METHOD AND DEVICE FOR SINGLING CIRCUITS

Description

[0001] The invention relates to a method and a device for separating circuit boards.

[0002] US 2016 / 0318126 A1 discloses a method and device for separating blanks. A sheet metal strip is continuously transported in a transport direction to a laser cutting station. In the laser cutting station, the sheet metal strip is cut in a continuous manner using at least one cutting laser. A cut sheet metal strip is formed, which comprises the blanks and any remaining blanks adjacent to the blanks. The cut sheet metal strip is transported downstream of the laser cutting station on a first conveyor belt in the transport direction. The blanks are then lifted from the first conveyor belt by a robot and fed to a collection station, for example, a stacker.

[0003] To lift the boards using the robot, a specific suction tool adapted to the geometry of the respective board must be attached to the end of the robot arm. If the board geometry changes, either the suction tool must be adjusted accordingly or a different suction tool must be attached to the end of the robot arm. This is time-consuming and costly.

[0004] To achieve the highest possible production rate of printed circuit boards, the sheet metal strip is usually transported through the laser cutting station so quickly that several robots are required to lift the boards. This further increases the complexity and space requirements of the conventional device.

[0005] The generic document WO 2009 / 105608 A1 discloses a method for cutting blanks. A continuously conveyed sheet metal strip is cut in one transport direction using two laser cutting stations. A first laser cutting station is located at the inlet of a first conveyor, and a second laser cutting station is located at the outlet of a second conveyor. The sheet metal strip is cut into blanks using the laser cutting stations. The blanks are then transported away in the transport direction.

[0006] DE 1 282 556 describes a device for the selective conveying and stacking of blanks fed in successively at a certain distance. The blanks are fed to different stacking positions depending on a measured thickness. The known device is only suitable for the selective conveying and stacking of blanks with a uniform, predetermined geometry.

[0007] The document EP 3 254 992 A1 relates to a transport device for the suspended transport of transport goods, in particular designed as sheet metal blanks, by means of negative pressure, with at least one belt conveyor device with at least one circulating transport belt which is guided along a negative pressure chamber in such a way that a rear side of the transport belt facing the negative pressure chamber is arranged opposite a chamber opening of the negative pressure chamber, and a contact side of the transport belt is provided with suction openings formed between the rear side and the contact side of the transport belt in order to form holding forces between the contact side of the transport belt and a contact side of the transport goods.

[0008] The object of the invention is to eliminate the disadvantages of the prior art. In particular, it is intended to provide a method and a device with which boards and adjacent remaining boards can be separated from one another, and the boards can be separated, with reduced effort. A further object of the invention is to increase the production rate for the boards.

[0009] The problem is solved by the features of claims 1 and 10. Advantageous embodiments of the invention emerge from the features of the dependent claims.

[0010] According to the invention, a method for separating circuit boards is proposed with the following steps: Continuously conveying a sheet metal strip in a transport direction to a laser cutting station, cutting the sheet metal strip by means of at least one cutting laser, wherein a cut sheet metal strip is formed from successive sections of the same cutting geometry, wherein each of the sections comprises at least one blank and at least one remaining blank adjacent to the blank,

[0011] Transporting the cut sheet metal strip on a first conveyor belt in the transport direction,

[0012] Transfer of the cut sheet metal strip from the first conveyor belt by means of a vacuum-operated suction conveyor, suspended transport of the cut sheet metal strip by means of the suction conveyor in the transport direction, separate discharge of at least one remaining blank of each section by first interrupting the negative pressure in predetermined areas of the suction conveyor,

[0013] Transporting the at least one board of each section in overlap with a second conveyor belt and dropping the at least one board from the suction conveyor by a second interruption of the negative pressure, and transporting the boards successively dropped from the suction conveyor in a horizontal position in the transport direction to a collecting station.

[0014] Through continuous cutting, the sheet metal strip is repeatedly cut into sections of a specified length extending in the direction of transport. This specified length is also referred to as the "pitch length."

[0015] Each section has the same cutting geometry. This means that in each section, the cutting geometry creates a pattern that is repeated in an identical or nearly identical manner in the subsequent section.

[0016] Within each section, at least one blank and an adjacent remaining blank are produced through at least one cut. The at least one blank and the at least one remaining blank typically have a different geometry. The at least one blank formed in each section constitutes a so-called "good part," whereas the remaining blank is discarded as scrap.

[0017] With the given invention, it is advantageously possible to separate one circuit board from at least one remaining circuit board within a section without great technical effort.

