Method for operating a machine tool and machine tool

Abstract

The invention relates to a method for operating a machine tool (12), comprising the following steps: - during a machining process, in which a first batch of at least one first workpiece is machined by means of the machine tool (12): detecting at least one measured value by means of a detection device (16) of the machine tool (12) (step S1); - determining at least one measured value (32) characterizing the machining process by means of an electronic computing device (12) on the basis of the measured variables detected during the machining process (step S2); and - comparing the determined measured value with at least one reference function determined on the basis of at least one reference machining process performed by means of the machine tool (10) and / or by means of another machine tool and stored in an electronic storage device (18) before the machining process in time, the reference function characterizing a reference machining process performed for machining a second batch of at least one second workpiece (step S3).

Description

TECHNICAL FIELD

[0001] The invention relates to a method for operating a machine tool and to a machine tool. BACKGROUND

[0002] The patent document WO 2012 / 153157 A2 discloses a method for optimizing the cutting force in a milling process for machining a workpiece by means of a milling tool. The patent document DE 10 2017 000 471 A1 describes a known numerical control system. Furthermore, a system for determining the wear state of a machine tool is known from the patent document DE 10 2006 006 273 A1.

[0003] Furthermore, the patent document US 4 719 586 A discloses a method for controlling a process for manufacturing a discontinuous workpiece. SUMMARY

[0004] The invention solves the technical problem of providing a method and a machine tool, with which different batches of workpieces can be processed particularly process-reliably by means of the machine.

[0005] According to the invention, the technical problem is solved by a method for operating a machine tool and by a machine tool for machining a workpiece.

[0006] A first aspect of the invention relates to a method for operating a machine tool. The machine tool is designed for machining, in particular mechanically machining, a workpiece. To this end, the machine tool comprises, for example, at least one tool and at least one drive device, by means of which at least one relative movement along at least one axis and / or about at least one axis can be generated between the workpiece and the tool, in particular when the tool at least temporarily contacts the workpiece, in order to process the respective workpiece. The respective workpiece can thereby be machined, in particular mechanically, by means of the tool and thereby by means of the machine tool. The machining that can be generated by means of the machine tool is, for example, a chip-removing machining, in particular turning or milling. In a first step of the method, at least one measured variable is detected by means of a detection device of the machine tool during a machining process, in which or during which at least one first workpiece of a first batch is machined by means of the machine tool. If, for example, the first workpiece is chip-removing machined and thereby chip-removing machined by means of the machine tool during the machining process, the machining process is, for example, a so-called chip-removing machining process.

[0007] It is preferred to use a detection device of the machine tool, i.e. a detection device which is arranged in the machine tool and which originally belongs to the machine tool, as the aforementioned detection device, for example to use a measurement signal or a plurality of measurement signals of the detection device in order to operate, in particular to control or regulate, the machine tool during the machining process. The measurement variable is here for example characterized by the measurement signal or by the plurality of measurement signals. The respective measurement signal is for example an electrical signal. It is therefore preferred to provide that the measurement variable is not detected or measured by an additional external sensor, but that the measurement variable is detected and thus measured by means of the originally provided internal detection device, also referred to as measurement device, of the machine tool.

[0008] In a second step of the method, at least one measurement value characterizing the machining process is determined by means of an electronic computing device, in particular a computing device of the machine tool, from the measurement variable detected during the machining process. The machining process during which the measurement variable is detected is also referred to as the current machining process, since at least a part of the method is executed during the current machining process and the measurement variable is detected here by means of the detection device. It can in particular be provided that the at least one measurement value is determined, in particular calculated, by means of the electronic computing device during the machining process, i.e. during the current machining process.

[0009] In a third step of the method, the determined measurement value, in particular the measurement value determined by means of the electronic computing device and / or during the machining process or during the current machining process, is compared with at least one function value of at least one preferably multi-dimensional function characterizing a reference machining process executed for machining at least one second workpiece of a second batch, the function being determined in time before the machining process from at least one reference machining process executed in time before the machining process by means of the machine tool and / or by means of a further machine tool and being stored in an electronic storage device, in particular a storage device of the machine tool or of the electronic computing device. For this purpose, the reference function is for example called from the storage device. The storage device can be an integral part of the machine tool and / or of a control device for operating, in particular for controlling or regulating, the machine tool, or the storage device is an external storage device with respect to the machine tool and / or with respect to the control device, for example a data cloud also referred to as cloud. In other words, the reference function can be stored locally or on or in a control device also referred to as machine control device, or on or in one or more peripherals of the machine control device and / or in particular centrally in a data cloud.

[0010] The reference function is preferably a multi-dimensional function, i.e. a multi-dimensional reference function. It is furthermore known that the reference function is a one-dimensional function, i.e. a one-dimensional reference function.

[0011] In other words, the reference function characterizes or describes a reference machining process, which was or is executed with the machine tool and / or with other machine tools, which are provided in addition to the machine tool, in time before the current machining process, in which or during which a second workpiece was or is machined, in particular mechanically and preferably cuttingly, with the machine tool or with the other machine tools. It can be provided in particular that the second workpiece, which belongs to the second batch, was machined in the reference machining process with the same tool or has been machined with the same tool, with which the first workpiece, which belongs to the first batch, is also machined in the current machining process.

