METHOD AND DEVICE FOR AUTOMATED MACHINING OF GEARWHEEL COMPONENTS
20180264570 ยท 2018-09-20
Inventors
Cpc classification
Y02P90/02
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
G05B2219/32187
PHYSICS
G05B2219/32221
PHYSICS
International classification
Abstract
A manufacturing environment having a machine tool, a measuring device, a storage medium, and having a computer programmed to control: a) chip producing machining of a first workpiece in a machine tool, b) acquiring at least two machine parameters of the machine tool during the chip producing machining of the first workpiece, c) storing the machine parameters in the storage medium, wherein the storing is performed with assignment to the first workpiece, and d) repeating steps a) to c) for a number of n workpieces; and, after one of steps a) to d), or later, triggering a testing method including: (i) selecting at least one of the workpieces, (ii) performing an automated test of the at least one selected workpiece using the measuring device, or (iii) performing a processor-controlled evaluation of the automated test to classify the at least one selected workpiece as a good part, or a reject part.
Claims
1. A method for the automated machining of workpieces, comprising the following steps: a) chip producing machining of a first workpiece in a machine tool, b) acquiring at least two machine parameters of the machine tool during the chip producing machining of the first workpiece, c) storing the at least two machine parameters in association with information identifying the first workpiece, d) repeating steps a) through c) for a number of n workpieces; and after one of steps a) though d), or at a later time, triggering a testing method comprising the following steps: (i) selecting at least one of the n workpieces, (ii) performing an automated test of the selected at least one workpiece, and (iii) performing a processor-controlled evaluation of the automated test adapted to classify the selected at least one workpiece as a good part or a reject part.
2. The method according to claim 1, wherein the automated test includes an automated measurement.
3. The method according to claim 1, including performing the automated test using a knowledge base or a databank.
4. The method according to claim 2, further including performing a correlation computation of said at least two machine parameters of multiple of said number of n workpieces and data acquired by said automated measurement of said multiple of workpieces, said correlation computation adapted to generate at least one evaluation criterion for the processor-controlled evaluation of method step (iii).
5. The method according to claim 2, further including data processing said at least two machine parameters of multiple of said number of n workpieces and data acquired by said automated measurement of said multiple of workpieces, said data processing adapted to generate at least one evaluation criterion for the processor-controlled evaluation of method step (iii) on the basis of correlations.
6. The method according to claim 1, further including the step of (iv) performing a processor-controlled correlation between the at least two machine parameters of the selected at least one workpiece and the processor-controlled evaluation of the selected at least one workpiece and storing said correlation in a databank.
7. The method according to claim 1, wherein at least one of the at least two machine parameters includes a mean value during said machining in step a), or at least one of the at least two machine parameters includes an interval defined by a minimum and a maximum during said machining in step a), or at least one of the at least two machine parameters includes multiple measured values during said machining in step a).
8. The method according to claim 1, including performing the processor-controlled evaluation in step (iii) using a workpiece specification, or using setpoint data, or using at least one evaluation criterion or a combination of evaluation criteria, so as to differentiate the selected at least one workpiece as a good part or a reject part.
9. The method according to claim 2, wherein the selecting step includes one of: selecting all of the n workpieces; selecting a subset of the n workpieces; selecting, during a first period of time, a number of the n workpieces so as to build up a databank and, during a second period of time that is chronologically later than the first period of time, selecting a smaller number of the n workpieces than selected during the first period of time; or selecting an n workpiece that existing data in a database indicates could qualify as a reject part.
10. The method according to claim 1, further including periodically performing a computer analysis using a databank or a storage medium so as to process a quantity of the data which is stored in the databank or the storage medium for more rapid access thereto.
11. The method according to claim 10, wherein the computer analysis includes a correlation analysis.
12. The method according to claim 1, further including triggering and performing a correction method that includes performing adaptations applied during automated machining of subsequent workpieces.
13. The method according to claim 12, wherein the correction method is triggered by one or more of software, the machine tool, or a measuring device or measuring machine.
14. A manufacturing environment comprising: at least one machine tool, at least one measuring device or measuring machine, at least one databank or storage medium, and a computer or processor programmed to control the following performed by the manufacturing environment: a) chip producing machining of a first workpiece in the at least one machine tool, b) acquiring at least two machine parameters of the at least one machine tool during the chip producing machining of the first workpiece, c) storing the at least two machine parameters in the at least one databank or storage medium in association with information identifying the first workpiece, d) repeating steps a) through c) for a number of n workpieces; and after one of steps a) through d), or at a later time, triggering a testing method comprising the following steps: (i) selecting at least one of the n workpieces, (ii) performing an automated test of the selected at least one workpiece with the measuring device or measuring machine, and (iii) performing a processor-controlled evaluation of the automated test adapted to classify the selected at least one workpiece as a good part or a reject part.
