METAL CONTAINERS AND PROCESS AND INSTALLATION FOR MANUFACTURING METAL CONTAINERS

Abstract

Process and installation for manufacturing metal containers and the metal container obtained with the process. The process includes supplying a metal disc, extruding the disc to form a metal container, applying a coating on the inside of the container, deforming the open end of the container to obtain a neck with a curled portion. The curled portion is pressed to obtain a flat surface in a plane normal to the main axis of the container. The process further includes machining the curled portion that has been previously pressed to remove the coating from the curled portion, leaving the metal of the container exposed.

Claims

1. A method of producing a neck in a metal container, the metal container including a metal cylindrical body, a bottom, and an open end opposite the bottom, the cylindrical body having a main axis and comprising an inner side wall having a protective barrier coating, the method comprising: deforming the side wall in a region of the open end of the cylindrical body to obtain the neck; curving the neck outwardly to obtain a curled portion at the open end; pressing on an upper part of the curled portion to produce in the curled portion a first flat surface that is in a plane normal to the main axis of the cylindrical body; and removing an entirety of the protective barrier coating from the first flat surface.

2. The method according to claim 1, further comprising removing metal from the first flat surface after the removal of the protective barrier coating.

3. The method according to claim 1, wherein the protective barrier coating is mechanically removed from the first flat surface.

4. The method according to claim 3, wherein the protective barrier coating is removed using a machining process.

5. The method according to claim 1, wherein the removal of the protective barrier coating from the first flat surface is done by machining the first flat surface at an angle between 5 and 5 with respect to the normal plane.

6. The method according to claim 1, wherein the removal of the protective barrier coating from the first flat surface is done by machining the first flat surface at an angle of 0 with respect to the normal plane.

7. The method according to claim 1, further comprising producing a second flat surface in a lower part of the curled portion, the lower part being opposite the upper part, the second flat surface being parallel to the first flat surface.

8. The method according to claim 7, wherein a thickness of the curled portion at the location of the first and second flat surfaces is the same before and after producing the first and second flat surfaces.

9. The method according to claim 7, wherein the second flat surface is produced by the pressing on the upper part of the curled portion to produce the first flat surface.

10. The method according to claim 1, further comprising aspirating particulates of the protective barrier coating as the protective barrier coating is removed.

11. The method according to claim 1, wherein the removal of the protective barrier coating from the first flat surface is done by machining the first flat portion with a depth of less than 0.1 millimeters to remove metal, the side wall of the cylindrical body having a thickness of 0.5 to 0.7 millimeters.

12. The method according to claim 1, wherein the first flat surface is formed by clamping the metal container by the bottom using a clamping tool and subsequently acting on the open end of the cylindrical body with a first tool that forms the first flat surface, the first tool being attached to tool table.

13. The method according to claim 12, wherein the tool table has a second tool, the protective barrier coating being removed from the first flat surface using the second tool.

14. The method according to claim 1, wherein the protective barrier coating is a lacquer coating.

15. A system for producing a neck in a metal container, the metal container including a metal cylindrical body, a bottom, and an open end opposite the bottom, the cylindrical body having a main axis and comprising an inner side wall having a protective barrier coating, the system comprising: a clamping table with a clamping station configured to clamp the metal container by the bottom; and a tool table that faces the clamping table, one or both of the tool table and the clamping table being moveable with respect to the other to vary a distance between them, the tool table including a first tool that is configured to form the neck in a region of the open end of the cylindrical body, a second tool that is configured to curve the neck outwardly to obtain a curled portion at the open end, a third tool that is configured to press on an upper part of the curled portion to produce in the curled portion a flat surface that is in a plane normal to the main axis of the cylindrical body, and a fourth tool that is configured to remove an entirety of the protective barrier coating from the flat surface.

16. The system according to claim 15, wherein the clamping table is configured to rotate with respect to the clamping table.

17. The system according to claim 16, wherein the clamping table is rotatable around a horizonal axis.

18. The system according to claim 16, wherein the clamping station is arranged at or near a periphery of the clamping table.

19. The system according to claim 17, wherein the clamping station is arranged at or near a periphery of the clamping table.

20. A system for manufacturing a metal container, the system comprising: an extrusion press configured to extrude a metal disc to form a cylindrical body having a main axis, a bottom, and an open end opposite the bottom; a varnishing machine configured to apply a protective barrier coating on the inside wall of the cylindrical body; and a necking machine comprising: a clamping table with a clamping station configured to clamp the metal container by the bottom; and a tool table that faces the clamping table, one or both of the tool table and the clamping table being moveable with respect to the other to vary a distance between them, the tool table including a first tool that is configured to form a neck in a region of the open end of the cylindrical body, a second tool that is configured to curve the neck outwardly to obtain a curled portion at the open end, a third tool that is configured to press on an upper part of the curled portion to produce in the curled portion a flat surface that is in a plane normal to the main axis of the cylindrical body, and a fourth tool that is configured to remove an entirety of the protective barrier coating from the flat surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 shows a block diagram of an example of an installation for manufacturing metal containers.

