Method and apparatus for varying processing parameter values during beam processing method

Abstract

The invention relates to a method for changing processing parameter values when performing a beam processing method, comprising the following steps: changing, preferably manually, a forward speed of the beam processing method with respect to a predefined forward speed; and varying a value of a second processing parameter with respect to a predefined value of the second processing parameter for the beam processing method and according to a change in the forward speed. The invention also relates to a beam processing system and a computer program product for implementing the method.

Description

Technical Field

[0001] The present invention relates to the field of beam processing methods, in particular to laser processing methods. In particular, the present invention relates to a method and a device for changing the value of a processing parameter relative to a predefined value during a beam processing method. Background Art

[0002] With regard to beam processing methods, it is known to adjust other processing parameters accordingly when the processing speed (i.e. the advance speed of the processing beam relative to the surface of the workpiece to be processed) changes. For example, when laser cutting metal workpieces, a common measure is to reduce the advance speed of the cutting beam when cutting angles or narrow radii are carried out in order to achieve a good cutting quality in these contour areas. When the advance speed is reduced, other cutting parameters usually also have to be adjusted in order to achieve the best cutting result. These other cutting parameters include laser power, cutting gas pressure, focus position, distance from the cutting head to the workpiece, etc. Such parameter changes during workpiece processing are usually preprogrammable and can be selected according to the contour to be processed, so that the processing machine performing the processing method independently adjusts the parameter values.

[0003] For example, DE 100 40 920 A1 discloses a method for process control of a laser processing process, in which method the travel speed of a laser processing head is set manually or automatically and the laser power is adjusted according to a predefined dependency on the travel speed when the travel speed changes.

[0004] The beam processing system also offers the possibility of manually controlling the advance speed during the process, for example by means of a so-called potentiometer. By manually intervening in the ongoing process, the operator can manually reduce the advance speed relative to the predefined advance speed in order to gain a better overview and thinking time in case of a hazard that is detected at short notice. Even when introducing new processes for which the optimal process speed has not yet been determined, the operator can approach the optimal advance speed by making manual changes.

[0005] If the advance speed is changed manually during the processing method, the other processing parameters are usually not adjusted. In this way, the operator can generate excess power in the processing method, for example by reducing the advance speed, and thus increase the process reliability during laser cutting. However, as the laser power increases, the following problem arises: if the excess power is too much, the workpiece support area and other machine parts can be damaged or even destroyed. Therefore, a solution for the advance adjustment, in particular manual advance adjustment, is needed, in which even at high rated outputs of the beam processing machine (for example, in the case of a laser power of 10 kW for a laser cutting machine), machine parts, in particular workpiece holders or workpiece supports, are not damaged. Summary of the invention

[0006] In order to solve the problem to be solved by the present invention, a method for changing the value of a processing parameter while executing a beam processing method is provided. In other words, for the beam processing method, the value of the processing parameter has been predefined (e.g., preprogrammed), the method is performed using this value, and the value can also be changed in addition to the preprogrammed change.

[0007] The method comprises: in a first step, changing the forward speed of the beam treatment method relative to a predefined forward speed. The forward speed is the speed at which the treatment beam of the beam treatment method moves relative to the surface of the workpiece to be treated. Preferably, the forward speed can be changed manually. For example, this can be done using a potentiometer. A predefined forward speed is understood to mean in particular a forward speed preprogrammed for the beam treatment method. The predefined forward speed does not have to be a constant forward speed. For example, the predefined forward speed along the contour of the workpiece to be treated can be preprogrammed with different values. For example, the forward speed predefined for the treatment process can be predefined to be higher along the straight contour section of the contour to be treated than along the curved area or angular area of ​​the contour to be treated. The change of the forward speed according to the invention refers to the forward speed values ​​predefined for the treatment process, regardless of whether these forward speed values ​​are already different from each other.

[0008] In a second step, the method comprises: changing the value of a second processing parameter relative to a predefined value for the second processing parameter of the beam processing method and depending on the change of the advancement speed according to the first step. In the context of the present disclosure, the advancement speed may also be understood as a first processing parameter.

[0009] With respect to the second processing parameter, it should also be understood that the predefined processing parameter value refers to a value preprogrammed for the current beam processing method. Therefore, a change in the value of the second processing parameter according to the present invention only occurs when the value of the second parameter changes relative to the parameter value preprogrammed for the current processing method.

