• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a method for separating a workpiece (2) with a punch (3), wherein withdrawal forces acting on the punch (3) are measured as a function of a punch position, from which a remaining service life of the punch (3) is determined. Furthermore, the invention relates to a device (1) for separating a workpiece (2), comprising a punch (3), wherein the punch (3) a sensor (4) 10 is arranged to on the punch (3) acting retraction forces in Dependence of a punch position to measure.
    公开号:AT518154A1
    申请号:T51064/2015
    申请日:2015-12-14
    公开日:2017-07-15
    发明作者:Prof Reinhold Ebner Dr；Werner Ecker Dr；Thomas Klünsner Dr；Krobath Martin；Stefan Marsoner Dr
    申请人:Mat Center Leoben Forschung Gmbh；
    IPC主号:
    专利说明:

    Method and device for separating a workpiece
    The invention relates to a method for separating a workpiece with a punch.
    Furthermore, the invention relates to a device for separating a workpiece, comprising a punch.
    Various methods for separating a workpiece from sheet metal or the like have become known from the prior art. In the case of production of workpieces close to the final dimensions, punching, shearing or fineblanking are particularly suitable.
    During fineblanking, several forces act which, given a correspondingly long or frequent use of a fineblanking device, adversely affect the quality of individual elements of the same, because their surfaces change due to the load and welds. The elements, in particular the moving punch, are exposed to continuous wear and a risk of spontaneous breakage of a cutting edge and chipping of a stamp head, which ultimately also a quality of the workpiece to be separated is significantly reduced. A quality of the stamp that is no longer sufficient for a cutting process is often recognized only on the basis of the workpieces produced with a lower quality. However, these workpieces can not be used or disposed of as scrap. In the end, a lasting deterioration of a quality of the stamp leads to a break of it and this must be exchanged, which comes at a cost.
    There is a technical need to recognize a change in a production process, in particular a deterioration of a quality of a stamp in time so that no workpieces are produced with inferior quality or timely extending life span measures for tool components such as the stamp can be set. One known approach to detecting changes in the production process is to inspect or measure cutting forces of a punch. However, this approach has not yet proved to be suitable for satisfactorily predicting a life of a stamp.
    This is where the invention starts. The object of the invention is to provide a method of the type mentioned above, with which a change in a separation process detected in time and in particular a duration of use of a stamp can be reliably predicted, especially before a fraction thereof.
    Another object of the invention is to provide a device of the type mentioned, with which a deterioration of a quality of a stamp reliably recognizable and in particular a service life of the punch is predictable.
    The procedural object is achieved in that in a method of the type mentioned on the stamp acting retraction forces are measured as a function of a punch position, resulting in a residual service life of the punch is determined.
    An advantage achieved by the invention is to be seen in particular in that a change in a separation process is reliably detected by the measurement of the withdrawal forces, which act on the stamp before a rupture of the stamp. Moreover, it is also possible with the inventive method to predict a quality of the workpiece, which is produced by the separation process. With the method according to the invention thus changes in a production process are reliably detected.
    In the context of the invention, it has been found, in particular, that the withdrawal forces, which act on the punch during retraction into a starting position after a cutting process, are particularly relevant for the tool failure. In contrast to a forward movement of the punch occur during the withdrawal of the same namely large tensile forces, by which the punch is damaged more and more. Above all, a stamp of high-strength materials such as a wear-resistant and therefore basically durable carbide or possibly higher-strength steel, this is continuously damaged by the retraction forces, which is the starting point for a material failure. In addition, wear or damage to the stamp is also caused or accelerated by so-called welds. With each stroke of the punch this is coated with small parts of the workpiece material or components of a separator. These welds affect the friction between the workpiece and the adjacent tool components and thus also the tensile forces and cracking in the stamp.
    Moreover, with a method according to the invention, it is also possible to predict the useful life of the stamp, which is technically or with respect to a quality of the workpieces, in such a way that a cutting process is stopped before its quality deteriorates so that the workpiece is unusable. In addition, an entire lifetime or life of the stamp can be determined. In particular, it is advantageous that the quality of the separation process is detected without special quality control of the workpieces themselves. Thus, it is only on the basis of the retraction forces that it is possible to reliably predict a time for re-sharpening or regrooving the stamp, as a result of which a stamp life and a workpiece quality can be simultaneously optimized.
