DE19643383A1 - Material processing device for machining tool - Google Patents

Material processing device for machining tool

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Publication number
DE19643383A1
DE19643383A1 DE19643383A DE19643383A DE19643383A1 DE 19643383 A1 DE19643383 A1 DE 19643383A1 DE 19643383 A DE19643383 A DE 19643383A DE 19643383 A DE19643383 A DE 19643383A DE 19643383 A1 DE19643383 A1 DE 19643383A1
Authority
DE
Germany
Prior art keywords
processing
signal
tool
workpiece
sensor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
DE19643383A
Other languages
German (de)
Inventor
Helmut F Schiessl
Original Assignee
Helmut F Schiessl
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Helmut F Schiessl filed Critical Helmut F Schiessl
Priority to DE19643383A priority Critical patent/DE19643383A1/en
Publication of DE19643383A1 publication Critical patent/DE19643383A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23QDETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q17/00Arrangements for observing, indicating or measuring on machine tools
    • B23Q17/09Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool
    • B23Q17/0952Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool during machining
    • B23Q17/0971Arrangements for observing, indicating or measuring on machine tools for indicating or measuring cutting pressure or for determining cutting-tool condition, e.g. cutting ability, load on tool during machining by measuring mechanical vibrations of parts of the machine
    • B23Q17/0976Detection or control of chatter
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B23MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23QDETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q15/00Automatic control or regulation of feed movement, cutting velocity or position of tool or work
    • B23Q15/007Automatic control or regulation of feed movement, cutting velocity or position of tool or work while the tool acts upon the workpiece
    • B23Q15/12Adaptive control, i.e. adjusting itself to have a performance which is optimum according to a preassigned criterion
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00Programme-control systems
    • G05B19/02Programme-control systems electric
    • G05B19/18Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/406Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by monitoring or safety
    • G05B19/4065Monitoring tool breakage, life or condition
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/33Director till display
    • G05B2219/33027Artificial neural network controller
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/33Director till display
    • G05B2219/33192Radio link, wireless
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/33Director till display
    • G05B2219/33198Laser, light link, infrared
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/34Director, elements to supervisory
    • G05B2219/34048Fourier transformation, analysis, fft
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/37Measurements
    • G05B2219/37274Strain gauge
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/37Measurements
    • G05B2219/37494Intelligent sensor, data handling incorporated in sensor
    • GPHYSICS
    • G05CONTROLLING; REGULATING
    • G05BCONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B2219/00Program-control systems
    • G05B2219/30Nc systems
    • G05B2219/37Measurements
    • G05B2219/37534Frequency analysis
    • Y02P90/265

Abstract

The device is for machining a workpiece (12) using a fixed or attachable tool (14). A sensor (16,17,18,19) is provided to detect the forces during the machining process and to provide time dependent signals which correspond to the forces. A processor (30) processes these signals and includes a frequency analyser for these signals. The analyser can be designed to subject the signals to a Fourier analysis. Each sensor can be attached to a drive unit which moves during machining and is connected to a tool holder. The drive unit can be a rotating spindle.

Description

This invention relates to a material processing device for mechanical processing of a workpiece using a attached or attachable tool, at least a sensor is provided for the detection of the machining forces and for the output of the forces corresponding time-dependent signals, and further being a Processing unit for processing the by or each Sensor output signal is provided. Further concerns this invention a method of monitoring and control a material processing operation in a mechanical measure material processing device with which by means of at least one egg a workpiece attached or attachable is editable with the following steps: operating the Material processing device for processing the plant pieces with the tool, capturing during machining occurring forces and generating one corresponding to the forces appropriate, time-dependent force signal, and processing the Force signal.

