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EP0108718A2 - Method of bending sheet metal with a folding press - Google Patents

Method of bending sheet metal with a folding press Download PDF

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Publication number
EP0108718A2
EP0108718A2 EP83810486A EP83810486A EP0108718A2 EP 0108718 A2 EP0108718 A2 EP 0108718A2 EP 83810486 A EP83810486 A EP 83810486A EP 83810486 A EP83810486 A EP 83810486A EP 0108718 A2 EP0108718 A2 EP 0108718A2
Authority
EP
European Patent Office
Prior art keywords
sheet
sensors
matrix
thickness
punch
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.)
Granted
Application number
EP83810486A
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German (de)
French (fr)
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EP0108718A3 (en
EP0108718B1 (en
Inventor
Jean-Daniel Aubert
André Fornerod
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Cybelec SA
Original Assignee
Cybelec SA
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Publication date
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Publication of EP0108718A2 publication Critical patent/EP0108718A2/en
Publication of EP0108718A3 publication Critical patent/EP0108718A3/en
Application granted granted Critical
Publication of EP0108718B1 publication Critical patent/EP0108718B1/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
    • B21D5/006—Bending sheet metal along straight lines, e.g. to form simple curves combined with measuring of bends
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D5/00—Bending sheet metal along straight lines, e.g. to form simple curves
    • B21D5/02—Bending sheet metal along straight lines, e.g. to form simple curves on press brakes without making use of clamping means

Definitions

  • the precision of the folding angle obtained essentially depends on the precision of the two elements present, namely that of the press and that of the material to be folded.
  • the precision of the two elements present namely that of the press and that of the material to be folded.
  • sheets of the same dimensions although belonging to the same batch, have thickness differences due to manufacturing tolerances and that this thickness can vary in very appreciable proportions (up to 10%) d 'one sheet to another.
  • the thickness of a sheet can vary from place to place thereof.
  • the sheets may have undulations or deformations.
  • the stroke of the punch is therefore primarily determined by the thickness of the sheet to be bent. If we just set the press for the average thickness of a batch of sheets, the value of the folding angle obtained will present significant differences from one sheet to another which will in most cases be unacceptable. In order to avoid this dispersion, it is necessary to measure the thickness of each sheet very precisely before folding.
  • the known methods involve an operator who, using a suitable measuring device, determines the thickness of the sheet which will control the stroke of the punch. But this operation requires time and will lengthen the duration of the folding cycle very appreciably.
  • the object of the invention is to automatically determine the thickness of the sheet to be bent during the bending cycle itself and to take it into account to immediately modify the stroke that the punch must perform in order to obtain the desired bending angle. , and this without interrupting the folding movement. It is therefore a question, during the folding cycle, and without lengthening the cycle time, of determining the thickness of the sheet, of transmitting this value to an analysis center which compares it to the programmed value of the thickness and determines, on this basis, the variation of the stroke of the punch, then orders a modification of this stroke even before the folding cycle is finished.
  • the present invention relates to a method of folding a sheet using a press brake as defined in claim 1.
  • the invention also relates to a device for implementing the method as defined in claim 4.
  • the advantages of the process resulting from the present invention are obvious. Knowing very precisely the thickness of the sheet to be folded, at the very place of folding, the central analysis unit determines in a time significantly less than that of the descent of the punch, the exact stroke that the punch must make and gives the command to the press, without the operator having to intervene. In addition, this method makes it possible to greatly reduce the influence of the differences in thickness that a sheet can have from one point to another thereof, as well as that of any corrugations or other defects of this sheet.
  • the method according to the invention consists in determining the thickness of the sheet by measuring the difference between the position of the end of the punch and the upper surface of the matrix on which the sheet rests., When the part b of the sheet is raised, that is to say when the lower surface of this part of the sheet is no longer in contact with the upper surface of the matrix. It is then a question of taking into account the measurement of this thickness by an analysis center which will determine exactly the distance that the punch must travel to obtain the desired bending angle, taking into account the real thickness of the sheet.
  • sheet metal used here must be understood in its broadest sense, that is to say that of any material to be folded whatever its material.
  • An example of a device allowing the implementation of this method consists in placing sensors 1 at the level of the upper surface of the matrix 2, on the matrix itself or preferably on a bar 3 which is fixed on the side of the matrix so that the sensors are located located at the top surface of the matrix.
  • a bar 3 which is fixed on the side of the matrix so that the sensors are located located at the top surface of the matrix.
  • two bars 3.3 ′ located on either side of the matrix. It should be noted that the device can also operate quite satisfactorily with a single bar. These sensors are intended to determine the moment of loss of contact between the lower surface of the sheet and the upper surface of the matrix when the sheet 4 lifts.
  • a digital control device 5 programmed to determine in a very short time the value AD of the correction of the stroke of the punch 6 as a function of the difference between the measured thickness of the sheet and the thickness initially programmed.
  • This device operates in the following manner: the measurement zone formed by the sensors 1 is unlocked when the lower end of the punch is at a distance equal to twice the programmed thickness of the sheet relative to the surface top of the matrix. At this time, depending on its size, the sheet 4 covers a greater or lesser number of sensors 1, which are then put into action. When the punch reaches the surface of the sheet, part b of it begins to lift. However, the sensors will not be released immediately.
  • the correction to Y to be made to the depth of the punch stroke can be calculated, for example, using the following formula: where: ⁇ represents the value of the desired folding angle.
  • This correction is then automatically controlled by the press by digital control.
  • any material detection device can be used with or without contact, such as inductive, capacitive, laser, ultrasonic, etc. sensors.
  • the sheet undergoes decompression (which is called "SPRING BACK") which causes a variation in the folding angle.
  • SPRING BACK decompression
  • the value of this variation can be predicted with fairly high precision, which makes it possible to take it into account already during the initial programming of the numerical control.
  • sensors with a wide measurement range, such as proportional voltage sensors, and provided that sensors are installed on each side of the matrix, the device described above still makes it possible to control the bending angle, either during the folding cycle itself, or after decompression, the sensors making it possible to identify the position of the points of the sheet located at the right of these. Knowing then the position of the punch, as well as the actual thickness of the sheet, the bending angle can easily be calculated.
  • Such a control naturally requires prior recording in the digital control of the response curve of the sensors.
  • the sensors are photoelectric cells arranged at the ends of the matrix or of the bars (3.3 ′) and whose horizontal beam is parallel to the upper surface of the matrix is restored when the sheet is lifted.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)

