WO2023083509A1

WO2023083509A1 - Method for operating a production line for processing metal sheets

Info

Publication number: WO2023083509A1
Application number: PCT/EP2022/072414
Authority: WO
Inventors: Andreas Vollmann
Original assignee: Koenig & Bauer Ag
Priority date: 2021-11-11
Filing date: 2022-08-10
Publication date: 2023-05-19
Also published as: JP2024509733A; EP4259438A1; DE102021129338B3

Abstract

The invention relates to a method for operating a production line (01) having a continuous dryer (17) for drying painted metal sheets (08), wherein: a loading station (02) which has a plurality of rotating wire frames (22) is located upstream of the continuous dryer (17) in the transport direction (T) of the metal sheets (08); each of these wire frames (22) uprights one of the metal sheets (08) which lie flat; in the transport plane of the metal sheets (08), the loading station (02) has a plurality of nozzles (14) out of which blown air is blown against the lower face of each metal sheet (08); at least one subset of the nozzles (14) are operated cyclically; these cyclically operated nozzles (14) are switched on while the relevant metal sheet (08) is being taken up by the wire frame (22) and raised; and these cyclically operated nozzles (14) are switched off before the blown air therefrom acts on the leading edge of the subsequent metal sheet (08).

Description

Method for operating a production line for processing sheet metal

The invention relates to a method for operating a production line for processing sheet metal according to the preamble of claim 1.

DE 102019 118647 B3 discloses a production line for processing metal sheets that has a number of different machine units. B. is linear, with a metal plate printing machine and/or a coating machine and/or a loading station and/or a dryer and/or an unloading station being provided as machine units in the direction of transport of metal sheets to be processed in succession, with at least two machine units each having at least one transport device for transport have at least one sheet metal plate lying individually on a transport plane, wherein the transport device of the loading station has a wire frame that lifts a sheet metal plate, this wire frame being designed in such a way that it surrounds the transport plane of the metal plates in a circular manner about an axis of rotation extending transversely to the transport direction of the metal plates to be transported an area in which a metal sheet is fed to the loading station from bottom to top.

The invention is based on the object of creating a method for operating a production line for processing metal sheets, wherein in a mass production of metal sheets with a production speed of several thousand metal sheets per hour, their trouble-free individual transport through the production line is ensured.

The object is achieved according to the invention by the features of claim 1. The The dependent claims relate to advantageous refinements and/or developments of the solution found.

The advantages that can be achieved with the invention are, in particular, that in a mass production of metal sheets with a production speed of several thousand metal sheets per hour, their trouble-free individual transport through the production line z. B. with a monitoring of the synchronization point and / or without an unintentional running and / or tilting or snagging of successively transported metal sheets is ensured.

An exemplary embodiment of the invention is shown in the drawings and is described in more detail below, which shows further advantages of the solution found.

Show it:

1 shows a production line for processing metal sheets with a number of machine units;

2 shows a sheet metal panel;

3 shows a plan view of a transport device;

4 shows the transport device in a perspective view;

5 shows an enlarged representation of the transport device;

6 shows a perspective representation of a loading station with a preceding transport module; FIG. 7 shows a plan view of the loading station of FIG. 6;

8 shows a plan view of an unloading station;

9 shows a sketch of an arrangement of cyclically operated nozzles formed in a loading station;

10 shows a sketch of a controller for monitoring and/or setting a synchronization point at a loading station;

11 shows a lifting device supporting the lifting of a wire frame by means of compressed air nozzles and/or electromagnets;

Fig. 12 shows a lifting device assisting lifting of a wire frame by means of a cam;

13a, 13b a lifting device supporting the lifting of a wire frame by means of a lever;

14a, 14b a lifting device supporting the lifting of a wire frame by means of a ram;

15 shows a production line with wire frames coupled hanging on the lower run of a traction means;

16 shows a continuous dryer with traction means in several horizontal planes arranged vertically one above the other. In industrial metal sheet printing, metal sheets 08 (Fig. 2) are usually printed with at least one printed image on a production line 01 by applying at least one printing fluid using a metal sheet printing machine 03 and/or in a sheet metal painting machine 06, e.g. B. to protect their surface or at least the printed image and / or z. B. to produce a gloss effect in each case painted over the entire surface or part of the surface. The metal sheets 08 to be processed in this way have a format z. B. between 500 mm x 650 mm and 950 mm x 1,900 mm and each have a sheet thickness z. B. between 0.1 mm and 1.0 mm, preferably between 0.14 mm and 0.5 mm. Each of these metal sheets 08 can, depending on their format and their material - whether made of tin-plated steel or tin-free steel or aluminum - thus a mass z. B. from a few hundred grams to a few kilograms, z. B. from at least 300 grams up to five kilograms or more. Particularly in the production of tin packaging, ie in tin packaging printing, metal sheets 08 of this type are industrially mass-produced at a production speed of several thousand metal sheets 08 per hour, e.g. B. of at least 6,000 metal panels 08 per hour printed and / or painted.

1 shows a highly simplified schematic representation of such a production line 01 for processing metal sheets 08, which has a number of machine units, in which these machine units are each arranged one behind the other in a row and work together to carry out production that processes metal sheets 08. So are in this production line 01 in the transport direction T of the metal sheets to be processed 08 (Fig. 2) z. B. a sheet metal printing machine 03 and / or a sheet metal painting machine 06 is provided, followed by a loading station 02, a continuous dryer 17 and an unloading station 07, in particular the loading station 02 and / or the unloading station 07 each z. B. can interact with a transport module 04 designed as an independent machine unit. The metal printing machine 03 and the metal painting machine 06 can also be combined in a single machine unit. As a continuous dryer 17 trained machine unit is z. B. designed as a hot air dryer.

