Method and apparatus for separating blanks

Abstract

The present invention relates to a method for separating blanks, comprising the steps of: continuously conveying a sheet metal strip (2) in a conveying direction (T) to a laser cutting station (3), simultaneously cutting the sheet metal strip (2) so that the cut sheet metal strip (2) is formed from successive sections (AT) of the same cut shape, each section (AT) comprising at least one blank (P) and at least one residual blank (RP) adjacent to the blank (P), conveying the cut sheet metal strip (2) on a first conveyor belt (4) in the conveying direction (T), and removing the cut sheet metal strip (2) from the first conveyor belt (4) by means of a suction conveyor (5) operating under negative pressure. The cut sheet metal strips (2) taken from the conveyor belt (4) and suspended by the suction conveyor (5) are transported, and at least one remaining blank (RP) of each section (AT) is individually removed by a first intermediate stage of negative pressure in a predetermined area of ​​the suction conveyor (5), and at least one blank (P) of each section (AT) is transported until it overlaps with the second conveyor belt (6), and at least one blank (P) is removed from the suction conveyor (5) by a second interruption of the negative pressure, and the blanks (P) sequentially removed from the suction conveyor are transported horizontally in the conveying direction to a collection station (7).

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for separating blanks.

Background Art

[0002] Methods and apparatuses for separating blanks are known from US2016 / 0318126A1. A metal sheet strip is continuously conveyed in a conveying direction up to a laser cutting station. At the laser cutting station, the metal sheet strip is continuously cut by at least one cutting laser. A cut metal sheet strip is formed that includes a plurality of blanks and a plurality of residual blanks adjacent to the plurality of blanks. The cut metal sheet strip is conveyed downstream of the laser cutting station by a first conveyor belt. Then, the blanks are lifted from the first conveyor belt by a robot and supplied to a collection station such as a stacker, for example.

[0003] In order to lift the blanks by a robot, it is necessary to attach a specific suction tool adapted to the shape of each blank to the end of the robot arm. When the shape of the blank is changed, it is necessary to adapt the suction tool accordingly or attach another suction tool to the end of the robot arm. This requires time and cost.

[0004] In order to achieve the highest possible blank production speed, usually, since the metal sheet strip passes through the laser cutting station very quickly, a plurality of robots are required to lift the blanks. This further increases not only the required space of the known apparatus but also the cost.

[0005] WO2009 / 105608A1 discloses a method for cutting blanks. In this method, a continuously conveyed strip of metal sheet is cut in the conveying direction by two laser cutting stations. The first laser cutting station is arranged at the inlet of the first conveying device, and the second laser cutting station is arranged at the outlet of the second conveying device. The strip of metal sheet is cut into a plurality of blanks by the laser cutting stations. Thereafter, the plurality of blanks are conveyed in the conveying direction.

[0006] DE1282556 describes an apparatus for selectively conveying and stacking a plurality of blanks that are successively supplied at a predetermined distance apart. The plurality of blanks are supplied to different stack positions according to the measured thickness. This known apparatus is only suitable for the selective conveying and stacking of blanks having a uniform predetermined shape.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] The object of the present invention is to eliminate the drawbacks of the prior art. In particular, a method and an apparatus should be specified that can separate a plurality of blanks and a plurality of residual blanks adjacent thereto from each other with less labor, and can separate the plurality of blanks. According to another object of the present invention, the manufacturing speed for manufacturing a plurality of blanks should be improved.

Means for Solving the Problems

[0009] This object is solved by the features of claims 1 and 10. Preferred embodiments of the invention result from the features of the dependent claims.

[0010] According to the present invention, a method for separating blanks is proposed, which includes the following steps. Continuously convey a metal sheet strip in the conveying direction to a laser cutting station, Cut the metal sheet strip with at least one cutting laser, While conveying The cut sheet metal strip is formed from a plurality of consecutive sections of the same cutting shape, and each of the sections includes at least one blank and at least one residual blank adjacent to the blank. Convey the cut metal sheet strip in the conveying direction by a first conveyor belt, Transfer the cut metal sheet strip from the first conveyor belt by a suction conveyor operating under negative pressure, Suspend and convey the cut metal sheet strip in the conveying direction by the suction conveyor, Discard separately at least one residual board of each section by a first interruption of the negative pressure in a predetermined area of the suction conveyor, Convey at least one blank of each section until it overlaps with a second conveyor, and discharge the blank from the suction conveyor by a second interruption of the negative pressure, Horizontally convey in the conveying direction the blanks that have fallen one after another by the suction conveyor to a collection station.

