DD225086B1 - Indirect, continuous, process-based working process monitoring and control system for tooling machines - Google Patents

Indirect, continuous, process-based working process monitoring and control system for tooling machines Download PDF

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Publication number
DD225086B1
DD225086B1 DD26438384A DD26438384A DD225086B1 DD 225086 B1 DD225086 B1 DD 225086B1 DD 26438384 A DD26438384 A DD 26438384A DD 26438384 A DD26438384 A DD 26438384A DD 225086 B1 DD225086 B1 DD 225086B1
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DD
German Democratic Republic
Prior art keywords
control
tool
pressure
feed
monitoring
Prior art date
Application number
DD26438384A
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German (de)
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DD225086A1 (en
Inventor
Siegfried Eilenberger
Peter Weiss
Christian Bergmann
Original Assignee
Maw Industriearmaturen Und App
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.)
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Application filed by Maw Industriearmaturen Und App filed Critical Maw Industriearmaturen Und App
Priority to DD26438384A priority Critical patent/DD225086B1/en
Publication of DD225086A1 publication Critical patent/DD225086A1/en
Publication of DD225086B1 publication Critical patent/DD225086B1/en

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Description

Fields of application of the invention

The invention relates to a comprehensive and reliable process monitoring and control system with appropriate process control, which detects and compensates for process-related problems (tool wear, tool breakage, machine overload). It is particularly suitable for increasing the availability of automatic, unattended work processes) and for reducing the temporal loss of use of processing machines, in particular automatically operating, cutting machine tools.

Characteristic of the known technical solutions

Monitoring devices are known which guarantee protection against damage to tools, workpieces and machines and reduce the loss of power at the processing machines and the loss of quality of the workpieces. Monitoring devices are distinguished according to the procedure of the measured value acquisition, the Meßwertumformung and the measuring location on the machine tool.

1. Intermittent direct monitoring systems

2. continuous indirect monitoring systems

The intermittent direct measuring systems ensure a precise determination of a measured variable, since, for example, the measurement of the measured variable wear takes place directly on the tool.

Systems operating according to this procedure are described in several patents:

DD-PS 94300

DD-PS 94752

DD-PS 139344

All solutions are based on different principles of working tools or workpiece scanning elements.

These sensing elements scan the tools according to various procedures, determine tool breakage and tool wear through a target / actual comparison. A disadvantage of these methods is the attack of the measuring time as a secondary time (reducing the economic efficiency of the machine) and continue to take into account that process corrections can be made only after carried out processing.

In the patent DD-PS 113627 this disadvantage is avoided by a method by means of scanning electrode for detecting the wear of a tool during processing is proposed.

Since sensing elements work directly or directly in the vicinity of the effective points of the tools, they are also subject to interference such as chips, oil, temperature ... and are thus restricted in their functional reliability.

The control method by means of scanning electrode further allows no process-specific control according to the tool wear degree.

Continuous, indirect monitoring systems detect the current process condition, with a process-determining characteristic (e.g., motor current, cutting force) leading to a predetermined limit. They have the fundamental advantage that when a certain limit value is reached, the tool can be taken out of the cut as quickly as possible. In addition to shortening the main time (measuring time as a secondary time is omitted), this system includes the significant advantage of early detection tool breakage and consequential damage.

Suitable measurement characteristics for the continuous detection of process conditions are z. As motor current, torque, Zerspankraftkomponenten and cutting performance.

From this it is known to establish relationships with the process parameters (eg tool wear). To determine the measurement characteristics known per se and torque sensors are used. On this basis, various systems with different measuring locations and measuring methods are proposed.

All the systems known for this purpose are particularly deficient in terms of interfering influence such as friction, measured value superposition, low Meßwertauflösung because the Zerspankräfte example drill or cutting torque provide sufficient statements of the current process state.

In the proposed solution of DD-PS 129045 a method is used, which is carried out by measuring the cutting force or the cutting torque by means of a mechanical transducer, the changes in the output used as a signal to interrupt the workpiece machining.

The disadvantage here is that cutting force and cutting moment do not achieve sufficient significance as a parameter (low cutting force change).

In DE-AS 2058847 a similar, with the same disadvantages Affected means for measuring the main cutting force for engaged tools.

After the method of magnetic-electric torque measurement for the protection of tools and rotating machine parts, the proposal works according to DE-AS 2157984.

Also in this solution, the disadvantage is that the determination of cutting edge breakage or the end of life is very unreliable by the torque measurement, with additional superimpositions of disturbing influences can occur by rotating machine elements.

By known and own confirmatory investigations, the feed force measurement is the more meaningful parameter for process monitoring of the cutting process. This parameter provides detectable data, since the feed force reacts much more strongly to changes in the cutting edge geometry (wear, breakage) and makes itself felt by a pulse-shaped feed force increase.

The feed force measurements during machining require a different concept for detecting the machining process and are tailored in the known solutions only to the particular application.