When machining a workpiece, at for example milling, drilling, turning or grinding between a plant provided in a machine tool tool and the workpiece to be machined on the one hand from a variety of parameters of the Workpiece or its material and on the other hand by the Type and quality of the tool and other process parameters tern, such as B. Type of cooling lubricant, feed rate dependability etc. Exploitation of this machining forces to control and regulate the machining process has so far not been successful because Machining process relevant changes in the occurring  tending forces are very small and their sufficiently exact Measurement was not possible. Because it is currently available existing machine tools and tools have great potential has been in production technology for a long time Wanted solutions, workpiece machining, especially egg ne machining, taking advantage of the Machine tools provided potential with optimal Operating parameters. On the one hand, the cutting forces occurring during the cutting process sen, or on the other hand, the structure-borne noise detected and evaluated tet. The fundamentally very unreliable and prone to failure However, structure-borne noise signals could not be satisfactory lent and reliable solution to optimize the process para Provide meters. On the other hand, the machining forces are not recorded so precisely that a satisfactory lende regulation of the machine tool was possible, in particular if, for example, when monitoring the tool ver wear the control variables are very small. In addition, tre often due to material, for example due to work material inhomogeneities, changes in the cutting forces on, he draws conclusions about the properties of the tool heavy.

The automated material processing continues to play the exact observance of tolerances in the material measurement important role. For example, in manufacturing a countersunk hole for attaching a rivet for mounting sheet metal on a beam (e.g. in aircraft construction) to ensure that the dimensions of the countersink are observed exactly, because the rivet protrudes if the countersink is too small and if it is too large ßer Lower the holding force of the sheet on the carrier too low can be. Therefore, previous systems have an additional one Measuring device with which the distance before processing voltage of the tool is measured from the workpiece, and the Tool feed through the recorded distance  measured value is controlled. The upstream work Piece measurement increased due to the additionally necessary Length measuring device the cost of the machine tool and on the other hand, the knockout due to the longer processing most of the manufacturing process.

In view of the previous problems, it is therefore one Object of the present invention, an improved work To create a machine with a regulation of the machining processing of workpieces using the detected Machining staff is possible. It is also the task of present invention, a corresponding method create.

According to the invention, this object is achieved in a first solution triggers through a material processing device at the beginning mentioned type, which is characterized in that the Verar processing unit a device for frequency analysis of the given signal includes. Because of the in the invention ß material processing device included device The often very small control variables can be used for frequency analysis be determined very precisely, so that accurate monitoring of the workpiece machining process is possible. Especially the signals relevant for the control appear in character tical frequency ranges, which changes in Ver workpiece processing, for example due to a uniform tool wear, or on the other hand due to partial tool damage, recognizable and are separable. Also an upcoming occurrence of a Tool breakage can be caused by a certain frequency area occurring change in the force signals recognized who the. Since the force signal compo caused by the workpiece nents are in different frequency ranges than those with the Tool-related force signals, the Re gelung of the material processing device regardless of the  Type of workpiece to be machined. Consequently is the frequency analysis of the detected force signals Influence can be eliminated by the workpiece material, so that the Control parameters by the tool used alone are given, for example, already be manufacturer be provided. Elaborate learning phases after the State of the art for every combination of tool and work pieces that were required are now superfluous.

Due to the more precise detection of the tool condition the productivity of manufacturing by optimizing the bear processing parameters such as cutting speed, feed rate speed and by increasing process reliability under a reduction in committee can be increased significantly. The realizable with the device according to the invention more precise Regulation of the machining process also continues step in the automation because there is less personal due to the increased process reliability is. Due to the increased process reliability, in particular re also a production in a low-man third shift realize.

The sensors can, for example as strain gauges, on the moving drive part, for example one at Be driven rotating spindle. With one Forces or moments over the strains of the arrangement Strain gauges detected. Another, also preferred Possibility is, the sensors at one of the quietest during operation part of the material processing device, for example as the machine table or the headstock to provide. Piezo elements can preferably be used as sensors with which the inevitable when editing occurring reaction forces, which are vibrations make noticeable, be grasped.  

In an advantageous development, preprocessing is tion device provided to operate the Ma verial processing device amount of data to ver wrestle. Since the data processing and the response of the Sy stems on changes in the control parameters in one week considerable extent due to the limited transmission capacity of the connections between the individual elements is reduced by reducing the amount of data acceleration of processing and thus a faster start speak the control of the material processing device achieved.

