Sheet metal blank

Abstract

A process includes flexible rolling of a strip made of a metallic material, wherein a thickness profile with different sheet thicknesses along the length of the strip is produced such that successive regions of the flexibly rolled strip each correspond to a target thickness profile of a sheet metal blank to be cut out of same; determining a measured thickness profile of a plurality of successive regions of the strip; calculating a target position in the strip for a sheet metal blank to be cut out of the strip depending on the generated measured thickness profile of at least two successive regions of the strip; cutting the flexibly rolled strip by at least one cutting device along the target position for producing the sheet meal blank. A plant is further provided for producing a sheet metal blank.

Claims

1. An apparatus for producing a sheet metal blank from a strip to be provided to the apparatus and made of a metal based material, the apparatus comprising: a rolling unit for flexibly rolling the strip such that the strip obtains a variable thickness along a length of the strip; and a cutting unit for cutting individual sheet metal blanks out of the strip, wherein the cutting unit comprises a measuring device for measuring the thickness of the strip along the length of the strip, and at least one cutting device for cutting the flexibly rolled strip, an electronic control unit (ECU) connected to the measuring device and the cutting device and configured to control the cutting device on the basis of values measured by the measuring device such that the electronic control unit is configured to determine, upon a determination that a distance between the measuring device and the cutting device is greater than double a target length of the sheet metal blank to be cut out of the strip, a measuring profile for each of a plurality of successive regions of the strip, and to calculate a target position for a sheet metal blank to be worked out of the strip depending on the target length for the blank to be cut from the strip and the measuring profile of at least two successive regions of the strip.

2. The apparatus of claim 1, wherein the measuring device comprises a thickness sensor and a length position sensor to continuously measure a thickness of the strip along a length of the strip, wherein, in respective measurements, a measured length position and a measured thickness position are associated with one another.

3. The apparatus of claim 1, wherein the at least one cutting device is configured to be moveable along a plurality of axes independently of one another.

4. The apparatus of claim 1, wherein the at least one cutting device is a laser cutting device that is configured to control at least one cutting parameter of a cutting beam depending on at least one of the thickness and a material property of the strip.

5. The apparatus of claim 1, wherein several cutting devices are provided that are at least one of: controllable by the electronic control unit such that several sheet metal blanks can be cut simultaneously out of the strip, and controllable by the electronic control unit so as to jointly cut a sheet metal blank out of the strip.

6. The apparatus of claim 1, further comprising a transport device for transporting the strip through the measuring device and the cutting device, wherein the transport device comprises a plurality of rolling contact members on which the strip is rollingly supported.

7. The apparatus of claim 1, further comprising a feed arrangement for feeding the strip, wherein the feed arrangement includes a first feed device that is arranged in front of the cutting device and a second feed device that is arranged behind the cutting device, wherein the first feed device and the second feed device are controllable such that the strip is tensionable between the first feed device and the second feed device.

8. The apparatus of claim 1, wherein the measuring device comprises a thickness sensor and a length position sensor to measure the thickness of the strip along a length of the strip in a first region of the strip, and in a second region of the strip adjoining the first region, wherein the electronic control unit (ECU) is connected to the thickness sensor and to the length position sensor to calculate the target position for the first sheet metal blank to be cut out of the strip depending on the measured thickness profile of at least the first region and the second region of the strip.

9. A system, comprising a strip made of a metal-based material and an apparatus for producing a sheet metal blank from the strip, the apparatus comprising: a rolling unit for flexibly rolling the strip such that the strip obtains a variable thickness along a length of the strip; and a cutting unit for cutting individual sheet metal blanks out of the strip, wherein the strip comprises a plurality of successive regions, from each of which a sheet metal blank is to be cut with a target length; wherein the cutting unit comprises a measuring device for measuring the thickness of the strip along the length of the strip, at least one cutting device for cutting the flexibly rolled strip, and an electronic control unit (ECU) connected to the measuring device and the cutting device for controlling the cutting device on the basis of values measured by the measuring device; wherein, when the measuring device and the cutting device are arranged so that a distance between them is greater than double the target length of the sheet metal blank to be cut out of the strip, the electronic control unit determines a measuring profile for each of the successive regions of the strip, and calculates a target position for a sheet metal blank to be worked out of the strip depending on the measuring profile of at least two successive regions of the strip.