Abstract

Le procédé permet la détermination automatique de l'épaisseur de la tôle au moment du pliage et à l'endroit même du pilage. L'épaisseur réelle de la tôle est alors prise en considération par une commande numérique qui commande la course du poinçon de manière continue, sans interruption du mouvement de pliage, et permet ainsi d'obtenir une grande précision de l'angle de pliage. Le dispositif de mise en oeuvre du procédé utilise des capteurs (1) situés au niveau de la surface supérieure de la matrice (2) et reliés à une commande numérique (5). Ces capteurs sont destinés à repérer le moment où la partie b de la tôle se soulève.The process allows the automatic determination of the thickness of the sheet at the time of folding and at the location of the pounding. The actual thickness of the sheet is then taken into account by a numerical control which controls the stroke of the punch continuously, without interrupting the bending movement, and thus makes it possible to obtain high precision of the bending angle. The device for implementing the method uses sensors (1) located at the upper surface of the matrix (2) and connected to a digital control (5). These sensors are intended to identify the moment when part b of the sheet rises.

Description

Lors du pliage d'une tôle à l'aide d'une presse plieuse, la précision de l'angle de pliage obtenu dépend essentiellement de la précision des deux éléments en présence, à savoir celle de la presse et celle du matériel à plier. Or, bien que l'on dispose aujourd'hui de presses plieuses très perfectionnées et permettant une grande précision, il en est bien autrement de la précision du matériel à plier.When folding a sheet using a press brake, the precision of the folding angle obtained essentially depends on the precision of the two elements present, namely that of the press and that of the material to be folded. However, although we have today very sophisticated press brakes and allowing great precision, it is very different from the precision of the material to be folded.

Il est bien connu que des tôles de mêmes dimensions, bien qu'appartenant à un même lot, présentent des différences d'épaisseur dues aux tolérances de fabrication et que cette épaisseur peut varier dans des proportions très appréciables (jusqu'à 10 %) d'une tôle à une autre. D'autre part, l'épaisseur d'une tôle peut varier d'un endroit à' l'autre de celle-ci. De plus, suite à leur entreposage, les tôles peuvent présenter des ondulations ou des déformations.It is well known that sheets of the same dimensions, although belonging to the same batch, have thickness differences due to manufacturing tolerances and that this thickness can vary in very appreciable proportions (up to 10%) d 'one sheet to another. On the other hand, the thickness of a sheet can vary from place to place thereof. In addition, following their storage, the sheets may have undulations or deformations.