In a further advantageous development of the invention a transmission device is provided for at least partially wireless transmission of the signal from that at Be drove moving drive part to the processing device. The wireless transmission makes it reliable and powerful transmission of the data stream in the aggressive Environment of the drive part, e.g. B. the spindle, the tool machine in which coolants / lubricants and chips etc. as well as a increased temperature are ensured. In particular it is advantageous to transfer the from the sensors signal generated on the spindle by means of an infrared over carry out.

According to further advantageous developments, the Ver work system a neural network for adaptive, self-learning processing of the signal, and / or a Storage device for storing comparison data, the certain events in mechanical processing ent speak. By using a neural network in particular prevents individual strength excursions tips that are random in nature and not predetermined Event, such as a broken tool or an elevated work tool wear correspond to abort the machining process  who are recognized as accidental excursions the. The use of a storage device for storage of comparison data, also called "expert system", enables the largely automated operation of the front direction, as well as an improvement in self-learning ability in connection with the neural network.

The entire system advantageously comprises a control com puter with which the machine tool is taking into account of the detected and processed in the processing device th force signal is controllable.

The above problem is further solved by a process ren of the type mentioned above, which is characterized by that the processing of the signal includes frequency analysis. With this method according to the invention are the same parts achieved as described above in terms of material processing processing device according to the first basic solution the task was described.

The above task is further solved by a Ma material processing device of the type mentioned, the is characterized in that a pre-processing device together with the or each sensor at one while operating moving, in connection with a tool holder the drive part is provided. Through this invention another solution to the problem will be a very particular one fast transfer of data from the spindle to the machining processing device, since preprocessing of the Si gnals already on the moving drive part, at for example a spindle, to reduce the amount of data is carried out. So that the bottleneck can usually se rial transmission path due to the reduced data can be overcome much faster, so that a short-term response of the machine tool to changes  conditions in the forces detected by the sensors is possible. There can do that for certain material processing operations Process stage, for example the depth of the material processing tion with a hole, especially a counterbore, exactly be recorded, so that no additional measuring system for Workpiece measurement on the device according to the invention is required.

In an advantageous further development of this system Transmission device for at least partially wireless Transfer of the processing from the preprocessing device tied signal to the processing device. In particular, this transmission device is for generation an infrared transmission line. In order to is a safe and efficient transfer of processing data in the extremely aggressive environment of the spindle a coolant / lubricant, chips etc. and partially greatly increased temperatures possible.

The above problem is further solved by a process ren of the type mentioned that is characterized by that a tool drive depending on the force signal is controlled. In particular, one is created by the tool drive generated feed movement when reaching a predetermined level of the force signal stopped. So that is an auto Matic tool measurement based on an analysis of the Force signal possible, so that the Vorrich necessary so far Tool measurement in the inventive Ver driving can be omitted.

Further advantageous embodiments can be found in the lower sub sayings.

The present invention is exemplified below in with reference to the accompanying drawings and described. The drawings show:

Fig. 1 is a schematic representation of a material processing device according to an embodiment of the invention;

Fig. 2 is a schematic diagram of the time-dependent force signal occurring during a drilling process;

FIG. 3 shows a principle diagram comparable to FIG. 2, in which a characteristic curve for a drill break is shown;

FIG. 4 shows a diagram comparable to FIG. 2 with an increased scatter of the force signal;

Fig. 5 is a Ratterkarte stable to separation and instabi ler operating parameters of the machine tool;

Fig. 6, the tip of a Senkbohrers; and

FIG. 7 shows a basic diagram for a typical time-dependent force signal when using the drill tip shown in FIG. 6.

The embodiment shown in FIG. 1 of the material processing device according to the invention shows a tool 10 , for example a milling cutter or a drill, which is held on a spindle 14 . The spindle 14 is rotatably mounted in two conditions 22 and 24 . On the opposite side of the tool 10 , the spindle 14 is connected to a drive shaft 20 . The tool 10 is in Fig. 1 for carrying out a machining operation with a workpiece 12 in contact.

According to this exemplary embodiment, force sensors 16 , 17 , 18 and 19 are provided on the spindle 14 . The force sensors can be, for example, strain gauges, preferably in the form of semiconductor sensors. Another type of sensor would be sensors based on the piezo effect. Instead of sensors mounted on the spindle, an elec trical decrease in the force signal via the control current of the motor driving the drive shaft 20 is also conceivable.