Practice has shown that metal sheets 08 transported at high speed through the production line 01 tend to have problems during transport, specifically due to friction effects in their respective transport plane and/or as a result of contamination on their respective transport path. Disturbing friction effects also occur e.g. B. in the event of excessive wear or aging of a belt transport system used for transporting the metal sheets 08. Each of these undesirable influences can lead to e.g. B. several metal sheets 08 transported one after the other through the production line 01 unintentionally run up against each other and/or tilt or get caught. Metal sheets 08 can also be turned out of their linear transport path in their respective transport plane and thereby z. B. cause a collision with other metal sheets 08 and/or a component of one of the machine units of this production line 01. And even if no collision occurs, at least one free distance between successively transported sheet metal plates 08, i.e. the distance between the rear edge of a first metal plate 08 and the front edge of the next following second metal plate 08, can change despite a constant production speed in production line 01, see above that a so-called synchronization point shifts, which means that in particular the leading edge position of a metal sheet 08 shifts relative to devices arranged in different machine units of the production line 01. By shifting the synchronization point in this way, z. B. acceleration and / or deceleration processes provided in connection with the metal printing machine 03 and / or sheet metal painting machine 06 out of step, which in particular an interaction of machine units linked together in the production process, such as e.g. B. the metal printing machine 03 or a metal painting machine 06, the at least one transport module 04, the loading station 02, the continuous dryer 17 and the Unloading station 07 is disturbed. Such events lead to an undesired impairment of production and/or to damage up to a loss of production due to a machine downtime caused by a malfunction.

At least the respective transport module 04 and/or the loading station 02 and/or the unloading station 07 each have at least one transport device 09 (Fig. 3) for transporting the metal sheets 08 as one of their structural units. A transport route through this production line 01 is z. B. linear. At least the machine units embodied as a loading station 02 or as a continuous dryer 17 or as an unloading station 07 and arranged one behind the other in the transport direction T of the metal sheets 08 are linked together by at least one common traction mechanism 29 that runs through these machine units and is provided for the transport of the metal sheets 08 (Fig. 1) , e.g. B. by at least one circulating chain. The direction of rotation of the traction means 29 is indicated in FIG. 1 by directional arrows. In a preferred embodiment, the traction means 29 is formed by two mirror-image chains running, these chains over several, z. B. two shafts 31 each having gears are driven synchronously by a drive 32 designed in particular as an electric motor. Two of these shafts 31 are arranged at least at the two deflection points of the chains, i. H. at the ends of the transport section spanned by these chains through the production line 01. Rails 33 are preferably arranged in the continuous dryer 17, with each of these chains being supported on one of these rails 33 via rollers 36 attached at the side.

2 shows an example of a rectangular, generally flexible metal sheet 08 , a large number of which are to be transported one after the other along the transport path leading through the production line 01 . Each of these metal sheets 08 has a length L in the transport direction T intended for it and a width B transverse to this transport direction T, with the format of the respective metal sheet 08 is defined by specifying its length L times its width B.

FIG. 3 shows a top view of one of the transport devices 09 arranged in at least two different machine units of the production line 01 as an example. FIG. B. is arranged in the transport module 04.

Fig. 5 shows the transport device 09 in a plan view in an enlarged representation. In a preferred embodiment, the transport device 09 has at least one, preferably two, transport belts 11 only in its central region M, which extends longitudinally to the transport direction T of the metal sheets 08. B. as a flat belt consisting in particular of a flexible material in the form of an endless loop. the z. B. between 1 mm and 5 mm, preferably about 2 mm thick flat belts have a width B11 z. B. between 30 mm and 250 mm, preferably about 40 mm or 80 mm. the z. B. table-shaped transport device 09 preferably has a flat plate 12 (Fig. 4) which is arranged in a stationary manner in the transport plane of the metal sheets 08 and whose width B12, extending transversely to the transport direction T of the metal sheets 08, is at least as large as the width B of the maximum format of the metal sheets 08 to be transported with the transport device 09. B. over a maximum of 60%, preferably over a maximum of 30% of the width B12 of the plate 12 of this transport device 09, in particular over 10% to 20% of the width B12 of the plate 12 of the transport device 09, particularly preferably around 15% of the width B12 of the plate 12 of the transport device 09, and extends with its long side lengthways in the transport direction T of the metal sheets 08 to be transported. The plate 12 of this transport device 09 has a length L12, which is preferably at least as long as the length L of the maximum format of the transport device 09 metal sheets to be transported 08. The respective transport belt 11 of the transport device 09 is preferably arranged revolving on deflection rollers with its respective load side along the transport plane in such a way that each load side of the transport belt 11 resting and on the relevant transport belt 11 z. B. also held sheet metal 08 can be transported relative to the stationary plate 12 in question along a linear transport route, with this transport route z. B. at least over the length L12 of the transport device 09. The holding force required to hold a metal sheet 08 resting on the transport belt 11 in question is achieved, e.g. B. by a suction, the required suction z. B. is generated by a suction box arranged below the plate 12 of the transport device 09 in conjunction with a suction pump connected to it. The suction pump is preferably switched on and/or switched off as required, or at least can be switched on and/or switched off. Alternatively or additionally, magnetic holding means can also be provided for holding a sheet metal plate 08 resting on the transport belt 11 in question, which are preferably also switchable. The relevant transport device 09 can also have several, e.g. B. two mutually parallel transport belts 11 have.

In the production line 01, at least two of these transport devices 09 are preferably arranged separately from one another, ie as independent structural units in different machine units, with one of these transport devices 09 being arranged in particular in the loading station 02 or in the unloading station 07. The transport belts 11 of the relevant transport devices 09 are each driven by an electric drive 16 in such a way that transport belts 11 arranged in different transport devices 09 are preferably synchronized with one another in terms of their respective rotational speed, so that sheet metal panels 08 transported by these transport belts 11 each have permissible minor tolerances apart from be transported at the same linear speed, with these metal sheets 08 being transported on these transport belts 11, e.g. B. are held by suction and / or magnetically. The metal sheets 08 resting on the transport belts 11 are transported in their transport plane, i.e. in particular with respect to the plate 12 of the transport device 09, each largely floating on an air cushion and is therefore almost friction-free, but at least extremely low-friction and practically slip-free, because the respective Metal sheets 08 are only in physical contact with the comparatively narrow transport belts 11 . The respective electric drive 16 of the relevant transport devices 09 is z. B. in each case designed as an electric motor and preferably in each case connected at least in terms of data technology to a machine controller 34 of the production line 01 that is superordinate to the individual machine units, e.g. B. with a control station of this production line 01.