Lors du pliage d'une tôle à l'aide d'une presse plieuse, la course du poinçon est donc en premier lieu déterminée par l'épaisseur de la tôle à plier. Si l'on se contente de régler la presse pour l'épaisseur moyenne d'un lot de tôles, la valeur de l'angle de pliage obtenu va présenter des différences importantes d'une tôle à une autre qui seront dans la plupart des cas inacceptables. Afin d'éviter cette dispersion, il est nécessaire de mesurer très exactement l'épaisseur de chaque tôle avant le pliage. Les procédés connus font intervenir un opérateur qui, à l'aide d'un appareil de mesure adéquat, détermine l'épaisseur de la tôle qui commandera la course du poinçon. Mais cette opération nécessite du temps et va allonger la durée du cycle de pliage de façon très appréciable.When bending a sheet using a press brake, the stroke of the punch is therefore primarily determined by the thickness of the sheet to be bent. If we just set the press for the average thickness of a batch of sheets, the value of the folding angle obtained will present significant differences from one sheet to another which will in most cases be unacceptable. In order to avoid this dispersion, it is necessary to measure the thickness of each sheet very precisely before folding. The known methods involve an operator who, using a suitable measuring device, determines the thickness of the sheet which will control the stroke of the punch. But this operation requires time and will lengthen the duration of the folding cycle very appreciably.

Si l'on ne veut pas modifier cette durée, il devient alors nécessaire d'automatiser la mesure de l'épaisseur de la tôle. A cette fin, on pourrait envisager de déterminer le moment exact où le poinçon touche la tôle, et repérant alors à ce moment la position du poinçon, déterminer l'épaisseur de la tôle par la mesure de la différence entre la position de l'extrémité du poinçon et la position de la surface supérieure de la matrice. Mais ce procédé présente de nombreux inconvénients, tels la réduction de la vitesse de descente du poinçon à l'approche de la tôle et l'arrêt momentané du mouvement lors de ce contact.If one does not want to modify this duration, it then becomes necessary to automate the measurement of the thickness of the sheet. To this end, one could consider determining the exact moment when the punch touches the sheet, and then locating at this moment the position of the punch, determine the thickness of the sheet by measuring the difference between the position of the end of the punch and the position of the upper surface of the matrix. However, this process has many drawbacks, such as the reduction in the speed of descent of the punch when approaching the sheet and the momentary stopping of the movement during this contact.

Les problèmes ci-dessus sont résolus de façon beaucoup plus simple et de manière très précise selon la présente invention.The above problems are solved in a much simpler and very precise manner according to the present invention.

Le but de l'invention consiste à déterminer automatiquement l'épaisseur de la tôle à plier pendant le cycle de pliage même et d'en tenir compte pour modifier immédiatement la course que doit effectuer le poinçon afin d'obtenir l'angle de pliage désiré, et cela sans interruption du mouvement de pliage. Il s'agit donc, pendant le cycle de pliage, et sans allonger la durée du cycle, de déterminer l'épaisseur de la tôle, de transmettre cette valeur à une centrale d'analyse qui la compare à la valeur programmée de l'épaisseur et détermine, sur cette base, la variation de la course du poinçon, puis commande une modification de cette course avant même que soit fini le cycle de pliage.The object of the invention is to automatically determine the thickness of the sheet to be bent during the bending cycle itself and to take it into account to immediately modify the stroke that the punch must perform in order to obtain the desired bending angle. , and this without interrupting the folding movement. It is therefore a question, during the folding cycle, and without lengthening the cycle time, of determining the thickness of the sheet, of transmitting this value to an analysis center which compares it to the programmed value of the thickness and determines, on this basis, the variation of the stroke of the punch, then orders a modification of this stroke even before the folding cycle is finished.

A cet effet, la présente invention concerne un procédé de pliage d'une tôle à l'aide d'une presse plieuse tel que défini dans la revendication 1.To this end, the present invention relates to a method of folding a sheet using a press brake as defined in claim 1.

L'invention concerne également un dispositif de mise en oeuvre du procédé tel que défini dans la revendication 4.The invention also relates to a device for implementing the method as defined in claim 4.

