Method and device for determining cutting parameters of a laser cutting machine

Abstract

The invention relates to a method for determining cutting parameters of a laser cutting machine (18), comprising the following steps: A) receiving at least one machine parameter, at least one process parameter and / or at least one material parameter; B) outputting properties of a laser-cut edge that can be cut by the laser cutting machine (18) and that can be influenced by the cutting parameters; C) receiving weights for the properties; and D) determining the cutting parameters using the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and also using the weighted properties. The invention also relates to a device for carrying out the method, in particular a device for machining a workpiece and / or a device designed to simulate a production process.

Description

Technical Field

[0001] The invention relates to a method for determining cutting parameters of a laser cutting machine, and a device for carrying out the method, in particular a device for machining a workpiece and / or a device designed to simulate a production process. Background Art

[0002] Laser cutting machines are ideal for the rapid production and processing of precision workpieces. In this context, a laser is typically used to cut the workpiece from a plate, particularly a metal sheet. Depending on the method, the energy introduced by the laser causes the workpiece material at the cut to melt, burn, or sublime. The ablated material is typically removed from the cut with the aid of a process gas.

[0003] The resulting cut edge has a surface whose characteristic features also depend on the process sequence or process parameters such as cutting speed or nozzle-sheet distance. Depending on the process and the area of application of the workpiece being produced, the cut edge must achieve a certain surface texture.

[0004] WO 2012 / 000995 A1 describes a dialog system for inspecting machining processes performed on a machine tool. A solution is determined for improving at least one quality characteristic of a subsequent machining process. An operator can predetermine the quality characteristic to be improved using an input device. Stored expert knowledge is used to determine the solution for improving the quality characteristic. To determine this solution, data determined by the machine tool's sensor system and / or photographs of the machined workpiece, along with associated material and machining data, are also read. Summary of the Invention

[0005] The object of the present invention is to further improve the method and the device for determining cutting parameters, in particular to further simplify the operation.

[0006] This object is achieved by a method according to claim 1 , a device according to claim 11 and a device according to claim 14 .

[0007] Therefore, the present invention relates to a method for determining cutting parameters of a laser cutting machine, the method comprising the following steps:

[0008] A) receiving at least one machine parameter, at least one process parameter and / or at least one material parameter;

[0009] B) outputting properties of a laser cut edge that can be cut by the laser cutting machine and that can be influenced by the cutting parameters;

[0010] C) receiving weights of these attributes;

[0011] D) Determining the cutting parameters using the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and also using the weighted properties.

[0012] The method thus includes, in step A), receiving at least one machine parameter, at least one process parameter, and / or at least one material parameter. The machine parameter specifies which laser cutting machine is to be used. The process parameter specifies which laser cutting process is to be used. The material parameter specifies which material is to be cut, i.e., for example, the material of the metal sheet to be cut. The receiving in step A) can be performed, for example, by an operator via an input unit. The receiving in step A) can also be performed via a data interface.

[0013] The method comprises outputting, in step B), properties of a laser cut edge that can be cut by the laser cutting machine that can be influenced by the cutting parameters. The properties of the laser cut edge that can be influenced by the cutting parameters include, for example, characteristics of the cut edge itself and characteristics of the process used to produce the cut edge. Characteristics of the cut edge are, for example, burrs, burr height, burr thickness, edge inclination, roughness, discoloration, uniformity. Characteristics of the process are, for example, robustness, which is also called process reliability and indicates, for example, the risk of incorrect cutting. Other characteristics of the process can be the productivity and / or gas consumption of the process. For example, the properties can be output to the operator via an output unit. The output of the properties in step B) can also be accomplished, for example, via a data interface.

[0014] Cutting parameters for laser cutting on a laser cutting machine are, for example, feed (or forward rate), nozzle-metal sheet distance, setup size, gas pressure, focus diameter, laser power, nozzle diameter, gas type.