[0028] FIG. 2 shows a schematic example of the transformation of a metal disc into a metal container using an extruder of an extrusion press.

[0029] FIGS. 3A to 3E show the steps of transforming a metal disc into a metal container with a curled portion at the open end of the metal container.

[0030] FIG. 4A shows the curled portion of the open end of the metal container before obtaining the flat surface.

[0031] FIG. 4B shows the curled portion of the open end of the metal container after pressing the curled portion.

[0032] FIG. 4C shows the curled portion of the open end of the metal container after machining the curled portion that has been previously pressed.

[0033] FIG. 5 shows an example of a necking machine.

[0034] FIG. 6 shows the tool table of the necking machine.

[0035] FIG. 7 shows an aerosol comprising the metal container and a sprayer arranged in the metal container.

[0036] FIG. 8 shows the aerosol sprayer resting on the curled portion of the open end of the metal container.

DETAILED DESCRIPTION

[0037] The manufacture of metal containers, for example, containers made of aluminum such as cans or aerosols, for containing a product, such as beverages, foods, or cosmetic and pharmaceutical products, requires a process in which different machines which are arranged in an installation for manufacturing metal containers are used. Depending on the operations to be performed for manufacturing the container, different types of machines can be used, and the machines can be arranged in the installation in different ways.

[0038] The containers are processed in the installation continuously and at a high speed, for example, processing in the order of two hundred containers per minute. The machines are automatically linked by means of transfer units, such as linear conveyor belts, rotary carrousels, or similar elements, which transfer the containers from one machine to another.

[0039] FIG. 1 shows a block diagram of a non-limiting example of an installation for manufacturing metal containers 10. The installation comprises a feeder 101, an extrusion press 102, a trimming machine 103, a washing machine 104, a drying machine 105, an internal varnishing machine 106, a polymerization furnace 107, a print set comprising a glazing machine 108, a lithographic printing machine 109, and an overprint varnishing machine 110, a necking machine 200, an inspection machine 111, and a packaging machine 112.

[0040] The discs 1 are lubricated and supplied from the feeder 101 to the extrusion press 102 where the discs 1 are extruded to form metal containers 10. Preferably the discs 1 are aluminum discs.

[0041] Each metal container 10 obtained in the extrusion press 102 has a cylindrical body 11 with a main axis X. The container 10 is made in a single piece. The cylindrical body 11 comprises a side wall 12, a bottom 13, and an open end 14 opposite the bottom 13.

[0042] FIG. 2 shows a schematic example of the transformation of a metal disc 1 into a metal container 10 by means of an extruder 1020 of the extrusion press 102 which forces the material of the metal disc 1 to deform and be transformed into the cylindrical body 11. The extrusion process is well known and not described in further detail.

[0043] The open end 14 of the containers 10 is trimmed in the trimming machine 103 to remove impurities, and the containers 10 are brushed. The containers 10 are then washed in the washing machine 104 to remove impurities that may remain in the metal, for example, with alkaline water, and the containers 10 are then dried in the drying machine 105.

[0044] After drying, a coating 15 is applied on the inside of the cylindrical body 11 of the containers 10 in the internal varnishing machine 106 to create a protective barrier between the metal of the container 10 and the product to be contained in the container 10. The coating 15 can be a lacquer that complies with Regulation (EC) 1935/2004 and Regulation (EC) 2023/2006 on Materials and articles intended to come into contact with food. Once the coating 15 has been applied, the container 10 is heated in the polymerization furnace 107 to harden the coating, for example, the containers are heated at a temperature of about 250 C. depending on the type of lacquer used.

[0045] An outer coating of the container 10 is applied in the glazing machine 108 of the print set to prepare it for printing on same in the lithographic printing machine 109, and the container 10 is then externally coated in the overprint varnishing machine 110 to protect the print.

[0046] The open end 14 of the container 10 is then deformed in the necking machine 200 to create a neck 16 with a curled portion 17. The neck 16 is configured to receive a closure element for closing the container 10, such as the valve of an aerosol sprayer. Lastly, the container 10 is inspected in the inspection machine 111 to detect cracks in any area of the finished container 10, and lastly, the containers 10 are grouped together in the packaging machine 112 by batches to be sent to an external factory where the containers 10 are filled with the final product (beverages, foods, or cosmetic and pharmaceutical products), and the open end 14 of the containers 10 is closed with the closure element.