10. The system of claim 9, wherein the measuring device comprises a thickness sensor and a length position sensor to continuously measure a thickness of the strip along a length of the strip, wherein, in respective measurements, a measured length position and a measured thickness position are associated with one another.

11. The system of claim 9, wherein the at least one cutting device is configured to be moveable along a plurality of axes independently of one another.

12. The system of claim 9, wherein the at least one cutting device is a laser cutting device that is configured to control at least one cutting parameter of a cutting beam depending on at least one of the thickness and a material property of the strip.

13. The system of claim 9, wherein several cutting devices are provided that are at least one of: controllable by the electronic control unit such that several sheet metal blanks can be cut simultaneously out of the strip, and controllable by the electronic control unit so as to jointly cut a sheet metal blank out of the strip.

14. The system of claim 9, further comprising a transport device for transporting the strip through the measuring device and the cutting device, wherein the transport device comprises a plurality of rolling contact members on which the strip is rollingly supported.

15. The system of claim 9, further comprising a feed arrangement for feeding the strip, wherein the feed arrangement includes a first feed device that is arranged in front of the cutting device and a second feed device that is arranged behind the cutting device, wherein the first feed device and the second feed device are controllable such that the strip is tensionable between the first feed device and the second feed device.

16. The system of claim 9, wherein the strip comprises at least a first region out of which a first sheet metal blank is to be cut, and a second region which adjoins the first region and out of which a second sheet metal blank is to be cut, wherein the measuring device comprises a thickness sensor and a length position sensor to measure the thickness of the strip along the length of the strip in the first region of the strip, and in a second region of the strip adjoining the first region, wherein the electronic control unit (ECU) is connected to the thickness sensor and to the length position sensor to calculate the target position for the first sheet metal blank to be cut out of the strip depending on the measured thickness profile of at least the first region and the second region of the strip.

Description

SUMMARY OF THE DRAWINGS

(1) Example embodiments will be explained below with reference to the Figures wherein

(2) FIG. 1 shows an example process in the form of a flow diagram.

(3) FIG. 2 shows the cutting arrangement according to FIG. 1 schematically in the form of a detail.

(4) FIG. 3 shows the cutting arrangement according to FIG. 1 diagrammatically in the form of a detail in a modified embodiment.

(5) FIG. 4 shows the cutting arrangement according to FIG. 1 schematically in the form of a detail in a further embodiment.

(6) FIG. 5 shows the cutting arrangement according to FIG. 1 schematically in the form of a detail in a further embodiment.

(7) FIG. 6 shows the cutting arrangement according to FIG. 1 schematically in the form of a detail in a further embodiment.

(8) FIG. 7 shows the process according to FIG. 1 schematically in the form of a flow diagram with further process steps.

DETAIL DESCRIPTION

(9) FIGS. 1 to 7 will be initially described jointly blow with regard to the features they have in common. An exemplary process as well as an exemplary plant for producing a sheet metal blank 2 out of a flexibly rolled strip material 3 is shown. The starting material can be hot strip or cold strip made of a metallic material, more particularly made of a hardenable steel material. The material can be a slit strip or a strip with a natural edge.

(10) In process step S10, the strip material 3 is rollingly treated by a rolling unit 1, i.e., by being flexibly rolled. For this purpose, the strip material 3 which, in the starting condition, is wound up on a coil 4 and which, prior to being flexibly rolled, comprises a substantially constant sheet thickness along its length, is rolled by rolls 5, 6 such that it receives a variable sheet thickness along the rolling direction. During the rolling operation the process is monitored and controlled, with the data determined by a sheet thickness measuring device 7 being used as an input signal for controlling the rolls 5, 6. After the flexible rolling operation, the strip material 3 comprises different thicknesses along its length in the rolling direction. After the flexible rolling operation, the strip material 3 is again wound up to a coil 8, so that it can be moved to the next production step.

(11) During a subsequent process step S40, individual sheet metal blanks 2 are cut out of the flexibly rolled strip material 3. The cutting unit 23, which can also be referred to as cutting arrangement, comprises a measuring device 10, an electronic control unit (ECU) as well as one or several cutting devices 9. The sheet metal blanks 2 are cut out of the strip material 3 in a cutting process carried out by the cutting device 9, thereby taking into account the parameters measured by the measuring device 10. The cutting device 9, more particularly, is provided in the form of a beam cutting device, wherein in this case the blank 2 being separated from the strip material by a beam 11. In one embodiment, it is possible to use a laser beam cutting device, with the blank 2 being separated from the strip material by one or several laser beams 11. However, it is to be understood that, in principle, it is also possible to use a mechanical cutting device instead of the beam cutting device.