Transport belts 11 arranged in different transport devices 09 are preferably driven by their respective electric drive 16 in such a way that they B. rotate continuously, in particular in a synchronism. Alternatively, these transport belts 11 can also be driven in clocked fashion. It can also be provided that the transport belt 11 of a z. B. in the loading station 02 arranged transport device 09 preferably clocked by the machine controller 34 and / or resting on their transport belts 11 metal plate 08 are driven temporarily braking in their linear speed, whereas the transport belts 11 of a z. e.g. in the unloading station 07, the transport device 09 is preferably clocked by the machine controller 34 and/or a sheet metal plate 08 resting on its transport belt 11 is driven at times in an accelerating manner in terms of its linear speed. The synchronous operation of the transport belts 11 arranged in different transport devices 09 and thus above all the synchronous operation of the metal sheets 08 held by these transport belts 11 is particularly advantageous when the machine units of this production line 01 are started up or shut down. For a trouble-free Transport of the metal sheets 08 through the production line 01, the synchronous operation of the transport belts 11 arranged in different transport devices 09 and thus also of the metal sheets 08 must be ensured, but in particular also at the transitions between the machine units involved in the production process of this production line 01.

The plate 12 of the transport device 09 in question has a belt-free edge region R1 on both sides of its respective central region M; R2, these edge areas R1; R2 preferably have the same width extending transversely to the transport direction T of the metal sheets 08 and are preferably arranged symmetrically with respect to a longitudinal extension of the relevant transport device 09. At least in the belt-free edge areas R1; R2, e.g. B. but also additionally in the central region M of the transport device 09 in question, at least one nozzle array 13 each having a plurality of nozzles 14 is formed. The nozzles 14 arranged there are operated in such a way that, to form the air cushion, blown air is blown out of them against the underside of a sheet metal panel 08 resting on the at least one transport belt 11 of the transport device 09 in question and held on the transport belt(s) 11 in question. In an advantageous embodiment, at least some of the nozzles 14 of the nozzle arrays 13 z. B. are each designed as venturi nozzles. In the respective nozzle fields 13 z. B. a first subset of individual nozzles 14 and/or a second subset of individual nozzles 14 are each arranged in such a way that the first subset of nozzles 14 directs the blown air at an acute angle outwards in the transport direction T of the sheet metal panels 08, i. H. in each case in the direction of the nearest edge of the transport device 09 in question, which edge extends along the transport direction T of the metal sheets 08, and/or the second subset of nozzles 14 blow out the blown air vertically upwards.

FIG. 6 shows, by way of example, a perspective view of the production line 01 arranged loading station 02 together with a transport module 04 arranged immediately upstream in the transport direction T of the metal sheets 08. In this embodiment variant, both the loading station 02 and the transport module 04 each have their own frame 19; 21, these two machine units being joined together seamlessly, so that the frame 21 of the loading station 02 and the frame 19 of the transport module 04 form a joint joint. The transport module 04 has a transport device 09 z. B. with a plate 12, wherein a metal plate 08 to be transported in the transport direction T indicated by a directional arrow is shown both in its largest format and in its smallest format on the plate 12. For this purpose, the sheet metal plate 08 only rests on the transport belt 11 that runs longitudinally in the transport direction T and circulates on deflection rollers and is otherwise held floating above the plate 12 by an air cushion generated by the nozzles 14 . In contrast to the embodiment of the transport module 04 according to FIGS. 3 and 4, the embodiment variant of the transport device 09 shown in FIG.

Fig. 7 shows a plan view of the loading station 02 shown in Fig. 6. The loading station 02 has a transport device 09 for feeding sheet metal panels 08 lying flat one by one in a transport plane of this transport device 09 to the continuous-flow dryer 17, with the loading station 02 having at least one wire frame 22, the respective wire frame 22 generally being pivotable in a circular manner about an axis of rotation 23 extending transversely to the transport direction T of the metal sheets 08 to be transported. Each of the wire frames 22 is designed in such a way that it travels through the transport plane of the sheet metal panels 08 lying flat therein in a pivoting movement from bottom to top and uses this pivoting movement to erect a flat sheet metal panel 08 to be transported through the continuous dryer 17 vertically from its previous transport plane. In the preferred embodiment of the loading station 02, the central area M of its transport device 09 is parallel to each other two z. B. clocked and decelerating driven conveyor belt 11 arranged z. B. by a suction and / or a magnetic holding force on this transport belt 11 flat metal plate 08 and flat metal plate 08 z. B. up to a transverse to the direction of transport T of the metal sheets 08 to be transported extending stop 24, wherein this stop 24 z. B. is formed by arranged on the axis of rotation 23 rubber buffer. The transport device 09 of the loading station 02 preferably also has—as previously described in connection with FIG. 5—two belt-free edge regions R1; R2, in each of which a nozzle array 13 is formed. A plurality of nozzles 14 are arranged in the respective nozzle arrays 13 to form an air cushion that supports a metal sheet 08 lying flat on the transport belt 11. B. ejects a first subset of blown air in the transport direction T of the metal sheets 08 at an acute angle obliquely outwards and/or z. B. blows out a second subset of blown air vertically upwards in the direction of the underside of a sheet metal plate 08 resting on the transport belt 11 . At the respective wire frame 22 z. B. laterally in the direction of the nearest edge of the transport device 09 in question, which extends longitudinally to the transport direction T of the metal sheets 08, cantilevered arms 26 are arranged, each of which extends into one of the edge regions R1; R2 introduced recess 27 grab. In order to prevent the sheet metal panels 08 to be transported by the transport device 09 from getting caught, these recesses 27 preferably have a bevel 28 running at an acute angle counter to the transport direction T of the metal panels 08 in the direction of the nearest edge of the transport device 09 in question that extends longitudinally to the transport direction T of the metal panels 08 e.g. B. in the form of at least one corresponding edge.

