WO2023285085A1

WO2023285085A1 - Method for securing holding positions under the consideration of holding-down aspects for removing a workpiece part

Info

Publication number: WO2023285085A1
Application number: PCT/EP2022/066899
Authority: WO
Inventors: Joachim Wipper; Bernd Rüdiger Schwald; Florian Raichle; Dennis Wolf
Original assignee: TRUMPF Werkzeugmaschinen SE + Co. KG
Priority date: 2021-07-14
Filing date: 2022-06-21
Publication date: 2023-01-19
Also published as: DE102021118252A1

Abstract

There is provided a method for securing a positioning of at least two holding devices (24a-f) relative to a workpiece part (14, 14a-e) for removing the workpiece part (14, 14a-e) from a remaining workpiece (15) of a plate-shaped workpiece (2); wherein the workpiece (2) is clamped in a first edge region in a Y direction by means of a clamping device (13) of a laser cutting installation (1); wherein the at least two holding devices (24a-f) are arranged above the workpiece (2) and each have a plurality of holding elements (50) on their side facing the workpiece (2); and wherein at least one of the at least two holding devices (24a-f) comprises a separate holding-down element (25a, 25b) for holding down the remaining workpiece (15) during the removal of the workpiece part (14, 14a-e). The method comprises the following steps: a) initial securing of the positioning of the at least two holding devices (24a-f) in such a way that, in a holding position, at least one of the holding devices (24a-f) is at least partially positioned above the workpiece part (14, 14a-e) and that at least a further one of the holding devices (24a-f) or the holding-down element (25a, 25b) is positioned in a holding-down position outside the workpiece part (14, 14a-e) at a predeterminable minimum distance from an outer contour of the workpiece part (14, 14a-e); and b) iterative adaptation of the holding position and/or the holding-down position of the at least two holding devices (24a-f) in order to optimize the positioning of the holding devices (24a-f) for the removal of the workpiece part (14, 14a-e) from the remaining workpiece (15). Also provided are a computer program product, a removal device and a laser cutting installation for implementing the method.

Description

Method for determining holding positions, taking into account hold-down aspects for removing a

workpiece part

field of invention

The present invention relates to the field of removing workpiece parts which are separated from plate-shaped workpieces. In particular, the invention relates to a method for determining a positioning of holding devices relative to a workpiece part for removing the workpiece part from a remaining workpiece of a plate-shaped workpiece, as well as a device and a laser processing system for the respective application of the method.

State of the art

DE 10 2017 216 828 A1 discloses a method for determining lifting positions and/or holding positions for removing a workpiece part from a remaining workpiece of a plate-shaped workpiece. The method is used for the automated positioning of lifting devices and/or holding devices above or below the workpiece part in order to be able to reliably remove the workpiece part from the remaining workpiece.

Despite the optimized positioning of the lifting devices and/or holding devices, the workpiece parts to be removed occasionally tilt or get caught in the remaining workpiece when the workpiece is removed. As a rule, this leads to loss of time, as manual intervention by the machine operator is required. Furthermore, in extreme cases, the remaining workpiece can deform during removal and collide with the removal system, which can lead to damage to the holding devices. In order to avoid incorrect removal and critical deformation of the remaining workpiece when removing workpiece parts, the remaining workpiece can be held down while a workpiece part is being removed, i.e. pressed onto the workpiece support. However, the aspect of holding down is not taken into account in the method according to DE 10 2017 216 828 A1. Manual programming of the positioning of hold-down elements over the remaining workpiece for each individual removal process is complex and therefore not suitable for efficient production.

The object of the present invention is to provide a method, a device and a laser processing system which further improve the process reliability when removing a workpiece part from a remaining workpiece.

The invention

To solve the problem underlying the invention, according to a first aspect, a method for determining a positioning of at least two holding devices relative to a workpiece part for removing the workpiece part from a residual workpiece (surrounding the workpiece part) of a plate-shaped workpiece is provided. The workpiece is clamped in a first edge region in a Y-direction in a clamping device of a laser cutting system. The directional information X-direction, Y-direction and Z-direction relate to the main movement axes of a laser cutting system with a removal system that is suitable for carrying out the method according to the invention. The workpiece is thus fixed in its first edge region (along a workpiece edge) by means of the clamping device. The clamped workpiece edge can preferably extend in the X-direction. The clamping device is preferably connected to a movement unit of the laser cutting system, which is designed to move the workpiece via a workpiece holder. to move the laser cutting system. The plate-shaped workpiece can in particular be a metallic plate-shaped workpiece that has a thickness of between 0.5 mm and 15 mm.

The at least two holding devices are arranged above (in the Z-direction) the workpiece and each have a plurality of holding elements on their side facing the workpiece. The holding elements can in particular be suction elements which are connected to a pump unit for generating a negative pressure on the suction elements.

At least one of the at least two holding devices comprises a separate hold-down element for holding down the remaining workpiece when the workpiece part is removed. The holding devices and the hold-down element can be moved independently of one another in the Z-direction.