[0010] According to the invention, the second processing parameter is automatically adjusted when the advancement speed is changed, preferably manually, and according to a predefinable dependency on the advancement speed. In this way, the process can be better controlled, especially when there are large changes in the advancement speed.

[0011] According to one variant, the values ​​of other processing parameters (third, fourth, fifth processing parameters, etc.) predefined or pre-set for the beam processing method can also be automatically changed according to the change of the forward speed, which is similar to the change of the second processing parameter value.

[0012] The beam processing method may preferably be a laser processing method, in particular a laser cutting method. However, in principle, the invention may also be applied to other beam processing methods, such as electron beam processing, other thermal separation or joining processes, water jet cutting and other related methods.

[0013] When the present invention is applied to a laser processing method, the second processing parameter may preferably be the laser power. However, the second processing parameter may also be, for example, the focal position of the processing laser beam, the distance between the processing head and the workpiece surface, or the pressure of the processing gas used in the laser processing method.

[0014] When the advancement speed is reduced, it is preferred according to the invention to reduce the laser power. According to the prior art, if the advancement speed is reduced compared to a predefined value, there is a risk of overpower, which can damage or destroy machine parts. For example, during laser beam cutting of sheet metal workpieces, the distance energy at which the processing beam strikes the workpiece support (in particular a metal grating) through the resulting cutting gap can be so high that the workpiece support is deformed or melted. By automatically reducing the laser power in the event of a manual reduction in the advancement speed, an uncontrolled overpower and subsequent damage to machine parts can be prevented.

[0015] According to a preferred variant, when the forward speed is reduced by no more than 30% relative to the predefined forward speed, the laser power can be reduced to a lesser extent than the forward speed or not reduced at all. For example, in the case of a manual reduction of the forward speed, preferably up to at least 10%, for example about 20%, relative to the preprogrammed forward speed, the laser power is not reduced. In this way, a controlled excess power can be generated, which can increase the process reliability of the relevant processing part. If the forward speed is further reduced, the laser power can also be reduced, preferably to the same extent as the forward speed. In this way, the excess power generated at the beginning of the feed deceleration can be maintained in a controlled manner during the further reduction of the forward speed.

[0016] There may preferably be a linear relationship between the change in the advancement speed according to the invention and the change in the laser power.

[0017] According to a further variant, a minimum value can be predefined for the laser power, at which the laser power remains at the minimum value when the advance speed is further reduced. The minimum value of the laser power can be selected such that damage to machine components can be avoided at least to a large extent regardless of the advance speed. If the processing beam stops completely, i.e. if the advance speed is reduced to zero, the laser power can also be reduced to zero, in particular rapidly.

[0018] The laser power for carrying out the laser processing method according to the method of the invention can preferably be at least 10 kW. This means that, at least in some sections, the value of the laser power predefined for the laser processing method can be at least 10 kW. At lower laser powers, damage to machine parts is generally less severe. In this respect, the positive effect of the invention is particularly evident in the specified range of laser powers from 10 kW.

[0019] In order to solve the problem to be solved by the present invention, a laser cutting method for cutting a plate-like workpiece or a tubular workpiece is also provided, which is implemented according to at least one of the above-mentioned variants. The laser cutting method comprises: in a first step, providing a plate-like workpiece or a tubular workpiece. The workpiece can, for example, be composed of a metal material (in particular low carbon steel) and / or have, for example, a thickness of at least 2 mm, preferably at least 10 mm.

[0020] In a second step, the laser cutting method comprises: cutting the workpiece using a predefined forward speed and a predefined laser power. As mentioned above, the predefined laser power can be at least 10 kW. The predefined forward speed of the cutting beam can vary over the contour course depending on the contour to be cut.

[0021] In a third step, the laser cutting method comprises manually changing, in particular reducing, the advancement speed compared to a predefined advancement speed and in a fourth step automatically changing the laser power relative to a predefined laser power and in accordance with the change in advancement speed.

[0022] A further advantageous variant of the laser cutting method occurs in combination with the features of the above-described method for changing the value of a process parameter, here the value of a cutting parameter. In particular, the laser power can only be reduced if the advance speed is reduced by at least 10%, for example 20%, relative to a predefined advance speed. Alternatively or additionally, the laser power can only be reduced to a predefined lower limit, at which serious damage to machine parts is unlikely or can even be avoided, regardless of the advance speed of the cutting beam.