In the force sensors 16-19 shown in FIG. 1, a slight deformation of the spindle 14 generated due to the resistance force occurring between the tool 10 and the workpiece 12 during machining is detected. The Detekto ren are advantageously arranged so that a measurement of the deformation of the spindle along a line is pos Lich, which forms a 45 ° angle with a surface in the mounting surface of the sensors, parallel to the axis of rotation of the spindle line. Particularly when using four sensors, a particularly precise and reliable determination of the forces that occur is thus possible. The sensors 16 , 17 , 18 and 19 are connected to an electrical power supply 26 . The output of the electrical power supply 26 is z. B. connected to a common connection point of the connections of the four sensors 16-19 . The respective connection point opposite outputs of the sensors 16-19 are connected to the inputs of a preprocessing device 32 also arranged on the spindle 14 . The preprocessing device 32 is, for example, a user-specific integrated circuit (ASIC). An example of such an ASIC circuit is an FFT chip for performing a fast Fourier transform of the data.

The preprocessing device 32 is connected to a transmitter part 51 of a transmission device 50 fixed to the spin del 14 . The transmitter part 51 is a fixed Emp catcher part 52 opposite. The transmission device 50 is advantageously an infrared transmission device for wireless transmission of the signals from the rotating spindle during operation to the fixed system of the machine tool.

An output from the fixed receiver part 52 of the transmission device is connected to a signal processing device 30 , which in turn is connected to a control computer 40 for carrying out a CNC control.

Below, the operation of a device shown in FIG. 1 and, in particular, the advantages which can be achieved therewith compared to the prior art are explained using the time-dependent force signals shown in FIGS . 2-4.

In Fig. 2, a schematic diagram of a typical course of the time-dependent force signal is shown, as it example se when drilling a through hole, for. B. in a crankcase occurs. Initially at time t = 0, the force signal begins to rise from a value O immediately before the tip of the drill is placed on the workpiece with a relatively steep slope in proportion to the increase in the wall friction of the drill at the borehole. In part t 1 , when the entire tip of the drill has contact with the workpiece, an increase in the force signal begins with a substantially reduced gradient. In the time range from t 1 to t 2 , the drill penetrates deeper into the workpiece. At time t 2 , the workpiece is pierced and a rapid decrease in the force signal begins. According to the prior art, an empirically determined, relatively widely spaced upper limit of the force signal F 0 was set as the upper limit value for a maximum tolerable deviation of the force signal from the target curve, which is in principle drawn. When the upper limit value F 0 was reached, a quick shutdown of the machine tool was carried out as standard according to the prior art.

In Fig. 3 an example of a course of the power signal curve is shown in tool breakage. At time t 3 , a rapidly increasing force curve begins, which quickly exceeds the maximum allowable force limit F 0 . The complete tool break occurs at time t 4 , so that the measured force then drops suddenly. Between the times t 3 and t 4 , however, the machined workpiece is already damaged by the rapid increase in force. Therefore, the Schnellab circuit when the force limit F 0 is not prevented that the workpiece, which may have already experienced a significant value creation in a later machining process, is damaged and therefore unusable.

In FIG. 4 perform a realistic course is the force signal curve in dependence on the time shown. The force signal actually measured has a certain spread, which will vary in strength from material to material. Especially with special materials, such as. B. in aluminum with embedded silicon (quartz sand) for cylinder heads of motor vehicle engines, high fluctuations occur in the force signal due to Materia linhomogenitäten, occasional peaks of the force signal, the upper limit F 0 , at which the machine tool is switched off, exceeded . At time t 5 , for example, a case is shown in which a short-term fluctuation peak of the signal exceeds the maximum permitted value F 0 of the force signal. If the limit F 0 of the maximum force signal is raised, there is a risk according to the prior art that a reliable shutdown of the machine in the event of a tool breakage is no longer guaranteed.

