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EP0317830A2 - A method of bending metal objects - Google Patents
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EP0317830A2 - A method of bending metal objects - Google Patents

A method of bending metal objects Download PDF

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Publication number
EP0317830A2
EP0317830A2 EP88118683A EP88118683A EP0317830A2 EP 0317830 A2 EP0317830 A2 EP 0317830A2 EP 88118683 A EP88118683 A EP 88118683A EP 88118683 A EP88118683 A EP 88118683A EP 0317830 A2 EP0317830 A2 EP 0317830A2
Authority
EP
European Patent Office
Prior art keywords
heating
phase
bending
stream
bending line
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
EP88118683A
Other languages
German (de)
French (fr)
Other versions
EP0317830B1 (en
EP0317830A3 (en
Inventor
Henryk Frackiewicz
Zygmunt Mucha
Wieslaw Trampczynski
Adolf Baranowski
Andrzej Cybulski
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.)
Polska Akademia Nauk Instytut Podstawowych Problemow Techniki
Polska Akademia Nauk Instytut
Original Assignee
Polska Akademia Nauk Instytut Podstawowych Problemow Techniki
Polska Akademia Nauk Instytut
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=20039185&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0317830(A2) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Polska Akademia Nauk Instytut Podstawowych Problemow Techniki, Polska Akademia Nauk Instytut filed Critical Polska Akademia Nauk Instytut Podstawowych Problemow Techniki
Publication of EP0317830A2 publication Critical patent/EP0317830A2/en
Publication of EP0317830A3 publication Critical patent/EP0317830A3/en
Application granted granted Critical
Publication of EP0317830B1 publication Critical patent/EP0317830B1/en
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • 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
    • B21D11/00—Bending not restricted to forms of material mentioned in only one of groups B21D5/00, B21D7/00, B21D9/00; Bending not provided for in groups B21D5/00 - B21D9/00; Twisting
    • B21D11/20—Bending sheet metal, not otherwise provided for
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering

