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
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/10—Stamping using yieldable or resilient pads
  • B21D22/12—Stamping using yieldable or resilient pads using enclosed flexible chambers
• • 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
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/10—Stamping using yieldable or resilient pads
  • B21D22/12—Stamping using yieldable or resilient pads using enclosed flexible chambers
  • B21D22/125—Stamping using yieldable or resilient pads using enclosed flexible chambers of tubular products
• • 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
  • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
  • B21D22/20—Deep-drawing
  • B21D22/26—Deep-drawing for making peculiarly, e.g. irregularly, shaped articles

Definitions

• the present invention relates to a deep-drawing method in which a drawing part is arranged in a deep-drawing tool between a first deep-drawing tool part and a second deep-drawing tool part and is formed by relative movement of the deep-drawing tool parts to one another.
• the material of the drawn part is steel, martensite is formed in particular during the first drawing process, which reduces the deformability of the drawn part in a further deep-drawing process.
• the required deformability of the drawn part after the first deep-drawing process is therefore restored by annealing the drawn part at a temperature of approximately 1050 ° C., in particular the martensite that formed during the first deep-drawing process, in a more easily deformable manner Austenite is converted.
• the annealing of the drawn part may have to be repeated after each deep-drawing process.
• the present invention is therefore based on the object of providing a deep-drawing method of the type mentioned at the outset, which - in particular when carrying out several successive drawing processes - is more time and energy-saving than the known deep-drawing methods.
• This object is achieved according to the invention in a deep-drawing process with the features of preamble 1 in that, at a limited pressure section of one of the deep-drawing tool parts, a time-varying pressure is selectively generated during the drawing process, which pressure rests against a section of the drawn part against the respective other deep drawing tool part presses.
• the solution according to the invention is based on the concept of achieving a flow of the material of the drawn part sufficient for the deformation by targeted application of a limited area of the drawn part during the drawing process even if the flowability of the material of the drawn part itself is due to the history of the material, for example due to a previous previous pulling operation.
• the desired deformability of the drawn part can also be ensured with the deep-drawing method according to the invention if the drawn part contains martensite due to a previous drawing process.
• An annealing process and the cooling and washing processes associated with the annealing process can also be omitted in the deep-drawing process according to the invention if the deep-drawing process is carried out in multiple passes.
• the deep-drawing process according to the invention allows a particularly large drawing ratio to be achieved and leads to high dimensional stability of the drawn parts.
• the pressure at the pressure section is generated hydraulically or pneumatically by means of a pressure fluid.
• the hydraulic generation of a pressure on one of the deep-drawing tool parts is known per se from the so-called hydroforming process, in which the drawing body is provided with a membrane which is formed during the forming process. is put under water pressure.
• the drawing punch presses the drawing part against the membrane on the drawing body, the drawing part being deformed by the counteracting water pressure.
• the entire drawn part is exposed to the same water pressure during the drawing process, while in the deep-drawing method according to the invention, only a limited pressure section of one of the deep-drawing tool parts is used to selectively generate a pressure which presses the limited section of the drawn part against the other deep-drawing unit - part presses.
• the water pressure acting on the drawn part is constant during the drawing process.
• a variant of the hydroforming process is the so-called Hydro-Mec process, in which the drawing part is pressed into pressurized water by a descending drawing punch without a membrane being provided on the drawing body.
• Hydro-Mec process in which the drawing part is pressed into pressurized water by a descending drawing punch without a membrane being provided on the drawing body.
• the aim is to distribute the hydraulic pressure evenly over the surface of the drawn part, which is exactly the opposite of the inventive concept of selectively applying an increased pressure to a limited section of the drawn part.
• the pressure on the Pressure section is controlled and / or regulated according to a predetermined temporal pressure curve.
• This pressure curve can provide, for example, that the pressure section is depressurized during a first deformation phase and that an increased pressure that is constant over the second deformation phase is generated on the pressure section during a second deformation phase.
• Such a pressure curve is particularly easy to control and / or regulate.
• any other temporal pressure curve can also be controlled and / or regulated.
• the deformability of the drawn part during the drawing process is particularly increased if the pressure section is aligned essentially parallel to the drawing direction along which the deep-drawing tool parts are moved relative to one another.
• areas of the drawn part aligned essentially parallel to the direction of drawing can be pressed in a targeted manner onto areas of the other deep-drawing tool part aligned essentially parallel to the drawing direction, which is not possible with the conventional deep-drawing method.
• side wall regions of the drawn part that are oriented essentially parallel to the direction of drawing can be formed particularly precisely.
• the deep-drawing method according to the invention is particularly useful when only the frame of the drawn part is subjected to the time-varying pressure on the pressure section during the drawing process.