The device according to the invention now carries out a Fourier transformation for transforming the force signal obtained from the time domain into the frequency domain. This frequency signal, which is dependent on the frequency, is then analyzed in order to determine the optimum operating parameters of the machine tool. Surprisingly, in the frequency range, different influencing variables for the machining forces occurring between the tool and the workpiece are separated into different frequency ranges. In particular, the influence of the workpiece occurs, for example due to inhomogeneities such. B. with quartz sand storage, in a different frequency range, such as that of the tool, for. B. due to a tool wear or partial damage to the tool cause force signal components. For the drill fracture shown in FIG. 3 in the form of an F (t) diagram, there is, for example, a typical signal in the frequency representation in the range of a period of 4-5 ms. This frequency range, which is typical for drill breakage, is clearly separated from the frequency range of other influencing variables.

This is a much more reliable and also faster Tool breakage detection possible before damage tion or destruction of the machined workpiece occurs. There the workpiece be especially in finishing operations has already experienced considerable added value a significant contribution to cost-reducing manufacturing and to improve productivity.

Rapid detection of a broken tool is further promoted through the use of data preprocessing processing on the spindle to reduce the amount of data. There the transmission of the signal data from the spindle to the processor  processing device a bottleneck due to the mostly serial Transmission represents by reducing the over carrying data a significant increase in speed created to detect malfunction of the system.

The system according to the invention also has the possibility of tool wear from the recorded data for the Detect force signal in a reliable way. This process is not time critical and therefore does not require more wise data preprocessing. Because tool wear again in a typical frequency range of the F (ω) force signal manifests, can in turn be independent of a necessary tool change for the material to be machined sel be recognized by chance.

The system according to the invention also creates the possibility of an adaptive control of the workpiece machining process. In particular when using a neural network for post-processing the signal generated by the sensors, adaptive, self-learning control of the system is possible. If, for example, a signal peak shown in FIG. 4 at t = 5 occurs in the F (t) signal, further information about this signal, for example the occurrence of chatter phenomena, can be detected by means of the Fourier analysis, so that the The system itself learns to interpret the F (t) diagram on the one hand and the F (ω) diagram on the other without additional operator intervention. This learning effect can also be supported by entering and storing comparison data that were recorded for typical materials and comparable tools.

The main advantage of the adaptive control is that the machine tool can be operated in a better optimized area for better utilization of a potential provided by its accuracy. In Fig. 5, a so-called chatter card is shown, in which two areas are defined by a sawtooth-shaped curve as a function of the feed speed of the tool and a tool speed, for example a rotational speed of the spindle. The upper area of the curve represents an unstable operating area in which so-called rattling occurs during the machining process of the workpiece. This rattling leads, for example, to wavy surfaces, which cannot be tolerated in high-precision workpieces and consequently lead to rejects. According to the prior art, the machine tool had to be operated with carefully selected parameters in a safe operating area of the chatter card, for example at point P 1 . At this point, however, the feed speed and tool speed are relatively small, so that machining the workpiece is relatively time-consuming. According to the invention, the adaptive control and the much more precise recognition of the operating parameters with respect to tool wear mean that an operating point which further exploits the potential of the machine tool, for example at point P 2 , can be assumed. As soon as a deviation from the set operating point P 2 occurs due to changes in the properties of the tool, the machine itself can carry out the necessary correction in order to keep the operating point stable at the desired point within the chatter card. This means that significantly higher processing speeds and thus higher throughput when machining the workpiece can be achieved. Nevertheless, the machining reliability of the workpiece is increased and thus the machine can be used for a longer period of time and with less manpower.

According to the invention, the further advantage of the workpiece can be measurement based on the machining process achieve data without an additional measuring device.  

To illustrate this advantage, the typical force signal curve as a function of time is shown in FIG. 7 for a known countersink 80 shown in FIG. 6. The countersink 80 shown in Fig. 6 comprises a tip 82 with a subsequent angled bit bit rich 83rd Between the drill bit 82 and a Einsenkbe rich 85 , a cylindrical cutting area 84 is ausgebil det. Above the lowering area 85 , the drill can have a further cutting area 86 .