[0047] The necking machine 200 comprises a clamping table 210 with clamping stations 220 for clamping the containers 10 by the bottom 13, and a tool table 230 with tool stations 240 to form the upper end 14 of the containers 10. The clamping table 210 is facing the tool table 230, and the clamping stations 220 and tool stations 240 are movable with respect to the others to form the containers 10. See FIGS. 5 and 6.

[0048] The clamping table 210 is rotary and oriented vertically. The clamping table 210 has a rotational movement around a horizontal axis, in an indexed manner in defined positions. The clamping table 210 comprises the plurality of clamping stations 220 arranged on the periphery thereof. The containers 10 reach the clamping table 210 in a sequential manner, with the containers 10 being fed to said clamping table 210, and with each container 10 being arranged in one of the clamping stations 220.

[0049] The tool table 230 has a translational movement A towards the clamping table 210 from a set back position to a forward position, and a translational movement B from the forward position to the set back position. After each indexed rotational movement of the clamping table 210, the tool table 230 advances with the translational movement A and moves backwards with the translational movement B, before the following rotational movement of the clamping table 210. The tool table 230 comprises the plurality of tool stations 240 arranged on the periphery thereof. Each tool station 240 is located in a position facing one of the clamping stations 220 during formation of the container 10, said formation occurring during the translational movement of the tool table 230. An operation for forming the open end 14 of the container 10 occurs in each tool station 240. The tool stations 240 are configured depending on the shape of the container 10 to be obtained. For example, the tool table 230 can have forty tool stations 240. The containers 10 are formed by means of stamping strokes between the stations 220 and 240 of the forming machine 200.

[0050] FIGS. 3A to 3E show the steps of transforming a metal disc 1 into a metal container 10 with a curled portion 17 on the neck 16 of the open end 14 of the metal container 10. FIG. 3A shows the metal disc 1 which is supplied to the extrusion press 102. FIG. 3B shows the metal container 10 after exiting the extrusion press 102. FIG. 3B shows the open end 14 that has been trimmed in the trimming machine 103. FIG. 3C shows the container 10 after exiting the internal varnishing machine 106 with the coating 15 applied on the inside of the cylindrical body 11 of the container 10. FIG. 3D shows the container 10 with the neck 16 formed at the open end 14. FIG. 3E shows the container 10 with the curled portion 17 formed after curving the neck 16 outwardly. The neck 16 and the curled portion 17 are made in the necking machine 200.

[0051] FIG. 4A shows an enlarged detail of FIG. 3E denoted with reference IV, where the rounded shape of the curled portion 17 can be observed. According to the invention the process comprises obtaining a flat surface 18 in the curled portion 17 of the open end 14 of the metal container 10. To obtain the flat surface 18 the process comprises a first sub-step wherein the curled portion 17 is pressed to obtain the flat surface 18 in a plane N normal to the main axis X of the cylindrical body 11 of the metal container 10 (see FIG. 4B), and a second sub-step wherein the curled portion 17 that has been previously pressed is machined to remove the coating 15 from the curled portion 17, leaving the metal of the metal container 10 exposed. (See FIG. 4C). A flat surface 18 without the coating 15 is thereby obtained, which allows the metal of the container 10 to be seen, thereby allowing the valve gasket that is to be later arranged to be suitably supported and to establish a proper airtight closure with the open end 14 of the container 10, since the metal of the container 10 is rougher than the coating 15. In addition, obtaining the surface in two sub-steps minimizes the risks of reducing the thickness of the curled portion 17.

[0052] As observed in FIG. 4B, when the curled portion 17 is pressed, the flat surface 18 is obtained in the upper part of the curled portion 17, maintaining the thickness of the curled portion 17. In other words, in the first sub-step a first flat surface 18 is obtained in the upper part of the curled portion 17 and a second flat surface 18 is obtained in the lower part of the curled portion 17, which is parallel to the first flat surface 18, wherein the thickness of the curled portion 17 before and after pressing the curled portion 17 is the same. For example, the side wall 12 of the metal container 10 has a thickness of between 0.5-0.7 mm, and therefore the curled portion 17 has a thickness of between 0.5-0.7 mm, and after pressing the curled portion 17, the same thickness of between 0.5-0.7 mm is maintained.

[0053] Preferably, in the second sub-step the curled portion 17 is machined at an angle comprised between 5 and 5 with respect to the normal plane N, even more preferably at an angle of 0 with respect to the normal plane N.

[0054] Preferably, the excess material of the coating 15 removed from the curled portion 17 is aspirated. Although the first sub-step presses the coating 15 of the curled portion 17 and facilitates later machining, traces of coating 15 may remain at the open end 14, such that said material is aspirated, preferably the excess material of the coating 15 is aspirated while machining is being performed.

