EP1424146A1 - Vorrichtung zur automatischen Korrektur der inhärenten Biegeparameter des Bleches in einer Abkantpresse - Google Patents

Vorrichtung zur automatischen Korrektur der inhärenten Biegeparameter des Bleches in einer Abkantpresse Download PDF

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Publication number
EP1424146A1
EP1424146A1 EP03356171A EP03356171A EP1424146A1 EP 1424146 A1 EP1424146 A1 EP 1424146A1 EP 03356171 A EP03356171 A EP 03356171A EP 03356171 A EP03356171 A EP 03356171A EP 1424146 A1 EP1424146 A1 EP 1424146A1
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EP
European Patent Office
Prior art keywords
sheet
press brake
slide
folding
thickness
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Withdrawn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
EP03356171A
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English (en)
French (fr)
Inventor
Michel Brisard
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.)
RBH
Original Assignee
RBH
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Filing date
Publication date
Application filed by RBH filed Critical RBH
Publication of EP1424146A1 publication Critical patent/EP1424146A1/de
Withdrawn legal-status Critical Current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
    • B21D5/02—Bending sheet metal along straight lines, e.g. to form simple curves on press brakes without making use of clamping means

Definitions

  • the present invention relates generally to the field machine tools for metal deformation machining, and it is more particularly interested in so-called press brake machines, commonly used in industry for bending sheets. Again more particularly, the invention relates to a correction device automatic bending parameters inherent in the sheet, namely the thickness sheet metal and the strength of the sheet metal material, on a press brake.
  • the bending of the sheets on press brakes can be done by one or the other of two methods, namely folding "in the air” and folding fully of matrix, also known as “striking" folding.
  • the folding is carried out by means of a tool which comprises a punch and a matrix, between which the sheet metal to be bent is introduced, the matrix being able to particular have a "V" profile in which the folding angle of the sheet.
  • Folding "in the air” is an operation in which, as illustrated schematically Figure 1 of the accompanying drawing, three points of the tools, which are the two upper edges of the matrix 2 in "V" shape, and the end of the punch 3, to deform the sheet 4.
  • the exact shape of the die 2 is not involved here, and its "V" profile is adopted simply because it it is the most economical form and the most resistant.
  • the neutral fiber of the sheet 4 is not elongated, and the metal retains its elastic deformation zone. he it is therefore necessary to bend this sheet at an angle more closed than the desired bending angle, to take account of the elastic return of the sheet.
  • the punches and dies are cut at an angle of 85 °, or even 80 ° for thick sheets.
  • the force F (usually expressed in tonnes) to be applied to the punch to perform the folding can be determined from an abacus of folding, giving the force to be applied for a unit of length (1 meter) of sheet, depending on the sheet thickness and the width L of the "V", for a sheet given resistance, the force thus determined being to be increased by a coefficient safety, for example 20%, to be sure to bend securely prison.
  • This force can also be determined directly by the command digital press brake, based on the main data: sheet thickness, sheet strength, bending length and the opening of the "V".
  • Folding at the bottom of the die or "striking" partially avoids the disadvantages previously exposed.
  • the tools are machined at the desired folding angle, and the results are not influenced by the variations in sheet thickness, or by the elastic return of the sheet.
  • the force to be applied is very large, at least 30 tonnes per meter of bending length and per millimeter of thickness, for a steel sheet of mechanical strength equal to 48 daN / mm 2 .
  • the machines must be of very high capacity, and they carry out here a beginning of stamping, by deforming the neutral fiber of the sheet.
  • each folding angle requires different tools.
  • the adjustment of the bending angle of the sheet is made by first proceeding to an approximate folding, at an angle more open as the desired angle, on a first sheet, then by proceeding trial and error to obtain the desired folding angle.
  • This method remains empirical and artisanal, rather than industrial.
  • European patent EP 1 120 176 A1 (corresponding to the American US patent 2001/009106), in which it is expected that at least one sensor measures a physical parameter varying with the force exerted by the punch on the sheet placed on the die, during the folding operation "in the air". This allows to estimate the difference between the real value of the thickness of the sheet and its value of setpoint, and correct the bottom dead center position of the punch stroke, taking into account the estimated thickness difference.
  • the physical parameter measured is here, in particular, the hydraulic pressure prevailing in one or more cylinders hydraulics that control the vertical movement of the movable deck or press brake slide, conventionally supporting the punch.
  • this document also provides for the use of gauges for constraint, but this alternative is not detailed, the position of the gauges is not optimized, and anyway corrections related to resistance of the material and the value of the "convex" are not carried out either.
  • Another problem currently encountered consists in not exceeding a certain maximum pressure on the folding tools.
  • a specific pressure from 6 to 8 daN / mm 2 , on the bearing faces of the tools.
  • a simple rule consists in exerting a maximum force of 100 to 120 tonnes per meter of length of tool used.
