METHOD FOR PRODUCING WORKPIECE PARTS FROM A PLATE-SHAPED WORKPIECE, DATA PROCESSING PROGRAM AND PROCESSING MACHINE FOR PRODUCING THE WORKPIECE PARTS

Abstract

A method for producing workpiece parts from a plate-shaped workpiece in a processing machine or laser processing machine includes positioning and holding the workpiece on a workpiece support by clamping devices. A plurality of workpiece parts are cut out of the workpiece with a process beam. The process beam is moved relative to the workpiece support by a processing head and/or the workpiece is moved relative to the workpiece support by the clamping devices. A cutting process for processing the workpiece to produce the workpiece parts is interrupted at least once by a relaxation step for the workpiece. During the relaxation step at least one clamping device is released to relax the workpiece. The at least one clamping device is closed following the relaxation and before continuing the cutting process. A data processing program and a processing machine for producing the workpiece parts are also provided.

Claims

1. A method for producing workpiece parts from a plate-shaped workpiece in a processing machine or a laser processing machine, the method comprising: positioning the plate-shaped workpiece on a workpiece support and using clamping devices to hold the plate-shaped workpiece relative to the workpiece support; using a process beam to cut a plurality of workpiece parts out of the plate-shaped workpiece; at least one of using a processing head to move the process beam relative to the workpiece support or using the clamping devices to move the plate-shaped workpiece relative to the workpiece support; interrupting a cutting process for processing the plate-shaped workpiece to produce the workpiece parts at least once by a relaxation step for the plate-shaped workpiece; and during the relaxation step, releasing at least one clamping device in order to relax the plate-shaped workpiece and, following the relaxation of the plate-shaped workpiece and before continuing the cutting process, closing the at least one clamping device.

2. The method according to claim 1, which further comprises activating a number of relaxation steps during the cutting process for processing the plate-shaped workpiece according to at least one of a number of workpiece parts to be produced from the plate-shaped workpiece, a material thickness of the plate-shaped workpiece, a size of the workpiece parts or a power of the process beam.

3. The method according to claim 1, which further comprises interrupting the cutting process for the relaxation step after a cutting step for completely cutting a workpiece part and before a beginning of a next cutting step for cutting a subsequent workpiece part.

4. The method according to claim 1, which further comprises: holding the plate-shaped workpiece along a side edge by using a plurality of the clamping devices; releasing the clamping devices along the side edge one after another from an outside inward, for a relaxation of a partial region of the plate-shaped workpiece; keeping at least two of the plurality of clamping devices closed for fixedly holding the plate-shaped workpiece, and subsequently, following the relaxation of the partial region of the plate-shaped workpiece, closing the opened clamping devices again from an inside outward.

5. The method according to claim 1, which further comprises using three of the clamping devices to hold the plate-shaped workpiece along a side edge, and, for the relaxation of the plate-shaped workpiece, first of all opening and closing one outer clamping device and subsequently opening and closing an opposite outer clamping device.

6. The method according to claim 1, which further comprises: using four or more clamping devices to hold the plate-shaped workpiece along a side edge, and, for the relaxation of the plate-shaped workpiece, first of all opening an outer clamping device in one half of the workpiece, followed by at least one inner clamping device adjacent the outer clamping device; keeping two further clamping devices or the clamping devices from another half of the plate-shaped workpiece opposite to the opened clamping devices closed; and subsequently, first of all closing an inner clamping device and then a clamping device further outward, and repeating a closing an inner clamping device and then a further outer clamping device on an opposite side of the plate-shaped workpiece.

7. The method according to claim 1, which further comprises carrying out a greater number of relaxation steps for a material thickness of the plate-shaped workpiece of 4 mm or less, than for a material thickness of the plate-shaped workpiece of 4 mm or more.

8. The method according to claim 1, which further comprises carrying out a relaxation step at least one of before or after cutting a workpiece part having at least one of an edge length of greater than 500 mm or an elongate shape having a ratio of edge lengths of a surrounding rectangle to each other of greater than 2:1.

9. The method according to claim 1, which further comprises nesting the workpiece parts to be produced from the plate-shaped workpiece in rows and columns, and during the cutting of workpiece parts forming a row adjacent the clamping devices, activating at least one relaxation step following a final cutting of at least two workpiece parts.

10. The method according to claim 1, which further comprises: using the clamping devices to hold the plate-shaped workpiece along a side edge; and cutting the workpiece parts lying in a half or a third of the plate-shaped workpiece remote from the clamping devices without a relaxation step.

11. A non-transitory data processing program for a machine controller of a processing machine or a laser cutting machine having a workpiece support, clamping devices for gripping a plate-shaped workpiece positioned on the workpiece support, and a beam source for producing a process beam directed onto the plate-shaped workpiece by a processing head; the data processing program having instructions stored thereon, that when executed on a processor, activate the processing machine or laser cutting machine to perform the method according to claim 1.