[0015] In step C), the weights of the attributes are received. In this case, an attribute is a property of the laser cut edge that can be influenced by the cutting parameters. In this case, the attributes include characteristics of the cut edge as well as characteristics of the process. The weight of the attribute indicates the importance of the attribute relative to the other attributes. Not all attributes can be optimized at the same time; in some cases, the requirements of the various attributes for the cutting parameters are different or even contradictory. Therefore, weighting is beneficial for being able to accurately determine the importance of these attributes in their relationship to each other. The reception in step C) can be accomplished, for example, by an operator via an input unit. The input unit is preferably coupled to an output unit, via which the attributes are output in step B). In one embodiment, the reception in step C) can also be accomplished via a data interface.

[0016] In step D), the cutting parameters are determined using the at least one machine parameter, the at least one process parameter, and / or the at least one material parameter, as well as the weighted attributes. The cutting parameters are determined, for example, by weighted optimization of multiple objective functions. The objective functions are attributes of a laser-cut edge that can be cut by the laser cutting machine and that can be influenced by the cutting parameters. The parameters to be optimized are the cutting parameters. This solution is accomplished, for example, by at least one data aggregation routine based on a known data set.

[0017] The data aggregation routine can be designed to aggregate one or more known data sets (so-called input data sets) to form a new data set (i.e., output data set). The output data set can include one or more numbers or vectors. All or part of the output data set can be provided to another data aggregation routine in the form of an input data set. The determination of the cutting parameters is particularly preferably completed in the form of an algorithm with multiple associated data aggregation routines. In particular, hundreds, preferably thousands of such data aggregation routines can be associated with each other. This significantly improves quality and speed. One, in particular more, and particularly preferably all data aggregation routines can be configured to combine multiple output data with attribute weights in each case and thus aggregate them to form a new data set. Data sets belonging to different attribute weights can also be aggregated. In an embodiment of the present invention, at least one data aggregation routine can be changed and / or the combination of data aggregation routines can be changed. The data aggregation routine can, for example, be a neural network or a machine learning algorithm, such as an evolutionary algorithm.

[0018] Particularly preferred is a method in which the characteristics of the cut edge include one and / or more of the following cut edge quality characteristics:

[0019] Roughness intensity

[0020] Roughness shape

[0021] Burr height

[0022] Burr shape

[0023] Cutting edge inclination

[0024] Color change

[0025] Upper edge of the cut

[0026] Pitting, single pitting, pitting accumulation, spontaneous combustion

[0027] Hollow cutting surface profile

[0028] Edge melting at the upper cutting edge / lower cutting edge

[0029] Edge cavity cutting above the lower edge / below the upper edge

[0030] Local groove deviation

[0031] Cracks in the cut surface

[0032] Cutting the bead chain on the upper edge

[0033] The end of the cut surface is not cut through

[0034] Cutting angle deviation between the two cutting surfaces

[0035] Deviation of cutting angle of a cutting surface

[0036] Uneven groove depth

[0037] Corrugated cutting surface profile

[0038] Groove trails are too large

[0039] Widening of the cutouts on the upper side / edge and lower side / edge of the workpiece

[0040] The groove depth is too large and the surface is strongly roughened

[0041] The cutting surface is uneven along the cutting direction

[0042] Uneven cutting starting point

[0043] · Sticky residue on the lower side

[0044] Slag shell, cutting edge welding, welding beads, shear melt

[0045] Burr formation, burr beads, fine needle-like burrs, obvious burrs, long breakable burrs, short unbreakable burrs, very strong burrs

[0046] Longitudinal cutting interruption and beam attenuation

[0047] There are splashes on the surface of the material, forming filaments

[0048] Discoloration of the cut surface, discoloration of the cut ends, discoloration of the cut surface, discoloration of the corners, and smoke residue.

[0049] The determination of the cutting parameters is preferably performed by the computing unit. In one embodiment of the present invention, the reception of the machine parameters, material parameters, and process parameters, the output of the attributes, and / or the reception of the attribute weights are performed via an input / output unit coupled to the computing unit. The reception of the machine parameters, material parameters, and process parameters, the output of the attributes, and / or the reception of the attribute weights can also be performed via a data interface of the computing unit. In this case, the received data can, for example, be predetermined by another computing unit, and / or the output data can be processed by this another computing unit and / or a second additional computing unit. This can be used, for example, for plant simulations.