For example, in DD-PS 150711 a safety device for feed drives of machine tools was invented, which uses the feed force measurement in the form of the axial force generated by the feed drive.

From DE-OS 2911006 a safety shutdown device for protecting tool and drive is known, which allows a function of the size of the force exerted by the tool on the machine tool force component against the feed device a safety shutdown. However, these devices only allow protection against overload (e.g. tool breakage) and do not allow control over the condition of the wear quantity and no necessary corrections from a target-actual comparison.

Furthermore, these devices can not control the presence of, for example, a drilling tool.

Object of the invention

The object of the invention is to provide a process monitoring and control system integrated in a tool-carrying processing unit or in a machining center, which detects the tool breakage as a fluid sensor system by means of feed force measurement, determines the degree of wear (eg end of life) of the tool, signals machine overload and from this the necessary corrections are initiated by a target / actual comparison.

By ensuring the functionally reproducible relationship between the measured characteristic and the process parameter to be monitored, the possibility of regulating parameters for optimizing the process sequence should be achieved.

That is, it should be a comprehensive and powerful process monitoring and the tool wear proportional process control (eg feed control) to the protection of the tool, workpiece and machine addition to the workpiece quality-enhancing necessary completion of the process flow (eg Zerspanprozeß deep hole drilling ) to reach.

In addition, the following requirements must be met by the process monitoring and control system.

- The static and dynamic properties of the machine and the size of the working space must not be affected.

- The measured value recording should function independently of external influences (oil, dirt, temperature).

- The practical use should guarantee extensive freedom from maintenance and uncomplicated operation.

- With little technical and material effort, an easy retrofitting on existing machining centers can be achieved.

Explanation of the essence of the invention

According to the invention, the process monitoring and control system for continuous, indirect, process-accompanying measurement of the feed force is a fluid sensor system.

This sensor system allows influencing the process flow during processing, that is, according to the state of the tool (breakage, end of life) is the immediate interruption of the process flow, or the service life of the tool indicates a warning signal.

In contrast to the known technical solutions is also an interruption of the process flow, if the tool or workpiece missing and beyond this fluid sensor system guarantees a tool wear proportional feed control.

Thus, the system according to the invention ensures a functionally reproducible relationship between measured characteristic (feed force) and the process parameter to be monitored (tool wear ...) and thus embodying comprehensive and efficient process monitoring and control.

The process monitoring and control system is based on the combination of fluid technology and electronics / electrical engineering.

When machining with a geometrically determined cutting edge, a change in this (tool breakage, tool wear) causes a sudden increase in the ratio of the feed force to the cutting force.

The force exerted by a tool which acts opposite to the flow direction of a fluidic pressure system, can only be compensated if the counteracting proportional force (pressure) is expended provided a corresponding current control.

Depending on the size of the force acting on a pressure-dependent system by the cutting tool force component against the feed direction react according to the invention, at least one electro-fluidic transducer in conjunction with an electronic control, a timer, a control and positioning unit and a control and regulating device so on the pressure-dependent system, that according to a time size for a the cutting process can suddenly be canceled or the feed proportional to the opposite force component is controlled. For process monitoring, two target values are sufficient, this is an upper and a lower limit.

The upper limit marks the maximum pressure corresponding to the cutting or tool breakage.

The lower limit is set to the minimum pressure corresponding to the idling pressure, that is, the feed pressure under undisturbed process (cutting) conditions is not reached. This limit indicates that the cutting tool is not engaged, so the tool is no longer present. This process disturbance is caused, for example, by collision or other sudden overload that completely destroys the tool. Thus, if no cutting, so no increase in pressure beyond the idling pressure means that the tool or workpiece is missing.

Constant actual value detection by means of a transducer via the setpoint-actual-value comparison of the electronic control takes place with such process disturbances, the immediate stopping of the respective machining operation via the control and positioning unit.

For process control, the proportionality between feed pressure during machining and the electrical output (voltage) of the transducer is used. About the electronic control, which amplifies this electrical output variable (actual value) and compares with predetermined target values, is carried out by the control and regulating device, the degree of wear of the cutting tool corresponding proportional current control (feed control is in the area in which This effect of the control advantageously makes it possible to terminate the respective machining process even under bad machining parameters, for example, in the case of technically complex deep boring processes, irregularities can be detected in good time and, as a result, the cutting conditions can be corrected by feed control to this one process The values of the process faults are determined via a measuring device and recorded as data for the setpoint-actual-value comparison.

The process monitoring and control system is completed by the timer to bridge fluid pressure spikes.

embodiment

The invention will be explained in more detail below with reference to the figure.

The figure shows the process monitoring and control system.

In each workstation, for example on longitudinal and rotary transfer machines, tool-carrying processing units 1 are used on which the feed takes place hydraulically in stepless control by flow control valve 5.