The principle diagram of the force curve of this drill shown in FIG. 7 has an additional force increase at time t 7 when the lowering region 85 begins to touch the workpiece surface. At time t 6 , a total force F 1 occurs, at which it is decided that the desired sink depth has been reached. According to the prior art, this force profile could not be used for workpiece measurement, because due to the relatively weak forces and especially due to the relatively slow processing and transmission process of the data recorded by the force sensors, a sufficiently sensitive and fast control of the machine tool was not possible. The data preprocessing according to the invention on the spindle now enables a sufficient transmission speed in order to implement the "on process" workpiece measurement with sufficient accuracy.

The measurement of the relevant forces can be direct or indirect take place, for example by recording strains, Moments or vibrations. The method described is suitable in addition to recognizing tool wear or breakage also for early detection of bearing damage.

Claims (29)

1. Material processing device for mechanical processing of a workpiece ( 12 ) by means of an attached or attachable tool ( 14 ),
at least one sensor ( 16 , 17 , 18 , 19 ) is provided for detecting forces occurring during processing and for outputting time-dependent signals corresponding to the forces,
and further comprising a processing unit ( 30 ) for processing the signal output by the or each sensor, characterized in that the processing unit comprises a device for frequency analysis of the output signal.
2. Device according to claim 1, characterized in that the Frequency analysis device for carrying out a Fourier analysis of the signal suitably designed device is.
3. Apparatus according to claim 1 or 2, characterized in that the or each sensor ( 16 , 17 , 18 , 19 ) is attached to a drive part ( 14 ) which is connected to a tool holder and moves during operation.
4. The device according to claim 3, characterized in that the moving drive part ( 14 ) is a rotating spindle during operation.
5. The device according to claim 1 or 2, characterized in that the or at least one of the sensors on one with the Tool holder in connection, immobile during operation  part of the device, such as a clamping table or headstock, is appropriate.
6. Device according to one of the preceding claims, esp Special claim 5, characterized in that piezoelectric cal sensors are provided.
7. Device according to one of claims 1-6, characterized in that a preprocessing device ( 32 ) is provided for the un indirect signal coming from you or each sensor to reduce the amount of data generated during operation.
8. Apparatus according to claim 7 and claim 3 or 4, characterized in that the preprocessing device is attached to the movable drive part ( 14 ).
9. Device according to one of claims 1 to 8, characterized in that a transmission device ( 50 ) for least least partially wireless transmission of the signal to the processing device ( 30 ) is provided.
10. The device according to claim 9, characterized in that the transmission device ( 50 ) is suitably designed for transmitting a signal by means of infrared radiation.
11. Device according to one of the preceding claims, there characterized in that a neural network circuit before is seen for adaptive processing of the signal.
12. The apparatus according to claim 11, characterized by a Storage device for storing from the adaptive Ver working of the signal obtained comparison data.
13. Device according to one of the preceding claims, there characterized in that a storage device is provided  is for storing comparison data, the predetermined Er events in mechanical processing.
14. Device according to one of the preceding claims, characterized in that the processing device comprises a control computer ( 40 ) for controlling the material processing device taking into account the signal.
15. The apparatus according to claim 4, characterized in that the or each sensor is mounted so that a deformation of the spindle ( 14 ) along a line which is a 45 ° angle with a lying in the mounting surface of the sensor to the axis of rotation Spindle forms parallel line, is measurable.
16. Device according to one of the preceding claims, there characterized in that the sensors are strain gauges are.
17. Device according to one of the preceding claims, there characterized in that four sensors are provided.
18. Material processing device for mechanical machining of a workpiece ( 12 ) by means of an attached or attachable tool ( 14 ),
at least one sensor ( 16 , 17 , 18 , 19 ) is provided for detecting forces occurring during processing and for outputting time-dependent signals corresponding to the forces,
and further comprising a processing unit ( 30 ) for processing the signal output by the or each sensor, characterized in that a preprocessing device ( 32 ) together with the or each sensor ( 16 , 17 , 18 , 19 ) on one in operation moving, with a tool holder related drive part ( 14 ) is easily seen.
19. The apparatus according to claim 18, characterized in that a transmission device ( 50 ) is provided for at least partially wireless transmission of the signal from the preprocessing device ( 32 ) to the processing device ( 30 ).
20. The apparatus according to claim 19, characterized in that the transmission device ( 50 ) is suitably designed for generating an infrared transmission path.
21. A method for monitoring and controlling a material processing operation in a mechanical material processing device with which a workpiece ( 12 ) can be processed by means of at least one attached or attachable tool ( 14 ), with the following steps:
Operating the material processing device for processing the workpiece ( 12 ) with the tool ( 14 ),
Detection of forces occurring during processing and generating a time-dependent force signal corresponding to the forces,
and processing the force signal, characterized in that the processing of the signal comprises a frequency analysis.
22. The method according to claim 21, characterized in that the Frequency analysis includes a Fourier analysis.
23. The method according to claim 21 or 22, characterized in that that the signal when processing an adaptive and self learnable evaluation process is subjected.  
24. The method according to claim 23, characterized in that for Implementation of the adaptive and self-learning evaluation pro a neural network is used.
25. A method for controlling a material processing operation in a mechanical material processing apparatus capable of using at least one attached or attachable working a workpiece (12) can be machined finished product (14), comprising the following steps:
Operating the material processing device for processing the workpiece ( 12 ) with the tool ( 14 ),
Detection of forces occurring during processing and generating a time-dependent force signal corresponding to the forces,
and processing of the force signal, characterized in that a tool drive is controlled as a function of the force signal.
26. The method according to claim 25, characterized in that the Tool drive for generating a tool feed movement upon reaching a predetermined value of the force signal will hold.
27. The method according to any one of claims 21 to 26, characterized ge indicates that the signal is moving on one related to a tool holder pre-processing drive part attached preprocessing device is before it is transferred to post-processing.
28. The method according to claim 27, characterized in that the preprocessed signal wirelessly with electromagnetic waves is transmitted.  
29. The method according to claim 28, characterized in that the electromagnetic waves a wavelength in the range of In have infrared radiation.
DE19643383A 1996-10-21 1996-10-21 Material processing device for machining tool Withdrawn DE19643383A1 (en)

