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
  • B21D5/0209—Tools therefor
• • 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
  • B21D37/00—Tools as parts of machines covered by this subclass
  • B21D37/10—Die sets; Pillar guides
  • B21D37/12—Particular guiding equipment, e.g. pliers; Special arrangements for interconnection or cooperation of dies
• • 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
  • B21D5/002—Positioning devices
• • 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
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
  • G01B11/00—Measuring arrangements characterised by the use of optical techniques
  • G01B11/26—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes
  • G01B11/27—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes
  • G01B11/272—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes using photoelectric detection means

Definitions

• This document discloses a die for bending sheet metal, a system comprising such a die and a method of bending sheet metal, which can be used in particular when bending sheet metal having a thickness exceeding 5 mm, such as when bending sheet metal having a thickness of 5-20 mm, especially 8-15 mm.
• the groove of the die can generally be V- shaped, with a pair of walls or other support surfaces separated by a base.
• the walls form an angle corresponding to a maximum bending yield, apart from the possibility of spring-back.
• the knife can also have a point, which, when viewed in cross section, is generally V-shaped.
• the groove and the knife can have angles exceeding a maximum bending angle intended for the system. Instead, a true bending angle can be controlled by measuring the angle between the sheet metal shanks and bringing the knife and the die together sufficiently to provide the desired bending angle.
• Such measuring can be carried out continuously and most often with the aid of a line laser, which applies the respective lines on each shank of the piece of sheet metal perpendicular to the groove and reads the line with the aid of a camera or another sensor.
• the method above functions excellently when bending thinner pieces of sheet metal and when bending pieces of sheet metal where the length of the shanks, viewed from the angle, is sufficiently long.
• One object is thus to fully or partly eliminate the above problems when measuring the angle between the sheet metal shanks during the process of bending sheet metal.
• a die for bending sheet metal, comprising a die body and a groove formed in the die body.
• the die has a slot extending across the groove in such a way that a piece of sheet metal located in the groove is visible without being concealed by the die body.
• “Across” means that the slot intersects the groove in the longitudinal direction, for example with an angle between 30 and 90 degrees, preferably between 45 and 90 degrees or approximately 90 degrees.
• a die for bending sheet metal is placed with the groove facing upward and a bending knife is movable in a substantially vertical direction. Measuring devices can thus be placed underneath, or obliquely underneath, the die for bending sheet metal and, by virtue of the slot, a clear view toward the bent sheet metal shanks is still achieved.
• the slot can be formed in such a way that a side of the piece of sheet metal facing the die is visible through the die body.
• the groove can have a base and the slot can have slot portions on both sides of said base, in such a way that two shanks of the piece of sheet metal separated by a bending angle are visible without being concealed by the die body.
• the slot can extend through the entire die in such a way that the die comprises two separate die body portions.
• the slot can only partly extend across the die in such a way that the die body portions are connected by at least one material bridge.
• one or more material bridges can be located at one, two or more outer corners of the cross section.
• the groove can have a longitudinal direction, the slot having an extension in the longitudinal direction corresponding to 0.5-20 mm, preferably 1 -15 mm or 1 -5 mm.
• the slot can have an intersection area together with the groove, the intersection area, viewed perpendicularly to the longitudinal direction, having an extension corresponding to at least 20% of a depth of the groove, preferably at least 50% of said depth.
• a die as described above is provided for bending a piece of sheet metal having a thickness between 5 and 25 mm, preferably between 5 and 20 mm, between 7 and 15 mm or between 10 and 15 mm.
• a die as described above for bending a piece of sheet metal in order to provide a piece of sheet metal bent accordingly, which has a first shank and a second shank, where at least one of the shanks has a length, calculated from a bending angle, that is less than 150% of a distance between a base of the groove and an outer edge of the die, viewed in a direction parallel to the orientation of the piece of sheet metal just before the bending operation and perpendicular to the longitudinal direction of the groove, said length preferably being less than 100% of said distance or less than 70% of said distance.
• the distance is typically a horizontal distance.
• a system for bending sheet metal comprising a die as described above, a bending knife, extending parallel to the groove and being movable relative to the die in order to bend the piece of sheet metal by interacting with the groove, and at least one measuring device, arranged to determine, through the slot, an orientation of a sheet metal shank.
• the system can comprise a first measuring device, arranged to determine an orientation of a first sheet metal shank, and a second
• measuring device arranged to determine an orientation of a second sheet metal shank, the sheet metal shanks being separated by a bending angle.
• a method of bending a piece of sheet metal comprising arranging the piece of sheet metal relative to a groove of a bending die in such a way that a first portion of the piece of sheet metal is located on a first side of a longitudinal centre line of the groove and a second portion of the piece of sheet metal is located on a second, opposite side of the centre line, and with the aid of a bending knife, carrying out a bending operation in such a way that said first and second portions of the piece of sheet metal form respective shanks of a piece of sheet metal bent