Fig. 8 shows an example of a top view of an unloading station 07 arranged in the production line 01. The transport device 09 of the unloading station 07 is constructed similarly to the transport device 09 of the loading station 02, so that below for the same Components are also used the same reference numerals. The unloading station 07 also has at least one wire frame 22, with the respective wire frame 22 generally being pivotable in a circular manner about an axis of rotation 23 extending transversely to the transport direction T of the metal sheets 08 to be transported, with each of the wire frames 22 being designed in such a way that it travels through the transport plane of the sheet metal panels 08 to be transported with the transport device 09 in a pivoting movement from top to bottom and with this pivoting movement one of the vertically erected metal panels 08 transported through the continuous dryer 17 is deposited flat in the transport plane of the transport device 09 of the unloading station 07. In the preferred embodiment of the unloading station 07, two z. B. synchronously or clocked and accelerated driven conveyor belt 11 arranged z. B. by a suction and / or a magnetic holding force on this transport belt 11 flat metal plate 08 hold. The transport device 09 of the unloading station 07 preferably also has—as previously described in connection with FIG. 5—two belt-free edge regions R1; R2, in each of which a nozzle array 13 is formed. A plurality of nozzles 14 are arranged in the respective nozzle arrays 13 to form an air cushion that supports a metal sheet 08 lying flat on the transport belt 11. B. ejects a first subset of blown air in the transport direction T of the metal sheets 08 at an acute angle obliquely outwards and/or z. B. blows out a second subset of blown air vertically upwards in the direction of the underside of a sheet metal plate 08 lying flat on the transport belt 11 . On the wire frame 22 z. B. laterally in the direction of the nearest edge of the transport device 09 in question, which extends along the transport direction T of the metal sheets 08, cantilevered arms 26 are arranged, each of which extends into one of the edge regions R1; R2 introduced recess 27 grab. In order to prevent the metal sheets 08 to be transported by the transport device 09 from getting caught, these recesses 27 preferably each have an acute angle in the transport direction T of the metal sheets 08 in the direction of the nearest one along the Transport direction T of the metal sheets 08 extending edge of the relevant transport device 09 extending bevel 28 z. B. in the form of at least one corresponding edge.

In summary, the result is a production line 01 for processing metal sheets 08 and a method for operating this production line 01, with this production line 01 having a number of different machine units, with at least one of these machine units being designed as a continuous dryer 17. The continuous-flow dryer 17 is designed in such a way that metal panels 08 to be dried pass through this continuous-flow dryer 17 in a vertical position and generally at a distance from one another, with a loading station 02 for vertically erecting metal panels 08 lying flat in a transport plane of a transport device 09 arranged upstream of the continuous-flow dryer 17 and one through the continuous-flow dryer 17 vertically erected transported metal sheets 08 is arranged in a transport plane of a transport device 09 flat laying unloading station 07. The distance between adjacent metal sheets 08 transported in a vertically upright position by the continuous dryer 17 is only a few centimeters, e.g. B. between 1 cm and 5 cm, in particular less than 3 cm. At least one pressurized fluid has been applied to at least one surface of the sheet metal panels 08 to be dried in continuous-flow dryer 17, i.e. on one side or both sides, in at least one machine unit designed as a sheet metal printing machine 03 and/or in at least one machine unit designed as a sheet metal painting machine 06. The printed and/or coated sheet metal panels 08 are fed individually one after the other to the continuous-flow dryer 17, with these metal sheets 08 being erected vertically from their position in the loading station 02, which would otherwise lie flat in their transport plane in this production line 01, before they are fed to the continuous-flow dryer 17. A vertical erection is here z. B. an erection of the individual metal sheets 08 previously lying flat in the transport plane of the respective transport device 09 with a tolerance of less than ±30°, preferably less than ±15° to the vertical, with this vertical preferably on the transport plane of the respective Transport device 09 is related. After being transported in a vertically upright position through the continuous dryer 17, the metal sheets 08 in the unloading station 07 are laid down flat one after the other in the transport plane of a transport device 09. In the production line 01, metal sheets 08 to be processed in the transport direction T between the continuous dryer 17 and the unloading station 07, in particular, there is also a cooling zone 18 (Fig. 1), e.g. B. in the form of a cooling device, in order to cool down the sheet metal panels 08, which are strongly heated during their passage through the continuous dryer 17, to a significantly lower temperature.

In the preferred embodiment, at least two machine units of this production line 01 are each in their own frame 19; 21 trained. At least two of these machine units each have at least one transport device 09 for transporting at least one metal plate 08 lying flat in the respective transport plane, each of these separately arranged transport devices 09 having at least one transport belt 11 for transporting the metal plate 08 in question. The transport belts 11 of the relevant transport devices 09 are each preferably driven by an electric drive 16, in particular in such a way that transport belts 11 arranged in different transport devices 09 are synchronized with one another in terms of their respective rotational speed, so that metal sheets 08 transported by these transport belts 11 are each at least almost equal amount, d. H. apart from minor permissible tolerances, be transported at the same linear speed. In the transport plane of the metal plates 08 lying flat on the transport belt 11, an air cushion is preferably formed below these metal plates 08 and these metal plates 08 are arranged in a floating manner by the air cushion in their transport plane.

In the production line 01, the machine units of the The loading station 02, the continuous dryer 17, the cooling zone 18 and the unloading station 07 are always linked to one another, and not only by a functional, i.e. control-related, linking of the relevant transport devices 09, but also physically, i.e. mechanically by at least one provided for the transport of the metal sheets 08 traction means 29 z. B. in the form of at least one chain running through preferably all of these machine units. The at least one traction means 29 running through the relevant machine units engages both the pivoting wire frame 22 of the loading station 02 and the pivoting wire frame 22 of the unloading station 07, so that the wire frame 22 in question is coupled to the traction means 29, with the traction means 29 e.g. B. has at least one coupling element 37 (Fig. 1), to which the respective wire frames 22 are attached during the coupling. The at least one traction means 29 running through the relevant machine units is therefore designed to act both on the relevant pivotable wire frame 22 of the loading station 02 and on the relevant pivotable wire frame 22 of the unloading station 07 and to couple the relevant wire frame 22 to the relevant traction means 29. A rotational speed of the traction means 29 running through the relevant machine units and the respective linear speed of the transport belts 11 transporting the metal sheets 08 in the respective transport devices 09 of the production line 01 are coordinated with one another, in particular synchronized with one another, by the machine controller 34.

Especially at a high production speed of several thousand metal sheets 08 per hour, z. B. of at least 6,000 metal sheets 08 per hour, and / or in the case of a large format of the metal sheets 08 to be processed in the production line 01 of z. B. more than 700 mm x 1,000 mm and / or with a small sheet metal thickness of the metal panels 08 of z. B. less than 0.3 mm act on the metal sheets 08 in question at the moment when they are lifted by the respective wire frame 22 of the transport device of the loading station 02, increased acceleration forces. These acceleration forces result in corners of sheet metal panels 08 which are designed to be unstable under the aforementioned circumstances and which do not rest on the respective wire frame 22, bending downwards in the area of the rear edge of sheet metal panels 08 lifted by wire frame 22 as a result of the mass moments of inertia, as a result of gravity and thus get into the area of the transport path, in particular of a subsequent sheet metal panel 08. Since the corners of the raised metal sheet 08 are not supported in this area by the respective wire frame 22 of the transport device of the loading station 02, they can therefore sag. This can lead to a collision with the front edge of that sheet metal panel 08 that immediately follows the sheet metal panel 08 that is about to be lifted by the respective wire frame 22, with the result that production line 01 can be interrupted and/or sheet metal panels 08 can be rejected.

