Sheet metal working device with a feeding device and a method for use in the sheet metal working device

Abstract

The invention relates to a sheet metal processing device (1) for high-speed punching or pressing operations, comprising at least one tool (9) for carrying out cutting / forming processes and a feed device (3), in particular a continuous feed device, for rolled products (2) with a device (6) for detecting defects (7). A control unit identifies the position and contour of the affected area and derives a boundary (8) encompassing the defect (7) as a circumferential line. The control unit tracks the respective changes in the position of the defect (7). If the punching or pressing operation includes a processing area (10) that overlaps at least slightly with the previously defined boundary (8), including any defined safety distance, the defective products (11) thus produced are discharged at a reject station (12).This means that such ribbon-shaped products (2) are also suitable for the production of defect-free products (13) where local defects (7) cannot be reliably excluded.

Description

[0001] The invention relates to a sheet metal processing device for rapidly cycled punching or pressing processes with at least one tool for carrying out separating / forming processes and with a particularly continuous feeding device for rolled products, provided as a wound material supply, furthermore to a feeding device for such a sheet metal processing device and a method for use in the sheet metal processing device.

[0002] Such sheet metal processing devices, designed as high-speed presses, for example, in the form of an eccentric press, or as high-speed punches, are used when very large quantities of thin sheet metal are to be processed. They enable particularly high stroke rates and correspondingly fast cycle times. Due to the low material thickness, a low stroke height is sufficient for these sheet metal processing devices.

[0003] A typical product for high-speed punching and high-speed presses is the stator and rotor laminations of electric motors and generators, which require a large number of identically shaped laminations. This requires equipment and production processes designed for high-volume production with consistent quality. Even small deviations in tolerance can lead to eddy currents, which can trigger overheating in an electromechanical component.

[0004] DE 10 2019 113 290 A1 discloses a method for manufacturing an electromagnetic component intended for an electrical machine, such as an electric motor or a generator, in particular a laminated core as a stator core or rotor core. An adhesive is applied to the laminations punched from a sheet metal sheet and monitored using a thermal imaging camera or a layer thickness measurement system, which also enables the detection of holes in the electrical steel strip. A light source can also be used for hole detection, which a sensor detects and automatically removes the lamination from the process.

[0005] DE 42 44 694 A1 relates to a method for producing stamped parts for an electrical machine from a material that is unrolled from several drums and runs into a stamping machine in which segments are stamped out and defective parts are sorted out.

[0006] EP 3 477 248 A1 relates to a method for fault analysis of transformer laminations using an inspection system comprising an optical detection device, a conveyor device, and a processing device. A measuring device measures the movement speed of the transformer lamination and captures an image of the transformer lamination's contour.

[0007] Due to the manufacturing process of rolled products, defects cannot be completely ruled out in practice. These are typically identified during the product manufacturing process, and if necessary, a section of the strip-shaped product affected by the defect is cut out. The end pieces are then welded together. This means that products can enter the machining process whose properties may deviate only slightly due to the aforementioned weld, but which could lead to intolerable defects in the resulting product. Such defects are particularly detectable in the rotors or stators manufactured from them, or in the electrical machine manufactured from them.

[0008] To reliably exclude such error influences, the strip-shaped products are therefore only processed in flawless, unwelded lengths. In practice, products of varying lengths as coiled stock lead to logistical problems, particularly production interruptions due to frequent stock changes, and are therefore fundamentally undesirable.

[0009] Against this background, the invention is based on the object of designing a sheet metal processing device of the type mentioned above in such a way that defective products are reliably excluded from the subsequent manufacturing process when processing products with potential defects, while simultaneously achieving efficient material utilization. Furthermore, a correspondingly improved feeding device for such a sheet metal processing device and a method for use with the feeding device are to be created.

[0010] The first-mentioned object is achieved with a sheet metal processing device according to the features of patent claim 1. The subclaims relate to particularly expedient developments of the invention.

[0011] According to the invention, a sheet metal processing device is therefore provided in which the feeding device is equipped with a device for detecting defects and the sheet metal processing device is set up by means of a control unit for detecting the position and / or the area and for determining a virtual boundary enclosing at least one of the defects as a boundary line in relation to the product, wherein the control unit can detect the position of the product with the boundary within the sheet metal processing device relative to the tool, which position has been changed as a result of the feed movement, and a possible at least section-wise superimposition of the boundary with at least one processing area affected by the separating or forming process.The invention is based on the idea that the manufacture of products and the electrical machines or devices manufactured therefrom can be improved in a particularly efficient manner if the product is checked or examined for possible defects before processing in the sheet metal processing device in order to exclude the correspondingly identified areas within their respective boundaries from punching or pressing or further processing. If it is not possible, or only possible with great effort, to suspend the punching or pressing process for these limited areas or to restrict it to the areas outside the boundaries, the produced products can be excluded from further processing without further examination, which eliminates the need for complex quality checks in subsequent production steps and eliminates potential sources of error.In summary, the invention is based on excluding detected or known defects in a surface section within the boundary defined by the material supplied from further processing or on rejecting the products affected by them. In contrast to the prior art, in which quality control is performed on the basis of the products already manufactured, the invention generally excludes products with defects from further processing. This makes it possible to process even products containing defects because the corresponding surface sections do not enter the production process, whereby data on already detected defects can be taken into account. As a result of the multiple quality controls thus realized, high product quality requirements can be reliably met.Particular advantages also lie in the possibility of using products with defects, which were previously generally not considered due to their problematic effects on the final product. For example, this makes it possible to use strip-shaped products, especially those of comparatively short length, joined with several weld seams to achieve a sufficient overall length, for the production of these products.