[0011] The metal sheet strip is repeatedly cut into sections of a predetermined length extending in the conveying direction. This specified length is also referred to as the "pitch length".

[0012] Each section has the same cutting shape. This means that in each section, the cutting shape forms a pattern that is repeated so as to be the same or substantially the same in the next section.

[0013] Within a section, at least one blank and an adjacent residual blank are generated by at least one cut. The at least one blank and the at least one residual blank typically have different shapes from each other. At least one blank formed in each section forms a so-called "good product", and the residual blank is discarded as scrap.

[0014] According to the above invention, in one section, it is possible to advantageously separate one board from at least one residual board without requiring much technical effort.

[0015] Unlike the prior art, at least some of the plurality of blanks and residual blanks, or the cut thin plate strips, are picked up from the first conveyor belt by a suction conveyor, suspended, and conveyed in the conveying direction. During the suspended conveyance of the blanks, only the residual blanks are released from the suction conveyor. The plurality of blanks are first suspended and conveyed so as to overlap the second conveyor belt, and then released onto the second conveyor belt from the suction conveyor by a negative pressure second interruption.

[0016] There is no longer a need to provide a robot with a suction tool specially adapted to the shape of the blank to separate the blank. The proposed suction conveyor can release residual blanks of any shape without the need for design changes. Advantageously, the suction conveyor can be operated at the same conveying speed as the first conveyor. For example, when increasing the conveying speed of the first conveyor belt to increase the production speed of blanks with a simple shape, the conveying speed of the suction conveyor only needs to be adapted accordingly.

[0017] A suitable suction conveyor is known, for example, from EP1355838B1. In a known suction conveyor, a negative pressure channel is provided between two parallel conveyor belts. With a sheet-shaped metal part placed on the conveyor belt, a dynamic negative pressure is formed in the negative pressure channel according to the Venturi principle, whereby the sheet-shaped metal part is attracted to the conveyor belt.

[0018] To implement the method according to the invention, several suction conveyors arranged adjacent to each other in the y-direction extending orthogonally to the conveying direction are advantageously used. The distance between the suction conveyors can be varied in the y-direction, and the suction conveyors can be adapted to the shape of the blank and / or the residual blank.

[0019] According to an advantageous embodiment, the suction conveyor has a plurality of compressed air injection devices for interrupting the negative pressure, which are arranged continuously in the conveying direction and in the y-direction extending transversely to the conveying direction. Each compressed air injection device can be optionally connected to a compressed air source via an individually controllable valve for generating a compressed air blast. Thus, the suction conveyor has a two-dimensional array of a plurality of compressed air injection devices that can be selectively and individually controlled according to the predetermined shape of at least one residual blank in order to discharge at least one residual blank.

[0020] The negative pressure is advantageously interrupted by generating a surge of compressed air by the compressed air injection device. As a result, the device for generating the negative pressure can advantageously be operated continuously and used to supply the remaining area of the suction conveyor.

[0021] According to a further advantageous embodiment, a plurality of specific compressed air injection devices are selected in a CAM system configured for the production of blanks according to the shape of at least one remaining blank and transferred to a controller. In the CAM system, for example, at least one remaining blank and / or at least one blank can be marked. Then, using a suitable computer program, a compressed air injection device corresponding to the ejection of each remaining blank is selected. Information regarding the selected compressed air injection device is transferred to the control system or the controller of the device. This enables fast and easy programming for separating the blanks.

[0022] Advantageously, to generate a compressed air blast, the compressed air injection device selected for ejecting at least one remaining blank is controlled by the control system according to the conveying path of the metal sheet strip. In other words, the control system controls the compressed air injection device selected for generating a compressed air blast at exactly that time when the metal sheet strip covers a specific conveying path in the conveying direction. The conveying path is advantageously dimensioned such that the remaining sheet to be ejected is located directly opposite the selected compressed air injection device in the suction conveyor. By operating the compressed air injection device, the negative pressure is interrupted and the remaining blank is ejected from the suction conveyor.

[0023] It is convenient to eject the remaining blank to a remaining blank ejection device arranged between the first and second conveyor belts. In the remaining blank ejection device, the remaining blank is appropriately shredded by a shredding device. The shredded remaining blank may be supplied to a scrap container by a conveyor belt.

[0024] According to a particularly advantageous embodiment of the present invention, the first conveying speed of the first conveyor belt and the suction conveyor is slower than the second conveying speed of the second conveyor belt. That is, the blank taken over by the second conveyor belt is accelerated. As a result, the distance between the blanks successively placed on the second conveyor becomes larger than that of the cut sheet belt. This facilitates the handling of the blanks, such as collection and stacking.