[0018] In a departure from the prior art, the blanks and at least some of the remaining blanks or the cut sheet metal strip are picked up from the first conveyor belt by a suction conveyor and transported suspended in the direction of transport. During the suspended transport of the blanks, only the remaining blanks are discarded by the suction conveyor. The blanks are initially transported suspended in overlapping fashion with a second conveyor belt and then discarded by the suction conveyor onto the second conveyor belt by a second interruption of the vacuum.

[0019] It is no longer necessary to provide robots with suction tools specifically adapted to the board geometry for separating the blanks. The proposed suction conveyor enables the removal of leftover blanks of any geometry without requiring any structural changes. The suction conveyor can advantageously be operated at the same transport speed as the first conveyor belt. For example, if the transport speed of the first conveyor belt is increased to increase the production rate for blanks with a simple geometric design, the transport speed of the suction conveyor can easily be adjusted accordingly.

[0020] A suitable suction conveyor is known, for example, from EP 1 355 838 B1. In this known suction conveyor, a vacuum channel is provided between two parallel conveyor belts. When sheet metal parts are placed on the conveyor belts, a dynamic vacuum is created in the vacuum channel according to the Venturi principle, which draws the sheet metal parts toward the conveyor belts.

[0021] To carry out the method according to the invention, several suction conveyors arranged side by side in a y-direction perpendicular to the transport direction are advantageously used. The spacing between the suction conveyors can be adjusted in the y-direction, allowing the suction conveyor to be adapted to the geometry of the blanks and / or remaining blanks.

[0022] According to an advantageous embodiment, the suction conveyor comprises a plurality of compressed air blast devices for interrupting the negative pressure, which are arranged successively in the transport direction and in the y-direction extending transversely to the transport direction. Each compressed air blast device can be selectively connected to a compressed air source via a separately controllable valve for generating a compressed air blast. The suction conveyor thus comprises a two-dimensional array of compressed air blast devices, which can be selectively and separately controlled depending on a predetermined geometry of the at least one remaining blank to eject the same.

[0023] The negative pressure is advantageously interrupted by generating a compressed air blast using a compressed air blast device. Consequently, a device for generating the negative pressure can advantageously be operated continuously and used to supply the remaining areas of the suction conveyor.

[0024] According to a further advantageous embodiment, depending on the geometry of the at least one remaining blank, specific compressed air blast devices are selected in a CAM system designed for blank production and transferred to a controller. For example, the at least one remaining blank and / or the at least one blank can be marked in the CAM system. Using a suitable computer program, the compressed air blast devices corresponding to the ejection of the respective remaining blanks are then selected. The information from the selected compressed air blast devices is transferred to a controller or machine control system. This enables quick and easy programming for separating the blanks.

[0025] Advantageously, the selected compressed air blast devices for ejecting the at least one remaining blank are activated by the controller depending on the transport path of the sheet metal strip to generate a compressed air blast. This means that the controller activates the selected compressed air blast devices to generate a compressed air blast precisely when the sheet metal strip has traveled a specific transport path in the transport direction. The transport path is advantageously dimensioned such that the remaining blank to be ejected is then located exactly opposite the selected compressed air blast devices of the suction conveyor. By activating the compressed air blast devices, the vacuum is interrupted, and the remaining blank is ejected from the suction conveyor.

[0026] The remaining blanks are expediently discharged into a blank removal device located between the first and second conveyor belts. In the blank removal device, the remaining blanks are expediently shredded using a shredding device. The shredded blanks can then be fed to a scrap container via a conveyor belt.

[0027] According to a particularly advantageous embodiment of the invention, a first transport speed of the first conveyor belt and the suction conveyor is lower than a second transport speed of the second conveyor belt. This means that the blanks picked up by the second conveyor belt are accelerated. As a result, the spacing between the consecutive blanks deposited on the second conveyor belt is greater than in the cut sheet metal strip. This simplifies handling of the blanks, for example, collecting, stacking, etc.

[0028] The blanks are conveniently stacked in a collection station located downstream of the second conveyor belt. The collection station can also comprise several stackers that alternately pick up blanks.