Definitions

  • the subject of this present invention is a method of bending metal objects, such as plates, bars, etc., along straight lines.
  • This method it is possible to bend objects with constant and varying thickness, and also objects made of brittle materials and of materials with high hardness.
  • the hitherto known methods of bending objects of such type involve the plastic deformation of the material of the object being bent by applying external forces appropriate as to size and direction.
  • the bending is effected by means of the bending machines, bending dies and bending presses adapted to that purpose, frequently very powerful.
  • the purpose of this present invention has been to develop a method of changing the curvature of metal objects, in the way that would not require the appli­cation of heavy equipment and, simultaneously, should make it possible to apply a controlled bending process with a high accuracy of deformation.
  • the essence of this present invention involves sub­jecting the objects to the repetitive, two-phase process of heating and cooling the material along a selected line.
  • the material is subjected to heating with a concentrated stream of energy causing a thermal effect.
  • the heating either takes place simultaneously along the entire line, or the stream of energy is moving along the line at a predetermined speed.
  • the material is locally plasticised and partially melted in the region of the heating line.
  • the local nature of the action of the stream of energy together with the heating speed cause the material undergo plastic deformation in that region due to the phenomenon of thermal expansion.
  • the heating mentioned is conducted in such a way that the zone of the material in which the deformation occurs reaches a depth smaller than the thickness of the object.
  • the object is cooled at ambient temperature or, additionally, in a stream of blown gas, so as to reach the condition in which the material ceases to be plastic throughout the entire region.
  • the previously deformed zone of the material becomes shorter along the fibres perpendicular to the heating lines due to the thermal shrinkage of the material. Since the shrinking fibres of the material form the zone which does not cover the entire thickness of the object, the object bends at an angle along the line of the original heating.
  • the heating and cooling process take place under a protective gas atmosphere for the purpose of eliminating the harmful effect of air on the heated area. It is advantageous to carry out the heating process by means of a layer of a substance increasing the coefficient of absorption of the stream of energy.
  • a high-power laser or electron beam is used as the source of energy.
  • the method as per this present invention makes it possible to bend metal objects without the need of employing external forces.
  • the curvature of objects can be changed from a distance under the conditions in which the access to that object is impossible.
  • the same method allows bending of objects made of brittle and high-hardness materials, for which the previously known methods could not be employed.
  • Fig. 1 shows the method of bending a flat parallel plate object whose side view is shown
  • Fig. 2 shows the front view of the same plate
  • Fig. 3 shows a fragment of a section of the plate being heated
  • Fig. 4 shows the same fragment of the section of the plate when being cooled
  • Fig. 5 shows the diagram of the material heating temperature distribution vs. the thickness of the object within the heating phase
  • Fig. 6 shows a stress distribution diagram of the cooling phase.
  • the material of the object being bent is subject to heating with concentrated stream of energy SE of laser radiation.
  • Application of the stream of energy SE of laser radiation, moving at speed V along the bending line AA entails a local change in the condition of the material cha­racterised by different properties at depth G .
  • the temperature distribution of the heated material indicates additionally the material melting temperature T m .
  • the material of the first, S1 , and the second, S2 , zones flows out to occupy an increased volume as a result of the stresses caused by the effect of thermal expansion.
  • This temperature distribution related to melting temperature T m determines the size of the first, S1 , and the second, S2 zones relative to material thickness L.
  • the material is cooled at ambient temperature or, additionally, in the stream of a blown gas.
  • the material within the region of the bending line i. e. the liquid in first zone S1 and the plasticised material in the second zone, S2 , is transformed into solid state.
  • the boundary of the region encompassing the plasticising and melting zone in the heating phase has been marked with line U in Fig. 4.
  • the heating and cooling conditions are selected so that the tensile and compressive stresses created in the material should be much smaller than are their limit stresses.
  • the heating and cooling parameters such as the stream movement speed, the stream power, the absence or presence, and nature of a layer absorbing the stream of energy, etc.
  • control is exercised on the magnitude of the stresses created in the material in order to obtain the desired angle of bending (Figs. 1 and 4) during one cycle of heating and cooling along the bending line.
  • the slab 0.7 mm thick and 20 mm wide, is made of 50HSA steel and heated with a radiation beam of a continuously operating 300 W CO2 laser, the source of energy moving along line AA (Fig. 2) at the speed of 2,5 cm/sec.
  • the beam is directed perpendicu­larly to the surface of the slab.
  • the heating takes place under a protective argon atmosphere.
  • the slab was cooled in the ambient atmos­phere within about 1 second. With such conditions of the method employed and after a single heating and cooling cycle, the slab was bent at the angle of 2,8°.
  • the method of bending objects according to this present invention can be used for shaping objects of brittle or high-strength materials. Besides, this method can be employed for shaping objects when access to them is difficult, e. g. under vacuum or under hazardous conditions (high-tension, harmful radiation, etc.).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Bending Of Plates, Rods, And Pipes (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Laser Beam Processing (AREA)

Abstract

This present invention solves the problem of bending objects, particularly flat parallel ones, without employing an external force.
The method according to this present invention involves subjecting the material of the object bent to a repe­titive, two-phase heating and cooling process.
During the first phase, the material undergoes heating with a concentrated stream of energy causing a thermal effect along the predetermined bending line and a partial plasticising, melting and flowing out in the region of the bending line.
On the other hand, the material is subjected in the second phase to being cooled at ambient temperature or, additionally, in a stream of a blown air, thereby causing the previously heated material to shrink along fibres in the direction perpendicular to the bending line due to the internal stresses created by the thermal shrinkage of the material in the heated region, and thus the deformation of the material to be permanently changed.
The method is suitable for bending metal objects.