Par rapport à l'art antérieur, les avantages du procédé issu de la présente invention sont évidents. Connaissant très exactement l'épaisseur de la tôle à plier, à l'endroit même du pliage, la centrale d'analyse détermine dans un temps nettement inférieur à celui de la descente du poinçon, la course exacte que doit effectuer le poinçon et donne la commande à la presse, sans que l'opérateur doive intervenir. De plus, ce procédé permet de diminuer fortement l'influence des différences d'épaisseur que peut présenter une tôle d'un point à un autre de celle-ci, de même que celle des éventuelles ondulations ou autres défauts de'cette tôle.Compared to the prior art, the advantages of the process resulting from the present invention are obvious. Knowing very precisely the thickness of the sheet to be folded, at the very place of folding, the central analysis unit determines in a time significantly less than that of the descent of the punch, the exact stroke that the punch must make and gives the command to the press, without the operator having to intervene. In addition, this method makes it possible to greatly reduce the influence of the differences in thickness that a sheet can have from one point to another thereof, as well as that of any corrugations or other defects of this sheet.

On comprendre mieux l'invention à l'aide de la description qui suit, donnée à titre d'exemple et qui renvoie aux dessins ci-joints, sur lesquels :

  • la fig.l montre une vue schématique partielle en perspective d'une presse munie d'un dispositif selon l'invention
  • la fig.2 montre une coupe schématique de cette presse au niveau de la matrice.
The invention can be better understood with the aid of the following description, given by way of example and which refers to the attached drawings, in which:
  • fig.l shows a partial schematic perspective view of a press fitted with a device according to the invention
  • Fig.2 shows a schematic section of this press at the die.

Le procédé selon l'invention, décrit à la fig. 2, consiste à déterminer l'épaisseur de la tôle en mesurant la différence entre la position de l'extrémité du poinçon et la surface supérieure de la matrice sur laquelle repose la tôle., au moment où la partie b de la tôle se soulève, c'est-à-dire au moment où la surface inférieure de cette partie de la tôle n'est plus en contact avec la surface supérieure de la matrice. Il s'agit alors de prendre en considération la mesure de cette épaisseur par une centrale d'analyse qui déterminera exactement la distance que doit parcourir le poinçon pour obtenir l'angle de pliage désiré, compte tenu de l'épaisseur réelle de la tôle.The method according to the invention, described in FIG. 2, consists in determining the thickness of the sheet by measuring the difference between the position of the end of the punch and the upper surface of the matrix on which the sheet rests., When the part b of the sheet is raised, that is to say when the lower surface of this part of the sheet is no longer in contact with the upper surface of the matrix. It is then a question of taking into account the measurement of this thickness by an analysis center which will determine exactly the distance that the punch must travel to obtain the desired bending angle, taking into account the real thickness of the sheet.

Le terme "tôle" utilisé ici doit s'entendre dans son sens le plus large, c'est-à-dire celui de tout matériel à plier quelle que soit sa matière.The term "sheet metal" used here must be understood in its broadest sense, that is to say that of any material to be folded whatever its material.