• Such a deep-drawing process is particularly suitable for the production of Gastronorm food containers, which have a large depth. sen and tend to form unwanted bulges in the frame area, which can lead to poor stackability of the food containers.
• Such a bulging can be prevented or a bulge generated in a previous deep-drawing process can be eliminated by the targeted application of the time-varying pressure on the pressure section to the frame of the Gastronorm food container during the drawing process.
• the pressure section is annular.
• the time-varying pressure is generated by means of a pressure generating device which comprises a chamber for receiving a pressurized fluid and an elastically deformable chamber wall for transmitting the pressure from the pressurized fluid to the drawn part.
• Such a chamber can in particular be annular.
• Such a chamber is particularly easy to manufacture if it is delimited partly by the elastically deformable chamber wall and partly by a chamber boundary wall made of a material different from the material of the elastically deformable chamber wall, preferably a metallic material, in particular aluminum.
• the pressure section can be arranged on the first deep-drawing tool part or on the second deep-drawing tool part. Furthermore, it can be provided that both the first deep-drawing tool part and the second deep-drawing tool part each have one or more pressure sections, on which a time-varying pressure is generated during the drawing process.
• the first deep-drawing tool part is designed as a drawing body and the second deep-drawing tool part is designed as a punch and that the pressure section is arranged on the drawing body.
• the relative movement between the drawing die and the drawing body required for the deformation of the drawing part can be generated both by a movement of the drawing die and a movement of the drawing body or also by a movement of both deep-drawing tool parts.
• the drawing punch is stationary during the drawing process and the drawing body is moved towards the drawing punch.
• the deep-drawing method according to the invention is particularly advantageous if the drawing part is preformed in a first drawing process and is deformed in a second drawing process in which the time-varying pressure is generated at the printing section.
• the two drawing processes can be carried out in the same deep-drawing tool, it usually being necessary to replace the deep-drawing tool parts between the drawing processes, or the two drawing processes are carried out in different deep-drawing tools, which is recommended for series production, since in this case the one for the deep-drawing tool parts required for each drawing process can remain in the respective deep-drawing tool.
• the present invention further relates to a deep-drawing tool, comprising a first deep-drawing tool part and a second deep-drawing tool part, in which a drawing part can be deformed by relative movement of the deep-drawing tool parts.
• the present invention is based on the further object of creating such a deep-drawing tool, with the aid of which drawn parts - in particular in the context of a multi-pass deep-drawing process - can be deformed in a time- and energy-saving manner than with known deep-drawing tools.
• a deep-drawing tool with the features of the preamble of claim 13 in that one of the deep-drawing tool parts has a limited pressure section, on which a time-variable pressure can be selectively generated during the drawing process, which pressure counteracts a section of the drawing part that is in contact with the pressure section presses the other deep-drawing tool part.
• FIG. 1 shows a schematic perspective illustration of a deep-drawing tool
• FIG. 2 - 5 are schematic cross sections through the deep-drawing tool from FIG. 1 in four different phases of a conventional deep-drawing process
• 6 - 9 are schematic cross sections through a deep-drawing tool, which comprises a pressure bubble ring, in four different phases of a deep-drawing process according to the invention.
• 10 shows a schematic perspective illustration of a drawn part after two deep-drawing processes
• 11 is a plan view of a pressure bubble ring
• FIG. 12 shows a cross section through the pressure bubble ring from FIG. 11 along the line 12-12 in FIG. 11;
• FIG. 13 shows a cross section through the pressure bubble ring from FIG. 11 along the line 13-13 in FIG. 11.
• 1 to 5 shown in its entirety as 100 as a whole, comprises a base plate 102, a pulling die 104 arranged stationary on the upper side of the base plate 102, a sheet metal holder 106 which surrounds the pulling die 104 in an annular manner and which also has the pulling die on one 104 annularly surrounding support plate 108 is arranged, which is supported by sleeves 110 which can be moved vertically by means of a hydraulic movement device (not shown), so that the support plate 108 with the sheet holder 106 arranged thereon can be moved along the vertical direction of pull 112.
• the deep-drawing tool 100 comprises a drawing body 114 which is arranged above the drawing die 104 and the sheet metal holder 106 and which in turn comprises an annular drawing ring base 116 and a drawing ring 118 held on the underside thereof.
• the drawing ring base 116 is held on its upper side on a holding plate 120 which is moved along the drawing plate by means of a hydraulic movement device (not shown).
• direction 112 is movable relative to the punch 104 and the lead holder 106.
• the drawing body 114 forms the first deep-drawing tool part 122 of the deep-drawing tool 100; the drawing die 104 forms the second deep-drawing tool part 124 of the deep-drawing tool 100.
• a first deep-drawing process is carried out as follows:
• the drawing body 114 and the sheet metal holder 106 are moved into their respective upper starting positions by means of the respective hydraulic movement devices (not shown).