To avoid this potential disruption to operations, a method is proposed for operating a production line 01 for processing metal sheets 08, with production line 01 having a metal sheet printing machine 03 and/or a coating machine 06, with metal sheets 08 being transported in direction T after metal sheet printing machine 03 and/or the coating machine 06, a loading station 02 and, immediately downstream of the loading station 02, a continuous dryer 17 for drying the printed and/or painted metal panels 08. The loading station 02 has a plurality of wire frames 22, each rotating about an axis of rotation 23 extending transversely to the direction of transport T of the metal sheets 08 being transported, these wire frames 22 being arranged one after the other to lift the metal sheets 08 that are fed horizontally to the loading station 02, each individually out of their transport plane, with each of these wire frames 22 is designed in such a way that it travels through the transport plane of the metal sheets 08 in a circular manner from bottom to top in an area in which these metal sheets 08 are each fed individually to the loading station 02, and with this pivoting movement one of the flat ones passes through the continuous dryer 17 to be transported sheet metal 08 erects. The loading station 02 also has z. Am in the transport plane of the metal sheets 08 along the transport direction T formed edge regions R1; R2 each has at least one nozzle field 13, each with a plurality of nozzles 14, with nozzles 14 arranged there being operated in such a way that blown air is blown out of them, preferably vertically upwards against the underside of a sheet metal panel 08. At least a subset of the nozzles 14 that blow the blown air preferably vertically upwards are operated in a clocked manner, with these clocked nozzles 14 being switched on to eject blowing air, while the sheet metal panel 08 in question is taken over and lifted by the wire frame 22, and these nozzles 14 are switched off , before the blown air catches the front edge 46 of that sheet metal panel 08 that immediately follows the sheet metal panel 08 that has just been taken over and raised by the wire frame 22.

9 shows, in a simplified sectional view, an arrangement of at least one cyclically operated nozzle 14 that blows blown air preferably vertically upwards in a loading station 02. A plurality of such nozzles 14 are preferably provided. 9 shows a wire frame 22 of the transport device of the loading station 02 in three different positions, which this wire frame 22 assumes during its pivoting movement about the axis of rotation 23. A sheet metal panel 08 fed to the loading station 02 is preferably transported in its transport direction T by at least one transport belt 11, on which the sheet metal panel 08 in question lies flat, until its front edge 46 reaches the stop 24. In particular, when the front edge 46 reaches the stop 24, the sheet metal panel 08 in question is picked up by the wire frame 22 and pivoted upwards out of the transport plane in which the at least one transport belt 11 is located. As a result, the metal sheet 08 in question is preferably erected at least almost vertically from its previous transport level before it is fed to the continuous dryer 17.

In a preferred embodiment, the blown air are each preferably perpendicular blowing nozzles 14 operated at the top with a blowing pressure adjustable in its strength. The strength of the blowing pressure of the blowing air in each case preferably vertically blowing out nozzles 14 z. B. depending on a production speed of the metal sheets 08 to be processed in this production line 01 and/or depending on a format of the metal sheets 08 to be processed in the production line 01 and/or depending on a sheet thickness of the metal sheets 08 to be processed in the production line 01 adjusted or at least adjustable. To adjust the strength of the blowing pressure of the nozzles 14 that blow the blowing air preferably vertically upwards, a throttle valve 38 is preferably connected to these nozzles 14 on the output side and to a compressed air source 41 on the input side. B. remotely controlled, in particular at a z. B. as a control center of this production line 01 configured machine control 34, and a pressure gauge 39 is provided.

The nozzles 14, which preferably emit blown air vertically upwards, are only switched on to emit blown air when sheet metal panels 08 are being transported through the production line 01 at a production speed greater than a preset minimum speed. The blown air in each case preferably blowing vertically upwards nozzles 14 are z. B. until a preset minimum value is reached for the production speed of the metal sheets 08 to be processed in this production line 01 and/or for metal sheets 08 with a smaller format than a preset minimum format for the metal sheets 08 to be processed in the production line 01 and/or for metal sheets 08 switched off with a greater sheet thickness than a preset minimum sheet thickness for the sheet metal panels 08 to be processed in the production line 01. It can thereby be ensured that the above-described mode of operation of the production line 01 is only active when unstable corners of the metal sheets 08 actually bend. In this way, a breakdown in the production line 01 and/or an interruption in operation and/or the production of scrap metal sheets 08 can be avoided. In addition, the The solution described can be used both on a new production line 01 and for retrofitting in a production line 01 already in use by a customer.

As already mentioned, even with a constant production speed in the production line 01, due to disruptive influences such as e.g. B. a changing traction behavior between the respective metal plate 08 to be transported and the at least one transport belt 11 carrying the metal plate 08 in question, the free distance between successively transported metal plates 08, i. H. the distance between the rear edge of a first metal plate 08 and the front edge 46 of a second metal plate 08 immediately following the first metal plate 08 can change, so that the synchronization point shifts, which means that in particular the front edge position of a metal plate 08 currently fed to the loading station 02 also changes relatively to an end of that wire frame 22 of the transport device of this loading station 02 that faces this metal sheet 08, which wire frame 22 is provided for taking over the metal plate 08 currently being fed and which, precisely because of its pivoting movement, moves into the area in which it takes over the metal plate 08 currently being fed to the loading station 02 should. This is because all of the sheet metal plates 08 fed to the loading station 02 must be reliably picked up one after the other by one of the several wire frames 22 rotating about the axis of rotation 23 and lifted in good time as a result of the pivoting movement of the respective wire frame 22 before a metal plate 08 immediately following the currently lifted metal plate 08 in enters the effective range of another wire frame 22 . Otherwise, there will be disruptions in the transport of the metal sheets 08 and, as a result, production will be interrupted on the production line 01.