Un exemple de dispositif permettant la mise en oeuvre de ce procédé consiste à placer des capteurs 1 au niveau de la surface supérieure de la matrice 2, sur la matrice même ou de préférence sur une barre 3 que l'on fixe sur le côté de la matrice de telle manière que les capteurs se trouvent situés au niveau de la surface supérieure de la matrice. Sur les fig. 1 et 2 on a représenté deux barres 3,3' situées de part et d'autre de la matrice. Il est à noter que le dispositif peut aussi fonctionner de manière tout à fait satisfaisante avec une seule barre. Ces capteurs sont destinés à déterminer le moment de la perte de contact entre la surface inférieure de la tôle et la surface supérieure de la matrice au moment où la tôle 4 se soulève. Ils sont reliés à un appareil de commande numérique 5 programmé pour déterminer dans un temps très bref la valeur AD de la correction de la course du poinçon 6 en fonction de la différence entre l'épaisseur-mesurée de la tôle et l'épaisseur programmée initialement. Ce dispositif fonctionne de la manière suivante : le déverrouillage de la zone de mesure formée par les capteurs 1 a lieu lorsque l'extrémité inférieure du poinçon se trouve à une distance égale à deux fois l'épaisseur programmée de la tôle par rapport à la surface supérieure de la matrice. A ce moment, suivant sa taille, la tôle 4 recouvre un nombre plus ou moins grand de capteurs 1, qui sont alors mis en action. Lorsque le poinçon atteint la surface de la tôle, la partie b de celle-ci commence à se soulever. Mais, les capteurs ne vont pas être relâchés immédiatement. Il existe en effet une distance d de sensibilité des capteurs que l'on peut déterminer préalablement pour chaque type de capteur, le calibrage s'effectuant de façon très simple, en une seule opération : il suffit de plier une tôle d'épaisseur bien connue, et la commande numérique, programmée en un mode adéquat, donne immédiatement la valeur de d. Cette valeur est alors valable quelle que soit l'épaisseur de la tôle à plier, à condition qu'il s'agisse de la même matière.An example of a device allowing the implementation of this method consists in placing sensors 1 at the level of the upper surface of the matrix 2, on the matrix itself or preferably on a bar 3 which is fixed on the side of the matrix so that the sensors are located located at the top surface of the matrix. In fig. 1 and 2 there are shown two bars 3.3 ′ located on either side of the matrix. It should be noted that the device can also operate quite satisfactorily with a single bar. These sensors are intended to determine the moment of loss of contact between the lower surface of the sheet and the upper surface of the matrix when the sheet 4 lifts. They are connected to a digital control device 5 programmed to determine in a very short time the value AD of the correction of the stroke of the punch 6 as a function of the difference between the measured thickness of the sheet and the thickness initially programmed. . This device operates in the following manner: the measurement zone formed by the sensors 1 is unlocked when the lower end of the punch is at a distance equal to twice the programmed thickness of the sheet relative to the surface top of the matrix. At this time, depending on its size, the sheet 4 covers a greater or lesser number of sensors 1, which are then put into action. When the punch reaches the surface of the sheet, part b of it begins to lift. However, the sensors will not be released immediately. There is indeed a distance d of sensitivity of the sensors which can be determined beforehand for each type of sensor, the calibration being carried out in a very simple manner, in a single operation: it is enough to bend a sheet of well-known thickness. , and the numerical control, programmed in a suitable mode, immediately gives the value of d. This value is then valid regardless of the thickness of the sheet to be bent, provided that it is the same material.

Lors du relâchement du premier de ces capteurs, au moment où le soulèvement de la tôle atteint la distance de sensibilité d des capteurs au droit des capteurs, la commande numérique 5 mémorise alors les numéros de tous les capteurs qui sont en action. Puis, lorsque la moitié des capteurs pris en considération sont relâchés, un signal est transmis à la commande numérique qui mémorise alors la position du coulisseau 7 (et par conséquent celle du poinçon 6) par l'intermédiaire des règles digitales latérales 8,8' disposées sur les côtés de la matrice. Ces règles pouvant mesurer une position au 1/100 de mm, et la presse n'étant pas toujours réglée avec une absolue précision, il est possible que les valeurs indiquées par les deux règles 8,8' diffèrent quelque peu. D'une façon générale, la commande numérique est programmée pour mémoriser la valeur la plus basse des deux positions indiquées par les règles. Mais il est aussi possible de programmer cette commande numérique pour qu'elle mémorise la moyenne des deux valeurs ou encore une valeur déterminée selon une loi quelconque. La valeur de la différence entre l'épaisseur mesurée de la tôle et l'épaisseur programmée est donnée par la formule suivante :

Figure imgb0001

  • où: Y est la position du poinçon indiquée par les règles digitales latérales
  • Yref est la coordonnée verticale de la position du niveau supérieur de la matrice
  • V est l'ouverture de la matrice
  • D est la distance entre le centre d'un capteur et le bord de l'ouverture de la matrice
  • ep est l'épaisseur programmée de la tôle
  • d est la distance de sensibilité des capteurs.
When the first of these sensors is released, when the lifting of the sheet reaches the sensitivity distance d of the sensors in line with the sensors, the digital control 5 then stores the numbers of all the sensors that are in action. Then, when half of sensors taken into account are released, a signal is transmitted to the digital control which then memorizes the position of the slide 7 (and consequently that of the punch 6) by means of the lateral digital rules 8,8 'arranged on the sides of the matrix. Since these rules can measure a position to 1/100 mm, and the press is not always adjusted with absolute precision, the values indicated by the two rules 8,8 'may differ slightly. Generally speaking, the numerical control is programmed to memorize the lower value of the two positions indicated by the rules. But it is also possible to program this digital control so that it stores the average of the two values or a value determined according to any law. The value of the difference between the measured thickness of the sheet and the programmed thickness is given by the following formula:
Figure imgb0001
  • where: Y is the position of the punch indicated by the lateral digital rules
  • Yref is the vertical coordinate of the position of the upper level of the matrix
  • V is the opening of the matrix
  • D is the distance from the center of a sensor to the edge of the die opening
  • ep is the programmed thickness of the sheet
  • d is the sensitivity distance of the sensors.