15. The manufacturing environment according to claim 14, wherein the automated test includes an automated measurement.
16. The manufacturing environment according to claim 14, wherein the automated test uses a knowledge base.
17. The manufacturing environment according to claim 16, wherein the knowledge base is defined by the at least one databank or storage medium.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] Other advantages and features will become apparent from the following detailed description, which are to be understood not to be limiting and which will be described in greater detail hereafter with reference to the drawings, wherein:
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DETAILED DESCRIPTION
[0054] Terms are used in conjunction with the present description which are also used in relevant publications and patents. However, it is to be noted that the use of these terms is merely to serve for better comprehension. The concept of the invention and the scope of protection of the patent claims are not to be restricted in the interpretation by the specific selection of the terms. The invention may be readily applied to other term systems and/or technical fields. The terms are to be applied accordingly in other technical fields.
[0055] The present disclosure relates to, inter alia, chip-removing machines M.m, as are used, for example, in the machining of gearwheel workpieces. The reference sign M.m is to indicate that the device and/or method can be used in a manufacturing environment 100, which can comprise at least two structurally-identical chip-removing machines M.m or two different chip-removing machines M.m. Here, m is an integer greater than or equal to one.
[0056] Some embodiments of the present disclosure have been designed and optimized in particular for use in a manufacturing environment 100 for machining gearwheels.
[0057] The term measuring machine is used here for separate machines. The term measuring device, in contrast, is to indicate that this device can be, for example, integrated into the machine M.m or can be attached thereon.
[0058] Software SW refers here to a code sequence which is executable directly by a computer or processor, or which has to be converted into a machine code before the execution, to then be able to be executed by the computer or processor. The software SW can be provided in some embodiments as a software product (for example, as application software), which is installed, for example, on a computer before the execution. The software SW can also be constructed modularly and/or installed at multiple locations (for example, in the computer 10, the machine M.m, and the measuring machine 20), for example.
[0059] The term computer 10 represents here a microprocessor-controlled device, for microcomputers, processor-controlled facilities or facility parts, for a machine controller, and also for computers which can be embodied, for example, separately from the machine M.m.
[0060] Variables, values, or items of information which each have a reference to a workpiece W.n and were acquired in or on the machine M.m are considered as machine parameters Mp.sub.W.n. A listing of several examples is provided hereafter, wherein this listing is not complete:
[0061] temperature at one or more points of the machine M.m,
[0062] temperature of the workpiece W.n,
[0063] ambient conditions (for example, temperature, air pressure, ambient humidity, solar radiation on the machine M.m, etc.)
[0064] speed of a spindle of the machine M.m,
[0065] position and/or movement of individual axes of the machine M.m,
[0066] load or strain of individual axes of the machine M.m,
[0067] imbalance of a spindle of the machine M.m,
[0068] eccentricity,
[0069] structure-borne noise (for example, for absorbing vibrations),
[0070] power consumption of the drive of an axis of the machine M.m,
[0071] torque.
[0072] Process-accompanying parameters can also be used as machine parameters Mp.sub.W.n here, for example, the number of starts of the machine M.m since the production or shift beginning, the progressing number n of the machined workpieces W.n (for example, since the last tool change), etc.
[0073] The machine parameters Mp.sub.W.n are individual specifications which are associated with the workpiece W.n. These are specifications which only have an indirect reference to the workpiece W.n, however, since they contain a state information item, for example, the temperature of the workpiece W.n, or the like.
[0074] The machine parameters Mp are identified here with Mp.sub.W.n, to indicate that they have a reference to the respective workpiece W.n. This reference can be provided in some embodiments, for example, by a unique identification (unique ID or uID) of the workpiece.
[0075] An advantageous embodiment of the invention will be described hereafter on the basis of
[0076] In
[0077] It relates here to production-accompanying processing of data and items of information to make the technical sequence of the machining process 200 more efficient, reduce the rejects, and optimize the manufacturing.
[0078] The actual machining (method 200) of workpieces W.n is therefore only a partial aspect of the process.