  • the present invention aims to remedy all of the disadvantages previously exposed, by providing a device improved correction of bending parameters on a press brake, which allows all parameters to be taken into account simultaneously, also the resistance of the material to be bent, and which performs the correction in a particularly precise way, in particular thanks to a choice appropriate sensors and optimal positioning of these sensors, while providing adequate security.
  • the invention relates to a correction device automatic bending parameters inherent in the sheet, namely the thickness of sheet metal and the strength of the sheet material, on a press brake performing a folding "in the air", this device essentially comprising means for measuring the displacement of the slider carrying the punch bending, means for measuring the bending force, and means for processing of measurements which, from these, determine in real time, that is to say during the descent of the slide, the actual thickness of the sheet to bend, and the actual strength of that sheet being bent, and which perform, according to the thickness and resistance values thus determined, a automatic correction of the bottom dead center of the slide stroke and the bending force.
  • the device which is the subject of the invention also achieves, from the measurements mentioned above, an automatic correction of the "bulging".
  • the invention allows an effective automatic correction of the bottom dead center of the slide and bending force, taking into consideration, at each press brake operating cycle, the actual thickness of the sheet to be bent and the bending resistance of this sheet.
  • the "domed” can also be corrected “dynamically”, depending on the equipment the press brake, depending on the actual bending effort. So the folding angle desired is respected, at the ends of the fold line and also in the part median of this fold line.
  • the means for measuring the displacement of the slide consist of measurement rules incremental, mounted laterally on the slide and cooperating with Measuring "ce” attached to the lower apron of the press brake.
  • the advantage such "Ce” is to allow taking into account the deformations of the frame of the machine, without any adjustment or parameterization, whatever the characteristics of the machine as well as its conditions of use.
  • the means for measuring the bending force consist of strain gauges placed on the side uprights of the press brake frame, preferably at the "swan neck” of said press brake. So the strain gauges are mounted at a characteristic location of the stress state of the machine, under the effect bending force.
  • the advantage of this provision is that the measurement is taken directly on the "force” parameter, representative of the essential function of the press brake, namely to develop an effort which is function of the other main bending parameters: sheet thickness, sheet strength, bending length and "V" opening of the die folding.
  • the processing means compare actual thickness and strength determined of the sheet to be bent with admissible limit values predetermined, and control the interruption of the operation of the press brake, in particular the stop of the slide descent, in case of exceeding these limit values.
  • said processing means can also ensure, from the measurement of the bending force, a function of limitation of this force, in particular by comparison with a value admissible limit, with command to interrupt operation of the press brake if the limit value is exceeded.
  • a press brake comprises, in a generally known manner, a frame 5 provided with two uprights side 6 between which is vertically guided a slide 7, moved to by means of two vertical hydraulic cylinders 8 of respective axes Y1 and Y2.
  • the slide 7 carries the punch 3 at its lower part, while the die 2 is carried by a fixed lower deck 9.
  • Two incremental measurement rules 10 are mounted laterally on the slide 7, for measuring the vertical displacement of this slide 7, in cooperation with measuring "C" 11 attached to the deck lower 9. These means provide a measurement of the vertical position of the slide 7 with an accuracy of ⁇ 0.01 mm.
  • strain gauges 12 are placed on each of the lateral uprights 6 of the frame 5 of the machine, at a characteristic location of the stress state of the machine under the action of the bending force F exerted by the jacks 8, namely at the "swan neck” 13 of the press brake.
  • This press brake still includes a digital control 14 which centralizes information and oversees the various functions of the machine.
  • the digital control 14 receives and processes, in "real time”, the position measurements provided by incremental rules 10, as well as signals from the strain gauges 12, these signals being amplified for of their use in digital control 14.
  • Figure 6 illustrates the cycle of thickness and thickness measurement. resistance of the sheet to bend, and automatic correction of the bottom dead center of the slide 7, the folding force F exerted by the jacks 8 and the value of "curved", depending on the thickness and the real resistance of the sheet.
  • the operation may include security provisions and special adaptations.
  • the "adjustable curved tables" being an optional equipment of the press brakes, an easily understandable adaptation consists of correct the value of the "bulging" only in the case of a machine equipped with such a system, and to remove this correction in the case a press brake devoid of such equipment.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
EP03356171A 2002-11-29 2003-11-06 Vorrichtung zur automatischen Korrektur der inhärenten Biegeparameter des Bleches in einer Abkantpresse Withdrawn EP1424146A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0215081 2002-11-29
FR0215081A FR2847835B1 (fr) 2002-11-29 2002-11-29 Dispositif de correction automatique des parametres de pliage inherents a la tole, sur une presse-plieuse