    It is expedient if the withdrawal forces are measured with a sensor arranged on the stamp. For example, the sensor is formed as a disk-shaped thin-film pressure sensor, which is arranged at an upper end of the punch and measures a force acting on the stamp force change in the withdrawal of the same. When using a piezoresistive thin-film force sensor, the return forces correspond to a reduction of a pressure bias between the punch and a recording of the same within a machine tool during withdrawal of the punch. The disk-shaped sensor has, for example, the same cross-sectional area as the stamp, so that retraction forces can be measured particularly accurately. The sensor further preferably collects data, in particular from frictional forces, which are transmitted to an evaluation unit. The sensor can also be designed as a strain gauge or other piezobasiertes system.
    It is also advantageous if a mathematical model is predicted from data from the measured retraction forces and known data with which a lifetime of the stamp is predicted. As a result, deviations from a normal state of an undamaged stamp are subsequently recognized or displayed. By the already known data, which are created for example via a simulation and combined with the data from the measured withdrawal forces, the life of the stamp can be predicted even more accurately. The known data can also be data that is recorded once in the sense of a calibration until the punch breaks and thus represents a real representation of the course of the withdrawal forces during the service life of the punch. Standard values from known data are utilized in a theoretical setpoint curve, which are compared with a measurement curve and processed into the mathematical model. It is customary when the mathematical model is created by the evaluation unit or a computing unit and can be both an analytical and a numerical model. In particular, the occurring during retraction of the punch and time-varying friction forces are taken into account.
    In particular, it is favorable if the mathematical, theoretical model is continuously compared with measured values and thereby validated. The mathematical model detects deviations from measured data to known data of an undamaged tool or stamp.
    It is advantageous if data from the measured withdrawal forces is continuously taken into account by the mathematical model. Thus, the mathematical model is applicable to any device for separating a workpiece with a stamp, since on the one hand continuously the retraction forces, in particular frictional forces, are measured and on the other hand, these data are permanently processed in the mathematical model. Preferably, the evaluation unit is designed such that data that is currently measured are combined with already known, theoretical data, whereby a validated model is created. The mathematical model describes relationships between characteristic values of a material or material to be machined and other process variables such as yield strength, strip thickness, lubrication state, coefficient of friction or the resulting variables such as cutting force. In particular, the mathematical model is used for a qualitative and / or quantitative prediction of a withdrawal force of the stamp or of its dependence on a time and / or stamp position.
    It is also advantageous if an evaluation of the mathematical model makes a life of the punch extending measures. With the data of the mathematical model, real-time decisions can be made, so that life-prolonging measures can be set purposefully. For this purpose, it is favorable if a necessary rapid processing of process variables and their modification via an embedded system is realized. This is achieved with the mathematical model in computing units directly on a machine tool or device.
    It is not mandatory but may be beneficial if at least one vibration and / or temperature caused by the separation process is measured. Data from such a noise or temperature measurement and temperature measurement are then correlated with the data from the retraction forces and subsequently incorporated into the mathematical model. For measuring at least one type of sound, one or more sensors may be provided at an arbitrary position of a device for separating a workpiece, from which noise developments caused by different types of movement are measured. In addition, other sensors may be provided, such as an acceleration sensor, a temperature sensor and / or a vibration sensor. The further sensors can record a propagation speed of cracks in the stamp.
    In addition, indicators for setting life-prolonging measures are provided by the other measured values.
    It is favorable if the workpiece is pressed by a punch made of a hard metal or a steel against a die to separate the workpiece. Sensitivities of hard metals and steels are at least partially known, whereby material values are included in the mathematical model, so that the life of such a stamp is determined as accurately as possible. With a punch made of a carbide or possibly a high-strength steel, the workpiece is separated with a particularly sharp edge. Carbide is durable in itself, since this is damaged even at high mechanical stress only to a small extent. However, it has been recognized within the scope of the invention that it is precisely these small or, compared to cutting forces, small tensile components which occur during tool withdrawal that occur when the stamp is retracted that are decisive for material failure. With the method according to the invention, it is also possible to detect or measure such low tensile components in the event of a tool load, in order to subsequently predict a service life and, if appropriate, a service life of the hard metal punch. In particular, in the case of a die made of hard metal, it is favorable to be able to predict a deterioration of a quality or duration of use of the same, since this and thus an exchange thereof are relatively expensive. Now times for a regular re-sharpening and, if necessary, timely polishing of a punch made of hard metal can be reliably predicted, so that the punch made of hard metal can be used to the maximum, before it is exchanged.
    The stamp is preferably cylindrical and rotationally symmetrical. This can also be complex shaped. In addition to using a stamp made of hard metal or high-strength steel, for example, a ceramic stamp can be used.