La correction àY à apporter à la profondeur de la course du poinçon, qui sera déterminée par la commande numérique, peut être calculée, par exemple, à l'aide de la formule suivante :

Figure imgb0002
où : α représente la valeur de l'angle de pliage désiré.The correction to Y to be made to the depth of the punch stroke, which will be determined by numerical control, can be calculated, for example, using the following formula:
Figure imgb0002
 where: α represents the value of the desired folding angle.

Cette correction est alors automatiquement commandée à la presse par la commande numérique.This correction is then automatically controlled by the press by digital control.

Comme capteurs on peut utiliser tout dispositif de détection de matière avec ou sans contact, tels des capteurs inductifs, capacitifs, à laser, à ultrasons,'etc.As sensors, any material detection device can be used with or without contact, such as inductive, capacitive, laser, ultrasonic, etc. sensors.

Immédiatement après le pliage, la tôle subit une décompression (que l'on appelle "SPRING BACK") qui entraîne une variation de l'angle de pliage. Pour un matériau donné, la valeur de cette variation peut être prévue avec une précision assez grande, ce qui permet d'en tenir compte déjà lors de la programmation initiale-de la commande numérique. Toutefois, si l'on dispose de capteurs à large plage de mesure, tels des capteurs à tension proportionnelle, et à condition de mettre en place des capteurs de chaque côté de la matrice, le dispositif décrit ci-dessus permet encore de contrôler l'angle de pliage, soit durant le cycle de pliage même, soit après la décompression, les capteurs permettant de repérer la position des points de la tôle situés au droit de ceux-ci. Connaissant alors la position du poinçon, ainsi que l'épaisseur réelle de la tôle, l'angle de pliage peut facilement être calculé. Un tel contrôle nécessite bien entendu l'enregistrement préalable dans la commande numérique de la courbe de réponse des capteurs.Immediately after folding, the sheet undergoes decompression (which is called "SPRING BACK") which causes a variation in the folding angle. For a given material, the value of this variation can be predicted with fairly high precision, which makes it possible to take it into account already during the initial programming of the numerical control. However, if there are sensors with a wide measurement range, such as proportional voltage sensors, and provided that sensors are installed on each side of the matrix, the device described above still makes it possible to control the bending angle, either during the folding cycle itself, or after decompression, the sensors making it possible to identify the position of the points of the sheet located at the right of these. Knowing then the position of the punch, as well as the actual thickness of the sheet, the bending angle can easily be calculated. Such a control naturally requires prior recording in the digital control of the response curve of the sensors.

Dans une autre forme d'exécution du dispositif selon l'invention, les capteurs sont des cellules photo-électriques disposées aux extrémités de la matrice ou des barres (3,3') et dont le faisceau horizontal et parallèle à la surface supérieure de la matrice est rétabli au moment où la tôle se soulève.In another embodiment of the device according to the invention, the sensors are photoelectric cells arranged at the ends of the matrix or of the bars (3.3 ′) and whose horizontal beam is parallel to the upper surface of the matrix is restored when the sheet is lifted.

Claims (13)

