METHOD FOR OPERATING A PROCESSING INSTALLATION WITH A MOVABLE PUNCH

Abstract

The invention relates to a method for operating a processing installation (1) including a first processing machine (2), the first processing machine (2) comprising at least one movable punch (5) for separating, preferably punching or punch broaching, a workpiece (8), the method comprising the following steps: contactlessly, preferably optically, detecting a contour of a cut surface produced on the workpiece (8) by the punch (5) by means of at least one sensor unit (12) mounted on the processing installation (1), wherein the detecting is performed in-line in the processing installation (1) and consequently without removing the workpiece (8) from the processing installation (1), and evaluating the condition of the cut surface on the basis of the data detected by the sensor unit (12).

Claims

1. A method for operating a processing installation including a first processing machine, said first processing machine comprising at least one movable punch for separating, preferably punching or punch broaching, a workpiece, said method comprising the following steps: contactlessly detecting a contour of a cut surface produced on said workpiece by said punch by means of at least one sensor unit mounted on said processing installation, wherein the detecting is performed in-line in said processing installation and consequently without removing said workpiece from said processing installation, and evaluating the condition of the cut surface on the basis of the data detected by said sensor unit.

2. The method according to claim 1, wherein said workpiece is moved during detecting by said sensor unit in said processing installation and/or rests between two clocked movements.

3. The method according to claim 1, wherein said punch separates said workpiece into a punched strip and a punched piece, said workpiece is transported in said processing installation by means of a transport means through said first processing machine and, after said first processing machine, said punched strip is transported to a further processing machine or an end of said processing installation, and wherein said sensor unit detects the contour of the cut surface while said punched strip is moved by means of said transport means and/or rests on said transport means between two clocked movements.

4. The method according to claim 1, wherein said sensor unit is moved for detecting the cut surface in parallel to a cut surface axis and/or angled to the cut surface axis and/or in a rotatory manner.

5. The method according to claim 1, wherein said first processing machine comprises a tool carrier for receiving said at least one punch, said sensor unit being arranged on said tool carrier.

6. The method according to claim 1, wherein said punch presses a punched piece from said workpiece into a hollow die, wherein said sensor unit detects the contour of the cut surface while said punched piece is located in said hollow die.

7. The method according to claim 1, wherein the cut surface has a height parallel to a cut surface axis, wherein at least 50% of said height of the cut surface is detected with said sensor unit and then evaluated.

8. The method according to claim 1, wherein a plurality of cut surface regions of the cut surface are detected and then evaluated with said sensor unit; and wherein the plurality of cut surface regions comprise an edge indentation region and/or a smooth cut region and/or ta fractured surface region and/or a burr region.

9. The method according to claim 1, wherein the detected data of said at least one sensor unit are evaluated in a computing unit, and wherein said processing installation, is controlled by said computing unit based on the condition of the cut surface.

10. A processing installation for carrying out the method according to claim 1, comprising: a first processing machine including at least one movable punch for separating a workpiece, and at least one sensor unit on said processing installation which is configured to contactlessly detect a contour of a cut surface produced by said punch on said workpiece and which is arranged for detecting in-line in said processing installation.

11. The processing installation according to claim 10, wherein said workpiece is movable in said processing installation by means of a transport means during detecting by said sensor unit.

12. The processing installation according to claim 10, comprising a hollow die opposite said punch, said sensor unit being arranged in said hollow die.

13. The processing installation according to claim 10, wherein said sensor unit is movably arranged for detecting the cut surface.

14. The processing installation according to claim 10, wherein said first processing machine comprises a tool carrier for receiving said at least one punch, said sensor unit being arranged on said tool carrier.

15. A method for operating a processing machine, the processing machine comprising at least one movable punch for separating and/or forming a workpiece, said method comprising the following steps: contactlessly detecting at least one active surface of said punch with a sensor unit mounted on said processing machine, wherein the detecting is performed during production with said processing machine and thus without removing said punch from said processing machine, and evaluating the condition of said active surface based on the data detected by said sensor unit.

16. A processing machine for performing the method according to claim 15, comprising: at least one movable punch for separating and/or forming a workpiece, and at least one sensor unit on said processing machine which is configured to contactlessly detect at least one active surface of said punch and which is arranged for detecting during production with said processing machine.