    Appropriately, a lifetime of a punch is monitored during fineblanking. As a result, changing withdrawal forces and possibly additional other parameters are constantly monitored or observed. In combination with the mathematical model, a self-learning process for fine cutting or monitoring of such a process is finally created. In fineblanking, the workpiece, which is formed, for example, as a sheet, held by a pressure plate and die or performed below the press plate, which is held in a separation process by a arranged on the press plate ring prong. Caused by acting radially to a punch axis contact pressures and / or relative axial displacements so-called welds are applied to the stamp, which are usually metallic nature. To separate or cut the workpiece with a sharp cut, this is held by a counter-holder against the punch.
    The further goal is achieved when a sensor is arranged in a device of the type mentioned in the stamp to measure acting on the punch retraction forces in dependence of a punch position.
    An advantage achieved thereby is to be seen in particular in that by measuring the withdrawal forces with the sensor, a service life of the punch and optionally a quality of the workpiece can be predicted. Although any sensor is usable for this purpose, it is preferably formed as a disk-shaped thin-film pressure sensor and arranged at an upper end of the punch. In addition, the sensor preferably has the same cross-sectional area and the same rotational symmetry as the stamp, so that a force measurement takes place as precisely as possible. In the context of the invention, it has been recognized that the withdrawal forces have a significant share in a failure of the stamp and are therefore crucial for a life of the stamp. Decisive for this is the tensile load acting on the stamp, which occurs when it retreats. The sensor measures retraction forces that act on the punch when it is moved back to a starting position after a cutting process.
    It is advantageous if at least one further sensor is provided for measuring at least one vibration and / or temperature caused by the separation process. To measure a noise, for example, a sound sensor is arranged, which measures the sound caused by the retraction of the stamp and / or the cutting. In addition, further sensors may be provided, such as an acceleration sensor, temperature sensor and / or a vibration sensor. Data from all sensors are advantageously correlated with one another in order to predict the life of the stamp as accurately as possible. Thus, a time for regrinding, polishing or resharpening the stamp can be specified even more precisely.
    It is particularly advantageous if an evaluation unit is provided which evaluates data recorded by the sensor and compares it with known data in order to predict a service life and / or lifetime of the stamp. The evaluation unit evaluates recorded data directly and creates a mathematical model with already known data, which originate for example from a simulation. This mathematical model preferably takes into account continuously recorded data from the retraction forces and, as a consequence, predicts a lifetime of the stamp or a time for reworking the same. The mathematical model can be provided as an analytical or numerical model, which describes relationships between characteristic values of a material or material to be processed and other process variables such as yield point, strip thickness, lubrication state, friction coefficient or general resulting variables such as cutting force. In particular, the mathematical model says a retraction force of the
    Stamp qualitatively and / or quantitatively or their dependence on a time and / or a stamp position ahead.
    It is further expedient if the evaluation unit is designed as an embedded system in order to process process variables and their change efficiently. For this purpose, the evaluation unit is arranged, for example, as an electronic computer directly on the device or on a machine tool. Through an evaluation of the mathematical model, a lifetime of the punch extending measures are applicable. With the data of the mathematical model, real-time decisions can be made, so that life-prolonging measures can be set purposefully. It is advantageous if a matrix is provided in order to press and separate the workpiece from the punch. The stamp may for example be formed from a hard metal, a steel or a ceramic. Sensitivities of hard metals and steels or ceramics are at least partially known, whereby material values are included in the mathematical model, so that the life of such a stamp is determined as accurately as possible. With a punch made of a hard metal or possibly a high-strength steel, the workpiece with a particularly sharp edge is separable. Carbide is durable in itself, since this is damaged even at high mechanical stress only to a small extent. However, it has been recognized within the scope of the invention that it is precisely these small or, compared to cutting forces, small tensile components which occur during tool withdrawal that occur when the stamp is retracted that are decisive for material failure. With the device according to the invention, it is possible to detect or measure even such low tensile components in a tool load, in order to predict a duration of use and possibly life of the punch made of hard metal in a further consequence. In particular, in the case of a die made of hard metal, it is favorable to be able to predict a deterioration of a quality or duration of use of the same, since this and thus an exchange thereof are relatively expensive.
    It is advantageous if the device is designed as a fine cutting device. Alternatively, the device may be formed, for example, as a punching device. With a fineblanking device, it is possible to separate the workpiece with a particularly smooth cut. When fineblanking with a punch made of hard metal or high-strength steel, however, large withdrawal forces occur, which change depending on a punch position and a life of the punch. Preferably, such a measurement of the withdrawal forces and an evaluation of the same over a lifetime of the punch or the fine cutting device. As a result, a self-learning fine cutting device is created. In the fine blanking device, a press plate for holding the workpiece is provided. This is arranged above the workpiece and has for fixing the workpiece during the separation process on a ring point. When separating the workpiece, the punch first moves through the press plate and then separates the workpiece. When returning to a starting position, tensile forces occur, which the sensor measures. It is further provided a counter-holder, which is arranged below the workpiece relative to the stamp. As a result, the workpiece with a smooth cut on a die with the stamp is separable.