• the essentially flat upper side of the sheet metal holder 106 is arranged above the upper side of the drawing die 104.
• a sheet metal blank or a blank 126 from which the drawn part is to be produced, is inserted into the deep-drawing tool 100 in such a way that the edge of the blank 126 rests on the blank holder 106 (see FIG. 2).
• the deep-drawing tool 100 is then closed by moving the drawing body downwards along the direction of drawing 112 from its upper starting position by means of the hydraulic movement device (not shown) until the underside of the drawing ring 118 rests against the top of the board 126 and the edge of the Board 126 is clamped between the drawing ring 118 and the sheet metal holder 106 (see FIG. 3).
• the plate 126 is formed into a drawing part 128 by using the hydraulic movement device (not shown) to remove the sleeves 110 with the support plate 108 and the sheet metal holder 106 arranged thereon, and the drawing body 114 along the drawing direction 112 relative to the drawing punch 104 Drawing depth are moved downward, the plate 126 held at its edge between the drawing ring 118 and the sheet metal holder 106 nestling against the outer contours of the drawing ring 118 and the drawing punch 104 (see FIG. 4).
• the sleeves 110 with the support plate 108 and the sheet metal holder 106 arranged thereon are moved back into their upper starting position and the deep-drawing tool 100 is opened by pulling the drawing body 114 further upward in the upper direction in the drawing direction 112 Starting position is moved (see Fig. 5).
• the drawn part 128 formed in the first deep-drawing process is accessible from outside the deep-drawing tool 100 and can be removed therefrom.
• the deep-drawn part 128 has not yet got the desired final shape.
• the finished drawn part is to have the shape of a Gastronorm food container, which is provided with a stacking shoulder 132 running around its upper edge 130.
• the depth of the finished food container should be greater than the depth of the drawn part 128 after the first deep-drawing process, while the length and the The width of the finished food container should be smaller in the frame area than in the drawn part 128 obtained by the first drawing process.
• the basic structure of the second deep-drawing tool 100 ' corresponds to that of the first deep-drawing tool 100 described above, the drawing die 104 and the drawing body 114' being shaped accordingly in order to obtain the desired deformations of the drawing part 128.
• the drawing body 114 'of the second deep-drawing tool 100' comprises a pressure generating device, designated as a whole by 134, for generating a variable pressure.
• the device 134 in turn comprises a pressure bubble ring 136, which is received in an annular recess 138 on the inside of the drawing ring base 116 and has an annular pressure bubble chamber 140 which is enclosed by a chamber wall 142 made of an elastically deformable material, for example of a polyurethane.
• Fluid supply lines 144 lead through the chamber wall 142 into the pressure bubble chamber 140, via which a pressure fluid, for example a hydraulic oil, can be fed to the pressure bubble chamber 140 from a fluid pressure pump (not shown).
• a pressure fluid for example a hydraulic oil
• the second deep-drawing tool 100 ' is opened by bringing the drawing body 114' and the sheet metal holder 106 into their upper starting positions (see FIG. 6). Since the drawing part 128 is already pre-deformed by the first deep-drawing process, the top of the sheet metal holder 106 can be arranged in its upper starting position below the top of the drawing die 104.
• the deep-drawn part 128 obtained from the first deep-drawing process is then inserted into the deep-drawing tool 100 ′ and placed on the sheet metal holder 106.
• the second deep-drawing tool 100 ' is then closed by moving the drawing body 114' downward in the drawing direction 112 until the underside of the drawing ring 118 bears against the underside of the edge 130 of the drawing part 128 and the edge of the drawing part 128 between the drawing ring 118 and the sheet holder 106 is clamped.
• a first deformation phase is then carried out by moving the quills 110 with the support plate 108 arranged thereon and the sheet metal holder 106 together with the drawing body 114 ′ along the drawing direction 112 relative to the drawing punch 104 until the remaining drawing path is a distance h (see Fig. 7).
• the pressure bubble ring 136 is depressurized, that is to say the fluid pressure pump is switched off or the fluid supply lines 144 are separated from the fluid pressure pump by a check valve (not shown) that the fluid in the pressure bubble chamber 140 is not at a pressure higher than atmospheric pressure.
• the fluid in the pressure bubble chamber 140 is subjected to an increased pressure p by starting the fluid pressure pump and / or opening the shutoff valve between the fluid pressure pump and the fluid supply lines 144.
• the elastically deformable chamber wall 142 of the pressure bubble ring 136 transmits the increased pressure of the fluid in the pressure bubble chamber 140 to the section of the frame 146 of the drawing part 128 which bears against the pressure bubble ring 136 and which is formed by the side walls of the drawing part 128 which are oriented essentially parallel to the direction of drawing 112 so that this section of the frame 146 is pressed against the punch 104 under increased pressure.