[0012] The reference value can be obtained or determined, for example, from the reference machining process, which makes it possible to determine it with the machine tool and / or with the other machine tools by executing the reference machining process with the machine tool and / or with the other machine tools. Here, for example, the influence of machine-specific factors is compensated for, preferably only, by means of a machine model and / or by measuring specific factors. Examples of this are the current of a shaft or simply the torque, which must be dissipated without tool intervention, for example, due to friction.

[0013] The comparison of the measurement value with the reference function can be understood in particular as correlating and / or associating and / or relating the measurement value with the reference function. Alternatively or additionally, the comparison of the measurement value with the reference function can be understood as visualizing and here, for example, displaying on an electronic display device and / or determining or calculating, in particular with the aid of an electronic computing device, possible differences or possible differences between the measurement value and the reference function, in particular between the measurement value and at least one function value of the reference function. Alternatively or additionally, the comparison of the measurement value with the reference function can be understood as using both the reference function and the measurement value in order to execute at least one calculation process or determination process from the measurement value and the reference function, in order to determine, in particular to calculate, at least one calculation value and / or at least one calculation function therefrom, for example.

[0014] The reference machining process is a machining process executed with the machine tool or with the other machine tools, which was or has been executed in time before the current machining process and is referred to as the reference machining process, in particular in order to conceptually distinguish it from the current machining process. In order to be able to conceptually distinguish the machining process, during which the measurement variable is detected in the first step, from the reference machining process, the machining process during which the measurement variable is detected is also referred to as the current machining process or the first machining process.

[0015] The method according to the application achieves that the tool machine, in particular the operation of the tool machine, can be adapted to the first workpiece or to the first batch particularly early on the basis of the knowledge acquired from the reference machining process and thus from the machining of the second workpiece or of the second batch by means of the tool machine or by means of another tool machine. The knowledge is embodied, depicted or described here by means of the reference function. In other words, the method according to the application achieves that the tool machine, in particular the operation of the tool machine, can be adapted to the first batch particularly early on the basis of the reference machining process characterized by the reference function and thus on the basis of the second batch machined or machined at least partially before the current machining process is carried out by means of the tool machine or by means of another tool machine. The feature that the machining of the second batch in the scope of the reference machining process by means of the tool machine or by means of another tool machine is at least partially before the current machining process is carried out in time, in particular, is to be understood as meaning that at least a second workpiece of the second batch is machined by means of the tool machine or by means of another tool machine before the current machining process is carried out in time.

[0016] By comparing the measured values with the reference function, in particular, it is achieved that possible differences between the current machining process and the reference machining process and thus between the workpieces or between the batches are recognized particularly early, so that the tool machine, in particular process parameters for operating, in particular controlling or regulating, the tool machine, can be adapted to the possible differences particularly early.

[0017] The application is based, inter alia, on the recognition that a program, in particular a control program or a regulating program of a machine tool or a program for operating, in particular for controlling or regulating, a machine tool is usually optimized in today's manufacturing with regard to tool life, machining duration and component quality. However, the machinability, in particular the chipability, of certain materials has partly significant fluctuations, which can lead to different tool lives in connection with the respective batch. Without prior analysis of the material, these fluctuations, which are also referred to as variables, cannot currently be taken into account or lead to malfunctions or damage to the machine tool and the workpieces to be machined. The application now makes it possible, in particular automatically, to analyze batches, for example a first batch and a second batch, with regard to their properties, so that a particularly advantageous and optimized machining and minimization of malfunctions of the workpieces can be achieved thereafter. The respective batches are also referred to as material batches. In other words, the application is based, inter alia, on the recognition that, despite the same composition, in particular material composition, of the materials of the respective batches, it is possible to clearly distinguish the batches and thus the respective workpieces of the respective batches from one another with regard to their machinability. The machinability, in particular the chipability, of a first workpiece can thus be distinguished from the machinability, in particular the chipability, of a second workpiece, i.e. the workpieces, although composed of the same material and thus having the same material composition, are heat-treated in different ways. The respective batches can be distinguished from one another, inter alia, with regard to their machinability, whereas the respective workpieces of the respective batches are very similar or identical to one another, inter alia, with regard to their machinability. It can also be considered that the workpieces of the same batch can be distinguished from one another, inter alia, with regard to their shape. Only the method of machining should not differ significantly with regard to the reference function. Only after the inclusion of a plurality of reference functions in different operating points, in which a new reference function is generated by each cutting of a component or a workpiece, can such a deviation of the process occur.

[0018] The method according to the application now makes it possible, in particular automatically, to recognize possible differences between the workpieces and thus between the batches particularly early on the basis of the measurement values and on the basis of the reference functions. Process parameters influencing the operation and thus the machining process or the machining process carried out with the aid of the machine tool can then be adjusted, inter alia., in accordance with the comparison and adapted to the possible differences between the batches, so that, inter alia., the workpieces of the first batch can be machined, in particular cut, process-reliably and thus time-saving and cost-effectively and / or particularly economically for the machine tool.