17. The method according to claim 1, wherein contactlessly detecting the contour of the cut surface produced on said workpiece comprises optically detecting the contour.

18. The processing installation according to claim 10, wherein the at least one sensor unit is configured to optically detect the contour of the cut surface.

19. The method according to claim 15, wherein contactlessly detecting the at least one active surface of said punch comprises optically detecting the at least one active surface.

20. The processing machine of claim 16, wherein the at least one sensor unit is configured to optically detect the at least one active surface.

Description

[0060] Further details, advantages and features of the present invention are apparent from the following description of exemplary embodiments with reference to the drawing. In the figures:

[0061] FIG. 1 is a schematic view of a processing installation according to the invention for carrying out the method of detecting the cut surface according to the invention,

[0062] FIG. 2 shows a cut surface,

[0063] FIG. 3 shows a punched strip and a sensor unit in accordance with the method according to the invention,

[0064] FIG. 4 shows a schematic evaluation of the condition of the cut surface in accordance with the method according to the invention,

[0065] FIG. 5 shows a schematic illustration of optical detection in accordance with the method according to the invention,

[0066] FIG. 6 shows a further schematic illustration of optical detection in accordance with the method according to the invention,

[0067] FIG. 7 shows a schematic evaluation for optical detection according to FIG. 6,

[0068] FIG. 8 shows a further schematic illustration of optical detection in accordance with the method according to the invention, and

[0069] FIG. 9 shows a detailed schematic illustration of a processing machine according to the invention for carrying out the method for detecting the active surface according to the invention.

[0070] FIG. 1 shows a schematic view of a processing installation 1 according to the invention for carrying out the method according to the invention.

[0071] The processing installation 1 comprises a first processing machine 2 and a further processing machine 3. The first processing machine 2 is configured as a punching machine. The further processing machine 3 is configured as a bending machine.

[0072] The processing machine 2 comprises a movable tool carrier 4 having a plurality of punches 5 for punching a workpiece 8 made of sheet metal. The tool carrier 4 moves with the punches 5 along the direction of movement 13 illustrated. Merely schematically, a die 6 is shown opposite a punch 5. In fact, the processing machine 2 may have a plurality of dies.

[0073] The first processing installation 1 comprises a transport means 7. The workpiece 8 is transported by the first processing machine 2 by means of the transport means 7. In the first processing machine 2, the workpiece 8 is separated into punched strips 9 and punched pieces 10. The punched pieces 10 are pressed into the hollow die 6 by the punch 5. The subsequent punched pieces 10 push the punched pieces 10 through the die 6, so that the punched pieces 10 fall out on the bottom of the die 6. Thus, the punched pieces 10 move through the hollow die 6 in synchronization with the punching first processing machine 2.

[0074] The punched strips 9 are transported individually (or as a continuous punched strip) and in synchronization to the further processing machine 3 by means of the transport means 7. The transport with the transport means 7 takes place along the indicated conveying direction 14. The punched strips 9 are bent in the further processing machine 3 and then leave the processing installation 1.

[0075] FIG. 1 shows the system boundary of the processing installation 1. Within the processing installation 1, the punched strips 9 and punched pieces 10 are moved in an orderly manner according to the cycle of the punching machine. Only after leaving the processing installation 1, the punched strips 9 and punched pieces 10 are stored as bulk material 11.

[0076] FIG. 1 shows three different positions for the arrangement of a sensor unit 12. In the processing installation 1, at least one sensor unit 12 may be employed in one or more of the positions.

[0077] The punching produces a cut surface on the punched strip 9 and on the punched piece 10. The sensor unit 12 is configured to detect the cut surface without contact, in particular optically. The cut surfaces are detected in-line in the operating processing installation 1.

[0078] FIG. 1 shows, between the first processing machine 2 and the further processing machine 3, a sensor unit 12 for detecting the contour of the cut surface on the punched strip 9. Depending on the configuration of the sensor unit 12, it is contemplated that the sensor unit 12 is arranged fixedly or movably at this location.

[0079] FIG. 1 shows a sensor unit 12 on the tool carrier 4. In particular, this sensor unit 12 is moved together with the tool carrier 4 along the direction of movement 13. In particular, this allows for the sensor unit 12 to be moved up to the height of the punched strip 9 and thus makes it possible to measure at right angles to the cut surface axis 12 or at right angles to the cut surface. However, it is also possible to configure the sensor unit 12 on the tool carrier 4 such that the sensor unit 12 does not have to be moved up to the punched strip 9, but rather is only moved as close as possible to the cut surface to be measured.