The tool-carrying processing unit 1 is in this particular example a drilling unit on which a twist drill is used. With change of the geometrically determined drill cutting edge occurs at controlled feed rate through the flow control valve 5, depending on the size of the drilling tool on the tool-carrying processing unit 1 force against the advance through a fluid line 11, a proportional increase of the hydraulic pressure, provided there is a constant pressure flow generation or it exists a closed fluidic pressure system.

If the drilling tool reaches the end of its useful life or if the cutting edge is broken, the hydraulic feed pressure increases accordingly

After previously determined according to the degree of wear and determined pressure levels (upper limit), carried by a transducer 12, in this example, a pressure sensor, the actual value and -weitergäbe as the hydraulic feed pressure proportional voltage via an electric line 14 to an electronic control 15th This electronic control 15 essentially consists of a measuring amplifier for the transducers 12, au an assembly for the required nominal-actual value comparisons and an electronic control and regulating assembly for a control and regulation. 6

The evaluated by the electronic control 15 feed pressure increase is passed as an electrical signal via a timer actuator 16, which may compensate for short-term pressure peaks, to a control and Stelleinhe.it 2 and their control magnets 3,4, the immediate by a corresponding switching operation from the drilling tool Remove the cutting process. For early wear detection (eg end of life), a threshold that is above the upper limit causes the signaling to a warning device to prevent the normal tool breakage. A lower limit corresponds to the idling feed pressure of the tool-carrying processing unit 1 in which no cutting takes place. If no pressure increase corresponding to the drilling feed pressure is registered by the electronic drive 15 in a defined time unit, this means that the drilling tool (or workpiece) is missing. Analogous to the upper limit, this process fault is then evaluated.

In addition to this process monitoring, the fluid sensor system according to the invention includes process control.

The process control, as the cutting power adapted, continuous feed control, also works on the basis of the conversion fluidic to uniform electrical magnitudes, however, which are used as output variables for fluidic control processes.

In the concrete example, starting from the transducer 12 and the desired-actual value comparison, but via the electronic control and regulating assembly of the electronic control 15, the actuation of the control and regulating device 6, which is a proportional flow control valve with an associated pressure differential valve 10 in the embodiment , This proportional flow control valve exerts position-controlled control magnets 8, 9 on the tool-carrying processing unit 1 by means of a displacement sensor 7, a feed pressure-dependent current control. If the more and more abrasive drilling tool causes an increase in the counter-pressure, the electro-fluidic transducer 12 converts this pressure variable into a corresponding voltage magnitude. This voltage value (actual value) and the information about the position of the valve piston longitudinal slide by the displacement sensor 7, go into the electronic control 15 a. From this is an electrical reference value corresponding to a certain Kolbenlängsverschieberstellung, to the control magnets 8.9. Depending on the positive or negative instantaneous difference between the setpoint-actual value, the respective control magnet 8, 9 is energized and the piston longitudinal slide is displaced in the difference-reducing direction. There is thus a feed control of the tool-carrying processing unit 1 as a function of the process characteristic tool wear. The process control takes place in the area between the normal course of drilling and the end of life of the drilling tool at the upper limit. The determination of the required values for the process monitoring and control takes place by means of a measuring device 13, for example a precision measuring manometer. By means of this measuring device 13, all process faults simulated in a test series can be tracked and recorded.

The process monitoring and control system according to the invention can be easily retrofitted to corresponding processing machines, which must be installed directly in front of the tool-carrying processing unit 1 in order to determine an unadulterated process state.

Claims (1)

1. Indirect, continuous, process-accompanying process monitoring and control system which the feed pressure on machine tools in dependence on the size of a tool to be machined against the feed direction, such as a hydraulic cylinder as a processing unit, outgoing force component based on a pressure-dependent sequential control to protect tools Workpiece and machine, characterized in that the Prozeßüberwachungs- and -regelsystem for the tool-carrying processing unit (1) is a fluid sensor system consisting of at least one transducer (12), such as a pressure transducer, connected to an electronic control (15), a control - And control device (6), such as a proportional flow control valve, a timer actuator (16), a control and actuating unit (2) and a measuring device (13).
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DD26438384A 1984-06-21 1984-06-21 Indirect, continuous, process-based working process monitoring and control system for tooling machines DD225086B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DD26438384A DD225086B1 (en) 1984-06-21 1984-06-21 Indirect, continuous, process-based working process monitoring and control system for tooling machines

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DD26438384A DD225086B1 (en) 1984-06-21 1984-06-21 Indirect, continuous, process-based working process monitoring and control system for tooling machines

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DD225086A1 DD225086A1 (en) 1985-07-24
DD225086B1 true DD225086B1 (en) 1988-03-23

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2625123B1 (en) * 1987-12-23 1990-06-15 Aerospatiale Device for detecting drilling incidents which may be integrated with autonomous pneumatic units

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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

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Publication number Publication date
DD225086A1 (en) 1985-07-24

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