(12) An important sub-step in connection with cutting out the sheet metal blank 2 is measuring the thickness of the strip material 3 along its length. The measuring device 10 used for this purpose is arranged in front of the beam cutting device 9 with respect to the direction of feed of the strip material 3. The measuring device 10 comprises at least one sensor 12 for recording a value representing the thickness of the strip material 3, and a sensor 13 for recording a value presenting the length position of the strip material 3. The thickness and length values recorded by the sensors 12, 13 are transmitted to the electronic control unit (ECU). The electronic control unit serves to further process the measured thickness and length values and to control the beam cutting device 9. Measurement can take place continuously at the strip material 3 being unwound from the coil 8, wherein a respective thickness value is associated to each length position of the strip material 3, so that overall the thickness profile of the strip is recorded along the length of same. The length values and the associated thickness values are measured in the un-tensioned condition of the unwound strip material 3, i.e., apart from the required force of feed, in an essentially force-free condition.

(13) As can be seen in particular in FIG. 2, the distance L9 between the measuring device 10 and the beam cutting device 9 is greater than twice the length L2 of a sheet metal blank 2 to be cut out. The contours of the sheet metal blanks 2, 2, 2 as yet to be cut out and the individual strip regions 14, 14, 14 per sheet metal blank are shown in FIG. 2 in dashed lines. The contour of the blank 2, just being cut out is shown in a continuous line. Because of the given distance L9 between the measuring device 10 and the cutting device 9, the thickness profile of at least two strip regions 14, 14 can be recorded and taken into account for determining the contours to be cut. In this way, it is possible to compensate for length tolerances of the flexibly rolled strip material 3 and take them into account for the production of sheet metal blanks 2. In this way, production accuracy overall is improved and the rate of rejects reduced respectively.

(14) The contour of the sheet metal blanks 2 to be cut out of the strip material 3 is arbitrary and can be set individually to suit geometric specifications. A blank 2 cut out of the strip material 3, which can also be referred to as three-dimensional blank (3D-TRB) or contour cut, is diagrammatically illustrated in FIG. 1. To cut out contours as needed, the beam cutting device 9 can be moved at least along two or more axes X, Y, Z, i.e., in the direction of fed, in the transverse direction and optionally in the vertical direction of the strip material. In this case, the beam cutting device 9 can be moved along the X axis independently of its movement along the Y axis and/or the Z axis, which analogously applies to the remaining axes (Y, Z).

(15) To achieve a high positional accuracy of the blank 2 to be cut out, the strip material 3 can be tensioned during the beam cutting operation in the longitudinal direction L of the strip material. This can be achieved by a feeding device arranged in front of, and a feeding device arranged behind, the beam cutting device. The two feeding devices (not illustrated) are synchronised such that the strip material positioned therebetween is tensioned.

(16) The operation of cutting the sheet metal blanks 2 out of the strip material 3 can be carried out continuously or discontinuously. In the case of the continuous cutting process, the measuring and cutting processes take place during the feeding movement of the strip material 3. In the case of a discontinuous process, the strip material 3 is fed in steps, with the blanks 2 being cut out of the strip material 3 when the strip is stationary. After one or several blanks have been cut out, the strip material 3 is moved forward for the purpose of producing the next blank(s).

(17) Behind the last feeding device, the contour cuts and rejects can be separated by a further cutting unit, and the components can be transferred to a transport system. The transport system makes the blanks 2 available for a stacking system which stacks the blanks 2 in a customer container or on pallets.

(18) FIG. 3 shows a cutting unit 23 for carrying out the process step S40 in a modified embodiment. This embodiment largely corresponds to the embodiment according to FIG. 2, so that as far as common features are concerned reference is made to the above description. In this regard, identical or corresponding details have been given the same reference numbers as in FIG. 2.

