EP1424150A1 - Can height control - Google Patents
Can height control Download PDFInfo
- Publication number
- EP1424150A1 EP1424150A1 EP03023380A EP03023380A EP1424150A1 EP 1424150 A1 EP1424150 A1 EP 1424150A1 EP 03023380 A EP03023380 A EP 03023380A EP 03023380 A EP03023380 A EP 03023380A EP 1424150 A1 EP1424150 A1 EP 1424150A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- blank
- cylinder
- forming
- height
- feature
- 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- Withdrawn
Links
Images
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
- B21D51/00—Making hollow objects
- B21D51/16—Making hollow objects characterised by the use of the objects
- B21D51/26—Making hollow objects characterised by the use of the objects cans or tins; Closing same in a permanent manner
- B21D51/2615—Edge treatment of cans or tins
-
- 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
- B21D51/00—Making hollow objects
- B21D51/16—Making hollow objects characterised by the use of the objects
- B21D51/26—Making hollow objects characterised by the use of the objects cans or tins; Closing same in a permanent manner
Definitions
- This invention relates to a method of controlling can height.
- it relates to a method of controlling the height of a shaped three piece can in order to obtain the same dimensional tolerances as for a cylindrical can using standard production lines.
- Three piece cans conventionally comprise a cylinder formed from sheet metal by welding along a side "seam". This cylinder is then formed into a can on the production line by a series of processes such as forming flanges on the open ends of the cylinder and fixing a can end to one end of the cylinder. The finished can is then filled with a food product, for example, and closed at its remaining open end by the customer (i.e. the filler).
- tolerances are specified to control the operation.
- typical specifications require the height to be within ⁇ 0.5 mm, flange width within ⁇ 0.2 mm and internal diameter within ⁇ 0.1 mm.
- the height of a shaped cylinder of tinplate, for example, after such expansion cannot be controlled accurately due to the anisotropy of the tinplate from which the can body blank (shaped cylinder) is formed. Variations in height of the can blank after shaping may be up to ⁇ 1.5 mm. This variation is unacceptable as it is not compatible with the standard machinery used in the subsequent operations to form the finished can. Furthermore, the can formed at the end of the process cannot be guaranteed to be within the usual tolerances for finished can height, diameter and flange width (see above).
- This invention seeks to provide a solution to these problems which will be acceptable to the customer and reduce the quantity of scrap from can body blanks or finished cans which are outside acceptable tolerance levels.
- a method of forming a can body for a three piece can comprising: forming a can body blank comprising a cylinder of sheet metal; shaping the can body blank by expansion or compression at one or more positions along the side wall of the cylinder; and producing a finished can body from the can body blank; characterised by forming a feature which extends around the full circumference of the side wall of the cylinder; and calibrating the height of the can body blank by axially compressing the blank along its longitudinal axis so as selectively to deform the feature at one or more positions around the blank.
- cylinder and “circumference” above are intended herein to encompass any tube including those which are polygonal in cross-section, as desired.
- fully circumferential feature comprises a bead.
- the calibration step may include measuring the height of the blank around the whole circumference prior to or during axial loading.
- a fully circumferential feature such as a bead in order to calibrate can height
- special lines built with special machines could be used for different shapes of can, in practice the investments involved would not be compatible with the promotional markets generally involved.
- the calibrating step takes place on the shaped can body prior to finishing.
- calibrating can height after shaping any height variations due to the expansion (or compression) process are absorbed prior to the standard production process.
- the same level of dimensional quality can be achieved for shaped cans as for conventional cylindrical cans.
- the axial compression may comprise applying an axial load to an open end of the can body blank such that the load is transmitted axially along the side wall of the can body.
- the axial load can be varied around the circumference of the blank, according to the required height adjustment. As the height of the shaped can may vary around the circumference of the can, the ability to vary the applied load can compensate not only for variations between cans but also around the circumference of an individual can.
- the fully circumferential feature is formed in a region of smallest diameter such as a neck.
- the profile and size of the fully circumferential feature may be selected for optimum axial flexibility during calibration. It is easier to provide a bead on the smallest diameter portion, particularly where the shaping is by expansion, as this region will have been subjected to less thinning of the metal, which may arise during expansion.
- the step of forming a fully circumferential feature may be carried out as part of the shaping step, or as a separate forming or beading operation.
- the step of axially compressing the blank may be carried out as an independent step or as part of another operation which requires the blank to be compressed.
- FIG. 1 The standard production process for making cylindrical three piece cans is shown in figure 1.
- a blank of sheet metal is first formed into a cylinder 1 and joined, for example by welding along a side seam 2.
- the welded cylinder has a height H1 and a diameter D1.
- Standard canmaking machinery is used to produce a finished can 3 having finished height Hf, base 4 seamed onto the cylindrical side wall 5 and open end 6 with flanged edge 7.