[0019] Traditionally, possible differences between the batches are thus taken into account or undesired effects that can result from possible differences between the batches are thus avoided, i.e. for example, after processing one batch, another new or different batch is carefully introduced in the context of the manufacturing process. The personnel operating the machine tool here manually influence the process parameters on the basis of observations of the process and their experience. Furthermore, it can be considered in principle that a process monitoring takes place when a new batch is processed by means of a sensor device that is attached to the machine tool and is external with respect to the machine tool and that, for example, issues a warning or stops the process when defined limit values are exceeded or undershot. Due to the high outlay, a comprehensive pre-examination of the respective batch with respect to machinability, in particular to the ability to machine and to cut, is not usually carried out.

[0020] The method according to the application now makes it possible, in particular, to identify and take into account possible differences between the batches, in particular automatically or automatically using the internal detection means of the machine tool. By detecting the measured values by means of the detection means and comparing them with the reference function, it is possible to avoid or effectively and efficiently assist in manually adapting the process parameters to possible batch differences, so that, for example, the machine tool can be adapted to possible differences between the batches in a time-saving and cost-effective manner, i.e. quickly.

[0021] The detection of the measured variables is an analysis of the current machining process, for example designed as a cutting process or a cutting machining process, wherein, by means of this analysis of the current machining process, possible material-specific differences, i.e. possible differences, between the batches can be compensated for, in particular in such a way that, in particular, the process parameters or at least one parameter, simply also referred to as a parameter, and influencing the machining process carried out by means of the machine tool, are adjusted, i.e. changed or varied, in particular in accordance with the comparison. For this purpose, for example, measurement data are recorded on the machine tool, in particular by means of software. These measurement data are machine-internal data, which are provided, for example, in particular by the internal detection means and which characterize the detected measured variables. The data are characterized, for example, by or comprised by the aforementioned measurement signals. External sensors for detecting the measured variables are therefore not required and not provided.

[0022] The measurement variable is, for example, a torque, also referred to as a moment or a moment of an axis, which acts about an axis of the machine tool. In other words, the measurement variable can comprise the aforementioned torque. Alternatively or additionally, the measurement variable can be or comprise an electric current, for example, which flows through an electric or electronic component of the machine tool. The electric current can be, in particular, a motor current which flows through an electric motor of the machine tool. In other words, the motor current is supplied to the electric motor in order to thereby operate the electric motor. The electric motor is, for example, an integral part of the aforementioned drive device, such that the aforementioned relative movement between the tool and the workpiece is generated or can be generated during the current machining process by means of the electric motor by supplying the motor current to the electric motor. The measurement variable can alternatively or additionally comprise or be a deviation, in particular an adjustment deviation, of at least two axes of the machine tool. One of the at least two axes can be a feed axis along which the workpiece and the tool are moved linearly relative to one another, for example. A second one of the at least two axes can be a spindle or a spindle axis about which the workpiece and the tool are rotated relative to one another, for example.

[0023] The measurement variable is detected, for example, using measurement software. Alternatively or additionally, the aforementioned measurement data, which characterizes the detected measurement variable, is provided by means of the measurement software. It is particularly advantageous here that the measurement data is made available in real time or is provided for use in real time, in particular by means of the measurement software.

[0024] The measurement data or the measurement variable and / or the measurement value is stored and thereby buffered, for example, in an electronic storage device, in particular an electronic storage device of the machine tool, preferably an electronic computing device. After determining the measurement value or after detecting the measurement variable, the measurement value can be processed, in particular compared to a reference function, for example.

[0025] It is particularly advantageous that at least one parameter of a machining process to be carried out by means of the machine tool is adjusted, i.e. changed or varied, during the machining process, in particular by means of the electronic computing device, depending on the comparison. The parameter can thereby be the aforementioned process parameter, wherein the machining process or the corresponding machining process to be carried out by means of the machine tool for machining a corresponding workpiece is changed or can be changed by changing the parameter.

[0026] The process parameter, also referred to as the parameter, is adjusted, for example, automatically by means of the electronic computing device, in particular, depending on the comparison. It can also be considered that the parameter is adjusted depending on at least one input, in particular detected by means of the machine tool and generated by a person.

[0027] A further embodiment is characterized in that the determined measurement value is compared, in particular during the machining process, with at least one further function value of at least one, preferably multi-dimensional, second reference function, which is determined in time before the machining process from at least one second reference machining process carried out in time before the machining process by means of the machine tool and / or by means of a further machine tool and stored in the electronic storage device. The second reference function here characterizes a second reference machining process carried out for processing a third batch of at least one third workpiece. The aforementioned and the following design proposals for the first reference machining process, for the first reference function, for the second workpiece and for the second batch can also be transferred to the second reference machining process, the second reference function, the third workpiece and the third batch and vice versa. The second reference machining process is carried out in time between or after the first reference machining process, for example, by means of the machine tool and / or by means of a further machine tool, wherein in or during the second reference machining process the third workpiece is machined by means of the machine tool and / or by means of a further machine tool. In particular, the third workpiece is machined in the second reference machining process by means of the same tool by means of which the first workpiece is machined in the current machining process and / or the second workpiece is machined in the first reference machining process.