In a step a), the method according to the invention comprises an initial determination of the positioning of the at least two holding devices (arranged above the workpiece) in such a way that at least one of the holding devices is positioned at least partially over the workpiece part (i.e. at least partially covering the workpiece part) in a holding position and that at least one other of the holding devices or the hold-down element is located outside of the workpiece part (i.e. not covering the workpiece part) at a specifiable minimum distance from an outer contour of the workpiece part, preferably at least partially above the remaining workpiece (i.e. at least partially covering the remaining workpiece), in a hold down position is positioned. The positioning of the holding devices also determines a positioning of the hold-down element, which is encompassed by the at least one of the at least two holding devices or is connected thereto. With the minimum distance is the minimum distance in the Y direction or in the X-direction to the outer contour of the workpiece part. The minimum distance can be at least 1 mm, for example between 1 mm and 5 mm. By positioning a holding device or a holding-down element at a minimum distance from the outer contour of the workpiece part, this holding device or this holding-down element can be lowered onto the remaining workpiece when the workpiece part is removed and hold it down when the workpiece part is removed. If the workpiece catches or tilts in the remaining workpiece during removal, this avoids deformation of the remaining workpiece. Furthermore, snagging or edging of the workpiece part can be avoided from the outset by holding down the remaining workpiece. Depending on the contour (i.e. the shape) of the workpiece part to be removed and the dimensions of the holding devices and the hold-down element, it may make sense to use either a holding device to hold down the remaining workpiece or the hold-down element. The minimum distance can preferably be selected in such a way that the remaining workpiece is held down. By positioning the holding-down element (holding device or hold-down element) at the minimum distance from the outer contour of the workpiece part, positioning of the holding-down element over an empty space in the remaining workpiece or even outside the remaining workpiece can be avoided.

In a step b), the method also includes an iterative adjustment of the holding position and/or the hold-down position of the at least two holding devices in order to optimize the positioning of the holding devices for removing the workpiece part from the remaining workpiece (and holding down the remaining workpiece). Through the iterative adjustment of the holding position and / or the hold-down position of the holding devices, the intended positions for the removal of the holding devices relative to the workpiece part are adapted to the geometric conditions of the Workpiece part and, if necessary, geometric conditions of the remaining workpiece further adapted.

According to a preferred variant, the holding devices can be arranged on longitudinal rails such that they can be displaced relative to one another in the Y direction, where at least two longitudinal rails, each of which comprises at least two, preferably three, holding devices, are arranged such that they can be displaced in relation to one another in the X direction. Each longitudinal rail can comprise a hold-down element, which is arranged on the end of the holding device of this longitudinal rail, which is arranged farthest in the Y direction from the first edge region, and faces away from the first edge region of the workpiece in the Y direction. All holding devices that are mounted on a longitudinal rail can thus be moved together in the X-direction over the workpiece by means of the longitudinal rail. Furthermore, the holding devices of a longitudinal rail can be displaced along the longitudinal rail in the Y direction. According to the variant described, it is provided that the remainder of the workpiece is partially held down on that side of the workpiece which is opposite the first, clamped edge region of the workpiece or remainder of the workpiece in the Y-direction.

Method step a) can include the following sub-steps: al) Selecting, based on the dimensions of the holding devices in the X direction and a maximum dimension of the workpiece part in the X direction, how many and/or which of the available longitudinal rails for removing the workpiece part are to be used; a2) Initial determination of a uniform positioning of the longitudinal rails selected in step al) in the X direction over the workpiece part. The uniform positioning can be equidistant positioning of the longitudinal rails over the expansion of the workpiece part in the X direction. Method step a) can also include for each of the longitudinal rails selected in sub-step al): a3) determining a preferably rectangular holding area whose width is determined by the expansion of the holding devices in X- Direction and the length of which is defined by a maximum extension of the work piece part in the Y direction during the initial positioning of the respective longitudinal rail. The extension of the holding area in the Y direction therefore depends on the initial positioning of the respective longitudinal rail in the X direction; a4) determining, on the basis of the dimensions of the holding devices of the selected longitudinal rail in the Y-direction and the length of the respective holding area, a covering of the workpiece part by the holding devices in the Y-direction; a5) selecting, on the basis of the coverage determined in the Y-direction, whether the hold-down element or at least one of the holding devices is/are to be positioned outside of the workpiece part over the remaining workpiece; a6) Initial determination that the at least one selected holding device or the selected hold-down element of the selected longitudinal rail is positioned outside the workpiece part at the predefinable minimum distance in the Y-direction from the outer contour of the workpiece part over the remaining workpiece in the hold-down position; and a7) Initially determining the positioning of the remaining holding devices of the selected longitudinal rail in corresponding holding positions which are distributed at regular intervals, for example equidistantly, in the Y-direction over the holding area.

It can happen that for at least one of the selected longitudinal rails no hold-down position according to sub-step a6) can be specified. This can be the case if the workpiece part to be removed is positioned too close (e.g. less than 2 mm) to the second edge in the Y-direction of a rectangular residual workpiece, with the second edge lying opposite the first, clamped edge of the residual workpiece. A similar situation arises if another workpiece part that is very closely adjacent has already been removed in the Y-direction, so that holding-down elements can no longer be positioned in such a way that the remaining workpiece is securely held down. In such cases, invention according to the invention, that at least one of the holding devices of a longitudinal rail not selected in step a2) is positioned in a hold-down position at the predefinable minimum distance in the X-direction from the outer contour of the workpiece part. Even in the case of extreme positions of the workpiece part in the rest of the workpiece, it is possible in this way to ensure that the rest of the workpiece is fixed when the workpiece part is removed by holding it down at the side.

