped gap 14 on which the end of the fiber strand 18a protruding from the end of the thread guide 18d can be fixed. After fixing the fiber strand 18a, the fiber strand 18a can be wound around the shaped portions 15 in order to form a fiber fabric. After the winding operation is complete, the fiber strand 18a can be fixed to the same gap 14 or to an additional gap or a suitable shaped portion.

(22) FIGS. 9a-h show how such a fixing of the fiber strand 18a can be produced. The workpiece 2 is moved in such a manner that the fiber guide 18d is located in a position adjacent to the gap 14. The application device shown in FIG. 9a-h includes a gripping device 18e which can be moved along the thread guide 18d (perpendicularly relative to the workpiece surface) and rotated about an axis 22 (perpendicularly relative to the workpiece surface) (FIGS. 9a and 9e). In order to fix the fiber strand 18a, the gripping device 18e is moved to a height below the end of the thread guide 18d and subsequently rotated in a gripping device about the axis 22 so that the fiber strand 18a moves into engagement with a gripping element which is arranged in an eccentric manner with respect to the axis 22 and which is in the form of a gripping notch 18f of the gripping device 18e (FIGS. 9b and 9f). By means of further rotation of the gripping device 18e in the gripping direction, the fiber strand 18a is pulled out of the thread guide 18d and a loop is formed between the thread guide 18d and the gripping device 18e. In order to thread the fiber strand 18a into the gap 14, the thread guide 18d and the gripping device 18e are lowered onto the surface of the workpiece 2a (FIGS. 9c and 9g) and the workpiece 2 is moved in an appropriate manner until the fiber strand 18a is clamped in the gap 14. A corresponding fixing can also be carried out after the winding operation is complete in order to prevent the fiber strand 18a which has been wound around the shaped portions 15 from becoming detached independently.

(23) In the present example, the supply device 18, more specifically the application device 18c, has a cutting device 18g in order to sever a respective fiber strand 18a after the fiber fabric has been produced or after portions of the fiber fabric have been produced. The cutting device 18g can be used to separate the fiber strand 18a after the fixing operation, as shown in FIGS. 9d and 9h. The cutting device 18g is constructed in the example shown in the form of a cutting edge which is provided at a side of the gripping device 18e opposite the gripping notch 18f. In order to sever the fiber strand 18a, after the fiber strand 18a has been introduced into the fixing gap 14, the thread guide 18d and the gripping device 18e can first again be moved away from the surface of the workpiece 2 or the securing gap 14. During or after this movement, the gripping device 18a can be rotated counter to the gripping direction, the fiber strand 18a coming into contact with the cutting edge 18g and being severed thereby.

(24) The supply device 18 is installed in a fixed manner in the present example and may be constructed in a similar manner to a wire supply for welding or the thread supply in a textile machine, for example, in a sewing machine. However, it is also possible to leave the workpiece 2 in a fixed manner and to move the fiber rovings 18a around the shaped portions 15 using movable components of the supply device 18, in particular the application device 18c. Of course, the workpiece 2 may optionally also be moved in the XY-plane in addition in this instance.

(25) It is further self-evident that, when fiber rovings 18a are used to produce the fiber fabric, the production of shaped portions 15 does not have to take place in a first step and the fitting of the fiber fabric does not have to take place in a second step, as illustrated in FIGS. 2 and 3. Instead, it is optionally possible for a fiber roving 18a to be wound around a respective shaped portion 15 directly after production of a respective shaped portion 15, before the workpiece 2 is displaced in order to form a shaped portion at another location.

(26) In both of the cases described above, there is produced a fiber fabric 16 which can be moved together (that is to say, without relative movement) with the workpiece 2 in the processing plane so that in a subsequent processing step in the region of the shaped features 15, a non-positive-locking and/or positive-locking connection is produced between the workpiece 2 and the fiber fabric 16 and a composite fiber/metal workpiece can consequently be produced. For the production of the connection, a pre-fabricated metal covering sheet 20 can be placed on the fiber mat 16 and the fiber mat 16 can be clamped between the two metal sheets 2, 20 (FIG. 4). The mechanical clamping connection is preferably produced during punching operation, for example, by means of crimping, punch-riveting or clinching, for which the shaped features 15 formed in the previous step can be deformed.