- the initial height H1 of the welded cylinder is very precise (within ⁇ 0.1 mm tolerance) so that the critical parameters for the open end of the "finished" can 3 are well within the prescribed tolerance of ⁇ 0.5 mm for Hf, ⁇ 0.2 mm for flange width 8 and ⁇ 0.1 mm for internal diameter 9.
- a method according to the present invention is shown schematically in figure 3.
- a cylinder typically of tin plate, with a welded side seam 2 as in figures 1 and 2
- the cylinder is shaped into a can blank 20 by expanding its lower side wall 10 (figure 3(a)).
- a fully circumferential bead 21 is formed in the upper side wall 11.
- This "technical bead" 21 is defined to give axial flexibility to the shaped cylinder 20.
- the radius of the bead should be a small as possible to obtain optimum flexibility.
- the selected parameters are dependent on thickness, temper and control of operations which are not carried out by the manufacturer. The manufacturer may specify maximum seaming load to be applied by a customer applies if it is the customer who fills and closes the can but will be unable to control this in all instances.
- FIG. 3(c) A unique process step in the present invention is shown in figure 3(c), in which the shaped can body blank 20 is compressed axially as demonstrated by the arrows in bold. During this compression, the shape of the bead changes, depending on the difference in height it has to absorb. If necessary, the axial load applied may vary around the circumference of the can body blank so that can height can also be adjusted circumferentially.
- the can body blank comprises a shaped cylinder 22 having height variations H3 which fall within the acceptable dimensional tolerances to allow good finishing of the can using standard machinery.
- the dimensional tolerance of open end features of the finished can 23 such as finished can height Hf, flange width 24 and diameter 25 can also be guaranteed due to the calibration of the shaped can body blank.
Abstract
Description
- This invention relates to a method of controlling can height. In particular, but not exclusively, it relates to a method of controlling the height of a shaped three piece can in order to obtain the same dimensional tolerances as for a cylindrical can using standard production lines.
- Three piece cans conventionally comprise a cylinder formed from sheet metal by welding along a side "seam". This cylinder is then formed into a can on the production line by a series of processes such as forming flanges on the open ends of the cylinder and fixing a can end to one end of the cylinder. The finished can is then filled with a food product, for example, and closed at its remaining open end by the customer (i.e. the filler).
- In order for the initial cylinder to be compatible with the machinery used to form the "finished" can, tolerances are specified to control the operation. For the finished can to be closed by seaming after filling by the customer, typical specifications require the height to be within ± 0.5 mm, flange width within ± 0.2 mm and internal diameter within ± 0.1 mm.
- For standard processed cans, meeting these tolerances does not present any problem. With the introduction of shaped cans into the market in recent years, however, the height of the finished can is particularly prone to variation outside the acceptable tolerance levels. This often arises if any variation in diameter by expansion or compression of the open ended cylinder is required, as this shaping is conducted after welding but prior to finishing the can production process.
- The height of a shaped cylinder of tinplate, for example, after such expansion cannot be controlled accurately due to the anisotropy of the tinplate from which the can body blank (shaped cylinder) is formed. Variations in height of the can blank after shaping may be up to ± 1.5 mm. This variation is unacceptable as it is not compatible with the standard machinery used in the subsequent operations to form the finished can. Furthermore, the can formed at the end of the process cannot be guaranteed to be within the usual tolerances for finished can height, diameter and flange width (see above).
- This invention seeks to provide a solution to these problems which will be acceptable to the customer and reduce the quantity of scrap from can body blanks or finished cans which are outside acceptable tolerance levels.
- According to the present invention, there is provided a method of forming a can body for a three piece can, the method comprising: forming a can body blank comprising a cylinder of sheet metal; shaping the can body blank by expansion or compression at one or more positions along the side wall of the cylinder; and producing a finished can body from the can body blank; characterised by forming a feature which extends around the full circumference of the side wall of the cylinder; and calibrating the height of the can body blank by axially compressing the blank along its longitudinal axis so as selectively to deform the feature at one or more positions around the blank.
- The terms "cylinder" and "circumference" above are intended herein to encompass any tube including those which are polygonal in cross-section, as desired. Generally the fully circumferential feature comprises a bead.
- The calibration step may include measuring the height of the blank around the whole circumference prior to or during axial loading. By using a fully circumferential feature such as a bead in order to calibrate can height, it is possible to produce a wide variety of can shapes which can be finished, by necking/flanging and by having ends seamed to both ends of the tubular can body, using standard can making lines. Although in theory special lines built with special machines could be used for different shapes of can, in practice the investments involved would not be compatible with the promotional markets generally involved.