As can be seen from FIG. 10, in order to avoid this cause of the fault, it is proposed that a first detection device 42 and a second detection device 43 be provided in or on the loading station 02, the first Detection device 42 and the second detection device 43 are each signal-connected to a preferably digital control unit 44 . The first detection device 42 detects a first point in time at which one of the wire frames 22 of the transport device of the loading station 02 assumes a specific rotational angle position in relation to the transport plane of the metal sheets 08, with the first detection device 42 sending a first signal representing the detected first point in time to the control unit 44 . The first detection device 42 can be arranged at different positions in the loading station 02, which is indicated in FIG. 10 by a second alternative installation position. The second detection device 43 detects a second point in time at which the front edge 46 of the metal plate 08 currently fed to the loading station 02 reaches a specific position, this position in the transport plane of this metal plate 08 in the transport direction T of this metal plate 08 in front of an end of the metal plate 08 facing this metal plate the wire frame 22 provided for taking over this sheet metal panel 08, the second detection device 43 sending a second signal representing the detected second point in time to the control unit 44. Control unit 44 is designed in such a way that it determines an actual value for a time difference AT between the first point in time and the second point in time and compares this actual value with a target value specified for the time difference AT, preferably stored in control unit 44, and determines a deviation of the actual value from the target value , wherein the control unit 44 reports a deviation of the actual value from the target value that is outside permissible tolerance limits and/or a display device 48 z. B. graphically and / or numerically. This control unit 44 can, for. B. also integrated into the machine control 34 of the production line 01. The first detection device 42 and the second detection device 43 are preferably each designed as a non-contact sensor.

In a preferred embodiment, a signal connected to the control unit 44 controls the pivoting movement of the wire frame 22 about the axis of rotation 23 driving z. g. as an electric motor, control unit 44 is designed to control at least this drive 47 in the event that the actual value deviates from the setpoint value outside of permissible tolerance limits in such a way that the wire frame 22 that is required to take over the next loading station 02 supplied metal sheet 08 is provided, pivots at such a point in time into the transport plane of this next metal sheet 08, so that for this next metal sheet 08 the actual value of the time difference AT is again within the permissible tolerance limits. The permissible tolerance limits are e.g. B. in the single-digit percentage range of the target value or even below. In a particularly preferred embodiment, the drive 47 that pivots the wire frame 22 about the axis of rotation 23 is identical to the drive 32 that drives the traction mechanism 29, with the traction mechanism 29 being arranged to run through at least the loading station 02 and the continuous-flow dryer 17 downstream of it. This latter embodiment is very advantageous if the traction means 29 acts on the swiveling wire frame 22 in question of the loading station 02 and is designed to produce a preferably mechanical coupling of the wire frame 22 in question with the traction means 29 in question.

The control unit 44 can be designed in such a way that it determines several actual values for a time difference AT between the first point in time and the second point in time and sorts out an implausible actual value before it compares the actual values with the setpoint value specified for the time difference AT. The control unit 44 can also preferably be designed in such a way that it can also control upstream components of the production line on the drive 47, e.g. B. the loading station 02 or the painting machine 06 or acts on a virtual drive axis acting on several machine units of the production line.

The solution described makes it easier to set the optimum synchronization point for the feed of metal sheets 08 to the loading machine 02 when the production conditions. It also helps to avoid metal panels 08 colliding with the wire frames 22, which in turn avoids production stoppages and metal panels 08 rejects. This solution can also be retrofitted to old systems.

As already explained, one point in the production line 01 that is unfortunately very prone to failure with regard to the production process is the loading machine 02 upstream of the continuous-flow dryer 17. Because each of the sheet metal plates 08 transported through the production line 01 must be taken over in good time by one of the wire frames 22 at the loading machine 02 and be raised before a next sheet metal 08 enters the pivoting range of the wire frame 22. If this is unsuccessful, at least one of the metal panels 08 following a metal panel 08 that has just been picked up will abut against the end of the wire frame 22 facing the front edge of this metal panel 08, which has received the immediately preceding metal panel 08. Unfortunately, such a collision and thus a disruption in the production process of this production line 01 can even occur when the synchronization point for the upstream metal printing machine 03 or metal painting machine 06 is optimally set.

At the same time, the comparatively highest forces act on the relevant wire frame 22 in the pivoting range of the respective wire frame 22 of the loading machine 02, with each of these wire frames 22 being flexible due to their filigree construction. As a result of this flexible design of the wire frames 22, it can happen that one of these wire frames 22, which is actually rotating about the axis of rotation 23, remains in a position that is in the transport plane of the metal sheets 08 at a time when the wire frame 22 in question is just one of the loading machine 02 supplied sheet metal 08 has taken over. As already mentioned, metal sheets 08 can then collide and thus disrupt the production process of this production line 01. One reason for the delayed lifting of a sheet metal panel 08 that has just been picked up by one of the wire frames 22 can be that individual wire frames 22 are slightly bent. Even a slight game of wire frame 22 in the z. B. each configured as a receiving bore coupling element 37 on the traction means 29 configured as a transport chain running through the loading machine 02 and the downstream continuous dryer 17 as a result of wear or manufacturing inaccuracies can lead to a delayed lifting of individual wire frames 22. Slight irregularities in the guidance or in the deflection of the traction means 29 can also result in the wire frame 22 being raised unevenly and with jerking, and as a result individual sheet metal panels 08 are raised belatedly. The stated causes of a malfunction become particularly evident when, on top of that, sudden load changes and stresses act on the wire frame 22, as is the case due to the additional weight of the sheet metal panels 08 being held together with the retroactive acceleration forces on the loading machine 02.

At a high production speed of several thousand metal sheets 08 per hour, e.g. B. of at least 6,000 metal sheets 08 per hour naturally increase as well as heavy metal sheets 08 with a mass of z. B. more than 2 kilograms, the forces acting briefly on the wire frame 22 at the time of recording these metal sheets 08, which leads to an elastic deformation of the flexible wire frame 22 and subsequently to a mechanical vibration of the wire frame 22. In the worst case, these vibrations can damage the freshly printed and/or painted surface of these sheet metal panels 08. At the same time, the times available for the loading process are reduced at higher speeds, which further increases the problem of deformation of the flexible wire frame 22 and/or vibrations that occur. In order to improve the functional reliability of the loading machine 02 and thereby ensure less fault-prone operation of the production line 01, it is proposed to provide a lifting device in the loading machine 02 for its wire frame 22. This lifting device has the advantage that it supports the flexible wire frame 22 when a sheet metal panel 08 that has been taken over is lifted and absorbs part of the acceleration forces acting on the wire frame 22 in question, thus at least largely preventing elastic deformation of the wire frame 22 and its mechanical oscillation. Such a lifting device contributes to the fact that the weight of the wire frame 22 can be further reduced, as a result of which energy can ultimately be saved in the continuous dryer 17 .