(19) A difference between the embodiment according to FIG. 3 and that of FIG. 2 consists in that the cutting process takes place in two partial sub-steps. In the first cutting process, only part of the contour of the blank 2 is cut, so that the blank to be cut remains connected via several uncut webs 15, 15, 15,15 to the remaining edge region of the strip material 3. Complete separation of the sheet metal blank 2 from the remaining strip material 3 takes place during the subsequent second sub-step by means of a second cutting device 16. For this, the webs 15, 15, 15, 15 are cut through by the further cutting device 16 which follows the first cutting device 9 in the transport direction L of the strip material 3. It can be seen in FIG. 3 that in the present embodiment there is provided a total of four webs, i.e. a web 15 at the front end, two side webs 15, 15 and a web 15 at the rear end. However, it is to be understood that, per contour and size of the blank to be cut, any other technically sensible number of webs can be provided. In the condition of the second sub-step as shown, the front web 15 and the side web 15 have already been cut by the second cutting device 16.

(20) FIG. 4 shows a cutting unit 23 for carrying out the process step S40 in a further embodiment which largely corresponds to that of the embodiment according to FIG. 2, so that, as far as common features are concerned, reference is made to the above description, with identical or corresponding details having been given the same reference numbers as in FIG. 2.

(21) A difference between the embodiment according to FIG. 4 and that according to FIG. 2 consists in that two rows of sheet metal blanks 2, 102 are provided along the width B3 of the strip material 3 which are to be cut out of the strip material. Accordingly, there are provided two cutting devices 9, 109 which, synchronously, cut an associated blank 2, 102 out of the strip material 3. Both cutting devices 9, 109 are controlled by the electronic control unit (ECU) on the basis of the thickness of the strip material 3 recorded by the measuring device 10 along the length.

(22) In the present embodiment it is also proposed that the respective contour position for the blanks 2, 102 to be cut out of the strip material 3 is determined depending on the measured thickness distribution along the length of at least two successive blank regions. In concrete terms it is proposed that the distance L9 between the measuring device 10 and the beam cutting devices 9, 109 is greater than three times the length L2 of a sheet metal blank 2, 102 to be cut out. In this way, when calculating the contour position of the blanks 2, 102 to be cut out, the sheet thickness distribution (sheet thickness contour) of respectively three successive blank regions 14, 14 14, 14 can be taken into account.

(23) FIG. 5 shows a cutting unit 23 for carrying out process step S40 in a further embodiment which largely corresponds to that of the embodiment according to FIG. 3, so that, as far as common features are concerned, reference is made to the above description, with identical to corresponding details having been given the same reference numbers as in FIG. 3.

(24) A first difference concerning the embodiment according to FIG. 5 consists in that across the width B3 of the strip material 3 there are provided two rows of sheet metal blanks 2, 102 which are to be cut out of the strip material 3. Accordingly, there are also provided two cutting devices 9, 109 which, synchronously, each cut an associated sheet metal blank 2, 102 out of the strip material 3. Both cutting devices 9, 109 are controlled by the electronic control unit (ECU) on the basis of the thickness of the strip material 3 recorded by the measuring device 10 along its length. For the sake of simplicity, the measuring device is not shown in the present embodiment.

(25) A further difference consists in that the cutting process takes place in two sub-steps. In the first sub-step of the cutting process, per row of blanks, only part of the contour of the respective blank 2, 102 is cut, so that the blank remains connected to the remaining edge region of the strip material 3 via several uncut webs 15, 115. Complete separation of the blank 2, 102 from the remaining strip material 3 takes place in the subsequent second sub-step by means of the second cutting device 16, 116. In this case, the webs 15, 115 are cut through with the further cutting device 16, 116 which follows the first cutting device 9, 109 in the transporting direction L of the strip material 3.

(26) Furthermore, it is proposed that for carrying out the first sub-step, there are provided several cutting devices 9, 9, 109, 109 by which two successive blanks 2, 2, 102, 102 can be worked synchronously. It is thus possible to reduce the working time. For separating the webs 15, 115 in the second sub-step, it is sufficient to provide one cutting device 16, 116 for each row of blanks, because the remaining length of the webs 15, 115 to be cut is only small. The first cutting devices 9, 109; 9, 109 and the second cutting devices 16, 116 can be controlled individually by the electronic control unit.

(27) For the present embodiment, too, it is proposed that the respective contour position for the blank 2, 102 to be cut out of the strip material 3 is determined depending on the measured thickness profile along the length of at least two successive blank regions.

(28) FIG. 6 shows a cutting unit 23 for carrying out the process step S40 in a further embodiment which largely corresponds to that of the embodiment according to FIG. 5, so that, as far as common features are concerned, reference is made to the above description, with identical or corresponding details having been given the same reference numbers as in FIG. 5.