- Preferably, the calibrating step takes place on the shaped can body prior to finishing. By calibrating can height after shaping, any height variations due to the expansion (or compression) process are absorbed prior to the standard production process. As a result, the same level of dimensional quality can be achieved for shaped cans as for conventional cylindrical cans.
- The axial compression may comprise applying an axial load to an open end of the can body blank such that the load is transmitted axially along the side wall of the can body. The axial load can be varied around the circumference of the blank, according to the required height adjustment. As the height of the shaped can may vary around the circumference of the can, the ability to vary the applied load can compensate not only for variations between cans but also around the circumference of an individual can.
- Typically, the fully circumferential feature is formed in a region of smallest diameter such as a neck. The profile and size of the fully circumferential feature may be selected for optimum axial flexibility during calibration. It is easier to provide a bead on the smallest diameter portion, particularly where the shaping is by expansion, as this region will have been subjected to less thinning of the metal, which may arise during expansion.
- The step of forming a fully circumferential feature may be carried out as part of the shaping step, or as a separate forming or beading operation.
- The step of axially compressing the blank may be carried out as an independent step or as part of another operation which requires the blank to be compressed.
- A preferred embodiment of the invention will now be described, by way of example only, with reference to the drawings, in which:
- Figure 1 is a diagrammatic representation of the standard production process for making cylindrical cans;
- Figure 2 is a diagrammatic representation of a standard production process for making shaped cans; and
- Figure 3 diagrammatic representation of a process for making shaped cans according to the invention.
-
- The standard production process for making cylindrical three piece cans is shown in figure 1. A blank of sheet metal is first formed into a
cylinder 1 and joined, for example by welding along aside seam 2. In figure 1(a), the welded cylinder has a height H1 and a diameter D1. Standard canmaking machinery is used to produce a finished can 3 having finished height Hf, base 4 seamed onto thecylindrical side wall 5 and open end 6 with flanged edge 7. The initial height H1 of the welded cylinder is very precise (within ± 0.1 mm tolerance) so that the critical parameters for the open end of the "finished" can 3 are well within the prescribed tolerance of ± 0.5 mm for Hf, ± 0.2 mm for flange width 8 and ± 0.1 mm forinternal diameter 9. - In figure 2, the
welded cylinder 1 undergoes a shaping process (figure 2(b)) to expand the cylinder along a region of itslower side wall 10 such that the lower side wall diameter D2 is larger than the diameter D1 of theupper side wall 11. This results in a change in the height H2 of the expandedcylinder 12. Due to the standard anisotropy of the tin plate from which the cylinder is made, this height H2 after expansion cannot readily be controlled. For example, variations in H2 can often be ± 1.5 mm. This variation is not compatible with the standard machinery used to finish the can where good height control is necessary, for example, to produce a neck and flange. Furthermore, the open end dimensions (diameter 14,flange width 15 and height 15) of finished can 13, are often outside specified tolerance such that the finished can must be scrapped. - A method according to the present invention is shown schematically in figure 3. Starting with a
cylinder 1, typically of tin plate, with awelded side seam 2 as in figures 1 and 2, the cylinder is shaped into a can blank 20 by expanding its lower side wall 10 (figure 3(a)). As part of this shaping operation as shown, or as a separate beading step, a fully circumferential bead 21 is formed in theupper side wall 11. - The profile and size of this "technical bead" 21 is defined to give axial flexibility to the
shaped cylinder 20. The radius of the bead should be a small as possible to obtain optimum flexibility. The selected parameters are dependent on thickness, temper and control of operations which are not carried out by the manufacturer. The manufacturer may specify maximum seaming load to be applied by a customer applies if it is the customer who fills and closes the can but will be unable to control this in all instances. - A unique process step in the present invention is shown in figure 3(c), in which the shaped can body blank 20 is compressed axially as demonstrated by the arrows in bold. During this compression, the shape of the bead changes, depending on the difference in height it has to absorb. If necessary, the axial load applied may vary around the circumference of the can body blank so that can height can also be adjusted circumferentially.
- Although shown as an independent step, this calibration operation may be incorporated in a separate operation such as a die-flanging operation. At the end of the axial loading, the can body blank comprises a
shaped cylinder 22 having height variations H3 which fall within the acceptable dimensional tolerances to allow good finishing of the can using standard machinery. The dimensional tolerance of open end features of the finished can 23 such as finished can height Hf,flange width 24 anddiameter 25 can also be guaranteed due to the calibration of the shaped can body blank.
Claims (9)
- A method of forming a can body, the method comprising:forming a can body blank comprising a cylinder of sheet metal;shaping the can body blank by expansion or compression at one or more positions along the side wall of the cylinder; andproducing a finished can body from the can body blank;forming a feature which extends around the full circumference of the side wall of the cylinder; andcalibrating the height of the can body blank by axially compressing the blank along its longitudinal axis so as selectively to deform the feature at one or more positions around the blank.
