METHOD AND APPARATUS FOR SEPARATING BLANKS

Abstract

A method for separating blanks includes continuous conveying of a sheet metal strip in a transport direction to a laser cutting station, concurrent cutting of the sheet metal strip by at least one cutting laser, wherein a cut sheet metal strip is formed from successive sections of the same cutting geometry, transporting the cut sheet metal strip on a first conveyor belt in the transport direction, taking over the cut sheet metal strip from the first conveyor belt, transporting the cut sheet metal strip in the transport direction, separately ejecting the at least one residual blank of each section, transporting the at least one blank of each section into overlap with a second conveyor belt and ejecting the at least one blank from the suction conveyor, and transporting the blanks ejected one after the other from the suction conveyor horizontally in the transport direction to a collecting station.

Claims

1. A method for separating blanks with the following steps: continuous conveying of a sheet metal strip (2) in a transport direction (T) to a laser cutting station (3), concurrently cutting the sheet metal strip (2) by means of at least one cutting laser, a cut sheet metal strip (2) being formed from successive sections (AT) of the same cutting geometry, each of the sections (AT) comprising at least one blank (P) and at least one residual blank (RP) adjacent to the blank (P), transporting the cut sheet metal strip (2) on a first conveyor belt (4) in the transport direction (T), transfer of the cut sheet metal strip (2) from the first conveyor belt (4) by means of a suction conveyor (5) operated by negative pressure, suspended transport of the cut sheet metal strip (2) by means of the suction conveyor (5) in the transport direction (T), separately ejecting the at least one residual blank (RP) of each section (AT) by first interrupting the negative pressure in predetermined areas of the suction conveyor (5), transporting the at least one blank (P) of each section (AT) into overlap with a second conveyor belt (6) and ejecting the at least one blank (P) from the suction conveyor (5) by a second interruption of the negative pressure, and transporting the blanks (P) discharged one after the other by the suction conveyor (5) in the transport direction (T) to a collecting station (7).

2. The method according to claim 1, wherein the suction conveyor (5) has a plurality of compressed air blast devices (11, 11a) for interrupting the negative pressure, which are arranged successively in the transport direction (T) and in a y-direction extending transversely to the transport direction (T), wherein each compressed air blast device (11, 11a) can be selectively connected to a compressed air source via a separately controllable valve for generating a compressed air surge.

3. The method according to claim 1, wherein the negative pressure is interrupted by generating at least one compressed air shock produced by means of a compressed air blast device (11, 11a).

4. The method according to claim 1, wherein specific compressed air blast devices (11, 11a) are selected in dependence on a geometry of the at least one residual blank (RP) in a CAM system set up for the production of the blanks (P) and are transferred to a controller.

5. The method according to claim 1, wherein the selected compressed air blast devices (11, 11a) for ejecting the at least one residual blank (RP) are controlled by means of the control system as a function of the transport path of the sheet metal strip (2) for generating a compressed air impact.

6. The method according to claim 1, wherein the residual blanks (RP) are discharged into a residual blank discharge device (12, 13) arranged between the first (4) and the second conveyor belt (6).

7. The method according to claim 1, wherein the residual blank (RP) is crushed in the residual blank discharge device (12, 13).

8. The method according to claim 1, wherein a first transport speed of the first transport belt (4) and the suction conveyor (5) is smaller than a second transport speed of the second transport belt (6).

9. The method according to claim 1, wherein the blanks (P) are stacked in the collecting station (7).

10. Apparatus for separating blanks (P), comprising: a conveyor (1) for continuously conveying a sheet metal strip (2) in a transport direction (T) to a laser cutting station (3), a laser cutting station (3) having at least one cutting laser for concurrently cutting the sheet metal strip (2) so that a cut sheet metal strip (2) is formed from successive sections (AT) of the same cutting geometry, each of the sections (AT) comprising at least one blank (P) and at least one residual blank (RP) adjacent to the blank (P), a first conveyor belt (4) for transporting the cut sheet metal strip (2) downstream of the laser cutting station (3) in the transport direction (T), a suction conveyor (5) operated by means of negative pressure for taking over the cut sheet metal strip (2) from the first conveyor belt (4) and for transporting the cut sheet metal strip (2) overhead in the transport direction (T), a device (11, 11a) for separately ejecting the at least one residual blank (RP) of each section (AT) by first interrupting the negative pressure in predetermined areas of the suction conveyor (5), a second conveyor belt (6) arranged in partial overlap with the suction conveyor (5) for receiving the at least one blank (P) discharged from the suction conveyor (5) by a second interruption of the negative pressure and for transporting the successively discharged blanks (P) horizontally in the transport direction (T) to a collecting station (7).