Method step b) can include the following sub-steps: bl) Defining an effective range for each of the holding devices for which a holding position was initially defined at its respective defined holding position, and b2) Renewed definition of the holding position and/or the hold-down position of at least one of the holding devices and/or or the at least one hold-down element based on the geometric shape of the portion of the workpiece part to be removed that is in the respective effective area. It goes without saying that repositioning of the holding devices and/or the hold-down element of a longitudinal rail may also require repositioning of the longitudinal rail.

In a further development, sub-steps b1) and b2) can be repeated until a termination criterion is reached. The iteration of sub-steps b1) and b2) is carried out until a termination criterion is reached, which in the simplest case can be a fixed, predetermined number of repetitions or iterations. The teachings from DE 10 2017 216 828 A1, for example, can be applied analogously for carrying out the iterative method steps.

When determining the positioning of the holding devices according to one of the variants described above, the positioning of off-lifting devices can also be taken into account, each comprising a plurality of off-lifting elements and which are arranged below (in the Z-direction) of the workpiece in order to remove the workpiece part the rest of the workpiece to excavate. When positioning the holding devices relative to the lifting devices, it should be noted that only those lifting elements should be used for the removal or lifting of the workpiece part, which lie under the workpiece part and which are opposite a holding device on the upper side of the workpiece as a counter bearing presses on the workpiece part from above. It goes without saying that the positioning of the holding devices can be decisive for the positioning of the lifting devices, since the hold-down function is determined by the positions of the holding devices. The lifting devices are preferably positioned as precisely as possible below the holding devices intended for lifting and holding the workpiece part.

Method step b2) of re-determining the holding position(s) and/or the hold-down position(s) can include optimizing the positioning of individual holding devices for which a holding position was initially defined relative to the corresponding lifting devices. In this way, the number of lifting elements that can be used to remove the workpiece part can be increased. According to one variant, the positioning of the holding devices that do not hold down can first be individually optimized in the Y-direction in order to accommodate more holding elements on the workpiece part. The positioning of the lifting devices can then be optimized in the X and Y directions in order to accommodate more lifting elements under the workpiece part and the holding devices.

To achieve the object on which the invention is based, a computer program product is provided according to a second aspect, which is designed to carry out all the steps of the method according to one of the variants described above when the computer program runs on a data processing system. In order to achieve the object on which the invention is based, a device for removing a workpiece part from a remaining workpiece is provided according to a third aspect. The device comprises a lifting unit with at least two lifting devices, each having a plurality of lifting elements, and a counter-holding unit with at least two holding devices, each having a plurality of holding elements, wherein at least one of the holding devices also has at least one separate hold-down element. The device also includes a lifting device moving device for moving the lifting devices parallel to a storage plane of the remaining workpiece and a holding device moving device for moving the holding devices parallel to the storage plane of the remaining workpiece. The device also includes a control unit for controlling the lifting device movement device for moving the lifting devices to specified lifting positions and for controlling the holding device movement device for moving the holding devices to specified holding positions and/or hold-down positions, the control unit being designed to move the holding devices and lifting devices according to one to position fixed positioning relative to the workpiece part, wherein the positioning is determined by means of the method according to one of the variants described above.

In order to achieve the object on which the invention is based, according to a fourth aspect, a laser processing system is provided for the separating processing of, in particular metallic, plate-like workpieces by means of a laser processing unit. The laser processing system comprises a device as described above for removing a workpiece part separated from a remaining workpiece during the separating processing. exemplary embodiments

The following description of preferred exemplary embodiments serves to explain the invention in more detail in conjunction with the drawings.

Show it:

Fig. 1 is a schematic representation of an example of a

Laser cutting system for the separating processing of a workpiece by means of a laser beam;

Fig. 2 is an illustration of a device for removing a

Workpiece part from a residual workpiece on the laser cutting system of FIG. 1;

Figs. 3a-b schematically show the positioning of holding devices relative to a workpiece part to be removed according to the present invention, as well as the exposed workpiece part (Fig. 3b) in plan view;

Figs. 4a-b schematically the positioning of fixtures relative to a workpiece part according to the prior art (Fig. 4a) versus the positioning of fixtures relative to the same workpiece part according to the present invention (Fig. 4b);

Figs. 5a-b schematically the positioning of holding devices relative to another workpiece part according to the prior art (Fig. 5a) versus the positioning of the holding devices relative to the same workpiece part according to the present invention (Fig. 5b); Fig. 6 schematically aspects of the initial positioning of the

Holding devices according to method step a) of the method according to the invention;

Fig. 7 schematically aspects of the iterative adjustment of the

holding position(s) and/or the hold-down position(s) according to method step b) of the method according to the invention;

Fig. 8 schematically further aspects of the iterative adjustment of

holding position(s) and/or the hold-down position(s) according to method step b) of the method according to the invention; and

Fig. 9 shows schematically the inventive positioning of

Holding devices in a hold-down position at a minimum distance in the X-direction next to the contour of the workpiece part to be removed.

In the following description of the drawings, identical reference symbols are used for identical or functionally identical components.