[0028] Furthermore, the aforementioned and the following design proposals for comparing the measurement value with the first reference function can also be transferred to comparing the measurement value with the second reference function and vice versa. The reference functions preferably have the same dimensionality and the same variables. As the respective name suggests, the respective, preferably multi-dimensional, reference function has not only one variable, but rather a plurality of variables and thus a plurality of dimensions that can be varied. The respective variables of the respective reference function here are, for example, process parameters or several or a portion of process parameters. The respective reference function describes or defines, inter alia, the respective dependencies of the variables from one another and thus of the process parameters from one another.

[0029] By considering not only the first reference function, but also the second reference function, a comprehensive, extensive or also simply referred to as basic reference basis is provided, according to which reference technology possible differences between batches can be particularly identified and compensated. In particular, by considering the reference basis it is particularly advantageously achieved that the machine tool is particularly precisely adapted to the first batch and thus to possible differences between the first batch and the second batch and / or between the first batch and the third batch, so that the first batch or the workpieces of the first batch can be particularly process-reliably machined by means of the machine tool.

[0030] It is particularly advantageous if the comparison of the calculated value, which occurs, for example, during the machining process and / or is carried out by means of the electronic computing device, with the first reference function and / or with the second reference function comprises a mathematical combination, in particular a linear combination, and preferably a convex combination, which is carried out, that is to say calculated, by means of the electronic computing device. In other words, the first reference function is combined, for example by means of the electronic computing device, with the second reference function by means of a mathematical combination, in particular by means of a linear combination, and preferably by means of a convex combination. By means of this combination, an actual function, which is preferably multi-dimensional, is determined, that is to say calculated, or approximately calculated, which comprises the measured values and characterizes the current machining process. The aforementioned and the following design proposals for the first reference function and / or the second reference function can be transferred here to the actual function, which is preferably multi-dimensional. This means, for example, that the actual function has the same dimension and the same variables as the respective reference function. The actual function is referred to as actual function because it characterizes, that is to say describes, the current machining process and thereby characterizes, that is to say describes, the machining of the first workpiece carried out or to be carried out by means of the machine tool. The actual function describes, in particular, the dependencies or relationships of the process parameters to one another during the execution of the current machining process, that is to say during the or a machining of the first batch or of the respective workpiece of the first batch.

[0031] A further embodiment is characterized in that at least a portion of the actual function, which is preferably multi-dimensional, is visualized by means of at least one function image, in that the function image is displayed on the electronic display device, that is to say on the electronic screen, in particular on the electronic screen of the machine tool. The respective reference function is preferably visualized by means of a respective at least one reference function image, in that the respective reference function image is displayed on the electronic display device. The function image and the reference function image or the plurality of reference function images are preferably displayed simultaneously on the electronic display device. A person observing the electronic display device can thereby, for example, visually see the function image and the respective reference function image, thereby enabling the person to quickly and simply and understandably identify possible differences between the batches. Furthermore, the person can identify from the function image the dependencies between the process parameters, which are relevant to the current machining process and thereby to the first batch. The person can in particular identify what degree of influence or what degree of influence a possible change in a first process parameter of the process parameters has or has had on a possible change in a second process parameter of the process parameters.

[0032] In a particularly advantageous embodiment of the application, at least one value of a first parameter or a first process parameter influencing at least one machining process to be executed by means of the machine tool is calculated by means of the electronic computing device in such a way that at least one second value of at least one second parameter or a second process parameter meets at least one predefinable or predefined criterion, the dependency of the at least one second value on the first parameter or the first process parameter being described by an actual function. In other words, in this embodiment, in particular, an optimization process or an optimization function is executed by means of the electronic computing device. In the context of an optimization function, the first value is determined in such a way that the second parameter, for example, assumes a desired parameter value in the form of a second value or that the parameter value is below or above a predefined or predefinable range. In this way, for example, it is possible to operate the machine tool by adjusting the first value and to subsequently machine the first batch using the machine tool in such a way that the respective workpieces of the first batch are machined by means of the machine tool as quickly as possible and / or as economically as possible for the machine tool and / or with as little force as possible.

[0033] It is particularly advantageous here that the at least one first value of the at least one first parameter is automatically adjusted by means of the electronic computing device. Thereby, it is possible to ensure a particularly process-reliable and time-saving and cost-effective machining.

[0034] A further embodiment is characterized in that the at least one first value of the at least one first parameter is adjusted in accordance with at least one detected and by a person generated input. In this embodiment, for example, the determined optimization potential can be presented to the person in the form of the first value, wherein the person can then decide whether the first value should be adjusted.

[0035] In order to achieve a particularly demand-oriented machining, it is provided in a further embodiment of the application that at least one criterion is adjusted and thereby predefined in accordance with at least one detected and by a person generated input. This means, for example, that the person operating the machine tool can adjust and predefine the criterion, which is also referred to as optimization criterion, so that the at least one first parameter can be optimized towards the optimization criterion predefined by the person.