[0029] According to a further aspect of the invention, a device for separating circuit boards is proposed, comprising: a conveyor device for continuously conveying a sheet metal strip in a transport direction to a laser cutting station, a laser cutting station with at least one cutting laser for cutting the sheet metal strip in a continuous manner, so that a cut sheet metal strip is formed from successive sections of the same cutting geometry, each of the sections comprising at least one blank and at least one remaining blank adjacent to the blank, a first conveyor belt for transporting the cut sheet metal strip downstream of the laser cutting station in the transport direction, a vacuum-operated suction conveyor for receiving the cut sheet metal strip from the first conveyor belt and for suspended transport of the cut sheet metal strip in the transport direction, a device for separately ejecting the at least one remaining blank of each section by first interrupting the vacuum in predetermined areas of the suction conveyor,a second conveyor belt arranged in partial overlap with the suction conveyor for receiving the at least one blank ejected from the suction conveyor by a second interruption of the negative pressure and for transporting the successively ejected blanks horizontally in the transport direction to a collecting station.

[0030] The conveying device can, for example, be a roller straightening machine and / or a pair of opposing transport rollers. A laser cutting station with at least one cutting laser for the continuous cutting of a sheet metal strip is generally known in the prior art. Reference is made to DE 10 2010 042 067 A1 and WO 2009 / 105608 A1, for example.

[0031] Regarding the design of the suction conveyor, reference is made to the above explanations. Several transport devices arranged next to one another in the y-direction can be used, as are known, for example, from EP 1 355 838 B1. According to the invention, the known transport devices are modified such that they have a plurality of compressed air blast devices arranged one behind the other in the transport direction. By arranging several transport devices next to one another in the y-direction, an array of compressed air blast devices is created which extends in the transport direction and in the y-direction. The compressed air blast devices thus form a two-dimensional field. To eject remaining blanks, sections of the field which are in overlap with the respective remaining blank can be controlled to generate compressed air blasts.

[0032] For further embodiments of the device, reference is made to the preceding explanations of the features of the method, which also form features of the device.

[0033] An embodiment of the invention is explained in more detail below with reference to the drawings. They show: Fig. 1 a block diagram of a device, Fig. 2 a perspective view of a suction conveyor, Fig. 3 a sectional view according to Fig. 2 , Fig. 4 a plan view according to Fig. 2 , Fig. 5 a detailed view according to Fig. 3 , Fig. 6 a detailed view according to Fig. 5 , Fig. 7 a first sectional view through a compressed air blast device, Fig. 8 a sectional view according to the section line A - A in Fig. 7 , Fig. 9a sheet metal strip with a first cutting contour and Fig. 10a sheet metal strip with a second cutting contour.

[0034] Fig. 1 shows a block diagram of a device for separating blanks. Reference numeral 1 denotes a conveyor device, which may be, for example, a roller straightening machine. Reference numeral 2 denotes 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 remaining blanks RP. The cut sheet metal strip 2 is transported in the transport direction T by a first conveyor belt 4 provided downstream of the laser cutting station 3.

[0035] Reference numeral 5 denotes a suction conveyor arranged downstream of the first conveyor belt 4. The suction conveyor 5 picks up the blanks P and the remaining blanks RP and transports them suspended in the transport direction T.

[0036] Reference numeral 6 denotes a second conveyor belt, which is arranged downstream of the suction conveyor 5. The separated blanks P are fed by the second conveyor belt 6 to a downstream collection station 7. The remaining blanks RP are shredded in a shredding device (not visible here) and removed as scrap S.

[0037] The Fig. 2 bis 5 show in detail the arrangement of the first conveyor belt 4, suction conveyor 5 and second conveyor belt 6. The suction conveyor 5 is formed from a plurality of suction conveyor devices 7a arranged next to one another in the y-direction. Fig. 3 and 5 each show sectional views through one of the suction conveyor devices.

[0038] Each of the suction conveyor devices 7a has two parallel, circulating conveyor belts 8, between which a vacuum channel 9 is located. A plurality of suction lines 10 extend from the vacuum channel 9 in the transport direction T, one behind the other, which - as shown in the figures - can be branched. The suction lines 10 open into a suction channel 11 opposite the vacuum channel 9 (see Fig. 7 und 8 ).

[0039] As is particularly evident from Fig. 5 As can be seen, the suction conveyor 5 is arranged such that a first section A1 is located substantially between the first conveyor 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 partially covers the second conveyor belt 6.

[0040] In the first section A1, a larger number of suction lines 10 per unit length are provided in the transport direction T than in the second section A2.

[0041] As can be seen in particular from the Fig. 7 und 8 As can be seen, a compressed air line 11a, which is connected to a compressed air source (not shown here), opens into each of the suction lines 10. A valve (not shown here) is connected to each of the compressed air lines 11a, so that each of the suction lines 10 can be selectively and separately supplied with compressed air.