1 shows a laser processing system 1 for the separating processing of a plate-shaped workpiece 2 in the form of sheet metal, which has a laser cutting device 3 . The laser cutting device 3 has a portal-like guide structure 4 with a portal support 5 and a laser cutting head 6 guided on the portal support 5 . The laser cutting head 6 can be moved relative to the portal support 5 in the direction of double arrows 7, 8 in directions perpendicular to one another. The laser cutting head 6 is connected to a laser beam source in the form of a solid-state laser 52 via an optical fiber cable 51 . The portal-like guide structure 4 overlaps a two-part workpiece table 9, on which a workpiece in the form of a metal sheet 2 is stored before, during and after cutting processing. The metal sheet 2 is processed by means of the laser cutting head 6 of the laser cutting system 1 . In this case, the sheet metal 2 is mounted on the workpiece table 9 . Slag, dust and fumes formed during processing are sucked off through a gap S formed between the two parts of the work table 9 and a discharge device (eg a suction box, not shown) arranged below the gap S and connected to a blower. After processing, workpiece parts that have been cut free by means of the laser cutting head 6 are separated from a residual workpiece (residual grid) 15 (cf. FIG. 2) also produced during processing and then removed from the vicinity of the laser processing system 1.

A workpiece movement unit 10, which is shown in a highly schematic manner in FIG. 1, is used to move the sheet metal 2 before, during and after its processing and on which a metal sheet 2 can be fixed at a first edge 152 (cf. FIG. 2) by means of clamping claws 13. The laser processing system 1 shown is to be understood as an example. For example, there are also laser processing systems in which the directions of travel for the laser and sheet metal movement units are arranged differently (e.g. the laser unit can be moved in the X direction and the sheet metal movement unit in the Y direction). The present invention also extends to such laser processing systems.

The sheet metal 2 is positioned for processing in the working area of the laser cutting head 6 by means of the workpiece movement unit 10 . During processing, the sheet metal 2 can Moving unit 10 are moved in the direction of the double arrow 12. Processing movements superimposed therewith are carried out by the laser cutting head 6 in the direction of the double arrow 7 . In addition, the laser cutting head 6 has an additional axis that enables short, highly dynamic movements of the laser cutting head 6 in the direction of the double arrow 8 and thus in the direction of movement of the workpiece movement unit 10 . With a final separating cut, the laser cutting head 6 cuts a workpiece part (not shown in FIG. 1) free from the residual skeleton (not shown in FIG. 1). The workpiece part 14 (cf. FIG. 2) and the residual skeleton (or residual workpiece) 15 are each in a processing position on the laser processing system 1 . After completion of the processing, the workpiece moving unit 10 transfers the workpiece part 14 that has now been cut free and the residual skeleton 15 together from the respective processing position to an unloading position. When processing thin workpieces (e.g. sheet metal with a thickness <3 mm), when transferring a cut workpiece part 14 together with the remaining workpiece 15, the workpiece part 14 can already be fixed in the remaining workpiece 15 by holding devices 24a, 24b (cf. FIG. 2), so that the remaining workpiece 15 does not slide over or under the workpiece part 14 when it is moved.

If the workpiece part 14 cut free and the remaining workpiece 15 are transferred to their unloading positions, the conditions shown in FIG. For the sake of clarity, FIG. 2 shows only a single workpiece part 14 on the machined sheet metal 2, which is enclosed by the remaining workpiece 15 (residual skeleton). The workpiece part 14 is removed from the remaining workpiece 15 by means of the device 16 before the workpiece part 14 can be transported away from the vicinity of the laser processing system 1 (cf. FIG. 1). The remaining workpiece 15 remains on the workpiece table 9 (see FIG. 1), before it is also removed from the vicinity of the laser processing system 1 after all workpiece parts have been removed.

A plate-like workpiece support 17 of the workpiece table 9 serves as a workpiece support for the remaining workpiece 15 and the workpiece part 14. In a known manner, the workpiece support 17 is provided on its upper side with bristles or rollers, which cannot be seen in FIG Allow sheet metal 2 (see. Fig. 1) on the stationary workpiece support 17. The support points of the machined sheet metal 2 on the bristles or the rollers of the workpiece support 17 define a storage plane 18 of the workpiece support 17 indicated in Fig. 2. The storage plane 18 runs parallel to the main plate plane of the workpiece support 17. The workpiece part 14 is aligned along the storage plane 18 and the remaining workpiece 15 together.

As can be seen from FIG. 2, the workpiece support 17 of the laser processing system 1 is designed as a perforated plate with a large number of passage openings 19 in the example shown. Alternatively, the workpiece support 17 can be formed by a plurality of profile bodies which are spaced apart from one another in parallel, forming slit-shaped through-openings 19 , and which have a brush element comprising a plurality of bundles of bristles on their end face which faces the workpiece 2 . A lifting unit 20 is arranged below the workpiece support 17 and a counter-holding unit 21 of the device 16 is arranged above the workpiece support 17 . The lifting unit 20 comprises a plurality of lifting devices 22 of identical construction, of which a first and a second lifting device 22a, 22b can be seen in FIG. The counter-holding unit 21 comprises a plurality of holding devices 24 of identical construction, of which a first and second holding device 24a, 24b can be seen in FIG. The lifting devices 22 can be moved parallel to the storage plane 18 to any point below the workpiece support 17 by means of a lifting device movement device 26 and can be advanced there, whereby it must be ensured during the movement that the lifting devices 22 do not collide with each other and the lifting elements 47 under the Passage openings 19 are placed. The first and the second lifting device 22a, 22b are arranged on a support structure in the form of a first longitudinal rail 27a of the lifting device moving device 26, along which the first and second lifting device 22a, 22b can be driven by a motor in the Y direction of an XYZ coordinate system. A drive motor 28 of the lifting devices 22a, 22b can be seen in FIG. Together with the first and second lifting device 22a, 22b, the longitudinal rail 27a can be moved in the X direction on two transverse rails 29, 30 of the lifting device moving device 26 running perpendicularly to the first longitudinal rail 27a.

