METHOD FOR CHECKING AT LEAST ONE SUBREGION OF A COMPONENT AND CHECKING DEVICE FOR CHECKING AT LEAST ONE SUBREGION OF A COMPONENT

Abstract

A method for checking at least one subregion of a component, in particular a component of a turbomachine, including at least the steps of a) providing a blank; b) producing at least the subregion from the blank by machining the blank using at least one tool and using at least one force sensor-to record at least one force curve of at least one force acting during machining on the at least one tool; c) checking whether there is at least one deviation-of the at least one force curve from at least one predetermined target curve-of the at least one force curve, the at least one deviation-characterizing at least one material defect-contained in an unmachined segment of the subregion. A checking device for checking at least a subregion of a component is also provided.

Claims

1-13. (canceled)

14: A method for checking at least a subregion of a component, the method comprising at least the steps of: a) providing a blank; b) producing at least the subregion from the blank by machining the blank using at least one tool and using at least one force sensor to record at least one force curve of at least one force acting during machining on the at least one tool; c) checking whether there is at least one deviation of the at least one force curve from at least one predetermined target curve, the at least one deviation characterizing at least one material defect contained in an unmachined segment of the subregion.

15: The method as recited in claim 14 wherein step c) is performed during production of the at least one subregion (12) from blank (10) in accordance with step b).

16: The method as recited in claim 14 wherein, in step c), the at least one force curve is compared to at least one further force curve characterizing a machining of at least one further component, and the at least one deviation in the at least one subregion is thereby evaluated, the at least one further component having at least one further material defect that is similar to the at least one material defect and at least one further deviation of the at least one further force curve from the at least one predetermined target curve being present.

17: The method as recited in claim 16 wherein a position of the at least one material defect in the unmachined segment is at least approximately determined by comparing the at least one force curve with the at least one further force curve.

18: The method as recited in claim 16 wherein the at least one deviation in the at least one subregion is evaluated using at least one force gradient of the at least one force curve or of the at least one further force curve.

19: The method as recited in claim 18 wherein the at least one force gradient is time-dependent or location-dependent.

20: The method as recited in claim 18 wherein at least one change in the at least one force gradient effected by the layer-by-layer material removal from the blank during machining is used in order to evaluate the at least one deviation.

21: The method as recited in claim 16 wherein the at least one further force curve is determined before the at least one force curve.

22: The method as recited in claim 14 wherein an artificial neural network implements the checking in step c).

23: The method as recited in claim 14 wherein at least a cutting force acting during the machining on the at least one tool is used as the at least one force.

24: The method as recited in claim 14 wherein a milling cutter or a lathe tool is used as the at least one tool.

25: The method as recited in claim 14 wherein the component is a turbomachine component.

26: A checking device for checking at least a subregion of a component, the checking device comprising: a connection receiving force-curve sensor signals characterizing at least one force curve of at least one force acting during the machining on the at least one tool, from at least one force sensor upon a production of the at least one subregion from a blank by machining the blank by at least one tool; the checking device on the basis of the force-curve sensor signals characterizing the at least one force curve, checking whether there is at least one deviation of the at least one force curve from at least one predetermined target curve of the at least one force curve, the at least one deviation characterizing at least one material defect contained in an unmachined segment of the subregion.

27: The checking device as recited in claim 26 further comprising a display device for displaying at least the at least one deviation of the at least one force curve from the at least one predetermined target curve.

28: The checking device as recited in claim 26 wherein the component is a turbomachine component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other features of the present invention will become apparent from the claims, the figures, and the detailed description. The features and feature combinations mentioned above in the description, as well as the features and feature combinations mentioned below in the detailed description and/or shown in isolation in the figures may each be used not only in the indicated combination, but also in other combinations, without departing from the scope of the present invention. Thus, embodiments of the present invention that are not explicitly shown and explained in the figures, but derive from and can be produced from the explained embodiments on the basis of separate feature combinations, are also considered to be included and disclosed herein. In addition, embodiments and combinations of features which, therefore, do not have all of the features of an originally formulated independent claim are also considered to be disclosed. Moreover, variants and feature combinations, which go beyond or deviate from the feature combinations described in the antecedent references to the claims, are also considered to have been disclosed, in particular by the above explanations. In the drawing,

[0025] FIG. 1 is a schematic representation of a component for a turbomachine as well as of a blank, from which at least a subregion of the component may be produced by machining;

[0026] FIG. 2 is a cutaway view of the subregion of the component being produced by machining by a tool in the form of a milling cutter, a schematically illustrated checking device implementing a checking for material defects in an unmachined segment of the subregion; and

[0027] FIG. 3 is a diagram showing a force curve of a force acting on the tool during machining, a predetermined target curve of the at least one force curve as well as various deviations of the force curve from the target curve, the deviations characterizing various material defects contained in the unmachined segment of the subregion.