[0050] In one embodiment, at least one of the cutting parameters determined in step D) can be output in step E1). This can be done, for example, via an output unit to an operator, which is used to output the output in step B). Alternatively, the output can be done to the operator and / or another operator via another output unit. The output in step E1) can also be done via a data interface.

[0051] In a preferred embodiment, in step E1), all determined cutting parameters are output (i.e., transmitted) to the laser cutting machine. In one embodiment, the laser cutting process is then performed using the transmitted cutting parameters. Optionally, the cutting result can then be transmitted back, for example, via an optical image, and provided as an input data set to a data aggregation routine.

[0052] In one embodiment, information about at least one of these properties is output in step E2). On the one hand, this may involve outputting the input that has just been performed in the form of feedback to a possible operator. In addition, this may involve outputting information about the weight of the property that has just been entered and other properties. This is advantageous when inputting weights in step C), for outputting the influence of the input weights on other properties. Thus, for example, the way in which a property (i.e., the characteristics of the cutting edge itself and the characteristics of the process) changes due to a change in the weighting factor can be output. This output can be performed, for example, on the output unit used in step B) and / or E1).

[0053] In one embodiment, the reception in steps A) and / or C) is performed by means of a graphical user interface. In this context, the graphical user interface can be arranged on the input unit or connected to the input unit via a data line. The input unit can at the same time be part of the computing unit. Receiving can comprise, for example, receiving operator input. For the reception in step A), input fields can be displayed, for example, which are assigned to parameters, such as at least one machine parameter, at least one process parameter and / or at least one material parameter. An entry into the input fields makes it possible to subsequently receive the parameters. The graphical user interface can further be configured such that it displays optical images of sliding controls, each image corresponding to a property that can be influenced by a cutting parameter. By adjusting the displayed sliding controls, for example by means of a pointer instrument or by means of a touch-sensitive screen, the weighting of the properties can then be set—step C).

[0054] In one embodiment, the output in steps B), E1) and / or E2) is performed by means of a graphical user interface, which may correspond to the graphical user interface intended for the reception in steps A) and / or C). In this context, the graphical user interface may be arranged on the output unit, connected to the output unit via a data line, and / or be part of the input / output unit. The output unit and / or the input / output unit may simultaneously be part of the computing unit. For the output in step E2), for example, the influence of the input weights on other properties in addition to the weights input in step C) may be output. Thus, for example, the way in which properties (i.e., characteristics of the cutting edge itself and characteristics of the process) change due to a change in the weighting factor may be output. Numerical values and / or other visual displays may be indicated, for example in the form of colors and / or arrows, which clearly indicate which properties - for example, compared to the previous input - have been improved and / or deteriorated.

[0055] In one embodiment, in step F), a graphical representation of the laser cut edge is output, the graphical representation being associated with the use of the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and also associated with the cutting parameters. This makes it possible to provide the operator with optical feedback on the expected appearance of the laser cut edge at the selected weighting.

[0056] In one embodiment, in step F), for example, a photograph of a laser-cut edge is displayed, which is stored in a memory along with its parameters—machine parameters, process parameters, material parameters, cutting parameters. For the display in step F), the photograph with parameters closest to the current parameters is then selected. The memory can be located, for example, in the computing unit or at a remote location connected via a data line.

[0057] In another embodiment, the graphical representation of the laser cut edge displayed in step F) is determined by using a data aggregation routine, wherein the at least one machine parameter, the at least one process parameter and / or the at least one material parameter, and also the cutting parameters are used as input to the data aggregation routine. The data aggregation routine is used to generate a graphical representation of the expected laser cut edge.