In a corresponding manner, the holding devices 24 of the counter-holding unit 21 can approach any point on the machined sheet metal 2 parallel to the storage plane 18, provided they do not collide with one another. For this purpose, a holding device moving device 31 comprises a first longitudinal rail 32a, along which a first and second holding device 24a, 24b can be moved and advanced in a motor-driven manner in the Y direction. Together with the holding devices 24a, 24b, the longitudinal rail 32a can be moved in a motor-driven manner along two transverse rails 33, 34 in the X direction, which in turn run perpendicular to the first longitudinal rail 32a. Correspondingly, further holding devices 24 (not shown) of the holding device moving device 31 can be arranged on a supporting structure in the form of a second longitudinal rail 32b (not shown) along which the further holding devices 24 can be guided by means of a further, not shown Drive motor can move motor-driven in the Y direction.

The transverse rails 33, 34 and/or the longitudinal rails 32a, 32b attached thereto with the holding devices 24a, 24b and/or the holding devices 24 can be raised and lowered perpendicular to the workpiece support 17 or the storage plane 18 (in the Z direction).

All essential functions of the laser processing system 1 and thus in particular all essential functions of the device 16 are controlled numerically. A numerical control unit 35 used for this purpose is indicated in FIG. The coordinate axes of the numerical control of the laser processing system 1 or of the device 16 are denoted by X, Y, Z in FIG.

Aspects of a method according to the invention for determining a positioning of holding devices relative to a workpiece part for removing the workpiece part from a remaining workpiece are described below in connection with FIGS.

FIG. 3a shows a top view of a workpiece part 14a and the positioning of six holding devices 24a-f and six lifting devices 22a-f relative to the workpiece part 14a. For better understanding, FIG. 3b shows the exposed workpiece part 14a in a plan view. The holding devices 24a, 24b and 24c are arranged on the longitudinal rail 32a and the holding devices 24d, 24e and 24f are arranged on the longitudinal rail 32b. In contrast to the illustration according to FIG. 2, three holding devices 24a-f and three lifting devices 22a-f are attached to a respective longitudinal rail 32a-b, 27a-b. Corresponding arrows indicate the movability of the longitudinal rails 32a and 32b transversely to one another (ie in the X direction) and the movability of the holding devices 24a-f in the longitudinal direction (Y direction) along the respective longitudinal rails 32a, 32b. The holding devices 24a-f are arranged above (in the Z-direction) the workpiece part 14a. The lifting devices 22a-f are arranged below the workpiece part 14a, of which the lifting devices 22a, 22b and 22c are mounted on a longitudinal rail 27a, not shown in Figure 3a, and the lifting devices 22d, 22e and 22f are mounted on a further longitudinal rail 27b (also not shown) are attached.

A holding device 24a, 24d is arranged on each of the longitudinal rails 32a, 32b, each of which comprises an additional hold-down element 25a, 25b. More precisely, the hold-down elements 25a, 25b are each arranged on the holding device 24a, 24d, which is furthest away on its longitudinal rail 32a, 32b from the clamping claws 13 in which the remaining workpiece 15 is clamped (cf. FIGS. 1 and 2).

Each holding device 24a-f has a large number of holding elements 50 in the form of passive suction cups, which can each be subjected to a vacuum. The lifting devices 22a-f each have lifting elements 47 and are each positioned below a holding device 24a-f for removing the workpiece part 14a. Only those lifting elements 47 are shown in FIGS. 3-9 which can be activated for removing the workpiece part 14a, namely those which are positioned below the workpiece part 14a and are additionally covered by a holding device 24a-f.

To remove workpiece part 14a, holding devices 24a-f are positioned in such a way that hold-down element 25a attached to holding device 24a is positioned on longitudinal rail 32a and holding device 24d is positioned on longitudinal rail 32b at a minimum distance in the Y direction from the outer contour of workpiece part 14a , in order to ensure that when the workpiece part 14a is removed hold down the rest of the workpiece in this hold-down position. The hold-down position or the selection of a holding device 24a-f or a hold-down element 25a, 25b for holding down the remaining workpiece 15 is identified in the figures by a dash-dot border of the corresponding element highlighted in bold.

FIGS. 4a and 5a each show an example of the positioning of holding devices 24a-f for removing a workpiece part 14b or 14c according to the prior art. The positioning approach presented here, which is essentially based on a method according to DE 10 2017 216 828 A1, aims to grip the workpiece part 14b, 14c as centrally as possible. Subsequent activation of the holding-down elements can result in a comparatively large distance between the holding-down elements (cf. FIG. 4a holding devices 24a and 24b or FIG. 5a holding devices 24a and 24d) and the outer contour of the workpiece part 14b, 14c to be removed. In the worst case, no holding device 24a-f or no holding-down element 25a, 25b can then be selected for holding down the remaining workpiece 15 if the corresponding elements lie outside the edge of the remaining workpiece 15, for example.