11. The apparatus according to claim 10, wherein the suction conveyor (5) has a plurality of compressed air blast devices (11, 11a) which are arranged successively in the transport direction (T) and in a y-direction extending transversely to the transport direction (T), each of the compressed air blast devices (11, 11a) being selectively connectable to a compressed air source via a separately controllable valve for generating a compressed air surge.

12. The apparatus according to claim 10, wherein a CAM system for producing the blanks (P) is set up in such a way that, as a function of a geometry of the at least one residual blank (RP), specific compressed air blast devices (11, 11a) can be selected and transferred to a controller.

13. The apparatus according to claim 10, wherein the control is arranged such that the selected compressed air blast devices (11, 11a) for ejecting the at least one residual blank (RP) are controlled in dependence on the transport path (T) of the sheet metal strip (2) for generating a compressed air impact.

14. The apparatus according to claim 10, wherein a residual blank removal device (12, 13) for receiving discarded residual blanks (RP) is provided between the first (4) and the second conveyor belt (6).

15. The apparatus according to claim 10, wherein the residual blank removal apparatus (13) comprises means (12) for comminuting the residual blanks (RP).

16. The apparatus according to claim 10, wherein a first transport speed (T) of the first transport belt (4) and the suction conveyor (5) is lower than a second transport speed of the second transport belt (6).

17. The apparatus according to claim 10, wherein at least one stacking device for collecting the blanks (P) is provided downstream of the second conveyor belt (6).

Description

[0043] In the following, an embodiment of the invention is explained in more detail with reference to the drawings. It shows:

[0044] FIG. 1 a block diagram of an apparatus,

[0045] FIG. 2 a perspective view of a suction conveyor,

[0046] FIG. 3 a sectional view according to FIG. 2,

[0047] FIG. 4 a top view according to FIG. 2,

[0048] FIG. 5 a detailed view according to FIG. 3,

[0049] FIG. 6 a detailed view according to FIG. 5,

[0050] FIG. 7 a first sectional view through a compressed air blast device,

[0051] FIG. 8 a sectional view according to section line A-A in FIG. 7,

[0052] FIG. 9 a sheet metal strip with a first cutting contour and

[0053] FIG. 10a sheet metal strip with a second cutting contour.

[0054] FIG. 1 shows a block diagram of an apparatus for separating blanks. Reference sign 1 designates a conveying apparatus, which may be a roller leveler, for example. Reference sign 2 designates a sheet metal strip which is fed to a laser cutting station 3. In the laser cutting station 3, the sheet metal strip is cut into blanks P and adjacent residual blanks RP. The cut sheet metal strip 2 is transported in transport direction T by a first conveyor belt 4 provided downstream of the laser cutting station 3.

[0055] Reference sign 5 indicates a suction conveyor which is arranged downstream of the first conveyor belt 4. The blanks P and the residual blanks RP are picked up by the suction conveyor 5 and transported in the transport direction T in a suspended position.

[0056] Reference sign 6 designates a second conveyor belt, which is arranged downstream of the suction conveyor 5. The second conveyor belt 6 feeds the separated blanks P to a downstream collecting station 7. -The residual blanks RP are shredded in a shredding device (not visible here) and discharged as scrap S.

[0057] FIGS. 2 to 5 show in detail the arrangement of the first conveyor belt 4, the suction conveyor 5 and the second conveyor belt 6. The suction conveyor 5 is formed by a plurality of suction conveyors 7a arranged side by side in the y-direction. FIGS. 3 and 5 each show sectional views through one of the suction conveyors.

[0058] Each of the suction conveyors 7a has two circulating conveyor belts 8 arranged parallel to one another, between which a negative pressure channel 9 is located. A plurality of suction lines 10, which—as shown in the figures—may be branched, extend one behind the other from the negative pressure channel 9 in the transport direction T. The suction lines 10 terminate opposite the negative pressure channel 9 in a suction channel 11 (see FIGS. 7 and 8).

[0059] As can be seen in particular from FIG. 5, the suction conveyor 5 is arranged such that a first section A1 is located substantially between the first conveyer belt 4 and the second conveyor belt 6. A second section A2 of the suction conveyor 5 extends downstream of the first section A1 and covers the second conveyor belt 6 in sections.

[0060] In the first section A1, a greater number of suction lines 10 per unit length are provided in the transport direction T than in the second section A2.