[0042] In the Fig. 2 and 3 Reference numeral 12 designates a comminution device provided at the end of a sliding surface 13. The sliding surface 13 extends downward from the downstream end of the first conveyor belt 4 toward the comminution device 12.

[0043] The Fig. 9 shows a top view of a first cutting contour of a sheet metal strip 2 in a CAM system. Small remaining blanks RP are provided within the blanks P.

[0044] Fig. 10 shows a second cutting contour of a sheet metal strip 2. Here, relatively large remaining blanks RP are provided within the blanks P.

[0045] The function of the device is as follows: First, in a CAM system, by manually setting marks M1, M2 (see Fig. 10 ) determines which sections of the cut sheet metal strip 2 are the remaining blanks RP to be discarded. For this purpose, the first markings M1, e.g., crosses, are placed within the remaining blanks RP. The blanks P, on the other hand, are marked with second markings M2, which are Fig. 10 e.g. circles.

[0046] If the remaining boards RP are small (see Fig. 9 ) no marking is performed. In this case, the remaining blanks RP do not adhere to the suction conveyor, but are fed directly by the first conveyor belt 4 to the sliding surface 13 and the subsequent shredding device 12.

[0047] The markings M1 and M2 are processed by the CAM system. Specifically, the system calculates which compressed air blast devices are to be activated to eject the respective remaining blanks RP. This information is transferred to a machine control system.

[0048] The sheet metal strip 2 passes through the laser cutting station 3. There, it is cut so that at the outlet of the laser cutting station 3, 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 remaining blank RP adjacent to the blank P (see Fig. 9). The cut sheet metal strip 2 is transported in the 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 the transport direction T. Small remaining blanks RP immediately fall onto the sliding surface 13 when the cut sheet metal strip is taken over.

[0049] The suction conveyor 5 has, in the first section A1, an array of compressed air blast devices extending in the transport direction T and in the y-direction. Each of the compressed air blast devices comprises a suction line 10 and a connected compressed air line 11a, which can be selectively 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 activates those compressed air blast devices that are overlapped with the residual blank RP. The compressed air blast devices generate a compressed air blast. As a result, the negative pressure in this area collapses, and the residual blank RP falls onto the sliding surface 13. It slides under gravity to the shredding device 12, where it is shredded. The resulting scrap S is removed.

[0050] The blanks P, on the other hand, are transported suspended from the first section A1 of the suction conveyor 5 to the second section A2. 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 the control system, so that the blanks P are dropped onto the second conveyor belt 6.

[0051] 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 dropped from the suction conveyor 5 onto the second conveyor belt 6 are accelerated. They are transported away on the second conveyor belt 6 at a greater distance than they were fed to the suction conveyor 5. This facilitates the handling of the blanks P, in particular their transfer to a forklift or the like. List of reference symbols

[0052] 1Conveyor device 2Sheet metal belt 3Laser cutting station 4First conveyor belt 5Suction conveyor 6Second conveyor belt 7Collection station 7aSuction conveyor device 8Conveyor belt 9Vacuum channel 10Suction line 11Suction channel 11aCompressed air line 12Crushing device 13Sliding surface A1first section A2second section ATsection LLength M1first marking M2second marking PPirm board RPRemaining board SScrap TTransport direction

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), the method characterized by the following steps: 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 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 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 any one of the preceding claims, wherein the negative pressure is interrupted by generating at least one compressed air shock produced by means of a compressed air blast.

4. The method according to claim 2 or 3, wherein specific compressed air blast devices 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 4, wherein the selected compressed air blast devices 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 any of the preceding claims, wherein the residual blanks (RP) are discharged into a residual blank discharge device arranged between the first conveyor belt (4) and the second conveyor belt (6).

7. The method according to claim 6, wherein the residual blank (RP) is crushed in the residual blank discharge device8. The method according to any one of the preceding claims, 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 any of the preceding claims, 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), characterized in that the apparatus further comprises 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 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 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 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 or 11, 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 can be selected and transferred to a controller.

13. The apparatus according to claim 12, wherein the control is arranged such that the selected compressed air blast devices 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 any one of claims 10 to 13, wherein a residual blank removal device for receiving discarded residual blanks (RP) is provided between the first conveyor belt (4) and the second conveyor belt (6).

15. The apparatus according to claim 14, wherein the residual blank removal apparatus comprises a shredding device (12) for comminuting the residual blanks (RP).

16. The apparatus according to any one of claims 10 to 15, 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 any one of claims 10 to 16, wherein at least one stacking device for collecting the blanks (P) is provided downstream of the second conveyor belt (6).