According to the present invention, the holding devices 24a-f are positioned over the workpiece part 14b, 14c in such a way that at least one holding device (cf. holding devices 24a, 24b in Figure 4b, holding devices 24a, 24d, 24e in Figure 5b) and/or at least one hold-down element (cf. eg hold-down element 25a in FIG. 3a) is positioned above the remaining workpiece 15 at a predeterminable minimum distance from the outer contour of the workpiece part 14a, 14b, 14c to be removed. The minimum distance can be set by a machine operator. The minimum distance can be 3 mm, for example. Furthermore, the elements that can be selected for holding down per longitudinal rail 32a, 32b are optimized depending on the geometry of the workpiece part. This can lead to an increased number of hold-down elements that can be activated, as shown by way of example in FIG. 5b. While for the longitudinal rail 32b according to Figure 5a (prior art) only the more distant holding device 24d can be selected for holding down, according to Figure 5b two holding devices 24d, 24e are activated for holding down the remaining workpiece 15, with the holding device 24e being at the specified minimum distance from the Outer contour of the workpiece part 14c is positioned.

If a holding device 24a-f is selected for holding down, it is generally not necessary to additionally activate a hold-down element 25a, 25b for holding down.

In connection with FIGS. 6 to 9, an example of the stepwise positioning of the holding devices 24a-f and lifting devices 22a-f relative to a workpiece part 14d to be removed is explained below.

The positioning method essentially comprises an initial positioning and a subsequent iterative repositioning of the holding devices 24a-f and lifting devices 22a-f to optimize the initial positioning. Strictly speaking, it is sufficient to carry out the iteration process only for the holding devices 24a-f and only to position the lifting devices 22a-f underneath again at the end. In the following, the focus will therefore be on the positioning and position optimization of the holding devices 24a-f.

In a first step, which is shown in FIG. 6, based on the extent of the workpiece part 14d in the transverse direction (X direction) determines how many longitudinal rails 32a, 32b with holding devices 24a-f are required in the X direction for the removal of the workpiece part 14d. According to the determined number of available longitudinal rails 32a, 32b with holding devices 24a-f in the X-direction, an initial uniform positioning of the longitudinal rails 32a, 32b is carried out within the maximum extension of the workpiece part 14d in the X-direction.

For each longitudinal rail 32a, 32b, an initial positioning of the holding devices 24a-c or 24d-f is also determined independently based on the dimensions of the workpiece part 14d in the longitudinal direction (Y-direction), so that at least one holding device 24a-b or 24d-f e or at least one hold-down element 25a or 25b is spaced at a minimum distance in the Y-direction from the outer contour of the workpiece part 14d. For the holding devices 24a, 24b, 24c, as well as 24e and 24f selected for holding the workpiece part 14d, holding positions are initially defined, which are distributed in the longitudinal direction (Y direction) along the respective longitudinal rail 32a, 32b at equal distances from one another over the workpiece part 14d.

For each longitudinal rail 32a, 32b, the area (holding area) of the workpiece part 14d that can be covered by the holding devices 24a-c or 24d-f arranged thereon is marked in the Y direction by a dash-dot line. Due to the Y dimension of the workpiece part 14d, three holding devices 24a, 24b, 24c can be positioned for the removal of the longitudinal rail 32a, which is why a hold-down position is initially defined for the hold-down element 25a at a minimum distance away from the workpiece part 14d in the Y direction. Due to the fixed connection between the hold-down element 25a and the holding device 24a, this also results in the initial holding position of the holding device 24a in the Y-direction. The remaining two holding devices 24b, 24c are equidistant over the workpiece part 14d for the given position of the longitudinal rail 32a in the Y direction or distributed over the corresponding holding area. In the case of the longitudinal rail 32b, only two holding devices 24e, 24f can be positioned for workpiece removal. The third holding device 24d is thus initially positioned at a minimum distance in the Y-direction in front of the workpiece part 14d in order to hold down the remaining workpiece 15 . The holding devices 24e, 24f are also distributed equidistantly in the longitudinal direction (Y direction) over the workpiece part 14d in the corresponding holding area.

For each holding device 24b, 24c, 24e, 24f that is not positioned for holding down (directly or indirectly by means of the connected hold-down element), the area of influence is determined, which is limited by the geometry of the workpiece part and the respective neighboring holding devices 24a-f (see FIG. 7). The area of influence is identified in FIG. 7 by means of a dash-dot line as an example for the holding device 24b. A new position for each of these holding devices 24b, 24c, 24e, 24f is then determined on the basis of geometric criteria. For example, it can be provided that the center point of a holding device 24b, 24c, 24e, 24f is moved to the center of gravity of the intersection of the area of influence determined for it with the workpiece part 14d. When one of the holding devices 24b, 24c, 24e, 24f is repositioned in the X direction, the respective longitudinal rail 32a, 32b must be displaced. The calculation of the new X positions of the holding devices 24b, 24c, 24e, 24f of a longitudinal rail 32a, 32b can result in different positions. In this case, the respective longitudinal rail 32a, 32b can be positioned at the respective mean value of the X positions of the connected holding devices. Depending on the outer contour of the workpiece part 14d, the displacement of a longitudinal rail 32a, 32b also makes it necessary to reposition the holding-down elements (in the example 25a and 24d) in order to continue to maintain the minimum distance from the workpiece part 14d for the correct positioning of the longitudinal rail 32a, 32b. Unless on the new Longitudinal rail position, the same hold-down elements can be used, these hold-down are optimally positioned at the minimum distance from the workpiece part 14d and the newly determined holding positions for the other holding devices 24b, 24c, 24e, 24f are adopted. If it is not possible or sensible to use the newly calculated holding positions (e.g. because all previously used holding devices for holding workpiece part 14d can no longer be positioned), holding devices 24a-f are used to remove workpiece part 14d for the new position of the corresponding longitudinal rail 32a , 32b are reset analogously to the initial positioning described above.