(29) Features that the embodiment of FIG. 6 has in common with FIG. 5 are that across the width B3 of the strip material 3 there are provided two rows of sheet metal blanks 2, 102, that the cutting process takes place in two sub-steps and that the respective contour position for the sheet metal blanks 2, 102 to be cut out of the strip material 3 is determined depending on the measured thickness profile along the length of at least two consecutive blank regions 14, 14, 14, 14.

(30) A difference of the embodiment according to FIG. 6 is that, for carrying out the first sub-step, there are provided several cutting devices 9, 9; 109, 109 by which respective blanks 2, 2; 102, 102 can be worked synchronously. This also leads to a reduction in the working time relative to using only one cutting device per row of blanks. For separating the webs 15 it is provided one cutting device 16, 116 per row.

(31) It is to be understood that further modifications are possible. For example, depending on the width B3 of the strip material 3 and the size of the blanks 2 to be cut out, it is possible to provide more than two rows. Furthermore, the blanks 2, 102 of the different rows can also be arranged so as to be offset relative to one another and/or comprise different contours.

(32) FIG. 7 shows an exemplary process with further possible process steps, which are all optional.

(33) After the flexible rolling operation (S10), the strip material 3 can be smoothed in process step S20 by a strip straightening unit 17. If necessary, the material can be annealed after the flexible rolling and smoothing operations respectively.

(34) After having been flexibly rolled (S10) and smoothed (S20) respectively, the strip material 3 can be provided with a corrosion protection in process step S30. For this purpose, the strip material 3 is moved through an electrolytic strip coating unit 18. It can be seen that the strip coating operation is continuous, i.e., the strip material 3 is unwound from coil 4, moves through the coating unit 18 and is again wound to a coil 4 after having been coated. The strip coating unit 18 comprises a dip tank 19 which is filled with an electrolytic liquid 20 through which the strip material 3 moves. The strip material is guided by roller sets 21, 22.

(35) For the present process it is proposed that after having been electrolytically coated (S30), the strip material is cut in accordance with the above-described process step S40, wherein individual sheet metal blanks 2 are cut out of the strip material. It is understood that the process of cutting out the sheet metal blanks can take place in accordance with any of the embodiments according to FIGS. 2 to 6, so that in this regard reference is made to the above descriptions.

(36) After the blanks 2 have been worked out of the strip material 3, the blank 2 can be formed into the required three-dimensional end product in the process step S50. According to a first possibility, the blanks can be hot-formed or, according to a second possibility, cold-formed.

(37) Hot-forming can take place as a direct or indirect process. In the case of the direct process, the blanks are heated to an austenitising temperature prior to being formed, which can be effected by induction heating or heating in a furnace. After having been heated to the austenitising temperature, the heated blank is formed in a forming tool 24 whereby the component receives its end-contour and simultaneously cooled at a high cooling speed, whereby the component is simultaneously hardened. In the case of indirect hot-forming, the blank 2, prior to being austenitised undergoes a pre-forming operation. Pre-forming takes place in the cold condition of the blank, i.e., without being previously heated. While being pre-formed, the component receives a profile which does not yet correspond to the end shape, but is close to the end shape. After the pre-forming operation, as in the case of the direct process, an austenitising operation and hot-forming operation take place in the course of which the component receives its end contour.

(38) As an alternative to hot-forming as the form-giving process, the blanks can also undergo a cold-forming process. Cold-forming is particularly suitable for soft vehicle body parts which do not have to meet special strength requirements. In the case of cold-forming, the blanks are formed at room temperature.

(39) It is understood that the process as shown can also be modified. For example, electrolytic coating can also precede flexible rolling or it can take place by means of piece coating after the blanks 2 have been cut out of the strip material or after these have been turned into a formed part.

LIST OF REFERENCE NUMBERS

(40) 1 rolling unit 2 (sheet metal) blank 3 strip material 4 coil 5 roll 6 roll 7 sheet measuring device 8 coil 9 cutting device 10 measuring device 11 laser beam 12 sensor 13 sensor 14 strip region 15 web 16 cutting device 17 strip straightening unit 18 strip coating unit 19 dip tank 20 liquid 21 roller set 22 roller set 23 cutting unit 24 forming unit B width L length R longitudinal direction