[0036] In a particularly advantageous embodiment of the application, the method according to the application comprises a first reference machining process and / or a second reference machining process. It is thereby preferably provided that, in the context of the method according to the application, a straight reference machining process, i.e. a first and / or a second reference machining process, precedes the current machining process in time, wherein, in particular if the reference machining process is the first reference machining process, a second workpiece is machined by means of the machine tool or another machine tool. During the reference machining process, at least one measurement variable is detected by means of a detection device of the machine tool or another machine tool, wherein at least one reference measurement value characterizing the reference machining process is determined by means of an electronic computing device from the measurement variables detected during the reference machining process. Furthermore, a reference function is determined from the reference measurement value. In particular, the reference function is calculated. Thereafter, the machine tool can be particularly advantageously adjusted for possible differences between batches.

[0037] Finally, it is particularly advantageous if the first reference function and / or the second reference function and / or the actual function and / or the measurement value and / or the reference measurement value and / or at least one first value of the at least one first parameter is provided by the electronic computing device and loaded into a data cloud which is external with respect to the machine tool. Other machine tools which are external with respect to the machine tool can call up or download the respective reference function, actual function, measurement value, reference measurement value and / or first value from this data cloud. Thereby, the data determined by means of the machine tool can be used in or on other machine tools in order to be able to machine, in particular to cut, workpieces particularly process-reliably by means of the other machine tools. Not only can data be loaded into the data cloud (cloud), but also data (reference functions) can be downloaded from the cloud and utilized or used for the current machining process.

[0038] A second aspect of the application relates to a machine tool for machining, in particular for mechanically machining, a workpiece, wherein the machine tool is designed to carry out the method according to the first aspect of the application. The advantages and advantageous design solutions of the first aspect of the application can be considered advantages and advantageous design solutions of the second aspect of the application and vice versa.

[0039] The measured values are stored, in particular temporarily, and thus buffered, as shown, for example. In particular, a plurality of measured variables and / or a plurality of measured values of a measured variable are detected, so that, preferably, a plurality of measured values are stored and thus buffered, for example. The buffered measured values are then analyzed, for example, in accordance with a model of a machining process, for example, designed as a cutting machining process, wherein the model embodies, i.e., includes, a characteristic function in the form of a reference function for a material batch, in particular for the second batch and the third batch. The model embodies the characteristic function, in particular, by taking into account important process parameters, for example, tool wear, feed, cutting speed and cutting depth. This means that a first process parameter among the process parameters can be tool wear, i.e., wear of the tool, a second process parameter among the process parameters can be feed, a third process parameter among the process parameters can be cutting speed and a fourth process parameter among the process parameters can be cutting depth. The actual function, which is preferably multi-dimensional, can also be or be referred to as the characteristic function. The respective characteristic function is denoted, for example, as Fc. Furthermore, for example, the tool wear is denoted as vb, the feed as f, the cutting speed as vcand the cutting depth as ap. Since the respective characteristic function Fcdepends on f, ap, vcand vb, the characteristic function can also be described as:

[0040] Fc(f, ap, vc, vb).

[0041] The model takes into account, in particular, tool- and / or machine-specific differences. Machine-specific differences are understood in the sense that the measured variables and thus the measured values are not only influenced by the interaction between the workpiece and the machine tool or the tool, but also by the machine tool itself, i.e., by machine-inherent factors, for example, internal friction of the machine tool. By taking into account the machine-specific differences, for example, the respective machine-inherent factors can be subtracted from the measured variables or measured values, so that the measured values and, for example, the actual function represent the first workpiece and thus the first batch particularly precisely.

[0042] Since the respective reference functions are obtained, for example, from a plurality of material lots, these reference functions form a synthetic function series which covers a defined working area of the process in question. The working area is usually given by the permissible cutting parameters of the tool. On the basis of the model, on the one hand, optimized cutting parameters and their temporal adaptation can be defined before the process in accordance with the changing cutting conditions due to tool wear. On the other hand, it is possible to estimate early in the process, for example at the beginning of the machining of a new workpiece, which material lot is present by means of buffered measurement values. On this basis, the measurement data is analyzed, for example by forming a convex combination, which is used, inter alia, to interpolate the characteristic function of the current material lot or the first lot. As a result, the forces expected in the continuous machining or machining process and the estimate of the tool wear can be visually displayed to the person operating the machine tool, also referred to as the operator, in order to provide information about the material lot, in particular about the material lot-specific properties of the material lot, and to adapt the process if necessary. The optimization function provides an aid for this, which determines a favorable or optimal combination of adaptable process parameters and thereby, for example, minimizes or keeps particularly small the forces in the machining process such that the tool wear is as low as possible. It is thereby possible, for example, to include the criterion that the forces occurring in the respective machining process are below a preset threshold and thus, for example, as low as possible. The optimized process parameters are taken up, for example, manually by the operator or, in particular, automatically in a control program for operating, in particular for regulating or controlling, the machine tool. The selection of the variable or adaptable process parameters for the optimization can be configurable and thus adaptable to the process specification. In addition to the display on the machine tool, a cross-machine analysis is advantageous, in particular by uploading or loading into the data cloud also referred to as data cloud above. On this basis, further algorithms can be advantageously carried out and suppliers can be evaluated in terms of machinability, in particular of the lots.