DETAILED DESCRIPTION

[0028] FIG. 1 schematically shows a blank 10 which has a blank outer contour. The outer contour of the blank is an outer contour of blank 10 prior to a machining by a tool 16 in the form of a milling cutter, which is shown exemplarily in FIG. 2.

[0029] FIG. 2 illustrates exemplarily a method for checking at least one subregion 12 of a component of a turbomachine that is shown in FIGS. 1 and 2, where, in a step a), blank 10 is first provided. In a step b), at least subregion 12 is produced from blank 10 by the machining of blank 10 using tool 16, and at least one force sensor 20 records force curve 18 of at least one force acting during the machining on the at least one tool 16. In step c), a checking takes place as to whether there are deviations 22, 24 of the at least one force curve 18 from at least one predetermined target curve 26 of the at least one force curve 18, deviations 22, 24 characterizing specific material defects 28, 36 contained in an unmachined segment 14 of subregion 12. Force curve 18, target curve 26 as well as deviations 22, 24 are exemplarily illustrated in a diagram shown in FIG. 3. In the diagram shown in FIG. 3, force values in [N] are plotted on an ordinate axis and time values in [s] on an abscissa axis. At least one cutting force, which acts during machining on the at least one tool 16, is used as the at least one force. Depending on whether tool 16 is in the form of a milling cutter or lathe tool, the cutting force may be composed of a plurality of cutting force components, which may include a feed force, a passive force and (in the case of the milling cutter) a normal feed force. In FIG. 3, the force values plotted on the coordinate axis are specific to the passive force.

[0030] In the present case, deviation 22 characterizes material defect 28, whereas deviation 24 characterizes material defect 36. Here, material defect 28 is in the form of a segregation or void and thus constitutes a relatively soft microstructural region. In the present case, material defect 36 is in the form of a carbide accumulation and constitutes an especially hard microstructural region in comparison to material defect 28, as is discernible from force curve 18.

[0031] Step c) of the method is performed here during production of the at least one subregion 12 from blank 10 in accordance with step b). In step c), the at least one force curve 18 is compared with a plurality of further force curves (which are not specifically shown in FIG. 3 for the sake of clarity). The further force curves each characterize a machining of a plurality of further components (not shown in detail here). By comparing the at least one force curve 18 with the further force curves, it is possible to evaluate deviations 22, 24 in the at least one subregion, the further components each having at least one further material defect, which, in comparison to material defects 28, 36, is substantially identical, and respective further deviations of the further force curves from target curve 26 being present. The further force curves are determined before the at least one force curve 18.

[0032] The respective further force curves of the plurality of further force curves may be correlated with metallography data sets determined from a respective metallography of the further components of the plurality of further components and, additionally or alternatively, with low-cycle fatigue data sets determined from a respective low-cycle fatigue of the further components of the plurality of further components. The respective further force curves, the metallography data sets and/or the low-cycle fatigue data sets may be recorded in a material-defect cutting force database. The material-defect cutting force database may be used for checking subregion 12 and thus the component as well as for checking future components, which, like the component, may be checked on the basis of the method, respectively using checking device 32, to render possible an especially informative checking and reliable detection of segregations or other material defects. On the basis of the material-defect cutting force database, which may also be abbreviated as database, it is possible to statistically evaluate a probability of defects (material defects) occurring in subregion 12 and/or in the entire component, whereby especially accurate information about a quality of subregion 12, respectively of the component is made possible. This makes it possible for non-specification compliant material (scrap) to be detected and separated out at an early stage. The method may also be applied to other machining methods, which, besides milling, also include drilling and broaching, for example, and the statistical significance may thereby be further enhanced. For this purpose, the database may include further empirical data sets determined during machining by the various machining methods.