[0058] A device for processing a workpiece on a laser cutting machine, adapted to perform a method for determining cutting parameters for the laser cutting machine, includes a graphical user interface configured to receive at least one machine parameter, at least one process parameter, and / or at least one material parameter. The graphical user interface is further configured to output properties of a laser-cut edge capable of being cut by the laser cutting machine, wherein these properties can be influenced by the cutting parameters. The graphical user interface is further configured to receive weightings for these properties. The graphical user interface is preferably part of an input / output unit. Furthermore, the device for processing a workpiece includes a calculation unit configured to determine the cutting parameters using the at least one machine parameter, the at least one process parameter, and / or the at least one material parameter, and also using weighted properties. By inputting the machine parameters, process parameters, and / or material parameters and receiving their weightings, the device provides the option of determining cutting parameters that best meet the requirements of the device operator. This makes it easier for the operator to set up the device.

[0059] In one embodiment, the device for processing a workpiece comprises a laser cutting machine, which is configured to cut the workpiece by laser cutting using the cutting parameters. This embodiment enables the determined cutting parameters to be transmitted to the laser cutting machine so that the cutting process can be performed using the determined parameters.

[0060] In one embodiment, the graphical user interface is further configured to output at least one of the determined cutting parameters and / or output information about at least one of the properties. In this way, the user can estimate the impact of his inputs and evaluate possible results.

[0061] In one embodiment, a device for performing the method according to the present invention is designed to simulate a production process, which includes a laser cutting machine on which the laser cutting process can be performed using the determined cutting parameters. This embodiment is particularly advantageous in factory simulations, where different parameters of different machine tools in a factory can be combined in a single simulation. This can be used, for example, to optimize parameters on multiple machine tools in a factory or a factory network. For example, optimization can be performed regarding whether it is advantageous to deburr the cut edge in a separate deburring process after the cutting operation, or whether it is advantageous to cut the cut edge with as few burrs as possible by laser cutting.

[0062] Further advantages of the present invention will be apparent from the description and the accompanying drawings. Likewise, according to the present invention, the features mentioned above and those still to be described can be used individually or in any desired combination as a plurality. The embodiments shown and described are not to be understood as exhaustive, but rather as illustrative examples for the purpose of outlining the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 Schematically shows a flow chart of the method according to the present invention;

[0064] Figure 2 schematically illustrates an apparatus for machining a workpiece; and

[0065] Figure 3 An example of a graphical user interface is shown. DETAILED DESCRIPTION

[0066] exist Figure 1 The method for determining the laser cutting machine 18 ( Figure 2 In a method for optimizing cutting parameters, at least one machine parameter, at least one process parameter, and / or at least one material parameter is received in step A). This can be accomplished, for example, by an operator selecting a process, material, machine, or other process for which the cutting parameters should be optimized. In step B), attributes of a laser-cut edge capable of being cut by a laser cutting machine 18 and that can be influenced by the cutting parameters are output. In step C), weights for the attributes are received. This is preferably accomplished through operator input related to the attributes output in step B). The importance of the individual attributes changes depending on the weights. If the same weight is entered for each attribute, all attributes have the same importance. In step D), the cutting parameters are determined using the at least one machine parameter, the at least one process parameter, and / or the at least one material parameter and the weighted attributes. In this determination, attributes with greater weights are assigned a higher importance. For example, if all attributes have the same weight, they have the same importance in determining the cutting parameters, as mentioned above.

[0067] The method can be implemented, for example, in the computing unit 14 ( Figure 2 ), the parameters and weights are input as operator preferences via the input / output unit into the calculation unit and can be received by the calculation unit 14. Taking these inputs as a starting point, the "optimal" cutting parameters are determined and output. In addition, it is visually indicated that a change in a parameter and / or a weight limits the possibilities at other points, and the approximately expected cutting edge is displayed.

[0068] This helps the operator to precisely obtain the cut edge that best meets his or her requirements during the laser cutting operation. The operator is also provided with the possibility of changing the settings related to the cutting parameters themselves and, in the process, is assisted by the method and / or the device in determining the set of cutting parameters that produces a cutting result that is closest to the desired laser cut edge.