[0043] Compared to conventional methods, by one aspect of the application process reliability can be increased by adapting the process parameters to the current batch, on the one hand, and the compensation carried out makes the effort when introducing a new material batch lower and saves costs for optimizing the program in terms of tool life. The automatic adaptation of the process parameters also reduces the intervention of the user and thereby saves the operator's time. The use of signals inside the machine, for example in the form of measured variables, is an advantageous aspect in order to save costs for additional sensors and to avoid limitations to the machine tool due to additional installations. In order to form or determine or carry out a combination, in particular a linear combination and preferably a convex combination, an algorithm is used, wherein the actual function is approximated by the combination and thereby the machinability or the machining property of the first batch. The algorithm for determining the convex combination for example calls these data and predicts the batch characteristics. The machine-specific reference characteristics are here represented by a statistical model or a system of functions and thereby represented by the respective function Fc. Furthermore, the continuity of the solution according to the application is an advantageous aspect, since the application can act on the machine tool itself and can also be used on other, additional machine tools, in particular via a data cloud. Thereby a global analysis is achieved. By the visual display a visual manufacturing can also be advantageously displayed. BRIEF DESCRIPTION OF DRAWINGS

[0044] Further advantages, features and details of the application result from the following description of preferred embodiments and from the attached drawings. The features and combinations of features mentioned in the above description of the application and the features and combinations of features mentioned in the following description of the drawings and / or shown alone in the drawings can be used not only in the respectively given combinations, but also in other combinations or on their own, without departing from the scope of the application.

[0045] In the drawings:

[0046] Figure 1 A diagram for illustrating the method according to the application and the machine tool according to the application is shown;

[0047] Figure 2 A flow chart for illustrating the method according to the application is shown;

[0048] Figure 3 An image for illustrating a multi-dimensional function is shown;

[0049] Figure 4 A further image for illustrating a multi-dimensional function is shown;

[0050] Figure 5 A further image for illustrating a multi-dimensional function is shown; and

[0051] Figure 6 A block diagram for further illustrating the method is shown.

[0052] In the drawings, identical or similar elements are denoted by the same reference signs. DETAILED DESCRIPTION

[0053] The following is based on Figure 1 A method for operating a machine tool 10, which is shown particularly diagrammatically in Figure 1 The machine tool 10 is designed for carrying out the method. By means of the machine tool 10, a workpiece can be machined, in particular mechanically and preferably cuttingly, so that a machining process in the form of a cutting machining process can be carried out by means of the machine tool 10. The machine tool 10 for this purpose comprises tools and drive devices, which are not shown in the drawing, by means of which, in the respective machining process, in particular when the tool is at least temporarily in contact with the workpiece, a relative movement is produced between the respective workpiece to be machined and the tool. By means of the tool and thus by means of the machine tool 10, the workpiece can thus be machined. In the respective machining process, the machine tool 10 is operated, in particular controlled or regulated, for example by means of an electronic computing device, wherein the electronic computing device for this purpose executes a program, in particular a digital program, which here is for example a control program or a regulation program. The electronic computing device can be an integral part of the machine tool 10, in Figure 1 which is shown particularly diagrammatically in and is denoted there by 12. The computing device 12 provides for example control signals by means of which the drive devices are controlled and thus operated, in particular controlled or regulated.

[0054] The design data 14 are for example input into the machine tool 10, so that the machine tool 10 is operated in accordance with the provided design data. On the basis of the design data, which for example originate from or are provided by a design software, the respective workpiece is machined in order thereby to manufacture from the respective workpiece a component which is described or defined for example by the design data.

[0055] Figure 2 A flow chart for further illustrating the method is shown. In a first step S1 of the method, at least one measured variable is detected by means of an internal detection device of the machine tool 10 during a machining process, in which or during which a first batch of at least one first workpiece is machined by means of the machine tool 10. The internal detection device of the machine tool 10 detects the at least one measured variable in Figure 1The measuring variable is, for example, an electric current, also referred to as motor current, which flows through or is supplied to the drive device in order to thereby move the workpiece and the tool relative to one another. The measuring variable can alternatively or additionally comprise a voltage which is applied to or supplied to the drive device in order to move the workpiece and the tool relative to one another by means of the drive device. In order to measure the motor current or the voltage, the detection device, for example 16, comprises an ammeter. The detection device 16, also referred to as measuring device, comprises, for example, a measurement software which is executed by the electronic computing device 12 and detects the measuring variable and / or calculates at least one measurement value which characterizes the machining process from the measuring variable in a second step S2 of the method. In other words, it is provided in the second step S2 that the measurement value is determined, in particular calculated, from the detected measuring variable, in particular by means of the electronic computing device 12. The measurement value is characterized, for example, by data which is also referred to as machine data or measurement data. The machine data are, for example, input into the electronic computing device 12, so that the electronic computing device 12 can operate the machine tool 10 in accordance with the machine data.

[0056] In a third step S3 of the method, the determined measurement value is compared with at least one multidimensional reference function which is stored in the electronic storage device 18, in particular in the electronic computing device 12, wherein the measurement value is compared with the reference function, for example by means of the electronic computing device 12. The reference function is determined or has been determined on the basis of at least one reference machining process which is performed by means of the machine tool 10 before the machining process in time, wherein the reference function characterizes a reference machining process which is performed for machining at least one second workpiece of a second batch of workpieces. In other words, in the context of the reference machining process, a second workpiece of the second batch is machined, in particular mechanically or cut, by means of the machine tool 10, wherein the multidimensional reference function characterizes the reference machining process. The reference function defines or describes, in particular, the interdependence of the process parameters, also referred to as parameters, on the basis of which the machine tool 10 is operated, in particular controlled or regulated, by the electronic computing device 12 during the reference machining process in order to machine the second workpiece of the second batch during the reference machining process.