[0012] Particularly preferably, the feed is controlled in such a way that the products are manufactured in a region of the product outside the boundary, wherein a transverse displacement of the tool transversely to the feed direction relative to the strip-shaped product can also be provided in order to exclude the regions enclosed by the boundary from processing.

[0013] One embodiment of the invention has proven particularly promising in which the sheet metal processing device has at least one discharge station for punched and / or pressed products. Using the discharge station, the previously identified products can be either transported for disposal or to a measuring or testing station, where compliance with relevant parameters or any deviations from predetermined criteria are checked.

[0014] Another particularly promising embodiment of the invention is also achieved by the feed device having a joining device for creating a material-to-material bond by fusing the supplied material from a first material supply with the material from a second material supply. This allows the sheet metal products wound on various coils to be welded, for example, using the joining device integrated into the feed device, thus enabling a continuous, uninterrupted production process. The self-generated connecting line is considered a defect, and corresponding products are removed.

[0015] For this purpose, a wound material supply is preferably provided in a receptacle of the feeding device, wherein an intermediate winding can be produced in a manner known per se on a separate reel on which a material reserve is stored in order to be able to carry out the connection of the material ends of the strip-shaped products provided on different reels by the joining device during a brief standstill of the products in the joining area, while the process can be continued uninterrupted and the strip-shaped product can be fed to the tool for processing with continuous feed.

[0016] In principle, all impairments or deviations from target values ​​relevant to the product to be manufactured can be recorded as defects by the device for detecting defects. In another, likewise particularly preferred embodiment of the invention, visible or invisible markings on the product, in particular limitations with regard to existing defects and those detected by previous inspection methods, are taken into account by the device. As a result, the impairments detected in a previous process, for example during the rolling process of the product, which are applied to the product as visually or otherwise readable markings, can be identified by the device through the defect detection and subjected to an evaluation with regard to the product to be manufactured.Such markings may be limited to simple position markers, where, for example, the type and origin of the impairment may be unknown. Furthermore, information about the impairment may be available, for example, via a barcode or QR code. Furthermore, at least one marker may be a starting position, for example, as a running marker, so that the coordinates of defects relative to this marker can be provided as data records.

[0017] In a particularly practical embodiment, the feed device is designed to mark at least one defect on the product. The associated products can thus be identified at any time in a subsequent station based on the marking and immediately forwarded there for disposal or other recycling or to an inspection station. This eliminates the need for an ejection station integrated into the sheet metal processing device. The marking, for example, a paint or laser marking, can also be designed in such a way that it can be easily visually detected by people, thus preventing any unintentional use of products classified as defective.

[0018] The object according to the invention is further achieved with a method for use in the sheet metal processing device or the feeding device by a method for sheet metal processing, in which defective products are excluded from a subsequent manufacturing process by processing products with possible defects, in that at least the position and / or the area of ​​existing defects is detected by means of a control unit and a virtual boundary enclosing the defect is determined, so that the position of the boundary within the sheet metal processing device relative to the tool, which has been changed as a result of the feed movement, and an at least partial overlap of the boundary with the processing area affected by the separating or forming process and / or the contour of the product is detected.This avoids sources of error resulting from defects in the sheet-like product on the final product. These defects, if relevant to the product, are classified as defects. By tracking the respective changed position, taking into account the known feed movement in the tool's machining area, it is determined whether the defect is at a sufficient distance from the product. If such a distance cannot be maintained, the corresponding product is excluded from further processing. This results in an upstream shift in quality control based on the supplied material in the form of the strip-like product. This, of course, does not preclude additional downstream quality control, and is therefore suitable for reliably meeting increased quality requirements.

[0019] One embodiment of the invention has proven particularly promising in which punched and / or pressed products are discharged that have a distance from at least one boundary to a processing area, the cutting / forming area, that is less than a minimum distance. This allows for a sufficient safety margin to be taken into account, which is determined by the control unit depending on the type and / or size of the defect. This allows for a qualitative assessment of the defect and the resulting boundary.

[0020] The invention permits numerous embodiments. To further clarify its basic principle, one of them is illustrated in the drawing and described below.