[0061] As can be seen in particular from FIGS. 7 and 8, a compressed air line 11a opens into each of the suction lines 10, which is connected to a compressed air source (not shown here). A valve (not shown here) is connected to each compressed air line 11a, so that each of the suction lines 10 can be selectively and separately supplied with compressed air.

[0062] In FIGS. 2 and 3, the reference sign 12 indicates a shredding device which is provided at the end of a sliding surface 13. The sliding surface 13 extends from the downstream end of the first conveyor belt 4 downward toward the shredding device 12.

[0063] FIG. 9 shows a top view of a first cutting contour of a sheet metal strip 2 in a CAM system. Small residual blanks RP are provided within the blanks P here.

[0064] FIG. 10 shows a second cutting contour of a sheet metal strip 2. Here, relatively large residual blanks RP are provided within the blanks P.

[0065] The function of the apparatus is as follows:

[0066] First, a CAM system is used to manually set marks M1, M2 (see FIG. 10) to determine which sections of the cut sheet metal strip 2 are residual blanks RP to be discarded. For this purpose, e.g. crosses are set as first marks M1 within the residual blanks RP. The blanks P, on the other hand, are marked with second marks M2, which in FIG. 10 are circles, for example.

[0067] If the residual blanks RP are small (see FIG. 9), no marking takes place. In this case, the residual blanks RP do not adhere to the suction conveyor, but are fed directly from the first conveyor belt 4 to the sliding surface 13 and the downstream shredding device 12.

[0068] The markings M1, M2 are processed by the CAM system. In particular, the system calculates which compressed air blast devices are to be controlled for ejecting the respective residual blanks RP. This information is transferred to a machine control system.

[0069] The sheet metal strip 2 passes through the laser cutting station 3, where it is cut so that at the outlet of the laser cutting station it has successive sections AT with essentially identical cutting geometry. Each of the sections AT has a predetermined length L or pitch length in the transport direction. Each of the sections AT comprises at least one blank P and at least one residual blank RP adjacent to the blank P (see FIG. 9). The cut sheet metal strip 2 is transported in transport direction T by means of the first conveyor belt 4. The cut sheet metal strip 2 is then taken over by the suction conveyor 5 and transported further in transport direction T. Small residual blanks RP immediately fall onto the sliding surface 13 when the cut sheet metal strip is taken over.

[0070] In the first section A1, the suction conveyor 5 has an array of compressed air blast devices extending in the transport direction T as well as in the y-direction. Each of the compressed air blast devices comprises a suction line 10 and a compressed air line 11a connected thereto, which can optionally be opened and closed by means of a valve (not shown here). As soon as a residual blank RP is completely overlapped with the first section A1, the control system actuates those compressed air blast devices which are overlapped with the residual blank RP. The compressed air blast devices generate a compressed air impact. As a result, the negative pressure in this area collapses and the residual blank RP falls onto the sliding surface 13. It slides by gravity to the shredding device 12 and is shredded there. The scrap S formed is discharged.

[0071] The blanks P, on the other hand, are transported from the first section A1 of the suction conveyor 5 to the second section A2 in a hanging position. As soon as the blanks P are completely overlapped with the second conveyor belt 6, the compressed air blast devices in the second section A2 are activated by means of the control system so that the blanks P are ejected onto the second conveyor belt 6.

[0072] The first conveyor belt 4 and the conveyor belts 8 of the suction conveyor 5 are operated at the same rotational speed. The second conveyor belt 6 is advantageously operated at a rotational speed that is greater than the rotational speed of the first conveyor belt 4. As a result, the blanks P discharged from the suction conveyor 5 onto the second conveyor belt 6 are accelerated. They are discharged at a greater distance on the second conveyor belt 6 than they are fed to the suction conveyor 5. This facilitates the handling of the blanks P, in particular their transfer to a stacker or the like.

LIST OF REFERENCE SIGNS

[0073] 1 conveyor

[0074] 2 cheet metal strip

[0075] 3 laser cutting station

[0076] 4 first conveyor belt

[0077] 5 suction conveyor

[0078] 6 second conveyor belt

[0079] 7 collecting station

[0080] 7a suction conveying device

[0081] 8 transport belt

[0082] 9 negative pressure channel

[0083] 10 suction line

[0084] 11 intake duct

[0085] 11a compressed air line

[0086] 12 shredding device

[0087] 13 sliding surface

[0088] A1 first section

[0089] A2 second section

[0090] AT section

[0091] L length

[0092] M1 first marker

[0093] M2 second marker

[0094] P blank

[0095] RP residual blank

[0096] S scrap

[0097] T transport direction