    A use of a device according to the invention is advantageously carried out when predicting a lifetime of a punch during fineblanking. In particular, this is used to make decisions about a life of the stamp extending measures.
    Other features, advantages and effects will become apparent from the embodiment illustrated below. In the drawings, to which reference is made, show:
    1 shows a device according to the invention;
    FIG. 2 shows a detail of a device according to the invention according to FIG. 1; FIG.
    Fig. 3 is a photograph of a stamp;
    4 shows a diagram with retraction forces as a function of a stamp position.
    Fig. 1 shows a section through an inventive device 1 for monitoring a separation process of a workpiece 2, which is designed as a fine cutting device. But it can also be provided that the device 1 is formed, for example, for punching. The workpiece 2 is formed, for example, as a sheet from which defined shapes are cut.
    The device 1 comprises a punch 3 with a sensor 4 designed as a thin-film pressure sensor for measuring withdrawal forces acting on the punch 3. The sensor 4 is arranged at an upper end of the punch 3 and has the same cross-sectional area and the same rotational symmetry as the punch 3, so that a force measurement is as accurate as possible. The punch 3 is cylindrical over its entire length or height. Furthermore, the device 1 comprises a pressing plate 7, a counter holder 8 and a die 5. For holding the workpiece 2 during the separation process, the pressing plate 7 has a ring point 9.
    In addition to the sensor 4 for measuring withdrawal forces, other sensors, not shown, may also be provided, such as a sound sensor, a vibration sensor, a temperature sensor and / or an acceleration sensor.
    Furthermore, the device 1 comprises an evaluation unit 6, which is connected to the sensor 4 wirelessly or via cable or the like. The evaluation unit 6 takes data from the sensor 4 to the retraction forces, combines them with already known data and subsequently creates a mathematical model for use or life prediction of the punch 3. The life of the punch 3 depends in particular on the withdrawal forces since an amplitude of tensile stresses when pulling out of the punch 3 is large, and these are crucial in particular for a durable in itself punch 3 made of hard metal or steel for the duration of use.
    In a method according to the invention for monitoring a separation process of a workpiece 2 with a punch 3, retraction forces acting on it are measured as a function of a punch position, whereby a residual service life of the punch 3 can be determined. The retraction forces, which depend in particular on a friction, are measured by a sensor 4, wherein the sensor 4 is arranged on or at the punch 3. By measuring the withdrawal forces, which act on the punch 3, a damage is reliably detected before a fracture thereof. Moreover, it is also possible with the method according to the invention to predict a quality of the workpiece 2 produced by the fine blanking. The withdrawal forces, which act on the punch 3 when retracting to a starting position after a cutting process, are particularly relevant to tool damage. In contrast to a forward or cutting movement of the punch 3 occur during the withdrawal of the same namely large tensile forces through which the punch 3 is increasingly damaged. In particular, in a stamp 3 made of hard metal or optionally higher strength steel this is continuously damaged by the retraction forces.
    Fig. 2 shows a section A of the punch 3, which is particularly worn due to changing withdrawal forces. The inherently sharp contour is rounded off by several cutting processes. Furthermore, the structure of the punch 3 changes, so that it subsequently breaks or tears. A proper application of the mathematical model further enables a location of highest damage of the punch 3 to be accurately located. It is determined by the remaining duration of use of the punch 3, so that it can be reground or recalculated even before a break.
    A photo of a stamp 3 is shown in Fig. 3, wherein a stamp 3 is shown with so-called welds on the surface thereof. Damage to the stamp 3 is also caused by these welds, in particular metallic welds. With each stroke of the punch 3, it is coated with small parts of the workpiece 2 or components of the fine cutting device. These welds further influence the tensile forces acting on the punch 3.
    Moreover, with a method of the present invention, it is possible to predict the period of use of the punch 3 so that a separation process is stopped before a quality thereof deteriorates so that the workpiece 2 becomes unusable.
    In particular, it is advantageous that the quality of the separation process without special quality control of the workpieces or 2 itself is detected. It is reliably recognized a time for re-sharpening or re-cutting of the stamp 3.