12. A processing machine for producing workpiece parts from a plate-shaped workpiece, the processing machine comprising: a workpiece support; clamping devices for gripping a plate-shaped workpiece positioned on said workpiece support; a processing head; and a beam source for producing a process beam directed onto the plate-shaped workpiece by said processing head; the processing machine producing the workpiece parts from the plate-shaped workpiece according to the method of claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0031] FIG. 1 is a diagrammatic, perspective view of a processing machine for producing workpiece parts from a plate-shaped workpiece;

[0032] FIG. 2 is an elevational view of a plate-shaped workpiece with clamping devices for describing a relaxation step;

[0033] FIG. 3 is an elevational view of the plate-shaped workpiece with an alternative number of clamping devices for illustrating a relaxation step; and

[0034] FIG. 4 is a diagram illustrating an exemplary time sequence of a relaxation step according to the variant illustrated in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

[0035] Referring now to the figures of the drawings in detail and first, particularly, to FIG. 1 thereof, there is seen a processing machine 11 for producing workpiece parts 14 from a plate-shaped workpiece 12. The workpiece parts 14 are produced from the plate-shaped workpiece 12 by a separating processing operation, in particular by using a process beam 13. The processing machine can be in the form of a laser processing machine for laser cutting of workpiece parts 14 with a laser beam as the process beam 13. For the cutting processing of the workpiece parts 14, the process beam 13 may also be a plasma beam.

[0036] During the processing, the plate-shaped workpiece 12 rests on a workpiece support 15 which is formed, for example, from two workpiece support surfaces 16 which are disposed adjacent to each other and which are spaced apart, with a gap 18 being formed. The workpiece support 15 includes a rest plane E which corresponds to an XY plane of the XYZ coordinates system illustrated in FIG. 1.

[0037] A plurality of clamping devices 20, 21, 22, 23 are activated by using a handling device 19, which includes a drive, not illustrated specifically. Through the use of the clamping devices 20, 21, 22, 23, the plate-shaped workpiece 12 can be displaced on the workpiece support 15 in a movement direction X and moved to a predefined processing position. The clamping devices 20, 21, 22, 23 are preferably configured as clamping claws which engage along a side edge 24 of the plate-shaped workpiece 12. Alternatively, it can also be provided that, in order to move or assist the movement of the plate-shaped workpiece 12 in the X direction, the workpiece support 15 itself is configured as a moving device, for example in the form of one or more revolving conveyor belts, as is described in German Application DE 10 2011 051 170 A1 by the Applicant pf the instant application.

[0038] The gap 18 lying between the workpiece support surfaces 16 of the workpiece support 15 extends in the Y direction preferably over the entire movement path of a processing head 25 which aligns and focuses the process beam 13 with and on the plate-shaped workpiece 12. The processing head 25 is guided by a driven carriage 26, which serves as the moving device, on a stationary gantry 27. The processing head 25 is activated so as to be movable in the Y direction above the gap 18. In the example illustrated, the processing head 25 can additionally also be movable in a controlled manner in the X direction within the gap 18. For this purpose, the carriage 26 can be moved in a controlled manner in the X direction by an additional moving device 28, for example in the form of a linear drive. With the aid of the moving devices 26, 28, which build on each other, the processing head 25 can be positioned both in the X direction and in the Y direction in a desired cutting position within the gap 18. The processing head 25 can optionally also be displaced along a third movement direction (Z direction) in order to adjust the distance between a processing nozzle 29 of the processing head 25 and the workpiece surface.

[0039] Disposed within the gap 18 are two support carriages 31, 32 which each extend over the width of the gap 18 and are movable in the gap in a controlled manner in the Y direction and also independently of each other. A respective covering element 33, 34, through the use of which the gap 18 is closed, is provided at the respective ends of the support carriages 31, 32 remote from the process beam 13. The process beam 13 is produced by a beam source 36, in particular a laser source, and fed by using a beam guide, not illustrated specifically, to the processing head 25 and output by the latter.

[0040] During the processing of the plate-shaped workpiece 12 which is held by the clamping device 20, 21, 22, 23 and which rests on the workpiece support 15, the following processing operations, for example, are carried out in order to avoid distortions occurring in the plate-shaped workpiece 12:

[0041] A first embodiment of the method for producing workpiece parts 14 from the plate-shaped workpiece 12 by a separating processing operation is described in more detail with reference to FIG. 2.

[0042] The plate-shaped workpiece 12 has an elongate rectangular geometry. Along one side edge 24, in particular the longer side edge of the plate-shaped workpiece 12, the plate-shaped workpiece 12 is held, for example, by three clamping devices 20, 21, 22. The engagement of three clamping devices 20, 21, 22 takes place in the case of smaller plate-shaped workpieces 12, for example up to a length of the side edge 24 of 2400 mm. The workpiece parts 14 are, for example, nested in six rows 41 and four columns 42. Starting from a starting point 44, the workpiece parts 14 are cut in the clockwise direction or in the counterclockwise direction and a cutting gap 45 is introduced by the process beam 13 until the process beam 13 again reaches the starting point 44. At the starting point 44, a microjoint which connects the workpiece part 14 to the plate-shaped workpiece 12 can be formed. The workpiece 14 can also be completely separated from the plate-shaped workpiece 12.