[0079] Concretely, it relates here to methods 200 for automated, chip-removing machining of multiple workpieces W.n, wherein n is an integer greater than or equal to two. The method 200 comprises the following steps, wherein the steps can be executed at least partially simultaneously or chronologically overlapping:
[0080] a) The chip producing machining of a first workpiece W.n takes place in a machine tool M.m (see
[0081] b) During this machining of the first workpiece W.n, at least two machine parameters Mp.sub.W.n of the machine tool M.m are acquired, which can be performed in some embodiments, for example, using sensors of the machine tool M.m and/or using external means.
[0082] c) In a further step, these machine parameters Mp.sub.W.n are stored with assignment to the first workpiece W.n. The machine parameters Mp.sub.W.n can be stored in some embodiments, for example, in a central databank 11. The reference sign 11 is used here both for the databank and also for the storage medium, since the actual organization and partitioning is unimportant. It is self-evident that the machine parameters Mp.sub.W.n can also be stored at various locations and/or in various storage media. In
[0083] d) These steps a)-c) are repeated (for example, in the context of a series production) for a number of n workpieces W.n. The machining of one workpiece W.n is illustrated in
[0084] According to one aspect, after one of steps a)-d), or at a later time, carrying out a measuring method 300 is triggered, which comprises at least the steps M1-M3 described hereafter. In
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[0086] Steps M1-M3 will be described in greater detail hereafter, wherein reference is also made here to exemplary
[0087] M1. At least one of the workpieces W.n is selected, for which previously at least two machine parameters Mp.sub.W.n were acquired and stored. This selection can take place immediately after the chip producing machining (method 200) of the workpiece W.n, however, it is also possible to transfer the workpiece W.n, for example, into a temporary store and then to select it later.
[0088] M2. An automated test (for example, a measurement 300 or a test on the basis of a knowledge base) of at least this one selected workpiece W.n is carried out in the measuring machine 20.
[0089] M3. After or during the testing, a processor-controlled evaluation is performed to be able to classify the selected workpiece W.n into one of at least two groups. The selected workpiece W.n may be classified after the automated test as a good part GT or as a reject part AT. This classification is illustrated in
[0090] The software SW can form a type of metalevel 250 in some embodiments together with the databank 11, as indicated in
[0091] In some embodiments, as shown in
[0092] The machining method 200 and/or the measuring method 300 can be independent in some embodiments from the process, which is used to perform targeted interventions or adaptations, to exhaust the optimization potential.
[0093] The basic principle will be described on the basis of the two
[0094] As already mentioned, at least two machine parameters Mp.sub.W.n of the machine tool M.m may be acquired during the machining of a workpiece W.n (the workpiece W.1 here). The time curve of two exemplary signals, which were acquired during the machining of the workpiece W.1, is shown by the embodiment illustrated in
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[0097] These exemplary signals T(t) and f(t) may be processed or analyzed (e.g., by a processor and/or a software module), before they are stored in the databank 11. This point can be critical, since one runs the risk during the processing or analysis of losing important items of information which are contained or coded in the signals. On the other hand, this is not real time monitoring of a machining method here, however. Rather, it relates to the collection of characteristic machine parameters Mp.sub.W.n during the machining of multiple workpieces W.n, to enable a production-accompanying evaluation in this manner.
[0098] In the case of a temperature signal as shown, for example, by the curve KT of
[0099] In the case of a frequency signal, as shown, for example, by the curve Kf of
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[0101] The various state combinations correspond in the example of
[0102] In the case of such an assignment, there can be, for example, state boxes, in which only a few or no workpieces at all fall (see state box C2).
[0103] The more measured (evaluated) workpieces W.n are provided for a state box, the better can a statement be predicted about the instantaneous manufacturing quality for a concrete state of the machine M.m (which is in turn recognizable on the basis of the machine parameters), which falls in this state box.
[0104] The resolution of the value ranges into intervals can be selected coarsely at the beginning and can be adaptively refined in the course of the data acquisition. Thus, for example, a constant ratio of 40:60 can result in a state box, which is unfavorable for evaluations of workpieces W.n, while a division could result in a ratio of 80:20 in one new state box and 10:90 in the other. Such a refinement of the division of state boxes does not always have to result in an improved evaluation, however.
[0105] In some embodiments, a fine resolution of the state boxes can also be specified from the beginning, which is then adaptively coarsened in the course of the data acquisition (after measurement of further workpieces W.n) by combination of adjacent state boxes with identical information.
[0106] The evaluation and/or division described in conjunction with
[0107] The goal of a suitable correlation is to advantageously make causal relationships visible and/or usable by processor-controlled evaluation.