Description

  • The subject of this present invention is a method of bending metal objects, such as plates, bars, etc., along straight lines. By this method it is possible to bend objects with constant and varying thickness, and also objects made of brittle materials and of materials with high hardness.
  • The hitherto known methods of bending objects of such type, being made of metals, involve the plastic deformation of the material of the object being bent by applying external forces appropriate as to size and direction. The bending is effected by means of the bending machines, bending dies and bending presses adapted to that purpose, frequently very powerful.
  • Elastic compressive and tensile stresses appear in the material bent and they cause the shape to be changed after the operation of the force has ceased. This affects the accuracy of the intended deformation and makes it difficult to control that process.
  • In addition to the above these stresses cause a decrease in the service life of the bent objects during their operation. The known methods cannot be used for bending brittle as well as high-strength and high-hardness materials.
  • The purpose of this present invention has been to develop a method of changing the curvature of metal objects, in the way that would not require the appli­cation of heavy equipment and, simultaneously, should make it possible to apply a controlled bending process with a high accuracy of deformation. The essence of this present invention involves sub­jecting the objects to the repetitive, two-phase process of heating and cooling the material along a selected line.
  • In the first phase, the material is subjected to heating with a concentrated stream of energy causing a thermal effect. The heating either takes place simultaneously along the entire line, or the stream of energy is moving along the line at a predetermined speed.
  • Consequently, the material is locally plasticised and partially melted in the region of the heating line.
  • The local nature of the action of the stream of energy together with the heating speed cause the material undergo plastic deformation in that region due to the phenomenon of thermal expansion. The heating mentioned is conducted in such a way that the zone of the material in which the deformation occurs reaches a depth smaller than the thickness of the object.
  • Next, during the second phase, the object is cooled at ambient temperature or, additionally, in a stream of blown gas, so as to reach the condition in which the material ceases to be plastic throughout the entire region. During cooling the previously deformed zone of the material becomes shorter along the fibres perpendicular to the heating lines due to the thermal shrinkage of the material. Since the shrinking fibres of the material form the zone which does not cover the entire thickness of the object, the object bends at an angle along the line of the original heating.
  • By repeating the above-mentioned operation many times, the object is given the required curvature.
  • It is recommended that the heating and cooling process take place under a protective gas atmosphere for the purpose of eliminating the harmful effect of air on the heated area. It is advantageous to carry out the heating process by means of a layer of a substance increasing the coefficient of absorption of the stream of energy.
  • A high-power laser or electron beam is used as the source of energy.
  • The method as per this present invention makes it possible to bend metal objects without the need of employing external forces. By this method, the curvature of objects can be changed from a distance under the conditions in which the access to that object is impossible. Besides, the same method allows bending of objects made of brittle and high-hardness materials, for which the previously known methods could not be employed.
  • The subject of this present invention is shown in the drawing where Fig. 1 shows the method of bending a flat parallel plate object whose side view is shown, Fig. 2 shows the front view of the same plate, Fig. 3 shows a fragment of a section of the plate being heated, Fig. 4 shows the same fragment of the section of the plate when being cooled, Fig. 5 shows the diagram of the material heating temperature distribution vs. the thickness of the object within the heating phase, and Fig. 6 shows a stress distribution diagram of the cooling phase.
  • During the first phase, the material of the object being bent is subject to heating with concentrated stream of energy SE of laser radiation. Application of the stream of energy SE of laser radiation, moving at speed V along the bending line AA entails a local change in the condition of the material cha­racterised by different properties at depth G.
  • Within that region, two zones can be observed, the material being liquid in the first zone S1 and plasticised in the second zone S2 with the boundary of the area encompassing the melting and plasticising zones shown with the line U.
  • The temperature distribution of the heated material, as shown schematically in Fig. 5 as a function of thicknessL of the object indicates additionally the material melting temperature T m. In the heating stage the material of the first, S1, and the second, S2, zones, flows out to occupy an increased volume as a result of the stresses caused by the effect of thermal expansion. This temperature distribution related to melting temperature T m determines the size of the first, S1, and the second, S2 zones relative to material thickness L.
  • During the second phase the material is cooled at ambient temperature or, additionally, in the stream of a blown gas. The material within the region of the bending line, i. e. the liquid in first zone S1 and the plasticised material in the second zone, S2, is transformed into solid state. The boundary of the region encompassing the plasticising and melting zone in the heating phase has been marked with line U in Fig. 4.
  • Due to internal stressesσt caused by the shrinkage of the cooled material, it becomes shorter along the fibres marked with arrow, which is shown through the stress distribution along the thickness L of the object in Fig. 6.
  • In this diagram, the values of limit compression σs and of limit tensile stress σr are marked. Should the limit tensile stress, σr, for example, be exceeded, the brittle materials may crack.
  • The heating and cooling conditions are selected so that the tensile and compressive stresses created in the material should be much smaller than are their limit stresses. By changing the heating and cooling parameters, such as the stream movement speed, the stream power, the absence or presence, and nature of a layer absorbing the stream of energy, etc., one may affect the temperature distribution in the heating phase (Fig. 5) and the stress distributon in the cooling phase (Fig. 6). In the above-mentioned manner, control is exercised on the magnitude of the stresses created in the material in order to obtain the desired angle of bending (Figs. 1 and 4) during one cycle of heating and cooling along the bending line. In one of the possible embodiments, a flat parallel slab shown in Figs. 1 and 2 has been subjected to a process of bending according to this present invention. The slab, 0.7 mm thick and 20 mm wide, is made of 50HSA steel and heated with a radiation beam of a continuously operating 300 W CO₂ laser, the source of energy moving along line AA (Fig. 2) at the speed of 2,5 cm/sec. The beam is directed perpendicu­larly to the surface of the slab.
  • The heating takes place under a protective argon atmosphere. The slab was cooled in the ambient atmos­phere within about 1 second. With such conditions of the method employed and after a single heating and cooling cycle, the slab was bent at the angle of 2,8°.
  • The method of bending objects according to this present invention, can be used for shaping objects of brittle or high-strength materials. Besides, this method can be employed for shaping objects when access to them is difficult, e. g. under vacuum or under hazardous conditions (high-tension, harmful radiation, etc.).