• the method comprises determining, with the aid of a measuring device, an orientation of at least one of the shanks through at least one slot in the bending die.
• the method can further comprise determining, based on said orientation, a reciprocal angle between the shanks.
• the orientation of both shanks can be determined through said at least one slot.
• the bending die can be arranged in such a way that the piece of sheet metal is positioned vertically above the bending die and the measuring device is positioned vertically under the bending die.
• the method can comprise, during the bending of the piece of sheet metal, determining a first orientation of at least one of the shanks, then moving the bending knife and the die relative to each other, and then determining a second orientation of said at least one of the shanks.
• Measuring the orientation of the shanks and, based thereon, determining the reciprocal angle of the shanks can thus occur a number of times during one and the same bending operation. For example, measuring and determining can occur substantially continuously during the bending operation. Measuring and determining can both occur during a first part of the bending operation, in which the knife moves toward the die, and during a second part of the bending operation, in which the knife moves away from the die.
• Fig. 1 shows a system for bending sheet metal before a bending operation.
• Fig. 2 shows the system for bending sheet metal when a bending operation is completed.
• Fig. 3 shows a first embodiment of a die for bending sheet metal.
• Fig. 4 shows a second embodiment of a die for bending sheet metal.
• Figs 1 and 2 show a system 1 for bending sheet metal comprising a bending die 10, a bending knife 1 1 and a pair of measuring devices 12a, 12b.
• the bending die 10 comprises a die body 100a, 100b, which can be formed from metal or ceramic material of sufficient hardness and toughness in order to be able to withstand the forces that the die is subjected to.
• the die 10 has a groove 101 , 101 a, 101 b, which can have a cross section (viewed in the X-Y plane) substantially forming a V, a U, or similar shape, and a longitudinal direction Z.
• the cross section of the groove 101 , 101 a, 101 b can be substantially constant along its longitudinal direction Z.
• the groove 101 , 101 a, 101 b can have, but does not have to have, groove walls that are continuous, viewed in the transverse direction of the groove.
• the walls of the groove 101 , 101 a, 101 b form support surfaces, determining a maximum bending angle.
• the bending knife 1 1 is movable relative to the die 10 in a direction which enables it to project down into the groove 101 , 101 a, 101 b and thereby bending the piece of sheet metal 2 through interaction between the groove and the knife.
• a resulting bending angle V can depend on how deep into the groove the knife 1 1 is brought.
• the die 10 has a slot extending across the longitudinal direction Z of the die. Through the slot, the side of the piece of sheet metal 2, 2' facing the die is visible for one or more measuring devices 12a, 12b. More specifically, both shanks S1 , S2 of the bent piece of sheet metal 2’ can be visible for the measuring device 12a, 12b, in such a way that the reciprocal angle of the shanks can be measured by the measuring device.
• the measuring device can comprise one or more measuring devices. Through the slot 102, 102a, 102b, a measuring device 12a, 12b can provide a laser line or other suitable light pattern on the shank S1 , S2. A camera or other light sensor can read the light pattern and, in a manner known per se, determine the orientation of the shank relative to the measuring device and thus also calculate the reciprocal angle of the shanks S1 , S2.
• the measuring device can comprise two measuring devices each generating a respective laser line or light pattern, or one measuring device generating a single laser line or a light pattern applied to both shanks.
• the measuring device can comprise two cameras or light sensors, each reading light from one of the shanks S1 , S2, or one camera or light sensor reading light from both of the shanks S1 , S2.
• the die 10 can be formed by substantially one piece of material and with at least two die portions 100a, 100b, connected by at least one material bridge 103.
• Such a die 10 can comprise one, two or more slots or slot portions 102a, 102b.
• the die 10 can be formed by two or more separate die portions 100a, 100b, a single slot 102 being formed between the die portions.
• the die portions 100a, 100b can thereby be held in position by a common die holder (not shown).
• the slot 102, 102a, 102b can have a width, viewed in the longitudinal direction of the groove Z, of 0.5-30 mm, preferably 1 -25 mm or 5-15 mm. It will be appreciated that a narrower slot reduces the risk of undesired embossing of the bent piece of sheet metal.
• the die can have a plurality of slots 102 or sets 102a, 102b of slots, which are separated in the longitudinal direction Z of the groove, in such a way that measuring at a plurality of positions along the groove is enabled.
• a plurality of measuring devices can be used during such measuring.
• a measuring device can be displaceable along the groove for measuring at different positions. It is possible to provide a measuring device with the ability to automatically detect the instance of a slot.
• a die 10 for bending sheet metal is placed with the groove 101 , 101 a, 101 b facing upward and the bending knife 1 1 is movable in a substantially vertical direction Y.
• the measuring devices can thus be placed underneath, or obliquely underneath, the die 10 for bending sheet metal and, by virtue of the slot, a clear view toward the sheet metal shanks is still achieved.
• the die, system and method described above can be applied for cold bending as well as warm bending of sheet metal.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Bending Of Plates, Rods, And Pipes (AREA)
• Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=68766822

Family Applications (1)

Country Status (3)

Family Cites Families (5)

• 2018
  • 2018-10-03 SE SE1830280A patent/SE542581C2/sv unknown
• 2019
  • 2019-10-03 EP EP19813672.3A patent/EP3860776A1/en active Pending
  • 2019-10-03 WO PCT/SE2019/050957 patent/WO2020071989A1/en unknown

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