[0108] In some embodiments, however, a correlation can also be used to be able to make, for example, a statement about the direction of a relationship (for example, of a positive correlation: if the temperature T2 is higher in the embodiment illustrated in
[0109] Criteria for the evaluation (called evaluation criteria BK) of the quality of a manufactured workpiece W.n can be defined on the basis of the state combination of the machine parameters acquired during its machining with the aid of a suitable correlation.
[0110] In some embodiments, a division into more than two groups can take place and/or multiple evaluation criteria BK can be used.
[0111] The following correlation methods may be used, for example, for finding a suitable correlation:
[0112] complete multidimensional assignment;
[0113] usage of mathematical aids of correlation analysis in (large) data quantities, for example, formal concept analysis for the identification of concepts (typical assignments of state combinations to evaluation combinations).
[0114] Various approaches are possible for the selection of the workpieces W.n to be measured. A selection on the basis of one of the following strategies may be applied:
[0115] Every workpiece W.n, which has previously passed through steps a) to c), is selected to be subjected to the measuring method 300. It is a disadvantage of this approach that the time and cost expenditure is high. This approach may therefore be applied at the beginning, to be able to provide a sufficiently large database in the databank 11 as rapidly as possible.
[0116] A subset of all workpieces W.n which have previously passed through steps a) to c) is selected to be subjected to the measuring method 300, wherein the subset may be specified by software SW or by a user.
[0117] During a first period of time 1, which is used to build up the databank 11, a larger number of the workpieces W.n, which have previously passed through the steps a) to c), is selected (for example, every second workpiece), than during a second period of time 2, which lies chronologically after the first period of time 1. During the second period of time 2, for example, only every tenth workpiece is then subjected to a measurement 300, for example. During the second period of time 2, the advantages of the disclosed methods are apparent, since their use enables problems to be recognized early in spite of a small number of concrete measurements 300. For example, if a state combination occurs which clearly indicates that the workpiece just machined probably will not correspond to the specification (this is the case in
[0122] These measures primarily relate to the actual machining of the workpiece(s) W.n, or the machine M.m, respectively.
[0123] The following measures relate to the measuring method 300, which is carried out in a measuring device 20 of the machine M.m or in a measuring machine 20: [0124] p5: adapting the measuring strategy, [0125] p6: changing a setting of the measuring device (for example, readjusting).
[0126] The mentioned measures p1 to p6, which are to be understood as examples, can also be combined with one another in any suitable combinations.
[0127] Furthermore, the selection can take place on the basis of the following strategies:
[0128] A workpiece W.n, which has previously passed through steps a) to c), is selected, for example, if already provided data from the databank 11 indicates that the affected workpiece W.n could be qualified as a reject part AT.
[0129] However, it is also possible to perform the selection of workpieces W.n on the basis of the accumulated knowledge of the databank 11. This will be explained hereafter using the example of
[0130] A higher-order goal in the selection of workpieces W.n which are subjected to the measuring method 300 is to expand the database 11 and thus to improve the decision accuracy on the basis of judgment criteria BK.
[0131] A further goal is the optimization of the overall machining process. Such an optimization is achieved in that an accurate differentiation is possible on-the-fly, for example, of good parts GT and reject parts AT.
[0132] In addition, the disclosed processes and methods, if used in a manufacturing environment 100, produces fewer rejects, since problems are already recognizable during the machining of workpieces W.n. In relation to conventional methods, in which production deviations or errors are sometimes only recognized when a workpiece is routinely measured later, a manufacturing environment 100 equipped accordingly can react more directly and therefore more rapidly.
[0133] The system may be designed so that it not only exerts a monitoring function in a manufacturing environment 100, but rather it also enables an intervention in the manufacturing environment 100.
[0134] Such an intervention can be performed as follows. It is decided on the basis of at least one correction criterion KK whether an intervention is necessary. A possible correction criterion KK can be linked, for example, to the assignment of the machine parameters Mp.sub.W.n of a workpiece W.n just acquired. If, for example, the affected workpiece W.n falls into a state box which has a probability of greater than 80% (for example, the state box B2 of
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[0136] The correction method 400 can be triggered and/or monitored by the software SW, as shown in
[0137] The correction method 400 can also be triggered and/or monitored, for example, by the machine M.m and/or by the measuring device 20.
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[0139] As may be recognized by those of ordinary skill in the pertinent art based on the teachings herein, numerous changes and modifications may be made to the above-described and other embodiments without departing from the spirit and/or scope of the invention. Accordingly, this detailed description of embodiments is to be taken in an illustrative as opposed to a limiting sense.