[0021] This shows a schematic diagram of the manufacturing process using the sheet metal processing device 1 according to the invention. The starting material for the manufacturing process is a strip-shaped product 2 in the form of a material supply 15 wound on a spool. Alternatively, cut strips of a specific length can also be used. The sheet metal processing device 1 can be used for processing any material thickness that can be punched by a press, with thin strip-shaped products 2 with a thickness of less than 0.5 mm being particularly suitable.

[0022] The sheet metal processing device 1 can process materials of different quality, thickness, properties and coating.

[0023] In the manufacturing process, the strip-shaped product 2 is first processed in a feeding device 3 in the feed direction V in a straightening station 4 and, after passing through a cleaning station 5, is fed to a device 6 for detecting defects 7. By means of a control unit (not shown), the position and contour of the affected area are identified and a boundary 8 enclosing the defect 7 is derived from this as a circumferential line. According to the invention, the feed V is not interrupted; rather, the synchronized punching or pressing processes are continued in a tool 9 of the sheet metal processing device 1. The respective changed position of the defect 7 is tracked by means of the control unit.If the punching or pressing process includes a processing area 10 that at least slightly overlaps the previously defined boundary 8, including a possibly defined safety distance, the defective products 11 thus produced are sent to a discharge station 12 for a merely sketchy follow-up inspection or for disposal. This makes even strip-shaped products 2 that have local defects 7 suitable for the production of defect-free products 13.

[0024] According to a suitable option, the feed device 3 can be provided with a joining device 14 for creating a material-to-material connection between the fed strip-shaped product 2 of a first material supply 15 and the same product 2 of a second material supply 15. For this purpose, the strip ends of the products 2 are machined by a cutting device 16 and then brought into a position where they abut one another at the end face, so that they can be joined by a weld.

[0025] Material residues 17 of the product 2 are separated in a disposal station 18, which can also be designed as an alternative discharge station for the products 11 identified as defective List of reference symbols 1 sheet metal processing device 2 Product 3 Feeding device 4 alignment station 5 cleaning stations 6 Furnishings 7 defects 8 Limitation 9 Tools 10 Editing area 11 Product 12 Discharge station 13 Product 14 Joining device 15 Material stock 16 Separator 17 material residues 18 disposal station V feed movement QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2019 113 290 A1

[0004] DE 42 44 694 A1

[0005] EP 3 477 248 A1

[0006]

Claims

[1] Sheet metal processing device (1) with at least one tool (9) for carrying out separating and / or forming processes and with a particularly continuous feeding device (3) for rolled products (2), provided as a wound material supply (15), characterized byin that the feed device (3) is equipped with a device (6) for detecting defects (7) and the sheet metal processing device (1) has a control unit for detecting the position and / or the area and for determining a boundary (8) enclosing at least one defect (7) in relation to the product (2), wherein the control unit can detect the position of the product (2) with the boundary (8) within the sheet metal processing device (1) relative to the tool (9), which position has been changed as a result of the feed movement (V), and a possible at least partial overlap of the boundary (8) with at least one processing area (10) affected by the separating and / or forming process. [2] Sheet metal processing device according to claim 1, characterized by that the sheet metal processing device (1) has at least one discharge station (12) for punched and / or pressed products (11, 13). [3] Sheet metal processing device (1) according to claim 1 or 2, characterized by that the feeding device (3) has a joining device (14) for producing a material-locking connection of the fed product (2) of a first material supply (15) with a second material supply (15). [4] Sheet metal processing device (1) according to at least one of the preceding claims, characterized by that the feeding device (3) of the sheet metal processing device (1) has a receptacle for several products (2), each provided as a wound material supply (15). [5] Sheet metal processing device (1) according to at least one of the preceding claims, characterized by that by means of the device (6) markings on the product, in particular limitations (8) with regard to existing defects (7), can be detected. [6] Sheet metal processing device (1) according to at least one of the preceding claims, characterized bythat the feeding device (3) is designed to introduce at least one marking on the product (2). [7] Feeding device (3) for a sheet metal processing device (1) according to at least one of the preceding claims. [8] Method for sheet metal processing by means of a sheet metal processing device (1) according to at least one of the preceding claims, in which defective products (11) as a result of processing products (2) with defects (7) are excluded from a subsequent manufacturing process by detecting at least the position and / or the area of ​​a defect (7) by means of a control unit and determining a boundary (8) enclosing the defect (7), so that the changed position of the boundary (8) within the sheet metal processing device (1) relative to the tool (9) as a result of the movement of the product (2) in the direction of the feed movement (V) and an at least partial overlap of the boundary (8) with the processing area (10) affected by the separating and / or forming process and / or the contour of the product (11, 13) is detected. [9] Method according to claim 8, characterized bythat punched and / or pressed products (11) are discharged which have a distance from at least one boundary (8) to a processing area (10) which is less than a minimum distance. [10] Method according to claim 8 or 9, characterized by that data relating to the defects (7) and / or the contour, in particular position data, from previously recorded position data of the defects (7) are processed by means of the control unit.

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