[0057] Furthermore, it is possible to consider a second reference machining process performed or executed temporally before or after the first reference machining process. A multidimensional second reference function is determined or defined based on the second reference machining process, the second reference function characterizing the reference machining process. At least one third workpiece in a third batch is machined or processed using machine tool 10 during the second reference machining process. The second reference function, in particular, describes the interdependence of process parameters, based on which the machine tool 10 operates, in particular controls, or regulates, during the second reference machining process, especially by means of an electronic computing device 12. The multidimensional reference functions have the same dimension and, particularly, the same type of variables or process parameters, such that the process parameters whose interdependence is described by the first reference function are the same process parameters whose interdependence is described by the second reference function; however, the process parameters whose interdependence is described by the first reference function differ from those whose interdependence is described by the second reference function in terms of their respective values. Here, for example, the electronic computing device 12 is also used to compare the measured values ​​with the second reference function. Specifically, the comparison comprises performing a convex combination of multidimensional reference functions using an electronic computing device, thereby determining a multidimensional actual function that includes measurements and characterizes the machining process. The reference function and the actual function have the same variables or process parameters and the same dimension. The process parameters may, for example, be tool wear, feed rate, cutting speed, and / or depth of cut.

[0058] Depend on Figures 3 to 5 It is understood that, for example, at least a first part of a multidimensional actual function is visualized by a first function image 20, by displaying the function image 20 on an electronic display device 22, also known as an electronic screen, particularly on the machine tool 10. Furthermore, at least corresponding parts of the first and second reference functions, as well as the third and fourth reference functions, are visualized by corresponding function images 24, 26, 28, and 30, by displaying the function images 24, 26, 28, and 30 on the display device 22. Simultaneously, function images 20, 24, 26, 28, and 30 are displayed on the display device 22. Furthermore, in Figure 3 The aforementioned measured values ​​can be seen in the image, and these measured values ​​are represented by 32. The measured value 32 can specifically be a measurement point. Figure 3 It can be clearly seen that the actual function is a convex combination of the reference function and is approximated or approximately calculated through this convex combination.

[0059] Figure 4It is shown that alternatively or additionally the actual function and the reference function are visualized by the fact that the respective function images 20', 24', 26', 28' and 30' at least on the respective portions of the actual function and the reference function are displayed simultaneously on the display device 22. This can also be seen from Figure 5 Figure 5 It is shown that alternatively or additionally the function images 24", 26", 28" and 30" can be displayed simultaneously on the display device 22, which at least indicate the respective portions of the actual function and the reference function. Figure 3 Here, for example, the dependency of a first process parameter among the process parameters, which is designated by 34 and plotted on the ordinate, on a second process parameter among the process parameters, which is designated by 36 and plotted on the abscissa, is indicated. The first process parameter is, for example, the motor current and the second process parameter is, for example, the cutting speed. In contrast, Figure 4 The dependency of a third process parameter among the process parameters, which is designated by 38, on a fourth process parameter among the process parameters, which is designated by 40, is indicated. The third process parameter is, for example, plotted on the ordinate and is the motor current, and the fourth process parameter is, for example, the feed. Furthermore, Figure 5 The dependency of a fifth process parameter among the process parameters, which is designated by 42, on a sixth process parameter among the process parameters, which is designated by 44, is indicated. The fifth process parameter is, for example, the motor current and the sixth process parameter is, for example, the tool wear. At least one of the other process parameters, in particular the value of the other process parameters, is influenced, for example, by changing one of the process parameters, in particular the value of one of the process parameters, since the process parameters are in a dependency on one another. This dependency of the process parameters on one another is described by the actual function or by the respective reference function.

[0060] Finally, Figure 6 A block diagram for further indicating the method is shown. In block 46, the measured values or machine data, which are buffered, for example, and are also referred to as axis values, are read out. In block 48, the tool wear is calculated, for example, from the read-out axis values and from the intervention history. In block 50, the measured values are filtered, for example. In block 52, a convex combination is formed in order to approximate the actual function and thus the cutting characteristics of the current first batch, in particular of the first batch.

[0061] ​In block 54 a visualization is carried out, in the context of which the function image is displayed on the display device 22, for example. In block 56 an optimization of the variables and thus of the adjustable process parameters is carried out, for example, in particular in such a way that at least one first value of at least one first process parameter influencing the machining process to be carried out with the aid of the tool 10 is calculated, for example, with the aid of the electronic computing device 12, in such a way that at least one second value of a second process parameter meets a preset or presettable criterion and / or corresponds to a predetermined value and / or exceeds a threshold value and / or falls below a limit value, for example.

[0062] In block 58 an automatic adaptation of the process parameters is carried out, in such a way that the calculated first value is automatically adjusted, for example, with the aid of the electronic computing device 12. Alternatively or additionally, in block 60 a manual adaptation of the process parameters is carried out, for example, in such a way that the calculated first value or a different value of the first process parameter from the first value is adjusted by a person operating the machine tool.