1. Procédé de pliage d'une tôle à l'aide d'une presse plieuse, caractérisé en ce que l'on détermine l'épaisseur de la tôle et en ce que l'on adapte la course du poinçon à l'épaisseur de la tôle de manière continue sans interruption du mouvement de pliage1. A method of folding a sheet using a press brake, characterized in that the thickness of the sheet is determined and that the stroke of the punch is adapted to the thickness of the sheet continuously without interrupting the bending movement 2. Procédé selon la revendication 1, caractérisé en ce que l'on détermine l'épaisseur de la tôle au moment de la perte de contact entre la surface inférieure de la tôle et la surface supérieure de la matrice, en mesurant la différence entre la position de l'extrêmité inférieure de travail du poinçon et la position de la surface supérieure de la matrice.2. Method according to claim 1, characterized in that the thickness of the sheet is determined at the time of the loss of contact between the lower surface of the sheet and the upper surface of the matrix, by measuring the difference between the position of the lower working end of the punch and the position of the upper surface of the die. 3. Procédé selon la revendication 2, caractérisé en ce que l'on détermine l'épaisseur de la tôle en tenant compte de l'angle de pliage initial au moment de la perte de contact entre la surface inférieure de la tôle et la surface supérieure de la matrice.3. Method according to claim 2, characterized in that the thickness of the sheet is determined by taking into account the initial bending angle at the time of the loss of contact between the lower surface of the sheet and the upper surface of the matrix. 4. Dispositif de mise en oeuvre du procédé selon l'une des revendications 1 à 3, caractérisé en ce qu'il comporte au moins un capteur (1) situé au niveau de la surface supérieure de la matrice et un moyen (8) destiné à déterminer l'épaisseur de la tôle.4. Device for implementing the method according to one of claims 1 to 3, characterized in that it comprises at least one sensor (1) situated at the level of the upper surface of the matrix and a means (8) intended to determine the thickness of the sheet. 5. Dispositif selon la revendication 4, caractérisé en ce que les capteurs sont supportés par au moins une barre fixée sur le côté de la matrice.5. Device according to claim 4, characterized in that the sensors are supported by at least one bar fixed to the side of the matrix. 6. Dispositif selon l'une des revendications 4 ou 5, caractérisé en ce que le moyen (8) est constitué par au moins une règle digitale disposée sur le côté de la presse.6. Device according to one of claims 4 or 5, characterized in that the means (8) consists of at minus a digital rule placed on the side of the press. 7. Dispositif selon l'une des revendications,4 à 6, caractérisé en ce qu'il comporte un moyen de commande continue de la course du poinçon.7. Device according to one of claims, 4 to 6, characterized in that it comprises means for continuously controlling the stroke of the punch. 8. Dispositif selon la revendication 7, caractérisé en ce que ce moyen de commande continue consiste en une commande numérique (5).8. Device according to claim 7, characterized in that this continuous control means consists of a digital control (5). 9. Dispositif selon l'une des revendications 4 à 8, caractérisé en ce que les capteurs (1) sont des systèmes de détection de matière sans contact.9. Device according to one of claims 4 to 8, characterized in that the sensors (1) are non-contact material detection systems. 10. Dispositif selon la revendication 9, caractérisé en ce que les capteurs (1) sont des capteurs à induction.10. Device according to claim 9, characterized in that the sensors (1) are induction sensors. 11. Dispositif selon l'une des revendications 4 à 8, caractérisé en ce que les capteurs sont disposés aux extrémités de la matrice (2) et en ce que ces capteurs sont des cellules photo-électriques à faisceau horizontal parallèle à la surface supérieure de la matrice.11. Device according to one of claims 4 to 8, characterized in that the sensors are arranged at the ends of the matrix (2) and in that these sensors are photoelectric cells with horizontal beam parallel to the upper surface of the matrix. 12. Dispositif selon l'une des revendication 4 à 8, caractérisé en ce que les capteurs (1) sont des systèmes de détection de matière avec contact.12. Device according to one of claims 4 to 8, characterized in that the sensors (1) are material detection systems with contact. 13. Dispositif selon l'une des revendications 1 à 9, caractérisé en ce que les capteurs (1) sont des capteurs à tension proportionnelle situés des deux côtés de la matrice et agencés de façon à déterminer la position des points de la tôle situés au droit d'eux-mêmes à un instant quelconque pendant ou après le cycle de pliage.13. Device according to one of claims 1 to 9, characterized in that the sensors (1) are proportional voltage sensors located on both sides of the matrix and arranged so as to determine the position of the points of the sheet located at right of themselves at any time during or after the folding cycle.
EP83810486A 1982-11-05 1983-10-21 Method of bending sheet metal with a folding press Expired EP0108718B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH6440/82 1982-11-05
CH6440/82A CH651767A5 (en) 1982-11-05 1982-11-05 PROCESS FOR FOLDING A SHEET USING A BENDING PRESS.

Publications (3)

Publication Number Publication Date
EP0108718A2 true EP0108718A2 (en) 1984-05-16
EP0108718A3 EP0108718A3 (en) 1984-08-15
EP0108718B1 EP0108718B1 (en) 1987-07-08

Family

ID=4309662

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83810486A Expired EP0108718B1 (en) 1982-11-05 1983-10-21 Method of bending sheet metal with a folding press

Country Status (4)

Country Link
US (1) US4550586A (en)
EP (1) EP0108718B1 (en)
CH (1) CH651767A5 (en)
DE (1) DE3372326D1 (en)