Claims (5)

1. A method of bending metal objects along straight lines, involving deformation of the objects, cha­racterised in that the material of the object being bent is subjected to a repetitive, two-­phase heating and cooling process where during its first phase the material is subjected to heating with a concentrated stream of energy causing a thermal effect along the predermined bending line and brought to being partially plasticised, melted and flowed out within the region of the bending line, whereas during the second phase the material is subjected to being cooled at ambient temperature or, additionally, in a stream of a blown gas causing the material to shrink along the fibres perpendicular to the bending line due to the internal stresses originated by the thermal shrinkage of the material in the heated region and the deformation of the object to be permanently changed.
2. A method according to Claim 1, characteri­sed in that the heating is performed with a focussed laser radiation beam or a concentrated high-power electron beam.
3. A method according to Claim 1, characte­rised in that the material is brought up to the plasticising and melting state to a depth G smaller than the thickness L of the object.
4. A method according to Claim 1, characte­rised in that the heating takes place under a protective atmosphere, thereby preventing the access of air to the region being heated.
5. A method according to Claim 1, characte­rised in that the surface of the heated material is covered with a substance increasing the coefficient of absorption of the stream of energy.
EP19880118683 1987-11-26 1988-11-09 A method of bending metal objects Expired EP0317830B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
PL269039 1987-11-26
PL26903987A PL155358B1 (en) 1987-11-26 1987-11-26 Method of bending metal workpieces

Publications (3)

Publication Number Publication Date
EP0317830A2 true EP0317830A2 (en) 1989-05-31
EP0317830A3 EP0317830A3 (en) 1990-05-23
EP0317830B1 EP0317830B1 (en) 1992-09-30

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ID=20039185

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EP19880118683 Expired EP0317830B1 (en) 1987-11-26 1988-11-09 A method of bending metal objects

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EP (1) EP0317830B1 (en)
JP (1) JPH01192423A (en)
DE (1) DE3875078T2 (en)
ES (1) ES2035219T3 (en)
PL (1) PL155358B1 (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3905551A1 (en) * 1989-02-23 1990-08-30 Gartzen Johannes Method and apparatus for treating surfaces by means of laser beam
EP0594096A1 (en) * 1992-10-19 1994-04-27 T.T.K. KUNSTSTOFF-TECHNOLOGIE GmbH Process and apparatus for deforming, particularly for bending, essentially flat ofjects
WO1995002475A1 (en) * 1993-07-15 1995-01-26 Instytut Podstawowych Problemów Techniki PAN Bending method for metallic objects
WO1996033838A1 (en) * 1995-04-24 1996-10-31 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Device and process for shaping workpieces with laser diode radiation
EP0794562A3 (en) * 1996-03-07 1998-08-05 Seiko Instruments Inc. Micromachining method and micromachined structure
FR2771471A1 (en) * 1997-11-24 1999-05-28 Siemens Ag METHOD FOR ADJUSTING NEEDLE STROKE IN METERING VALVES AND METERING VALVE ADJUSTED BY THIS METHOD
CN100434203C (en) * 2006-02-28 2008-11-19 江南造船(集团)有限责任公司 Water and fire rectification method for aluminum-magnesium alloy hull
CN105414246A (en) * 2015-12-16 2016-03-23 西北工业大学 Prediction method of bending angle of titanium alloy laser bending forming part