[0033] By comparing the at least one force curve 18 with the further force curves, it is possible to at least approximately determine a respective position of material defects 28, 36 in unmachined segment 14.

[0034] Deviations 22, 24 in the at least one subregion 12 are evaluated using respective force gradients of the at least one force curve 18 and, additionally or alternatively, of the further force curves. For the sake of clarity, FIG. 3 merely shows a force gradient 30 of the respective force gradients associated with the at least one force curve 18.

[0035] The respective force gradients of force curve 18 and, additionally or alternatively, of the further force curves are time-dependent here, as is discernible on the basis of force gradient 30 in FIG. 3.

[0036] To evaluate deviations 22, 24, at least one change in the at least one force gradient 30 effected by the layer-by-layer material removal from blank 10 during machining is used over time. If, for example, during the layer-by-layer material removal, material defect 28 in the form of a segregation or void is passed over multiple times, characteristic cutting force curve 18 results, which may be evaluated and analyzed in a positionally accurate (spatially resolved) manner.

[0037] In step c), an artificial neural network, in particular a deep learning method is performed to implement the checking. The artificial neural network thereby includes respective data sets characterizing the further force curves as respective parts of an empirical data set, whereby training may be initiated. The artificial neural network may be trained, for example, on the basis of the material-defect cutting force database. Overall, therefore, the data sets, which characterize the further force curves, form an empirical data set. The material-defect cutting force database may include the empirical data set.

[0038] In greatly simplified form, FIG. 2 shows a checking device 32 for checking subregion 12. Checking device 32 is adapted for recording the at least one force curve 18 of the force acting during the machining on tool 16 during production of subregion 12 from blank 10 by the machining thereof by tool 16, by the checking device receiving force-curve sensor signals, which characterize force curve 18, from force sensor 20. In addition, checking device 32 is adapted for checking whether there are deviations 22, 24 of force curve 18 from predetermined target curve 26 of force curve 18 on the basis of the force-curve sensor signals characterizing the at least one force curve 18.

[0039] The feed force, the passive force and the normal feed force may be recorded separately from one another with the aid of force sensor 20 and digitized as time series, for example, at a sampling rate within the range of from 20 to 40 kHz, thus transmitted as the force-curve sensor signals to checking device 32 or to a processor device (not shown) of checking device 32.

[0040] In addition, checking device 32 includes a display device 34 for displaying the at least one deviation 22, 24 of the at least one force curve 18 from the at least one predetermined target curve 26.

[0041] The present method as well as the present checking device 32 make it possible to detect defects, in particular in the form of segregations, as in the present example of material defects 28. This eliminates the need for a costly and time-consuming etch test.

[0042] The method, respectively checking device 32 makes it possible for a volume of blank 10, respectively of the component and thus also of subregion 12, which is to be machine-cut during machining, to be evaluated by dynamic cutting force measurement (in which corresponding force curve 18 is determined) with regard to the occurrence, for example, of the segregation (material defect 28) or with regard to an occurrence of a plurality of segregations, it being possible, for example, for a size, a position and, additionally or alternatively, a brittle behavior of the individual segregations to be evaluated.

[0043] In comparison to a pure etching surface test (etch test) known from the related art, where it is merely possible to check a test volume extending over a depth of approximately 0.5 mm, a significantly larger volume may be evaluated on the basis of the method, respectively using checking device 32.

[0044] At least one characteristic value may preferably be ascertained from a number of deviations 22, 24 and thus from the number of material defects 28, 36, which may be used as a quality criterion for producing future components, thus, for example, future turbine disks. This characteristic value may characterize a number of segregations per volume element of blank 10 and/or of subregion 12 or a size distribution of the segregations of blank 10 and/or of subregion 12, for example.

LIST OF REFERENCE NUMERALS

[0045] 10 blank [0046] 12 subregion [0047] 14 unmachined segment [0048] 16 tool [0049] 18 force curve [0050] 20 force sensor [0051] 22 deviation [0052] 24 deviation [0053] 26 target curve [0054] 28 material defect [0055] 30 force gradient [0056] 32 checking device [0057] 34 display device [0058] 36 material defect