    4 shows a diagram with retraction forces as a function of a position of the stamp 3. The dashed line shows experimentally determined values Fp_EXP, whereas the solid line shows simulated values Fp_SIM. A comparison of the two values Fp_EXP, Fp SIM shows a good match. The experimentally determined values Fp EXP are incorporated into the simulated values Fp_SIM or combined with these, so that subsequently a simulated theoretical model is created from the simulated values Fp_SIM. As shown in FIG. 4, the withdrawal forces are measured several times at different punch positions or at different process times with different cutting progress. By comparison with the theoretical or simulated values or, if appropriate, a real calibration curve for an analogous process, it is possible to predict when the stamp 3 will be re-sharpened or, if necessary, replaced.
    权利要求:
    Claims (13)
    [1]
    claims
    1. A method for separating a workpiece (2) with a punch (3), characterized in that on the punch (3) acting retraction forces are measured in dependence of a punch position, from which a residual service life of the punch (3) is determined.
    [2]
    2. The method according to claim 1, characterized in that the withdrawal forces with a on the punch (3) arranged sensor (4) are measured.
    [3]
    3. The method according to claim 1 or 2, characterized in that from data from the measured withdrawal forces and known data, a mathematical model is created, with which a lifetime of the punch (3) is predicted.
    [4]
    4. The method according to claim 3, characterized in that the mathematical model continuously data from the measured withdrawal forces are taken into account.
    [5]
    5. The method according to claim 3 or 4, characterized in that a lifetime of the punch (3) extending measures are taken by an evaluation of the mathematical model.
    [6]
    6. The method according to any one of claims 1 to 5, characterized in that at least one caused by the separation process vibration and / or temperature are measured.
    [7]
    7. The method according to any one of claims 1 to 6, characterized in that the workpiece (2) by a punch (3) made of a hard metal or a steel against a die (5) is pressed to separate the workpiece (2).
    [8]
    8. Device (1) for separating a workpiece (2), comprising a punch (3), characterized in that the punch (3) a sensor (4) is arranged to the punch (3) acting retraction forces in dependence of Stamp position to measure.
    [9]
    9. Device (1) according to claim 8, characterized in that at least one further sensor for measuring at least one caused by the separation process vibration and / or temperature is provided.
    [10]
    10. Device (1) according to claim 8 or 9, characterized in that an evaluation unit (6) is provided which evaluates data recorded by the sensor (4) and compares it with known data in order to determine a service life and / or life of the stamp (3 ) to predict.
    [11]
    11. The device according to claim 10, characterized in that the evaluation unit (6) is designed as an embedded system.
    [12]
    12. Device (1) according to any one of claims 8 to 11, characterized in that a die (5) is provided.
    [13]
    13. Device (1) according to one of claims 8 to 12, characterized in that the device (1) is designed as a fine cutting device.
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    同族专利:
    公开号 | 公开日
    EP3389890A1|2018-10-24|
    WO2017100810A1|2017-06-22|
    AT518154B1|2017-10-15|
    EP3389890B1|2019-10-02|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    DE102005053350A1|2005-11-07|2007-05-10|Schuler Pressen Gmbh & Co. Kg|Press with cutting impact damping|
    DE102006015711B3|2006-04-04|2007-10-11|Schuler Pressen Gmbh & Co. Kg|punch|
    WO2012035413A1|2010-09-15|2012-03-22|Matrix Srl|Device to detect force to optimize the functions of a punching machine|
    CH669748A5|1984-11-28|1989-04-14|Feintool Int Holding|
    JP2617072B2|1993-01-04|1997-06-04|株式会社アマダメトレックス|Punch die and die life management device|
    DE10101724A1|2001-01-15|2002-07-18|Emhart Inc|Workpiece operating method involves correcting operating force to predetermined amount by measuring deformation of C-shaped counterforce structure carrying workpiece|CN113723016A|2021-11-01|2021-11-30|深圳市信润富联数字科技有限公司|Punch residual life prediction method, device and system and readable storage medium|
    法律状态:
    2021-08-15| MM01| Lapse because of not paying annual fees|Effective date: 20201214 |
    优先权:
    申请号 | 申请日 | 专利标题
    ATA51064/2015A|AT518154B1|2015-12-14|2015-12-14|Method and device for separating a workpiece|ATA51064/2015A| AT518154B1|2015-12-14|2015-12-14|Method and device for separating a workpiece|
    EP16819417.3A| EP3389890B1|2015-12-14|2016-12-02|Method and device for cutting a workpiece|
    PCT/AT2016/060116| WO2017100810A1|2015-12-14|2016-12-02|Method and device for cutting a workpiece|
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