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EP1677170A1 (en) * 2004-12-30 2006-07-05 C.R.F. Societa' Consortile per Azioni Module with sensor means for monitoring industrial processes
EP2916187A1 (en) 2014-03-05 2015-09-09 Mikron Agie Charmilles AG Improved database for chatter predictions
DE102014103240A1 (en) * 2014-03-11 2015-10-01 Pro-Micron Gmbh & Co. Kg Method for setting up and / or monitoring operating parameters of a workpiece processing machine
US10649435B2 (en) 2016-12-22 2020-05-12 Fanuc Corporation Tool life estimating device

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002031434A1 (en) * 2000-10-07 2002-04-18 Dr. Johannes Heidenhain Gmbh Device for detecting a thermal linear dilation on part of a machine
US6866451B2 (en) 2000-10-07 2005-03-15 Dr. Johannes Heidenhain Gmbh Device for detecting a thermal linear dilation on part of a machine
EP1677170A1 (en) * 2004-12-30 2006-07-05 C.R.F. Societa' Consortile per Azioni Module with sensor means for monitoring industrial processes
US7124063B2 (en) 2004-12-30 2006-10-17 C.R.F. Societa Consortile Per Aziono Module with sensor means for monitoring industrial processes
EP2916187A1 (en) 2014-03-05 2015-09-09 Mikron Agie Charmilles AG Improved database for chatter predictions
US10042922B2 (en) 2014-03-05 2018-08-07 Mikron Agie Charmilles Ag Database for chatter predictions
DE102014103240A1 (en) * 2014-03-11 2015-10-01 Pro-Micron Gmbh & Co. Kg Method for setting up and / or monitoring operating parameters of a workpiece processing machine
US9864362B2 (en) 2014-03-11 2018-01-09 Pro-Micron Gmbh & Co. Kg Method for setting and/or monitoring operating parameters of a workpiece processing machine
US10649435B2 (en) 2016-12-22 2020-05-12 Fanuc Corporation Tool life estimating device

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