[0063] The blocks 46, 48, 50, 52, 54, 56, 58 and 60 thus indicate a flow on the machine tool 10. Block 62 indicates a subsequent processing of data determined or calculated in the context of the method, which is also referred to as process data. These process data are shown schematically and are denoted by 64, in particular in block Figure 1 The process data 64 are transferred, for example, to a data cloud 66, which is also referred to as data cloud or cloud and is located externally with respect to the machine tool 10. The process data comprise, in particular, at least one reference function and / or an actual function, so that, for example, the process data 64 characterize the first batch and / or the second batch and / or the third batch, for example. Blocks 68 and 70 indicate a configuration. In block 68 a statistical model is adapted to the machine tool 10. The statistical model uses the reference function and thus a function series consisting of reference functions, here. In block 70 the statistical model is adapted to the tool. The statistical model thus takes into account, for example, tool and machine tool, in particular machine-specific, differences.

[0064] Finally, from the data cloud 66 the process data 64 can be retrieved and used for a process optimization 72, wherein the knowledge gained from the process optimization 72 can be incorporated into the design data 14 or into other design data. Figure 1 It can be seen that the process data 64 can be retrieved from the data cloud 66 and used for a process optimization 72, wherein the knowledge gained from the process optimization 72 can be incorporated into the design data 14 or into other design data.

Claims

1. A method for operating a machine tool (10), the method having the following steps: - a measured variable is characterized by at least one measurement signal of a detection device, the measurement signal being used to control or regulate the machine tool during a machining process, wherein the measured variable is a torque or comprises a torque, or the measured variable is a current or comprises a current, or the measured variable is a deviation of at least two axes of the machine tool or comprises a deviation of at least two axes of the machine tool; - at least one measurement value (32) characterizing the machining process is determined by means of an electronic computing device (12) from the measured variable detected during the machining process (step S2); and - the determined measurement value is compared with at least one function value of at least one reference function, the at least one reference function being determined in time before the machining process from at least one reference machining process performed in time before the machining process by means of the machine tool (10) and / or by means of other machine tools and being stored in an electronic storage device (18), the reference function characterizing a reference machining process performed for machining a second batch of at least one second workpiece (step S3). During the machining process, at least one first workpiece of the first batch is machined in the machining process by means of the machine tool (10): at least one measurement variable is detected by means of a detection device (16) of the machine tool (10) (step S1), wherein 2. The method according to claim 1, - at least one parameter influencing the machining process to be performed by means of the machine tool (10) is adjusted in accordance with the comparison.

3. The method according to claim 1, - the determined measurement value is compared with at least one further function value of at least one second reference function, the at least one second reference function being determined in time before the machining process from at least one second reference machining process performed in time before the machining process by means of the machine tool (10) and / or by means of other machine tools and being stored in an electronic storage device (18), the second reference function characterizing a second reference machining process performed for machining a third batch of at least one third workpiece.

4. The method according to claim 3, - the comparison comprises a combination of the reference functions performed by means of the electronic computing device, whereby an actual function comprising the measurement value (32) and characterizing the machining process is determined.

5. The method according to claim 4, - the combination is a linear combination. wherein 6. The method according to claim 4, - the combination is a convex combination.

7. The method according to claim 4, - at least a part of the actual function is visualized by means of at least one function image (20, 20', 20") displayed on an electronic display device (22) in such a way that the function image (20, 20', 20") is displayed on the electronic display device (22). wherein 8. The method according to claim 4, - at least one first value of at least one first parameter influencing the machining process to be performed by means of the machine tool (10) is calculated by means of the electronic computing device (12) in such a way that at least one second value of at least one second parameter dependent on the first parameter is at least satisfied by a predefinable or predefined criterion, the second parameter being described by the actual function.

9. The method according to claim 8, - at least one first value of at least one first parameter is automatically adjusted by means of the electronic computing device (12). wherein 10. The method according to claim 8, - 5. The method of claim 4, wherein, ​ 6. The method of claim 4, wherein, ​ ​ wherein ​ ​ wherein ​ ​ wherein ​ ​ wherein At least one first value of at least one first parameter is adjusted in accordance with at least one detected and by a person generated input.

11. The method according to claim 8, wherein, At least one criterion is adjusted and thereby preset in accordance with at least one detected and by a person generated input.

12. The method according to claim 1, wherein A reference machining process is executed in time before the machining process, in which a second workpiece is machined by means of the machine tool (10), wherein at least one measured variable is detected by means of a detection device (16) of the machine tool (10) during the reference machining process, wherein at least one reference measurement value characterizing the reference machining process is determined by means of an electronic computing device (12) from the measured variable detected during the reference machining process, and wherein the reference function is determined from the reference measurement value.

13. The method according to claim 1 or 4 or 8 or 12, wherein, The reference function and / or the actual function and / or the measurement value (32) and / or the reference measurement value and / or at least one first value of at least one first parameter are provided and loaded into a data cloud (66) which is located externally relative to the machine tool (10).

14. A machine tool (10) for machining a workpiece, wherein The machine tool (10) is designed to execute the method according to one of the preceding claims.

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