(27) FIGS. 5a and 5b show a section through a shaped portion 15 of the workpiece 2 which is provided with the fiber mat 16 before and after the deformation of the shaped portions 15, respectively. As can be seen with reference to FIGS. 5a and 5b, using the punching head 3, the collars of the shaped features 15 which are formed as rim holes are bent outwards so that a crimped edge is produced which engages over inclined portions or chamfers provided on the metal covering sheet 20 and fixes the fiber mat 16 in this manner.

(28) FIGS. 6a and 6b show a cross-section through a shaped portion 15 of the workpiece 2 which is provided with the fiber mat 16 and in which, in contrast to FIGS. 5a and 5b, a metal covering sheet for producing the non-positive-locking and/or positive-locking connection has been dispensed with. Using the punching head 3 of the machine tool 1, the collars of the rim holes 15 are also bent outwards in this instance so that they engage over the fiber mat 16. The regions which are bent outwards are in the present example constructed in a claw-like manner in order to clamp the fiber mat 16 and consequently to produce a positive-locking and non-positive-locking connection.

(29) The connection of the fiber mat 16 to the workpiece 2 can be carried out as described above in the region of the shaped features 15, which also serve to fix the fiber mat 16 in the x-y direction. In this manner, a positive-locking connection of the workpiece/fiber fabric/metal covering sheet sandwich is achieved. However, it is also possible, before or after the fiber mat 16 has been positioned, to introduce additional shaped portions (not shown) into the workpiece 2, for example, outside the region in which the fiber fabric 16 is applied or is intended to be applied. The connection of the workpiece 2 and fiber mat 16 can additionally or exclusively be carried out by means of these additional shaped portions, which are preferably formed adjacent to the fiber mat 16 on the workpiece 2 and which after shaping or deformation at least partially extend over the workpiece region covered by the fiber mat 16. The workpiece 2, the fiber mat 16 and an optionally present covering metal sheet may also be shaped together, for example, in the form of a crimped portion in order to thus produce a non-positive-locking and/or positive-locking connection.

(30) Of course, the procedure shown with reference to FIGS. 5a and 5b and FIGS. 6a and 6b for non-positive-locking and/or positive-locking connection of the fiber mat 16 and workpiece 2 can also be used in a similar manner to the non-positive-locking and/or positive-locking connection of the workpiece 2 and a fiber fabric produced from fiber rovings. It is also self-evident that part-regions of the fiber fabric can be constructed as fiber mats and other part-regions can be constructed in the form of fiber rovings.

(31) After the joining operation, the fiber/metal composition is separated from the workpiece 2 in a last processing step along a cutting contour 19. This can be carried out by means of laser cutting using the laser processing head 4 or optionally by means of nibbling using the punching head 3. The completed composite fiber/metal workpiece 23 (FIG. 7) can then be discharged from the machine tool 1 by means of a transport device which is not illustrated in the Figures. Although the possibility of cutting or separation of the composite fiber/metal workpiece 23 from the remaining workpiece directly on the machine tool 1 is advantageous, this processing step may also be carried out where applicable at another location. This is optionally advantageous when the above-described production operation is not carried out as illustrated in FIG. 1 on a laser/punching combination machine 1, but instead a punching machine without a laser cutting function is used for the production of the composite workpiece 23.

(32) The method described above and the associated machine tool enable the production of composite workpieces of metal and fiber fabrics as a pre-step for the production of planar or spatially shaped hybrid components of metal and fiber/plastics material composites. Composite fiber/metal workpieces 23 which have been produced in the manner described above can in other processing steps, for example, by means of bending, be shaped in a three-dimensional manner and subsequently be infiltrated with resin in a tool, for example, in the RTM (Resin Transfer Molding) method or be injection-molded around with a thermoplastic material.

(33) In the method described above, the composite is produced by means of a direct force transmission between the metal sheet and fibers by means of non-positive-locking and/or positive-locking connection. Both the processing of the metal workpiece and the connection of the workpiece to the fiber fabric can be carried out in one and the same machine tool, that is to say, the cutting of the sheet metal component, the connection of the workpiece to the fiber fabric and optionally also the production of the fiber fabric can be carried out in a single operating step and consequently composite fiber/metal workpieces can be produced in a particularly economical manner.

(34) A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.