As can be seen from FIG. B. by means of clocked compressed air nozzles 49, these compressed air nozzles 49 in the loading machine 02 below the transport level of an accrued, i. H. the metal sheet 08 fed to the loading machine 02 and are operated in such a way that they blow the underside of the metal sheet 08 to be lifted, preferably vertically upwards, with a brief blast of pressure at the moment when the metal sheet 08 in question is taken over by the wire frame 22 in question. Although this design of the lifting device does not act directly on the wire frame 22, but only indirectly, it does support the lifting of the relevant sheet metal panel 08.

A second embodiment of the lifting device is also shown by way of example in FIG. B. clocked electromagnets 51 arranged just above the transport plane of an approaching sheet metal panel 08, in particular in the area of at least one spacer 52, the spacer 52 in question being arranged on the end of each wire frame 22 facing away from the axis of rotation 23. These electromagnets 51 are switched clocked by a control unit 53 and support the wire frames 22 by means of a magnetic force that attracts the wire frames 22 . Alternatively, these clocked electromagnets 51 could also be arranged below the transport plane of an incoming sheet metal panel 08 and have a supporting effect by means of a magnetic force repelling the wire frame 22 . The electromagnets 51 switching control unit 53 is z. B. integrated in the machine control 34 of the production line 01.

In a third embodiment of the lifting device—as shown by way of example in FIG. 12—at least one z. B. rotating cam 54 is provided, wherein the relevant cam 54 mechanically lifts the relevant wire frame 22 and the relevant cam 54 is cyclically pivoted away, while a metal plate 08 enters the loading machine 02.

According to a fourth embodiment shown in Figs. 13a (longitudinal section) and 13b (cross-section) as well as Figs. 14a (longitudinal section) and 14b (cross-section) only in sketches, the lifting device is designed as a lifting device, which is below the transport level of an approaching metal sheet 08 is arranged on the loading machine 02 and which lifts at least one of the longitudinal rods 59 or longitudinal bars 59 of the wire frame 22, preferably in the middle region, in a form-fitting manner. This lifting device can, for example, take the form of a cyclically moved lever 57, in particular one equipped with a roller 56 at its free end, which rotates about an axis of rotation 61 preferably in the transport direction T of the metal sheets 08, or a lever 57 that moves at an angle to the underside of the metal sheets 08 to be lifted by the relevant wire frame 22 on its free end end also z. B. equipped with a roller 56 ram 58, wherein preferably a cyclic traversing of the lever 57 or the ram 58 transverse to the transport direction T of the metal sheets 08 is provided in order to move the lever 57 or ram 58 after the currently raised wire frame 22 has been lifted to move the pivoting range of the following wire frame 22. The cyclic axial traversal of the lever 57 is indicated by a double arrow in FIG. 13b implied. In FIGS. 14a and 14b, the lifting movement of the plunger 58 is indicated in each case by a double arrow.

An essential advantage of the lifting device mentioned is that the flexible wire frames 22 do not have to apply the force to lift the sheet metal panels 08 alone.

In order to make the transport of the metal sheets 08 even more efficient, in particular through the continuous dryer 17, it is proposed that the loading station 02 in the described production line 01 for processing metal sheets 08 be designed in such a way that metal sheets 08 that are fed to it one after the other are each loaded individually in one of several in the loading station 02 loosely provided wire frame 22 are arranged, and to provide an endlessly revolving at least the continuous dryer 17 continuous traction means 29 with at least one coupling element 37, wherein the z. g. as a coupling element 37 configured as a suspension bracket, acting on the wire frame 22 in question received on one of the sheet metal panels 08 and producing a coupling of the wire frame 22 in question with the traction means 29, with the wire frame 22 through the continuous dryer 17, the wire frame 22 in question, which is accommodated in the sheet metal panel 08, is coupled in a hanging manner on the lower strand of the traction means 29 and is arranged at its lower end so that it is supported on a support 62, with the wire frame 22 arranged in a hanging and supporting manner in this way being in an inclined position at an angle W in the region between 10° and 45° from the vertical. The inclined position of the hanging and supporting arranged wire frame 22 can vary in its operating state of passage through the continuous dryer 17 along the transport route through this continuous dryer 17 and can assume different angles W at different positions of this transport route. The hanging on the lower run of the traction means 29 to be coupled wire frame 22 has z. B. one Locating bolts for latching into the suspension brackets of the traction mechanism 29. The respective lower end of a metal sheet 08 recorded wire frame 22 supporting support 62 is z. B. as a permanently installed rail or as a with the traction means 29 preferably synchronously revolving support system z. B. in the form of a belt. The inclined position of the hanging and supporting arranged wire frame 22 ensures the stability of the metal sheets 08 transported in this way, to the extent that these metal sheets 08 neither sink nor bulge in the respective inclined position. The particularly efficient design of the production line 01 proposed here is illustrated in FIG. 15 by way of example.

This configuration of production line 01 has the advantage that, in contrast to wire frames 22 designed to rotate about an axis of rotation 23, the wire frames 22 hanging on the lower strand of traction means 29 can be designed to be very filigree, so that only a very small mass has to be moved Operation of production line 01 leads to energy savings. In addition, when transporting by means of a wire frame 22 suspended from the lower run of the traction means 29, the sheet metal panels 08 fed to the loading station 02 do not have to be completely reduced in their transport speed before they are taken over by the relevant wire frame 22, in contrast to transport by means of a wire frame 22 designed to rotate about an axis of rotation 23 be slowed down, so that the production line 01 can be operated with a higher throughput of metal sheets 08. In addition, wire frames 22 suspended from the lower run of the traction means 29 reduce the risk of a sheet metal panel 08 being transported being damaged on the printed and/or painted surface, e.g. B. by vibrations in a contact zone between the relevant sheet metal 08 and wire frame 22 damage.