[0023] In order to solve the problem to be solved by the present invention, a beam processing system is also provided. The beam processing system can be a laser cutting system in particular. The beam processing system comprises a beam processing machine, in particular a laser cutting machine, which is configured to process a plate-shaped workpiece or a tubular workpiece, in particular a metal workpiece. In addition, the beam processing system comprises: a control device, which is configured to control the beam processing machine to perform a beam processing method, in particular a laser cutting method, using predefined processing parameters; and a controller, which is used to manually change the forward speed relative to a predefined forward speed during the execution of the beam processing method. The control device is configured to change the value of a second processing parameter, in particular the value of the laser power, relative to the predefined value of the processing parameter and according to the manual change of the forward speed.

[0024] The control device may comprise an operating panel for inputting commands to the beam processing machine, wherein the controller is arranged on the operating panel. By means of the controller, which may preferably be designed as a control knob, the advancement speed may be manually changed during an automated (in particular preprogrammed) processing method. The controller may preferably be a potentiometer. The controller may also be implemented as a touch function in a touch display of the operating panel, for example.

[0025] In order to solve the problem to be solved by the present invention, a computer program product is also provided, which contains computer-readable information for executing the method according to one of the above variants.

[0026] Preferably, the computer program product, which may comprise a computer program with program code, is readable by a control device of a beam processing system as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following description of preferred exemplary embodiments serves to explain the invention in more detail with reference to the accompanying drawings.

[0028] In the attached picture:

[0029] Figure 1 A laser cutting machine for laser beam cutting is shown in schematic perspective view;

[0030] Figure 2 shows the Figure 1 An operating panel for inputting control and / or adjustment commands to a laser cutting machine;

[0031] Figure 3 and Figure 4 Graphs showing the dependency of laser power variation on advancement speed variation according to the present invention are each shown. DETAILED DESCRIPTION

[0032] Figure 1A laser cutting system 10 is shown, which has a laser cutting machine 12 and a metal workpiece 14 arranged on the laser cutting machine 12 for laser beam cutting. The laser cutting machine 12 preferably has: a CO2 laser, a solid-state laser or a diode laser as a laser beam source 16; a movable cutting head 18; and a workpiece support 20 on which the metal workpiece 14 is arranged. A laser beam 22 is generated in the laser beam source 16, which is guided from the laser beam source 16 to the cutting head 18 by means of an optical fiber cable (not shown) or a bending mirror 24. The laser beam 22 is directed to the metal workpiece 14 by means of a focusing optical unit arranged in the cutting head 18. The laser cutting machine 12 is also supplied with a cutting gas 26, such as oxygen and / or nitrogen. The cutting gas 26 is preferably supplied to the cutting head 18 in a pressure-controlled manner and is emitted from the cutting head together with the laser beam 22. The laser cutting machine 12 also includes a control device, which is programmed to move the cutting head 18 relative to the metal workpiece 14 according to a cutting contour 32. The control device includes an operation panel ( Figure 1 (not shown) an operator of the laser cutting system 10 may input control commands for the laser cutting machine 12 on the operation panel.

[0033] Figure 2 A beam processing system according to the present invention, in particular according to Figure 1 The operating panel 40 of the laser cutting system 10. In particular, the operating panel 40 can be part of a control device of the laser cutting system or of another beam processing system. The operating panel 40 comprises a screen 42 for displaying functions and information for operating the beam processing system. In addition, the operating panel comprises control and / or adjustment elements 44a to 44e, by means of which, for example, functions for setting and / or controlling processing processes that can be performed by means of the beam processing system can be controlled and displayed on the screen 42. The screen 42 or the display 42 can also include a touch function, which supplements or replaces the control and / or adjustment elements 44a to 44e shown. For example, it is possible to control the laser cutting system 10 by means of a touch function according to the embodiment of the present invention. Figure 1 The cutting process for cutting the contour 32 is set by means of an operating panel 40 on the laser cutting system 10. In order to perform the cutting process, the cutting parameters are predefined, for example, according to the material of the workpiece 14, the workpiece thickness and / or the cutting contour. The cutting parameters can be based on a technical table stored in a control device of the laser cutting system 10. In addition, the forward speed for cutting the workpiece 14 is also predefined. During the cutting process, the predefined forward speed can be changed, in particular reduced, by means of a control knob 44c in the control and / or adjustment elements 44a to 44e. According to the invention, the laser power is also adjusted according to the manual change of the forward speed to prevent a serious excess of power during the cutting process and to protect machine parts from damage.