[0080] FIG. 1 shows, in the die 6, a sensor unit 12 for detecting the contour of the cut surface on the punched pieces 10. In particular, it is useful for this measurement that the punched pieces 10 move through the hollow die 6. As a result, the cut surface can be detected along the full height of the punched piece 10 with the sensor unit 12.

[0081] FIG. 2 shows a schematic view of a cut surface detected by the sensor unit 12. Particularly, the following parameters are characteristic for the cut surface or the contour of the cut surface: cut surface height H, edge indentation height hE, edge indentation width bE, smooth cut height hS, fractured surface height hB, burr height hG, burr width bG, fractured surface angle G. In addition to this, the illustration in FIG. 3 shows the division of the cut surface into an edge indentation region 16, a smooth cut region 17, a fractured surface region 18 and a burr region 19. The cut surface axis 15, which is defined based on the direction of movement 13 of the punch 5, is illustrated on the punched strip 9. The four regions extend over the height H of the cut surface.

[0082] FIG. 3 also shows a sensor unit 12 having a sensor lance 20 and an optical measuring tip 21. The optical measuring tip 21 shows, purely schematically, the optical path and the focus of the sensor unit 12. If the sensor unit 12 is configured to be movable, it may move, for example, along the degrees of freedom 22 illustrated. This makes it possible to move the measuring tip 21 up to the height of the punched strip 9. The entire height H of the cut surface may be measured by means of this movement. Furthermore, it is possible to rotate the sensor unit 12 such that the cut surface is not only detected on one line. As already described, however, it is also possible to use a fixedly installed sensor unit 12.

[0083] FIG. 4 shows an example of how the evaluation of the detected data of the sensor unit 12 may be performed. For example, the detected contour 24 of the cut surface may be compared with an envelope curve 23. The conclusions, for example on the wear of the punch, can be drawn with a corresponding deviation of the detected contour 24 from the envelope 23. However, the evaluation may also be carried out in any other way, in particular by comparing the detected contour 24 with comparison values stored in a computing unit.

[0084] FIGS. 5 to 8 show schematic structures of the sensor unit 12. These sensor units 12 may preferably be installed fixedly and do not have to be moved for detecting the cut surfaces.

[0085] FIG. 5 shows a sensor unit 12 comprising a camera 25 with an objective 26 and lighting 27. The camera 25 and the lighting 27 are located on two different sides of the workpiece 8. With respect to a plane perpendicular to the cut surface axis 15, the camera 25 is oriented at a camera angle and the lighting 27 is oriented at a lighting angle .

[0086] The camera 25 and the lighting 27 are arranged statically and do not have to be moved into the punching opening for the measurement. With this measuring system, the cut surface is detected in-line and evaluated using digital image processing. In particular, with the aid of edge detection algorithms, the transitions, e.g. between the edge indentation region 16, the smooth cut region 17, the fractured surface region 18 and the burr region 19, are recognized and evaluated. Due to the integration into the process, changes in the surface characteristics over time may be recognized and trends may be defined. This allows conclusions to be drawn about the quality of the components and the state of wear of the punch 5. By specifying the quality parameters accordingly, parts can be marked as deficient and automatically recognized. Furthermore, countermeasures for the punch 5 may be inferred and adapted manually or by an automatic control system during the ongoing process.

[0087] Since, with this static structure, the cut surface to be imaged is oblique and not at right angles to the optical axis of the camera 25, the so-called Scheimpflug condition is violated. As a result, the usable depth of field is reduced and one may not be able to image the entire cut surface in focus. This disruptive effect may preferably be reduced by (i) restoring the Scheimpflug condition, e.g. with the aid of a special Scheimpflug lens; and/or (ii) by minimizing the negative effect of the violation of the Scheimpflug condition by choosing a camera angle for the camera 25 that is as flat as possible; and/or (iii) by installing the camera 25 on the side of the fractured surface region 18 or burr region 19 of the cut surface, since these regions tend to face more towards the camera 25 for this camera arrangement due to the geometric shape.