[0043] During a cutting process for processing the plate-shaped workpiece 12, one or more workpiece parts 14 are cut with the process beam 13. In order to reduce the distortions produced by heat being input into the plate-shaped workpiece 12, a relaxation step is carried out at least once during the cutting process for processing the workpiece between two cutting steps for cutting workpiece parts. The sequence of such a relaxation step is described below.

[0044] For example, first of all the first, or outer, clamping device 20 can be opened so that the partial region of the plate-shaped workpiece 12 which is assigned to the clamping device 20 can relax. The two further clamping devices 21, 22 remain closed in order to maintain the position and orientation of the plate-shaped workpiece 12. After the one partial region of the plate-shaped workpiece 12 which is assigned to the first clamping device 20 has relaxed, this clamping device 20 is closed. Subsequently, the third, or outer, clamping device 22 which is provided on the opposite side of the plate-shaped workpiece 12 is opened. After the partial region of the plate-shaped workpiece 12 which is assigned to the third clamping device 22 has relaxed, the clamping device 22 is closed again. The relaxation step in the case of, for example, three clamping devices 20, 21, 22 for the plate-shaped workpiece 12 is then finished. In this relaxation step, the central clamping device 21 remains permanently closed.

[0045] Such a relaxation step can be carried out, for example, whenever one or more workpiece parts 14 in the first and/or in the second and/or in the third row 41 are processed. A relaxation step can also take place whenever the workpiece parts 14 are produced in columns 42. When the workpiece parts 14 are produced along a column 42, the number of relaxation steps is increasingly increased as the workpiece parts 14 get increasingly closer to the clamping device 20, 21, 22.

[0046] FIG. 3 illustrates a diagrammatic view of a plate-shaped workpiece 12 which has a length of the side edge 24 of, for example, greater than 2400 mm. In this case, at least four clamping devices 20, 21, 22, 23 engage on the side edge 24. When the plate-shaped workpiece 12 is of such a size, the relaxation step takes place, for example, as follows:

[0047] The clamping devices 20, 21, 22, 23 clamp the plate-shaped workpiece 12 during the production of the at least one workpiece part 14. After the one workpiece part 14 is completely cut, the relaxation step is initiated before the at least one next workpiece part 14 is cut. First of all, an outermost clamping device, for example the clamping device 23, is opened. The adjacent inner clamping device 22 is then opened. As a result, the partial region of the plate-shaped workpiece 12 that is assigned to the clamping devices 22, 23 can be relaxed. The opened clamping devices 22, 23 are then closed from the inside outward, i.e. first of all the inner clamping device 22, followed by the outer clamping device 23. As a result, for example, a right half of the plate-shaped workpiece 12 is relaxed. The clamping devices 20, 21 remain closed during the first phase of the previously described relaxation step.

[0048] This sequence is subsequently carried out for the left half of the plate-shaped workpiece 12, i.e. first of all the clamping device 20 is opened, followed by the clamping device 21, while the clamping devices 22 and 23 remain closed. Subsequently, the clamping device 21 and finally the clamping device 20 are closed again. A second phase of the relaxation step and therefore the entire relaxation step are then finished.

[0049] An analogous procedure for carrying out the relaxation step is also provided whenever, for example, five, six or more clamping devices engage on a side edge 24 of the plate-shaped workpiece 12. The consecutive opening of the clamping devices from the outer edge toward the center takes place to the extent that at least two clamping devices are always kept closed during the relaxation step.

[0050] FIG. 4 shows the time sequence of opening (or releasing) and of closing the clamping devices 20, 21, 22, 23 during a relaxation step according to the variant described in conjunction with FIG. 3. In the top half of the illustration, the clamping pressure profile (in hPa) is depicted over the duration of the relaxation step (time in s) for each clamping device 20, 21, 22, 23. In the bottom half, the sensor signals 20b, 21b, 22b, 23b corresponding to the respective pressure curves 20a, 21a, 22a, 23a are depicted (the value “0” indicates the closed (desired) state and the value “1” indicates the opened (desired) state of the respective clamping device 20, 21, 22, 23).

[0051] If the clamping pressure is reduced below a predetermined value (5000 hPa in the example illustrated), the respective clamping device can be considered to be opened or released. In order to release distortions in a clamped plate-shaped workpiece, it is therefore not necessarily required for all of the clamping devices 20, 21, 22, 23 to be completely released (i.e. clamping pressure = 0) (in the example, the clamping pressure of the inner clamping devices 21 and 22 is in each case not reduced to 0).

[0052] The second phase of the relaxation step can be initiated as soon as the clamping pressure of the clamping devices 22, 23 from the first phase lies above a minimum clamping pressure (e.g. 5000 hPa). Since the plate-shaped workpiece 12 is not moved during the relaxation step, a lower clamping pressure than during the cutting operation is already sufficient to securely fix the workpiece 12.

[0053] The relaxation step is finished if the clamping pressure of each of the clamping devices 20, 21, 22, 23 has again reached the desired value necessary for the operation (9300 hPa in the example).