[0069] Figure 2 A device 10 for machining a workpiece is schematically shown. The device 10 has a graphical user interface 12, which can be part of an input / output unit, for example. The graphical user interface 12 is configured to execute at least Figure 1 Steps A), B), and C) of the method are as follows: receiving at least one machine parameter, at least one process parameter, and / or at least one material parameter; outputting properties of a laser-cut edge that can be cut by a laser cutting machine, wherein these properties can be influenced by the cutting parameters; and receiving weights of these properties. In addition, the device 10 has a calculation unit 14, which is configured to determine these cutting parameters by using the at least one machine parameter, the at least one process parameter, and / or the at least one material parameter and by using the weighted properties. For example, a program code for implementing the method can be stored in the memory 16 of the device 10. The laser cutting machine 18 is designed to cut a workpiece by means of a laser beam, i.e., a laser cutting method is implemented using the determined cutting parameters. For this purpose, the cutting parameters determined in the calculation unit 14 can be output to the laser cutting machine 18.

[0070] Figure 3 By way of example, a graphical user interface 12 is shown which may be used in accordance with Figure 2 In the device 10.

[0071] Graphical user elements that allow the operator to input material parameters, machine parameters, and process parameters are arranged in a first area 12.1 of the surface 12. In the example shown, the material parameters "Material" - the material of the workpiece to be cut - and "Thickness" - the thickness of the workpiece - can be indicated. For example, stainless steel, construction steel, aluminum, or copper, or a combination thereof, can be used as the material. Depending on the material, the thickness of the workpiece can vary from less than 1 mm to several centimeters. In addition, "Machine" can be indicated, i.e. the type of laser cutting machine 18 used. Examples of laser cutting machines 18 that can be used have been disclosed under the names Trumpf TruLaser 5030 and Trumpf TruLaser Center 7030. For example, the optical system used, etc., can be different depending on the laser cutting machine. In addition, "Laser" can indicate the type of laser used. Examples of laser specifications are disk lasers, CO2 lasers, each with a possible maximum laser power output specification.

[0072] In the second area 12.2, properties of the laser cut edge that can be cut by the laser cutting machine 18 and that can be influenced by the cutting parameters can be output and weights can be provided for these properties. For this purpose, the properties are output, for example, under the name of the property, in this case, for example "productivity", "process reliability", "burr", "edge inclination", "roughness". Preferably, a sliding control is displayed next to each property, by means of which the weight of this property can be adjusted with respect to the other properties from the second area 12.2. In this case, one end of the sliding control (for example the left) means "less important" and the other end of the sliding control (for example the right) means "very important". Further conditions that "bundle" multiple properties together can also be set in the second area 12.2. An example of this is that the cut edge is expected to comply with the standard DIN EN ISO 9013, which provides maximum values for roughness and edge inclination. In Figure 3 In the example shown, this condition is selected by ticking a checkbox. One condition that can be selected in the example shown is that cutting should be performed according to the machine manufacturer's recommendations. These recommendations include a set of cutting parameters for each material, thickness, machine, etc. This means that these parameters are not completely individually defined but rather generally valid, for example, based on empirical knowledge.

[0073] In the third area 12.3, the determined cutting parameters are output at the bottom. In the example shown, the values for "Feed (or Advance Rate)", "Nozzle-to-Sheet Distance", "Setting Size", and "Gas Pressure" are output here. The values to be adopted for the cutting parameters are advantageously limited by additional conditions so that the cutting process itself remains executable. For example, the nozzle-to-sheet distance should not be set too small to prevent collisions between the laser cutting head and the workpiece.

[0074] Above this—in the center area of 12.3—the expected properties of the laser-cut edge are displayed. In the example shown, these properties include characteristics of the cut edge itself, in this case "burr," "edge tilt," and "roughness." They also include characteristics of the process that produced the cut edge, in this case "productivity" and "process reliability." Next to the properties, there's a graphical indication of the quality of the property. This can, for example, indicate whether the property value has improved compared to the last cutting parameter determination—a green upward arrow—or whether it has deteriorated compared to the last cutting parameter determination—a red downward arrow.

[0075] In the upper part of the area 12.3 a graphic representation 20 is shown, for example a photograph of the laser cut edge, as would be expected under the determined cutting parameters shown in the bottom area of 12.3. The graphic representation 20 of the laser cut edge associated with the machine parameters, process parameters, material parameters and cutting parameters can be stored in the memory 16 ( Figure 2 In this way, with respect to given parameters, the graphical representation 20 that best matches the laser cutting result to be achieved can be read from the memory 16 and output on the graphical user interface 12 to provide information to the operator.