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BE1001412A5 (en) * 1987-09-28 1989-10-24 Lvd Co Metal plate thickness measuring assembly for press - has hydraulic piston on edge of pin unit clamping plate against base, with portion measuring displacement
WO1995005905A1 (en) * 1993-08-27 1995-03-02 L.V.D. Company N.V. Adaptive folding
WO2011000013A1 (en) * 2009-06-29 2011-01-06 Trumpf Maschinen Austria Gmbh & Co. Kg. Device and method for bending a workpiece
WO2011000011A1 (en) * 2009-06-29 2011-01-06 Trumpf Maschinen Austria Gmbh & Co. Kg. Device and method for bending a workpiece
US9527122B2 (en) 2009-06-29 2016-12-27 Trumpf Maschinen Austria Gmbh & Co. Kg. Device and method for the laser-supported bending of workpieces

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US4819467A (en) * 1986-09-17 1989-04-11 Cincinnati Incorporated Adaptive control system for hydraulic press brake
JPH0230326A (en) * 1988-07-19 1990-01-31 Yamazaki Mazak Corp Press brake with work measuring means and measuring method for work thereof
SE505985C2 (en) * 1989-11-14 1997-10-27 Amada Co Ltd Method and apparatus for sensing bending angles of a metal sheet during bending
US5148693A (en) * 1989-11-14 1992-09-22 Amada Company, Limited Method and a device for detecting folding angles of a metal sheet during the folding and a method for folding of a metal sheet
JP2520368B2 (en) * 1993-07-30 1996-07-31 株式会社東洋工機 Bending method and apparatus
US5857366A (en) * 1994-07-08 1999-01-12 Amada Company, Ltd. Method of bending workpiece to target bending angle accurately and press brake for use in the same method
JP4750940B2 (en) * 2000-12-08 2011-08-17 株式会社アマダエンジニアリングセンター Blank processing equipment, workpiece thickness measurement equipment, springback measurement equipment used in sheet metal processing systems
US7040129B2 (en) * 2000-01-17 2006-05-09 Amada Company, Limited Sheet working method, sheet working system, and various devices related to such system
EP1120176B1 (en) * 2000-01-24 2005-04-20 Bystronic Laser AG Method for controlling the stroke of a press brake
ATE297272T1 (en) * 2001-03-16 2005-06-15 Bystronic Laser Ag METHOD FOR ADJUSTING THE PATH OF A PRESS BRAKE
US8692877B2 (en) 2005-06-20 2014-04-08 Lazer Safe Pty Ltd Imaging and safety system and method for an industrial machine
CN104624726B (en) * 2014-12-24 2016-08-24 广东中南声像灯光设计研究院 The bender of X-ray Thickness sensitivity based on PLC and bending speed regulation and Bending Processing method thereof
CN104965488A (en) * 2015-06-26 2015-10-07 苏州边桐传感科技有限公司 Metal plate folding system based on crack detection feedback torque adjustment and method

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DE2901376B2 (en) * 1979-01-15 1980-10-30 Karl Mengele & Soehne Maschinenfabrik Und Eisengiesserei Gmbh & Co, 8870 Guenzburg Control device on free bending machines

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE1001412A5 (en) * 1987-09-28 1989-10-24 Lvd Co Metal plate thickness measuring assembly for press - has hydraulic piston on edge of pin unit clamping plate against base, with portion measuring displacement
WO1995005905A1 (en) * 1993-08-27 1995-03-02 L.V.D. Company N.V. Adaptive folding
BE1007424A5 (en) * 1993-08-27 1995-06-13 Lvd Co Adaptive bending.
US5829288A (en) * 1993-08-27 1998-11-03 L.V.D. Company N.V. Adaptive folding
WO2011000013A1 (en) * 2009-06-29 2011-01-06 Trumpf Maschinen Austria Gmbh & Co. Kg. Device and method for bending a workpiece
WO2011000011A1 (en) * 2009-06-29 2011-01-06 Trumpf Maschinen Austria Gmbh & Co. Kg. Device and method for bending a workpiece
US9003847B2 (en) 2009-06-29 2015-04-14 Trumpf Maschinen Austria Gmbh & Co. Kg. Device and method for bending a workpiece
US9003848B2 (en) 2009-06-29 2015-04-14 Trumpf Maschinen Austria Gmbh & Co., Kg. Device and method for bending a workpiece
US9527122B2 (en) 2009-06-29 2016-12-27 Trumpf Maschinen Austria Gmbh & Co. Kg. Device and method for the laser-supported bending of workpieces

Also Published As

Publication number Publication date
EP0108718A3 (en) 1984-08-15
EP0108718B1 (en) 1987-07-08
CH651767A5 (en) 1985-10-15
US4550586A (en) 1985-11-05
DE3372326D1 (en) 1987-08-13

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