[0025] Preferably, a plurality of blanks are stacked at a collection station provided downstream of the second conveyor. The collection station may be provided with a plurality of stackers that pick up the blanks alternately.

[0026] According to a further aspect of the present invention, a conveying device for continuously conveying a metal sheet strip in a conveying direction to a laser cutting station, a laser cutting station having at least one cutting laser for cutting the metal sheet strip such that the cut metal sheet strip is formed from successive sections of the same cut shape, each of the sections including at least one blank and at least one residual blank adjacent to the blank, While conveying a first conveyor belt for conveying the cut metal sheet strip downstream of the laser cutting station in the conveying direction, a suction conveyor that operates by negative pressure, picks up the cut metal sheet strip from the first conveyor belt, and conveys the cut metal sheet strip upward in the conveying direction, and a device for individually discharging at least one residual blank of each section by a first interruption of the negative pressure in a predetermined region of the suction conveyor. ​A second conveyor belt is provided, which is arranged so as to partially overlap the suction conveyor, receives at least one blank released from the suction conveyor by a second interruption of the negative pressure, and horizontally conveys in the conveying direction a plurality of continuously released blanks to a collection station, for a device for separating blanks.

[0027] The conveying device may be, for example, a roll straightener and / or a pair of conveying rolls facing each other. The metal sheet strip While conveying A laser cutting station having at least one cutting laser for cutting is generally known in the prior art. By way of example, reference is made to DE102010042067A1 and WO2009 / 105608A1.

[0028] Regarding the design of the suction conveyor, reference should be made to the foregoing description. For example, several conveying devices arranged side by side in the y direction, such as those known from EP1335838B1, can be used. According to the present invention, the known conveying device is modified to have a plurality of compressed air injection devices arranged one behind the other in the conveying direction. By arranging a plurality of conveying devices side by side in the y direction, an array of compressed air injection devices extending in the conveying direction and the y direction is obtained. Thus, the compressed air injection devices form a two-dimensional array. In order to discharge the residual blanks, a plurality of sections of the array overlapping each respective residual blank can be controlled to generate a compressed air blast.

[0029] For a further embodiment of the device, reference should be made to the description of the features of the foregoing method, which description also constitutes, with the necessary modifications, the features of the device.

[0030] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.

Brief Description of the Drawings

[0031]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Mode for Carrying Out the Invention

[0032] FIG. 1 shows a block diagram of an apparatus for separating blanks. Reference numeral 1 denotes a conveying device, which may be, for example, a roller leveler. Reference numeral 2 denotes a sheet metal strip supplied to a laser cutting station 3. In the laser cutting station 3, the sheet metal strip is cut into a blank P and an adjacent residual blank RP. The cut sheet metal strip 2 is conveyed in the conveying direction T by a first conveyor belt 4 provided downstream of the laser cutting station 3.

[0033] Reference numeral 5 denotes a suction conveyor disposed downstream of the first conveyor belt 4. The blank P and the residual blank RP are picked up by the suction conveyor 5 and conveyed in the conveying direction T at a suspended position.

[0034] Reference numeral 6 denotes a second conveyor belt disposed downstream of the suction conveyor 5. The second conveyor belt 6 supplies the separated blank P to a downstream collection station 7. The residual blank RP is shredded by a shredding device (not shown here) and discharged as scrap S.

[0035] Figures 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. Figures 3 and 5 each show a cross-sectional view of one of the suction conveyors.

[0036] Each of the suction conveyors 7a has two circulating conveyor belts 8 arranged parallel to each other, and a negative pressure channel 9 is arranged therebetween. A plurality of suction lines 10 may branch as shown in the figure and extend forward and backward in the conveying direction T from the negative pressure channel 9. The suction line 10 terminates in a suction channel 11 on the opposite side of the negative pressure channel 9 (see Figures 7 and 8).

[0037] As can be seen particularly from Figure 5, the suction conveyor 5 is arranged such that the first section A1 is substantially located between the first conveyor belt 4 and the second conveyor belt 6. The second section A2 of the suction conveyor 5 extends downstream of the first section A1 and covers the second conveyor belt 6.

[0038] In the first section A1, more suction lines 10 are provided per unit length in the conveying direction T than in the second section A2.