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US5142778A (en) * 1991-03-13 1992-09-01 United Technologies Corporation Gas turbine engine component repair
DE19958232A1 (en) * 1999-12-03 2001-07-05 Siemens Ag Contactless bending method, for plastic parts with thermoplastic properties, comprises heating one side over period to produce temperature gradient through part before cooling to bend
EP1242229B1 (en) * 1999-12-03 2004-02-18 Siemens Aktiengesellschaft Method for non-contacting bending of components made of a thermosplastic plastic and a component bent or adjusted according to said method
DE19958231B4 (en) * 1999-12-03 2005-10-06 Siemens Ag Method for contactless bending of parts made of a plastic with thermoplastic properties and bent or adjusted part according to this method
EP1393418B1 (en) 2001-04-12 2005-06-22 Finisar Corporation Method and device for regulating the centre wavelength of a laser, especially a semiconductor laser
DE10118451A1 (en) 2001-04-12 2002-10-24 Aifotec Ag Fiberoptics Method for precisely aligning optical or fiber-optic components using high energy laser heating of bridge elements between actuator base and alignment regions
DE10128827A1 (en) 2001-06-15 2003-01-09 Aifotec Ag Fiberoptics Adjustment method, in particular laser adjustment method and actuator suitable for this
US20060000814A1 (en) 2004-06-30 2006-01-05 Bo Gu Laser-based method and system for processing targeted surface material and article produced thereby
CN114101391B (en) * 2021-09-08 2023-06-09 蓝箭航天空间科技股份有限公司 Orthopedic method for large-size low-rigidity piece for spaceflight and liquid rocket

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US2428825A (en) * 1941-02-27 1947-10-14 Linde Air Prod Co Method of controlling distortion, straightening distorted objects, and/or altering the shape of metal objects
DE888401C (en) * 1943-07-20 1953-08-31 Administration Sequestre Des R Process for straightening workpieces
DE1160815B (en) * 1959-07-21 1964-01-09 Hoesch Ag Process for the production of profiles from cold-rolled or tempered steel and non-ferrous metal strips
DE1627490A1 (en) * 1967-06-07 1970-05-06 Babcock & Wilcox Ag Method of making arches
JPS62110883A (en) * 1985-11-09 1987-05-21 Mitsubishi Electric Corp Production of dome like structure
JPS62134118A (en) * 1985-12-05 1987-06-17 Mitsubishi Electric Corp Method for correcting shape accuracy of plate spring
JPS62134117A (en) * 1985-12-05 1987-06-17 Mitsubishi Electric Corp Tube manufacturing method

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3905551A1 (en) * 1989-02-23 1990-08-30 Gartzen Johannes Method and apparatus for treating surfaces by means of laser beam
EP0594096A1 (en) * 1992-10-19 1994-04-27 T.T.K. KUNSTSTOFF-TECHNOLOGIE GmbH Process and apparatus for deforming, particularly for bending, essentially flat ofjects
WO1995002475A1 (en) * 1993-07-15 1995-01-26 Instytut Podstawowych Problemów Techniki PAN Bending method for metallic objects
WO1996033838A1 (en) * 1995-04-24 1996-10-31 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Device and process for shaping workpieces with laser diode radiation
EP0794562A3 (en) * 1996-03-07 1998-08-05 Seiko Instruments Inc. Micromachining method and micromachined structure
US5976390A (en) * 1996-03-07 1999-11-02 Seiko Instruments Inc. Micromachining method and micromachined structure
FR2771471A1 (en) * 1997-11-24 1999-05-28 Siemens Ag METHOD FOR ADJUSTING NEEDLE STROKE IN METERING VALVES AND METERING VALVE ADJUSTED BY THIS METHOD
DE19752028A1 (en) * 1997-11-24 1999-06-02 Siemens Ag Adjusting needle lift of dosing valves
DE19752028C2 (en) * 1997-11-24 1999-09-30 Siemens Ag Method for adjusting the valve needle stroke in metering valves and metering valve with valve needle stroke adjusted according to this method
CN100434203C (en) * 2006-02-28 2008-11-19 江南造船(集团)有限责任公司 Water and fire rectification method for aluminum-magnesium alloy hull
CN105414246A (en) * 2015-12-16 2016-03-23 西北工业大学 Prediction method of bending angle of titanium alloy laser bending forming part

Also Published As

Publication number Publication date
PL269039A1 (en) 1989-05-30
DE3875078D1 (en) 1992-11-05
EP0317830B1 (en) 1992-09-30
JPH01192423A (en) 1989-08-02
DE3875078T2 (en) 1993-02-18
ES2035219T3 (en) 1993-04-16
PL155358B1 (en) 1991-11-29
EP0317830A3 (en) 1990-05-23

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