[0034] Figure 3 and Figure 4 An example of the dependence of the laser power on the advance speed in the case of a manual adjustment (readjustment) of the advance speed is shown. The horizontal axis of the diagram indicates the percentage value of the advance speed (“potentiometer position” or position of the control knob 44c on the operating panel 40) during the laser cutting process, wherein the value “100%” corresponds to the advance speed predefined for the process in question and at the position of the cutting contour. Indicated on the vertical axis is the laser power—also as a percentage of the laser power predefined for the current process. According to Figure 3 According to curve 50a in FIG. 5 , the laser power initially remains unchanged when the forward speed is reduced by up to about 15%. If the forward speed is reduced further, the laser power is also reduced - here linearly with respect to the forward speed. If the laser power reaches a predefined minimum value of the laser power or a predefined minimum value of 50% of the laser power, the laser power will not be reduced further even if the forward speed is reduced further. The minimum value can be predefined variably depending on the requirements of the cutting process. Only when the cutting beam comes to a complete stop or immediately before coming to a stop, i.e. when the forward speed is reduced to 0%, the laser is switched off and the laser power is reduced to 0%. By delaying the reduction of the laser power when the forward speed is manually reduced, excess power can be generated during the cutting process and, therefore, the process reliability can be particularly increased if necessary. Setting a minimum value for the laser power can also contribute to ensuring process reliability. Preferably, the minimum value for the laser power can be selected so that damage to machine components - in particular to the workpiece support 20 (see FIG. 2 ) - can be avoided at least to a large extent. Figure 1 ) damage.

[0035] Figure 4 Another example of a change in the laser power condition during manual readjustment of the forward speed during laser cutting is shown. Figure 4 As shown in Figure 2, the laser power is reduced only when the forward speed is reduced by more than 30%. Figure 4 As shown, the minimum value of the laser power is set at 20%. The laser power is only reduced below this value when the forward speed is completely reduced to 0% or shortly before the forward speed is completely reduced to 0% (ie also by reducing the laser power to 0%).

Claims

1. A method for changing the value of a processing parameter when performing a beam processing method, the method comprising the following steps: varying, preferably manually varying, the advancement speed of the beam processing method relative to a predefined advancement speed; as well as The value of a second processing parameter of the beam processing method is varied relative to a predefined value of the second processing parameter and in accordance with the change in the advancement speed.

2. The method according to claim 1, wherein: The beam processing method is a laser processing method, in particular a laser cutting method.

3. The method according to claim 2, wherein: The second processing parameter is laser power.

4. The method according to claim 3, wherein: When the forward speed decreases, the laser power decreases.

5. The method according to claim 3 or 4, wherein: When the advancing speed is reduced by not more than 30% relative to the predefined advancing speed, the laser power is not reduced or is reduced to a lesser degree than the advancing speed.

6. The method according to any one of claims 3 to 5, wherein: There is a linear relationship between the change in the forward speed and the change in the laser power.

7. The method according to any one of claims 3 to 6, wherein: A minimum value can be predefined for the laser power, and wherein, when the laser power reaches the minimum value, the laser power remains at the minimum value when the advancement speed is further reduced.

8. The method according to any one of claims 3 to 7, wherein: The laser power is at least 10 kW.

9. A laser cutting method for cutting a plate-shaped workpiece or a tubular workpiece, the laser cutting method comprising: Provide plate-shaped or tubular workpieces; cutting the workpiece using a predefined forward speed and a predefined laser power; manually changing, in particular reducing, the forward speed relative to the predefined forward speed; as well as The laser power is automatically varied relative to the predefined laser power and in accordance with the variation of the advancement speed.

10. A beam processing system (10), comprising: A beam processing machine (12) configured for processing a plate-shaped workpiece and / or a tubular workpiece (14); a control device configured to operate the beam processing machine (12) to perform a beam processing method using predefinable processing parameters; a controller (44c) for manually varying the advancement speed relative to a predefined advancement speed during performance of the beam processing method; Therein, the control means is configured to vary the value of a second process parameter relative to a predefined value of the process parameter and in dependence on a manual variation of the forward speed.

11. The beam processing system (10) according to claim 10, in, The control device includes an operation panel (40) for inputting commands to the beam processing machine (12); and Wherein, the controller (44c) is arranged on the operation panel (40).

12. A computer program product comprising computer readable information for executing the method according to any one of claims 1 to 9.

13. The computer program product according to claim 12, which can be read by a control device of the beam processing system (10) according to any one of claims 10 to 11.

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