- A method according to claims 1, in which the calibrating step takes place on the shaped can body prior to finishing the can body.
- A method according to claim 1 or claims 2, in which the axial compression comprises applying an axial load to an open end of the can body blank, said load varying around the circumference of the blank, according to the required height adjustment.
- A method according to any one of claims 1 to 3, in which the fully circumferential feature is formed in a region of smallest diameter.
- A method according to any one of claims 1 to 4, in which the profile and size of the fully circumferential feature are selected for optimum axial flexibility during calibration.
- A method according to any one of claims 1 to 5, in which the step of forming a fully circumferential feature is carried out as part of the shaping step.
- A method according to any one of claims 1 to 5, in which the step of forming a fully circumferential feature is carried out as a separate forming or beading operation.
- A method according to any one of claims 1 to 7, in which the step of axially compressing the blank is carried out as an independent step.
- A method according to any one of claims 1 to 7, in which the step of axially compressing the blank is carried out as part of another operation which requires the blank to be compressed.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP03023380A EP1424150A1 (en) | 2002-11-30 | 2003-10-16 | Can height control |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP02026758A EP1424149A1 (en) | 2002-11-30 | 2002-11-30 | Can height control |
EP02026758 | 2002-11-30 | ||
EP03023380A EP1424150A1 (en) | 2002-11-30 | 2003-10-16 | Can height control |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1424150A1 true EP1424150A1 (en) | 2004-06-02 |
Family
ID=32299484
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03023380A Withdrawn EP1424150A1 (en) | 2002-11-30 | 2003-10-16 | Can height control |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP1424150A1 (en) |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3487665A (en) * | 1967-10-03 | 1970-01-06 | Borden Co | Straightener for deformed container flanges |
US3759203A (en) * | 1970-12-30 | 1973-09-18 | Continental Can Co | Container shaping apparatus |
EP1136154A1 (en) * | 1999-09-30 | 2001-09-26 | Daiwa Can Company | Method of manufacturing bottle type can |
-
2003
- 2003-10-16 EP EP03023380A patent/EP1424150A1/en not_active Withdrawn
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3487665A (en) * | 1967-10-03 | 1970-01-06 | Borden Co | Straightener for deformed container flanges |
US3759203A (en) * | 1970-12-30 | 1973-09-18 | Continental Can Co | Container shaping apparatus |
EP1136154A1 (en) * | 1999-09-30 | 2001-09-26 | Daiwa Can Company | Method of manufacturing bottle type can |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3995572A (en) | Forming small diameter opening for aerosol, screw cap, or crown cap by multistage necking-in of drawn or drawn and ironed container body | |
US4527412A (en) | Method for making a necked container | |
US4403493A (en) | Method for necking thin wall metallic containers | |
US5605069A (en) | Beverage container with wavy transition wall geometry and method for producing the same | |
EP0118926B1 (en) | Improved aluminum alloy food can body and method for making same | |
EP0864385B1 (en) | Body-necking a wall-ironed can | |
EP1210189B1 (en) | Reinforced hydroformed members and methods of making the same | |
US7395686B2 (en) | Bottom profile for drawn and ironed can body | |
JPS63125150A (en) | Method and device for molding bottom plate of vessel and bottom plate molded through said method | |
JP2002523239A (en) | Method of manufacturing tubular member | |
US20100107718A1 (en) | Necking die with redraw surface and method of die necking | |
US6286357B1 (en) | Process for manufacturing a shaped metal can | |
US20110011896A1 (en) | Steel one-piece necked-in aerosol can | |
US4412440A (en) | Process for making container | |
US5899106A (en) | Process for manufacturing a shaped metal can | |
US6132155A (en) | Process for can bottom manufacture for improved strength and material use reduction | |
US4753364A (en) | Necked container | |
EP1424150A1 (en) | Can height control | |
EP1424149A1 (en) | Can height control | |
EP0020926A1 (en) | Method for necking thin wall metallic containers and drawn container produced by this method | |
JP2017136604A (en) | Method of manufacturing can and can | |
JP2017136605A (en) | Manufacturing method of can | |
JP2017217700A (en) | Can manufacturing method | |
EP1184103B1 (en) | A method for producing a sheet metal container, such a container and an apparatus for performing the method | |
WO2000064609A1 (en) | Method of forming a can body |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20031016 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR |
|
AX | Request for extension of the european patent |
Extension state: AL LT LV MK |
|
RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: CROWN PACKAGING TECHNOLOGY, INC |
|
AKX | Designation fees paid |
Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PT RO SE SI SK TR |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN |
|
18W | Application withdrawn |
Effective date: 20051121 |