• the inside of the pressure bubble ring 136 facing the drawing part 128 serves as a pressure section 148 of the drawing body 114 ', by means of which a section of the drawing part 128 which is in contact with the pressure section 148 can be pressed selectively against the drawing punch 104 under a pressure which changes over time during the drawing process.
• the drawing part 128 is finished by moving the quills 110 with the support plate 108 arranged thereon and the sheet metal holder 106 together with the drawing body 114 ′ along the drawing direction 112 relative to the drawing punch 104 until the desired drawing depth for the second deep-drawing process is reached (see Fig. 8).
• the pressure p to the frame 146 of the drawing part 128 through the pressure section 148 of the drawing body 114 ', a sufficient amount of material flows downward along the drawing direction 112 when the drawing part 128 is deformed in order to form the stacking step 132 without Cracks occur on the drawn part 128.
• the pressure bubble ring 136 is depressurized again by switching off the fluid pressure pump and / or closing the shutoff valve between the fluid pressure pump and the fluid supply lines 144 to the pressure bubble ring 136.
• the second deep-drawing tool 100 ' is then opened by moving the quills 110 with the support plate 108 arranged thereon and the sheet metal holder 106 into the upper starting position and then moving the drawing body 114' further upwards in the drawing direction 112 into its upper starting position, so that the drawn part 128 is accessible from outside the deep-drawing tool 100 'and can be removed from the deep-drawing tool 100' (see FIG. 9).
• the pulling part 128 now has the desired final shape of a Gastronorm food container (see FIG. 10).
• 11 to 13 show in detail a preferred embodiment of a pressure bubble ring 136, as can be used in the deep-drawing process according to the invention.
• the pressure bubble ring 136 comprises an outer ring 150 made of an elastically deformable material, for example made of polyurethane, in which a chamber delimitation ring 152, which consists for example of a metallic material, in particular aluminum can, is embedded.
• the outer ring 150 is produced by introducing the chamber delimitation ring 152 into a casting mold, the inner contours of which correspond to the outer contours of the outer ring 150, and the space between the casting mold and the chamber delimiting ring 152 is filled with polyurethane.
• the inside of the chamber delimitation ring 152 is provided with a release agent so that the outer ring 150 made of polyurethane only adheres to the outside of the chamber delimitation ring 152, while on the inside of the chamber delimitation ring 152 the material of the outer ring 150 can be lifted off the chamber delimitation ring 152.
• the chamber limiting ring 152 is penetrated by a connecting piece 154, for example made of steel, which leads from the chamber limiting ring 152 to the outside of the outer ring 150 and can be connected at its outer end to a fluid supply line 144 ,
• a connecting piece 154 for example made of steel, which leads from the chamber limiting ring 152 to the outside of the outer ring 150 and can be connected at its outer end to a fluid supply line 144 .
• fluid supplied through the fluid supply line 144 can enter the space between the outer ring 150 and the chamber limiting ring 152 on the inside of the chamber limiting ring 152 and lift the material of the outer ring 150 from the chamber limiting ring 152, so that between the chamber limiting ring 152 and the outer ring 150 a pressure bubble chamber 140 is formed, the volume of which is dependent on the pressure under which the fluid is.
• the pressure bubble chamber 140 has only a small volume (corresponding to the solid boundary line in FIGS. 12 and 13). If the pressure of the fluid is high, the volume of the pressure bubble chamber 140 increases accordingly (compare the broken boundary lines in FIGS. 12 and 13).
• a hydraulic oil can be used as the pressure fluid for filling the pressure bubble chamber 140.
• the outer ring 150 of the pressure bubble ring 136 is made of natural rubber, castor oil, for example, should be used instead as the pressure fluid, since natural rubber is attacked by hydraulic oil.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Shaping Metal By Deep-Drawing, Or The Like (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7641955

Family Applications (1)

Country Status (8)

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• 2000
  • 2000-05-13 DE DE10023533A patent/DE10023533A1/de not_active Withdrawn
• 2001
  • 2001-03-13 ES ES01921328T patent/ES2223819T3/es not_active Expired - Lifetime
  • 2001-03-13 AT AT01921328T patent/ATE276059T1/de not_active IP Right Cessation
  • 2001-03-13 WO PCT/EP2001/002795 patent/WO2001087511A1/fr active IP Right Grant
  • 2001-03-13 AU AU48343/01A patent/AU4834301A/en not_active Abandoned
  • 2001-03-13 TR TR2004/02727T patent/TR200402727T4/xx unknown
  • 2001-03-13 EP EP01921328A patent/EP1207974B1/fr not_active Expired - Lifetime
  • 2001-03-13 DE DE50103612T patent/DE50103612D1/de not_active Expired - Lifetime
• 2002
  • 2002-01-10 US US10/044,133 patent/US6622539B2/en not_active Expired - Lifetime

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