[0039] As can be seen particularly from Figures 7 and 8, the compressed air line 11a opens inside each suction line 10 and is connected to a compressed air source (not shown here). A valve (not shown here) is connected to each compressed air line 11a, and compressed air can be selectively and individually supplied to each suction line 10.

[0040] In Figures 2 and 3, reference numeral 12 indicates a shredding device provided at the end of the sliding surface 13. The sliding surface 13 extends downward from the downstream end of the first conveyor belt 4 towards the shredding device 12.

[0041] Figure 9 shows a top view of the first cutting contour of the metal sheet strip 2 in the CAM system. Here, a plurality of small residual blanks RP are provided within the blank P.

[0042] Figure 10 shows the second cutting contour of the metal sheet strip 2. Here, a relatively large residual blank RP is provided within the blank P.

[0043] The functions of the device are as follows.

[0044] First, using the CAM system, marks M1, M2 (see Figure 10) are manually set to determine which section of the cut metal sheet strip 2 is the residual blank RP to be discarded. For this purpose, as the first mark M1 within the residual blank RP, for example, a cross is set. On the other hand, the blank P is marked with the second mark M2, which is, for example, a circle in Figure 10.

[0045] When the residual blank RP is small (see Figure 9), no marking is performed. In this case, the residual blank RP does not adhere to the suction conveyor and is directly supplied from the first conveyor belt 4 to the shearing device 12 downstream of the sliding surface 13.

[0046] The markings M1, M2 are processed by the CAM system. In particular, the system calculates which compressed air injection device should be controlled to remove each residual blank RP. This information is transferred to the machine control system.

[0047] The metal sheet strip 2 passes through the laser cutting station 3 and is cut at the outlet of the laser cutting station so as to have successive sections AT of essentially the same cut shape. Each of the sections AT has a predetermined length L or pitch length in the conveying direction. Each of the sections AT includes at least one blank P and at least one residual blank RP adjacent to the blank P (see FIG. 9). The cut metal sheet strip 2 is conveyed in the conveying direction T by the first conveyor belt 4. The cut metal sheet strip 2 is picked up by the suction conveyor 5 and further conveyed in the conveying direction T. When the cut metal sheet strip is picked up, the small residual blank RP immediately drops onto the sliding surface 13.

[0048] In the first section A1, the suction conveyor 5 has an array of compressed air injection devices extending in the conveying direction T and the y direction. Each of the compressed air injection devices includes a suction line 10 and a compressed air line 11a connected thereto, and can be arbitrarily opened and closed by a valve (not shown here). As soon as the residual blank RP completely overlaps the first section A1, the control system activates the compressed air injection device overlapping the residual blank RP. The compressed air injection device generates an impact of compressed air. As a result, the negative pressure in this area collapses and the residual blank RP drops onto the sliding surface 13. The residual blank RP slides by gravity to the shredding device 12 where it is shredded. The generated scrap S is discharged.

[0049] On the other hand, the blank P is conveyed in a suspended position from the first section A1 to the second section A2 of the suction conveyor 5. As soon as the blank P completely overlaps the second conveyor belt 6, the compressed air injection device in the second section A2 is activated by the control system, and the blank P is discharged onto the second conveyor belt 6.

[0050] The first conveyor belt 4 and the conveyor belt 8 of the suction conveyor 5 are operated at the same rotational speed. The second conveyor belt 6 is preferably operated at a rotational speed higher than that of the first conveyor belt 4. As a result, the blank P discharged from the suction conveyor 5 onto the second conveyor belt 6 is accelerated. They are discharged onto the second conveyor belt 6 at a greater distance than that supplied to the suction conveyor 5. This facilitates the handling of the blank P, particularly the transfer to a stacker or the like.

Explanation of Signs

[0051] 1 Conveyor 2 Metal sheet strip 3 Laser cutting station 4 First conveyor belt 5 Suction conveyor 6 Second belt conveyor 7 Collection station 7a Suction conveyor device 8 Conveyor belt 9 Negative pressure channel 10 Suction line 11 Intake duct 11a Compressed air line 12 Chopping device 13 Sliding surface A1 First section A2 Second section AT Section L Length M1 First marker M2 Second marker P Blank RP Residual blank S Scrap T Conveying direction