This repositioning can be iterated until there are no more significant changes in position, or until a termination criterion to be determined occurs (e.g. reaching a certain number of repositioning steps).

After this "global" position optimization of the holding devices 24a-f, a "local" repositioning of the holding devices 24b, 24c, 24e, 24f that do not actively or passively hold down takes place (cf. FIG. 8). The local repositioning can take place analogously to the “global repositioning” described above in respective iteration steps. In this case, however, only local surroundings of the relevant holding devices 24b, 24c, 24e, 24f are taken into account as areas of influence. The repositioning therefore takes place based on geometric criteria of the workpiece part 14d only in the immediate local vicinity of a holding device 24b, 24c, 24e, 24f. For example, the circumscribing rectangle of the respective holding device 24b, 24c, 24e, 24f enlarged by a determinable factor (eg factor 1.5) can be used as the local environment. In FIG. 8, a local environment to be taken into account is shown as an example by means of a dash-dot line for the holding device 24b. When positioning the holding-down elements (eg holding devices 24a, 24b, 24d, 24e and/or holding-down elements 25a, 25b) in the initial positioning as well as in the two subsequent iterative steps, the shape of the remaining workpiece 15 can also be taken into account. Criteria for this are, for example, meeting wider webs or avoiding the positioning of holding-down elements in gaps or empty spaces from other workpiece parts 14 that have already been removed.

The lifting devices 22a-f can be positioned essentially analogously to the positioning of the holding devices 24a-f, with the positioning of the lifting devices 22a-f taking into account the positioning of those holding devices 24a, 24b, 24c, 24e, 24f that are selected for holding the workpiece part 14d became.

In an additional repositioning step, which is not shown in the figures, technology-specific post-optimizations can be carried out. An example of this is the local displacement in the Y direction of holding devices 24b, 24c, 24e, 24f that are not involved in holding down in order to increase the number of holding elements 50 that can be activated and/or the subsequent local displacement of the lifting devices 22a-f in the X direction and/or or Y-direction to increase the number of lifting elements 47 that can be activated.

FIG. 9 shows a situation in which a workpiece part 14e to be removed is so close to the edge or the second edge 154 of the remaining workpiece 15 (which is opposite the first, clamped edge 152, see FIG. 2) in the Y direction. is positioned in such a way that the remaining workpiece 15 cannot be reliably held down in the Y direction with the holding device 24d. This is particularly the case when the distance between the outer contour of the workpiece part 14e in Y Direction and the second edge 154 of the remaining workpiece 15 is less than or equal to the minimum distance for positioning the holding-down element (holding device 24d). Depending on the availability of holding elements 24a-c in the X-direction, which are not required immediately for the removal of the workpiece part 14e, these holding devices 24a-c can be positioned at the specified minimum distance in the X-direction next to the outer contour of the workpiece part by means of suitable positioning of the longitudinal rail 32a 14e are positioned to hold down the remaining workpiece 15 laterally.

Reference List

1 laser cutting machine

2 sheet metal (workpiece)

3 Laser cutting device

4 management structure

5 portal supports

6 laser cutting head

7 double arrow

8 double arrow

9 work table

10 Sheet metal (workpiece) movement unit 11 Rail 12 Double arrow 13 Clamping claws (clamping device)

14, 14a-e workpiece part

15 Rest work piece 152 First edge of the work piece / rest work piece in the clamped first edge area

154 Second edge of the workpiece / remnant workpiece opposite the first edge

16 Device for removing the workpiece part

17 workpiece support

18 storage level

19 passage openings

20 lifting unit 21 counter holding unit

22a-f lifting device

24a-f holding device

25a-b hold-down element

26 digger moving means

27a-b longitudinal rail

28 drive motor 29 cross rail

30 cross rail

31 fixture moving means

32a-b longitudinal rail

33 cross rail

34 cross rail

35 control unit

46a-b lifting housing

47 lifting element (lifting pin)

48a-b Box-shaped case

50 holding element (suction element)

51 fiber optic cable

52 solid-state lasers

9 weight h holding force

P compressive force

Claims

patent claims

1. Method for determining a positioning of at least two holding devices (24a-f) relative to a workpiece part (14, 14a-e) for removing the workpiece part (14, 14a-e) from a remaining workpiece (15) of a plate-shaped workpiece (2) ;

The workpiece (2) being clamped in a first edge region in a Y-direction by means of a clamping device (13) of a laser cutting system (1);

The at least two holding devices (24a-f) being arranged above the workpiece (2) and each having a plurality of holding elements (50) on their side facing the workpiece (2); and

Wherein at least one of the at least two holding devices (24a-f) comprises a separate hold-down element (25a, 25b) for holding down the remaining workpiece (15) when the workpiece part (14, 14a-e) is removed;

The method comprises the following steps: a) Initial determination of the positioning of the at least two holding devices (24a-f) such that at least one of the holding devices (24a-f) is in a holding position at least partially above the workpiece part (14, 14a- e) is positioned and that at least one other of the holding devices (24a-f) or the hold-down element (25a, 25b) is outside the workpiece part (14, 14a-e) at a definable minimum distance from an outer contour of the workpiece part (14, 14a -e) is remotely positioned in a hold down position; and b) Iterative adjustment of the holding position and/or the hold-down position of the at least two holding devices (24a-f) in order to position the holding devices (24a-f) for the removal of the workpiece part (24a-f) from the remaining workpiece (15 ) to optimize.