As already described, the loading station 02 for loading the continuous dryer 17 with the printed and/or painted metal panels 08 is arranged directly in front of the continuous dryer 17 in the transport direction T of the metal panels 08. Furthermore An unloading station 07 for unloading the metal sheets 08 transported through the continuous dryer 17 is preferably arranged immediately downstream of the continuous-flow dryer 17, the unloading station 07 being designed in such a way that it detaches the relevant wire frame 22 transporting the metal sheet 08 from the lower run of the traction means 29. In a preferred development, a transport device 63 that is independent of the traction device 29 is also provided, with this transport device 63 being configured to transport wire frames 22 that have been detached from the lower run of the traction device 29 and are thus detached at the unloading station 07, individually or stacked or shingled, back to the loading station 02. In FIG. 15, the return transport of the wire frames 22 unhooked and unloaded in the unloading station 07 is indicated by directional arrows. In the unloading station 07, the wire frames 22 transported through the continuous dryer 17 are automatically unhooked from the lower run of the traction means 29 and returned to the loading station 02 by means of the transport device 63. The metal sheets 08 can be placed in the unloading station 07 either with their printed and/or painted surface facing up or down and from there they can be transported on to the production line 01.

The wire frame 22 hanging transporting traction means 29 is z. B. formed by two mirror-image chains, these chains being driven synchronously via a plurality of shafts 31 each having gear wheels, with two of these shafts 31 being arranged at the ends of the transport route spanned by these chains through the production line 01.

In a particularly efficient configuration of the production line 01 - as shown by way of example in Fig. 16 - at least two traction means 29 are provided, which are arranged vertically one above the other and each run through at least the continuous-flow dryer 17, with these traction means 29 in different configurations extending through the relevant continuous-flow dryer 17, preferably horizontally extending planes are arranged and at least one of these traction means 29 transported hanging from him Wire frame 22 each having a supporting pad 62. In this configuration of the production line 01, the loading station 02 has a diverter 64, this diverter 64 being designed to selectively feed metal sheets 08 fed to the loading station 02 to one of the traction means 29 arranged vertically one above the other. The switch 64 is z. B. upstream of the loading station 02 or designed as part of the loading station 02. The assignments of sheet metal plates 08 to the individual traction means 29 arranged vertically one above the other, which can be carried out by the switch 64, are indicated in FIG. 16 by arrows. This special configuration of the continuous-flow dryer 17 with at least two traction means 29 arranged vertically one above the other has the advantage that the length of the transport route through the relevant continuous-flow dryer 17 is reduced in comparison to the configuration with a traction means 29 in only a single plane running through the relevant continuous-flow dryer 17, in particular horizontally can be shortened.

Reference List

01 production line

02 loading station

03 Tin printing machine

04 transport module

05

06 Tin painting machine

07 unloading station

08 sheet metal

09 transport device

10

11 transport straps

12 plate

13 nozzle field

14 nozzle

15

16 drive

17 continuous dryer

18 cooling zone

19 frame

20

21 frame

22 wire frames

23 axis of rotation

24 stop

25

26 arms

27 recess bevel

traction means

Wave

drive

rail

machine control

roller

Coupling element throttle valve manometer

compressed air source first detection device second detection device control unit

leading edge

drive

Compressed air nozzle display device

Electromagnet spacer control unit cam

role 7 lever 8 plunger 9 longitudinal rod; Longitudinal beam 0 1 axis of rotation 2 support 3 transport device 4 points

B width

B11 width

B12 width

L length

L12 length

M mid range

R1; R2 edge area

T transport direction

W angle

Claims

34 claims

1. A method for operating a production line (01) for processing metal sheets (08), with a metal plate printing machine (03) and/or a coating machine (06) and with a continuous dryer (17) for drying the printed and printed metal plates with the metal plate printing machine (03). /or metal panels (08) painted with the painting machine (06), with a loading station (02) for loading this continuous dryer (17) with the printed and/or painted sheet metal panels (08), the loading station (02) having a plurality of wire frames (22) rotating around a rotation axis (23) extending transversely to the transport direction (T) of the metal panels (08) being transported, the wire frames (22) being arranged one after the other horizontally transported sheet metal panels (08) are each arranged to be lifted individually out of their transport plane, each of these wire frames (22) being designed in such a way that it is the transport plane of the metal panels (08) in an area in which these metal panels (08) each individually reach the loading station (02) are fed, travels through them in a circle from bottom to top and with this pivoting movement one of the flat sheet metal panels (08) to be transported through the continuous dryer (17) is erected, with the loading station (02) having several nozzles in the transport plane of the metal panels (08). (14), these nozzles (14) being operated in such a way that blown air is blown from them in each case against the underside of a sheet metal panel (08), characterized in that at least some of the nozzles (14) blowing out the blown air are operated in a clocked manner are switched on, these cyclically operated nozzles (14) being switched on while the sheet metal panel (08) in question is taken over and lifted by the wire frame (22), and these cyclically operated nozzles (14) being switched off before their blown air hits the front edge of that sheet metal panel ( 08) recorded, which immediately follows the metal plate (08) that has just been taken over and raised by the wire frame (22). 35 Method according to claim 1, characterized in that the nozzles (14) blowing out blown air in a clocked manner are operated with an adjustable blowing pressure. Method according to Claim 2, characterized in that the strength of the blowing pressure of the nozzles (14) blowing out the blowing air in a clocked manner as a function of a production speed of the sheet metal panels (08) to be processed in this production line (01) and/or as a function of a format of the in sheet metal panels (08) to be processed on the production line (01) and/or depending on a sheet metal thickness of the metal panels (08) to be processed on the production line (01) or at least adjustable. Method according to Claim 2 or 3, characterized in that a throttle valve (38) is provided to adjust the strength of the blowing pressure of the nozzles (14). Method according to Claim 4, characterized in that the throttle valve (38) is connected to a compressed air source (41) and that a pressure gauge (39) is provided, the throttle valve (38) being remote-controlled and/or on a machine control (34) of this production line (01) is adjustable. Method according to Claim 1 or 2 or 3 or 4 or 5, characterized in that the cyclically operated nozzles (14) are only switched on to emit blown air when sheet metal panels (08) are being transported through the production line (01) at a production speed greater than a preset minimum speed become. The method of claim 1 or 2 or 3 or 4 or 5 or 6, characterized in that the clocked operated nozzles (14) until reaching a preset minimum value for the production speed of the metal sheets (08) to be processed in this production line (01) and/or for metal sheets (08) with a smaller format than a preset minimum format for the metal sheets (08) to be processed in the production line (01) and/or or switched off for metal sheets (08) with a greater sheet thickness than a preset minimum sheet thickness for the metal sheets (08) to be processed in the production line (01).