[0088] The camera 25 with the objective 26 and the lighting 27 is preferably arranged in such a way that high-contrast images are obtained with regard to the features to be examined. In particular, different lighting configurations such as axial lighting or incident lighting (as shown in FIG. 5) can be used. With incident lighting, the lighting angle may in particular be optimized such that the features to be detected are imaged with maximum contrast.

[0089] Depending on the application and the material, color filters and/or polarization filters and/or monochromatic lighting with a specifically selected light wavelength may preferably be used. Flashing lighting may also be advantageous, in particular in order to achieve short exposure times.

[0090] Since the workpiece 8 moves past the sensor unit 12 due to its natural feed movement within the manufacturing process, this movement may also be used to detect a larger image area. To do this, an entire image sequence has to be captured during the movement and image processing has to be used to calculate an effectively larger image with a correspondingly larger coverage of the entire cut surface. The quality and geometry features may then be recognized therefrom.

[0091] FIG. 6 shows sensor units 12 as light section sensors 28. The structure consists of one or more optical light section sensors 28 based on the principle of laser triangulation.

[0092] The light section sensors 28 are preferably arranged statically and thus do not move when the cut surface is detected. With the light section sensors 28, a measurement is carried out along a vertical line over the cut surface, similar to the case of the movable sensor unit 12. Since this static structure does not allow the sensor to be positioned directly vertically above the cut surface, it may be necessary to arrange several light section sensors (see FIG. 6) such that as large a portion of the contour as possible can be obtained by combining all measurement signals. For this purpose, the light section sensors 28 are oriented at different angles and their spatial arrangement may also be below and above the workpiece 8. Corresponding scanning geometries are projected onto the test part surface by the light section sensors 28 and their reflections are detected, the contour is calculated and then superimposed to form an overall profile, as shown in FIG. 7.

[0093] As already described, the movement of the workpiece 8 may be used again with this method and thus a 3D contour of the cut surface may be calculated. It is also contemplated that the laser triangulation sensors (light section sensors 28) are replaced by fringe projection sensors.

[0094] FIG. 8 shows a sensor unit 12 consisting of one or more light section light sources 29 projecting a thin straight laser light line onto the cut surface, a camera 25 with an objective 26 and a lighting unit 27. This measurement setup is preferably arranged statically and does not have to be moved into the punching opening for the measurement. This arrangement is used for combined digital image acquisition with a light section source. The camera 25 is used for 2D image acquisition as well as for light section measurement.

[0095] The lighting unit and the laser lines are preferably switched on and off in succession and an image is detected with the camera 25. A profile of the cut surface may then be calculated from the image detecting with the laser line lighting, analogous to the light section method, using the triangulation algorithm. The surfaces may also be moved and the image may be captured at high frequency. In this way, the topography of the surface may be detected.

[0096] It may be necessary to switch off the lighting and to separate the image detecting without a laser unit from the image detecting with a laser unit in time. However, preferably this may also be simultaneous.

[0097] FIG. 9 shows a section of the first processing machine 2 with an arrangement for detecting an active surface 30 on the punch 5, in particular a cutting edge on the punch. For this purpose, the relative movement between the punch 5 and a guide plate of the tool carrier 4 is used to measure the worn active surface 30 of the punch 5. An optional separate drive of the sensor unit 12 may be implemented by means of various drives.

LIST OF REFERENCE SYMBOLS

[0098] 1 processing installation [0099] 2 first processing machine [0100] 3 further processing machine [0101] 4 tool carrier [0102] 5 punch [0103] 6 die [0104] 7 transport means [0105] 8 workpiece [0106] 9 punched strip [0107] 10 punched piece [0108] 11 bulk material [0109] 12 sensor unit [0110] 13 direction of movement [0111] 14 conveying direction [0112] 15 cut surface axis [0113] 16 edge indentation region [0114] 17 smooth cut region [0115] 18 fractured surface region [0116] 19 burr region [0117] 20 sensor lance [0118] 21 measuring tip [0119] 22 degrees of freedom [0120] 23 envelope [0121] 24 contour [0122] 25 camera [0123] 26 objective [0124] 27 lighting [0125] camera angle [0126] lighting angle [0127] 28 light section sensor [0128] 29 light section light source [0129] 30 cutting edge [0130] H cut surface height [0131] hE edge indentation height [0132] bE edge indentation width [0133] hS smooth cut height [0134] hB fractured surface height [0135] hG burr height [0136] bG burr width [0137] G fractured surface angle