Publications (1)

Publication Number Publication Date
EP1424146A1 true EP1424146A1 (de) 2004-06-02

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP03356171A Withdrawn EP1424146A1 (de) 2002-11-29 2003-11-06 Vorrichtung zur automatischen Korrektur der inhärenten Biegeparameter des Bleches in einer Abkantpresse

Country Status (2)

Country Link
EP (1) EP1424146A1 (de)
FR (1) FR2847835B1 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008119090A1 (de) * 2007-03-30 2008-10-09 Trumpf Maschinen Austria Gmbh & Co. Kg. Verfahren zur festlegung eines einstellparameterwerts einer biegepresse
EP2189275A3 (de) * 2008-11-21 2013-02-20 Murata Machinery, Ltd. Pressmaschine
CN113909342A (zh) * 2021-09-07 2022-01-11 广东省水利水电第三工程局有限公司 一种保护桥梁基础的u型结构的施工装置

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4819467A (en) * 1986-09-17 1989-04-11 Cincinnati Incorporated Adaptive control system for hydraulic press brake
JPH0230327A (ja) * 1988-07-15 1990-01-31 Matsushita Electric Works Ltd プレスブレーキのストローク制御装置
US6192732B1 (en) * 1996-10-03 2001-02-27 Komatsu Ltd. Bending method and bending apparatus for bending machine
US20010009106A1 (en) * 2000-01-24 2001-07-26 Gerrit Gerritsen Method of adjusting the stroke of a press brake

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4819467A (en) * 1986-09-17 1989-04-11 Cincinnati Incorporated Adaptive control system for hydraulic press brake
JPH0230327A (ja) * 1988-07-15 1990-01-31 Matsushita Electric Works Ltd プレスブレーキのストローク制御装置
US6192732B1 (en) * 1996-10-03 2001-02-27 Komatsu Ltd. Bending method and bending apparatus for bending machine
US20010009106A1 (en) * 2000-01-24 2001-07-26 Gerrit Gerritsen Method of adjusting the stroke of a press brake

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 014, no. 177 (M - 0960) 9 April 1990 (1990-04-09) *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008119090A1 (de) * 2007-03-30 2008-10-09 Trumpf Maschinen Austria Gmbh & Co. Kg. Verfahren zur festlegung eines einstellparameterwerts einer biegepresse
EP2189275A3 (de) * 2008-11-21 2013-02-20 Murata Machinery, Ltd. Pressmaschine
CN113909342A (zh) * 2021-09-07 2022-01-11 广东省水利水电第三工程局有限公司 一种保护桥梁基础的u型结构的施工装置

Also Published As

Publication number Publication date
FR2847835A1 (fr) 2004-06-04
FR2847835B1 (fr) 2005-09-09

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