[0076] The present invention allows for an objective, transparent, and personalized display of the quality of the cut edge. Settings can be made intuitively. The operator is clearly shown how the properties of the cut edge are related, and how improving one property affects the quality of another. However, this also clearly illustrates the limits of the cutting process that can be set using cutting parameters. The cutting process becomes much more predictable.

[0077] List of Reference Numerals

[0078] 10 Devices

[0079] 12 Graphical User Interface

[0080] 12.1 First Area of the Graphical User Interface 12

[0081] 12.2 Second Area of Graphical User Interface 12

[0082] 12.3 The Third Area of the Graphical User Interface 12

[0083] 14 computing units

[0084] 16 Memory

[0085] 18. Laser cutting machine

[0086] 20 Graphical representation.

Claims

1. A method for determining cutting parameters of a laser cutting machine (18), the method comprising the following steps: A) receiving at least one machine parameter, at least one process parameter and / or at least one material parameter; B) outputting properties of a laser-cut edge that can be cut by the laser cutting machine (18) and can be influenced by the cutting parameters, wherein: The properties of the laser cut edge include characteristics of the cut edge itself and characteristics of the process used to produce the cut edge, wherein the properties can be output to an operator via an output unit; C) receiving weights of the properties, wherein the weights of the properties indicate the importance of one property relative to other properties, wherein the receiving can be completed by the operator via an input unit; D) determining the cutting parameters by using the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and by using the weighted properties; F) outputting a graphical representation (20) of the laser cut edge, which is associated with the use of the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and with the cutting parameters.

2. The method according to claim 1, wherein In step E1), at least one of the determined cutting parameters is output.

3. The method according to claim 2, wherein The determined cutting parameters are transmitted to the laser cutting machine (18).

4. The method according to claim 3, wherein The laser cutting process is performed by using the transferred cutting parameters.

5. The method according to claim 2, wherein In step E2), information about at least one of the attributes is output.

6. The method according to any one of claims 1 to 5, characterized in that The receiving in steps A) and / or C) is completed via the graphical user interface (12).

7. The method according to claim 5, wherein The output in steps B), E1) and / or E2) is completed via a graphical user interface (12).

8. The method according to claim 1, wherein The graphical representation (20) of the laser cut edge is read from a memory (16) based on the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and based on the cutting parameter.

9. The method according to claim 1, wherein A graphical representation (20) of the laser cut edge is determined by using a data aggregation routine, wherein the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and the cutting parameter are used as inputs to the data aggregation routine.

10. A device (10) for machining a workpiece, wherein: The device (10) comprises the following: • a graphical user interface (12) configured to: receive at least one machine parameter, at least one process parameter and / or at least one material parameter; and output properties of a laser cut edge that can be cut by a laser cutting machine (18), wherein the properties can be influenced by the cutting parameters, wherein the properties of the laser cut edge include characteristics of the cut edge itself and characteristics of the process for producing the cut edge, wherein the properties can be output to an operator via an output unit; and receive weights of the properties, wherein the weights of the properties indicate the importance of one property relative to other properties, wherein the receiving can be performed by the operator via an input unit, wherein the graphical user interface (12) is further configured to output a graphical representation (20) of the laser cut edge, which is associated with the use of the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and with the cutting parameter; • a calculation unit (14) configured to determine the cutting parameter by using the at least one machine parameter, the at least one process parameter and / or the at least one material parameter and by using the weighted properties.

11. The device according to claim 10, characterized in that A laser cutting machine (18) is configured to cut a workpiece by laser cutting using the cutting parameters.

12. The device according to claim 10 or 11, characterized in that The graphical user interface (12) is further configured to output at least one of the determined cutting parameters and / or to output information about at least one of the properties.

13. A device for carrying out the method according to any one of claims 1 to 9, characterized in that The device (10) is designed to simulate a production process, wherein the production process includes a laser cutting machine (18) on which a laser cutting process can be carried out by using determined cutting parameters.

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