Claims

1. A method for separating blanks, comprising: continuously conveying a metal sheet strip (2) in a conveying direction (T) to a laser cutting station (3); cutting the metal sheet strip (2) while conveying it by at least one cutting laser, wherein the cut metal sheet strip (2) is formed from continuous sections (AT) of the same cutting shape, and each section (AT) includes at least one blank (P) and at least one residual blank (RP) adjacent to the blank (P); conveying the cut metal sheet strip (2) in the conveying direction (T) by a first conveyor belt (4); transferring the cut metal sheet strip (2) from the first conveyor belt (4) by a suction conveyor (5) operated by negative pressure; suspending and conveying the cut metal sheet strip (2) in the conveying direction by the suction conveyor (5); removing at least one residual blank (RP) of each section (AT) individually by a first shut-off of the negative pressure in a predetermined area of the suction conveyor (5); conveying at least one blank (P) of each section (AT) until it overlaps with a second conveyor belt (6), and removing at least one blank (P) by a second shut-off of the negative pressure; conveying the blanks (P) discharged one after another by the suction conveyor (5) in the conveying direction (T) to a collection station (7).

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

3. The method according to claim 1 or 2, wherein the negative pressure is interrupted by generating at least one compressed air impact generated by the compressed air injection devices (11, 11a).

4. The method according to any one of claims 1 to 3, wherein in a CAM system configured for manufacturing blanks (P), a specific compressed air injection device (11, 11a) is selected according to the shape of at least one residual blank (RP) and transferred to a controller.

5. A method according to any one of claims 1 to 4, wherein at least one selected compressed air injection device (11, 11a) for removing at least one residual blank (RP) is controlled by a control system according to the transport path of the sheet metal strip (2) to generate a compressed air impact.

6. A method according to any one of claims 1 to 5, wherein the residual blank (RP) is discharged to a residual blank discharge device (12, 13) arranged between the first conveyor belt (4) and the second conveyor belt (6).

7. A method according to any one of claims 1 to 6, wherein the residual blank (RP) is crushed within the residual blank discharge device (12, 13).

8. A method according to any one of claims 1 to 7, wherein the first transport speed of the first conveyor belt (4) and the suction conveyor (5) is smaller than the second transport speed of the second conveyor belt (6).

9. A method according to any one of claims 1 to 8, wherein the blanks (P) are stacked at the collection station (7).

10. A device for separating blanks (P), a conveyor (1) for continuously transporting the sheet metal strip (2) in the transport direction (T) to the laser cutting station (3), a laser cutting station (3) having at least one cutting laser for cutting the sheet metal strip (2) while transporting it so that the cut sheet metal strip (2) is formed from successive sections (AT) of the same cut shape, each section (AT) including 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) in the transport direction (T) downstream of the laser cutting station (3), a suction conveyor (5) operating by negative pressure, receiving the cut sheet metal strip (2) from the first conveyor belt (4) and transporting the cut sheet metal strip (2) above the transport direction, a device (11, 11a) for individually removing at least one residual blank (RP) of each section (AT) by a first interruption of the negative pressure in a predetermined region of the suction conveyor (5). An apparatus comprising a second conveyor belt (6) which is arranged to overlap partially with the suction conveyor (5), receives at least one blank (P) discharged from the suction conveyor (5) by a second interruption of negative pressure, and subsequently horizontally conveys the discharged blank (P) in the conveying direction (T) to a collection station (7).

11. The suction conveyor (5) has a plurality of compressed air injection devices (11, 11a) which are arranged continuously in the conveying direction (T) and in the y-direction extending transversely to the conveying direction, and each compressed air injection device (11, 11a) is selectively connectable to a compressed air source via an individually controllable valve to generate a compressed air surge. The apparatus according to claim 10.

12. The CAM system for manufacturing the blank (P) is configured such that specific compressed air injection devices (11, 11a) are selected according to the shape of at least one residual blank (RP) and transferred to a controller. The apparatus according to claim 10 or 11.

13. The selected compressed air injection device (11, 11a) for discharging at least one residual blank (RP) to generate a compressed air impact is controlled according to the conveying path (T) of the metal sheet strip (2). The apparatus according to any one of claims 10 to 12.

14. A residual blank removal device (12, 13) for receiving the discarded residual blank (RP) is provided between the first conveyor belt (4) and the second conveyor belt (6). The apparatus according to any one of claims 10 to 13.

15. The residual blank removal device (13) comprises means (12) for pulverizing the residual blank (RP). The apparatus according to any one of claims 10 to 14.

16. The first conveying speed (T) of the first conveyor belt (4) and the suction conveyor (5) is slower than the second conveying speed of the second conveyor belt (6). The apparatus according to any one of claims 10 to 15.

17. At least one stacking device for collecting the blank (P) is provided downstream of the second conveyor belt (6). The apparatus according to any one of claims 10 to 16.

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