2. The method according to claim 1, wherein the holding devices (24a-f) are arranged on longitudinal rails (32a, 32b) such that they can be displaced relative to one another in the Y direction; wherein at least two longitudinal rails (32a, 32b), each of which comprises at least two, preferably three, holding devices (24a-f), are arranged such that they can be displaced relative to one another in the X direction; and wherein each longitudinal rail (32a, 32b) comprises a hold-down element (25a, 25b) which is arranged at the end facing away from the first edge area of the workpiece (2) in the Y direction of the end that is furthest in the Y direction from the first edge area Holding device (24a, 24d) of this longitudinal rail (32a, 32b) is arranged.

3. The method according to claim 2, wherein step a) further comprises: al) selecting based on the dimensions of the holding devices (24a-f) in the X-direction and a maximum dimension of the workpiece part (14, 14a-e) in the X-direction , which of the available longitudinal rails (32a, 32b) are to be used for the removal of the workpiece part (14, 14a-e); a2) Initial determination of a uniform positioning of the longitudinal rails (32a, 32b) selected in step al) in the X direction over the workpiece part (14, 14a-e); and for each of the selected longitudinal rails (32a, 32b): a3) determining a preferably rectangular holding area whose width is determined by the expansion of the holding devices in the X-direction and whose length is determined by a maximum expansion of the workpiece part (14, 14a-e) is defined in the Y-direction when the respective longitudinal rail (32a, 32b) is initially positioned; a4) determining, based on the dimensions of the holding devices (24a-f) of the selected longitudinal rail (32a, 32b) in the Y-direction and the length of the respective holding area, a covering of the workpiece part (14, 14a-e) by the holding devices (24a- f) in the Y direction; a5) Select, based on the coverage determined in the Y direction, whether the hold-down element (25a, 25b) or at least one of the holding devices (24a-f) outside the workpiece part (14, 14a-e) above the remaining workpiece (15) is/are to be positioned; a6) Initial determination that the at least one selected holding device (24a-f) or the selected hold-down element (25a,

25b) of the selected longitudinal rail (32a, 32b) outside of the workpiece part (14, 14a-e) at the predefinable minimum distance in the Y-direction away from the outer contour of the workpiece part (14, 14a-e) above the remaining workpiece in the hold-down position ; and a7) initially determining the positioning of the remaining holding devices (24a-f) of the selected longitudinal rail (32a, 32b) in corresponding holding positions which are distributed at equal intervals in the Y-direction over the holding area.

4. The method according to claim 3, wherein for at least one of the selected longitudinal rails (32a, 32b) no hold-down position according to sub-step a6) can be specified and it is further specified that at least one of the holding devices (24a-f) is not one in step a2) the selected longitudinal rail (32a, 32b) is positioned in a hold-down position at the predeterminable minimum distance in the X direction from the outer contour of the workpiece part (14, 14a-e).

5. The method according to any one of the preceding claims, wherein step b) comprises the following sub-steps: bl) defining an effective range for each of the holding devices (24a-f) for which a holding position was initially defined at their respectively defined holding position, and b2) defining again the holding position and/or the hold-down position of at least one of the holding devices (24a-f) and/or the at least one hold-down element (25a, 25b) based on the geometric shape of that part of the workpiece part (14, 14a-e) to be removed that is in the respective effective area.

6. The method according to any one of the preceding claims, wherein when determining the positioning, the positioning of lifting devices (22a-f) is also taken into account, which each comprise a large number of lifting elements (47) and which are located below the workpiece in the Z direction ( 2) are arranged to dig the workpiece part (14, 14a-e) from the rest of the workpiece (15).

7. The method according to claim 6, wherein step b2) of redetermining the fold position and/or the hold-down position optimizes the positioning of individual fold devices (24a-f), for which a fold position was initially defined, relative to the corresponding lifting devices (22a-f).

8. Computer program product which is designed to carry out all the steps of the method according to one of the preceding claims when the computer program runs on a data processing system.

9. Device (16) for removing a workpiece part (14, 14a-e) from a remaining workpiece (15), comprising: a lifting unit (20) with at least two lifting devices (22a-f), each having a plurality of lifting elements (47) exhibit; a back-up unit (21) having at least two folders (24a-f) each having a plurality of folders (50), wherein at least one of the folders (24a-f) further includes at least one separate hold-down member (25a, 25b); a lifting device moving device (26) for moving the lifting devices (22a-f) parallel to a storage plane (18) of the remaining workpiece (15); a jig moving means (31) for moving the jigs (24a-f) parallel to the storage plane (18) of the remainder workpiece (15); a control unit (35) for controlling the lifting device moving device (26) for moving the lifting devices (22a-f) to fixed lifting positions and for controlling the holding device moving device (31) for moving the holding devices (24a-f) to fixed holding positions and/ or hold-down positions, wherein the control unit (35) is designed to position the holding devices (24a-f) and lifting devices (22a-f) according to a fixed positioning relative to the workpiece part (14, 14a-e), the positioning using the method as defined in any one of claims 1 to 7.

10. Laser cutting system (1) for the cutting processing of, in particular metallic, plate-like workpieces (2) by means of a laser cutting device (3), comprising: a device (16) according to claim 9 for removing a residual workpiece (15) during cutting processing separate workpiece part (14, 14a-e).