[0055] After the extrusion of the metal disc 1, a container 10 with a thin side wall 12 is obtained, for example, the side wall 12 of the metal container 10 has a thickness of between 0.5-0.7 mm, such that in the second sub-step, the curled portion 17 is machined with a depth of less than 0.1 mm to minimize the risk of weakening the curled portion. That depth allows the coating 15 to be removed without weakening the curled portion 17.

[0056] Preferably, in the second sub-step the coating 15 of the curled portion 17 that has been pressed is removed and part of the metal is removed from the metal container 10. This allows guaranteeing a complete removal of the coating 15 and allows the metal of the container to be lightly machined to improve the fixing with the valve gasket that is to be later arranged.

[0057] Preferably, the flat surface 18 is formed in the necking machine 200. Some of the tool stations 240 of the forming machine 200 are thereby used to make the flat surface 18.

[0058] One of the tool stations 240 has a first tooling 241 for pressing the curled portion 17 and obtaining the flat surface 18, and another one of the tool stations 240 has a second tooling 242 for machining the curled portion 17 and removing the coating 15, leaving the metal of the metal containers 10 exposed.

[0059] For example, the first tooling 241 may comprise rotating cylindrical wheels that press the curled portion 17 of the container 10 and obtaining the flat surface 18, and the second tooling 242 may comprise front cutting blades for machining the previously pressed curled portion 17 and removing the coating 15.

[0060] The first flat surface 18 of the upper part of the curled portion 17 is obtained by applying pressure on the upper part of the curled portion 17 and the second flat surface 18 of the lower part of the curled portion 17 is generated at the same time by the pressure exerted on the upper part of the curled portion 17. When aluminum is used as the material of the container 10, it is not necessary to use a lower die to obtain the second flat surface 18 of the lower part of the curled portion 17, and it is sufficient for the first tooling 241 to apply pressure on the upper part of the curled portion 17.

[0061] In this sense, the neck 16 of the container 10 is initially formed progressively in the first tool stations 240 of the necking machine 200, in the antepenultimate tool station 240 the neck 16 is curved outwardly to obtain the curled portion 17, in the penultimate tool station 240, with the first tooling 241, the curled portion 17 is pressed to obtain the flat surface 18, and in the last tool station 240, with the second tooling 242, the coating 15 that covers the previously pressed curled portion 17 is machined. The second tooling 242 may comprise a pipe for aspirating the chips of coating 15 that detach during machining.

[0062] FIG. 7 shows an aerosol 20 comprising the metal container 10 and a sprayer 21 arranged in the metal container 10, and FIG. 8 shows the sprayer 21 of the aerosol 20 resting on the curled portion 17 of the open end 14 of the metal container 10.

[0063] Accordingly, the aerosol 20 comprises a metal container 10 as described above and a sprayer 21 arranged in the metal container 10 for spraying the product from the interior of the metal container 10.

[0064] The metal container 10 of the aerosol 20 comprises a cylindrical body 11 having a main axis X and a coating 15 applied to the interior of the cylindrical body 11. The cylindrical body 11 comprises a side wall 12, a bottom 13 and an open end 14 opposite the bottom 13, and the open end 14 has a neck 16 with a curled portion 17 having a flat surface 18 in a plane N normal to the main axis X of the cylindrical body 11, wherein the flat surface 18 is manufactured in a first sub-step wherein the curled portion 17 is pressed to obtain the flat surface 18 in the normal plane N with respect to the main axis X of the cylindrical body 11 of the metal container 10, and a second sub-step wherein the curled portion 17 that has been previously pressed is machined to remove the coating 15 from the curled portion 17, leaving the metal of the metal container 10 exposed.

[0065] The metal of the side wall 12 and the metal of the curled portion 17 have the same thickness after obtaining the flat surface 18.

[0066] The sprayer 21 has a valve 22 with a gasket 23 which is supported on the flat surface 18 to establish an airtight closure of the open end 14 of the metal container 10.

[0067] The valve 22 has a flanged portion 24 which fits over the curled portion 17 of the neck 16 of the metal container 10, and between the flanged portion 24 and the curled portion 17 is disposed the gasket 23.

[0068] The gasket 23 is an elastic element which is compressed in the cavity defined between the flanged portion 24 and the curled portion 17. The flat surface 18 of the curled portion 17 ensures the contact of the gasket 23 and improves the sealing of the metal container 10.

[0069] Embodiments are disclosed in the following clauses/

[0070] Clause 1. Process for manufacturing metal containers, comprising the following steps: [0071] supplying a metal disc (1), [0072] extruding the metal disc (1) to form a metal container (10) having a cylindrical body (11) with a main axis (x), the cylindrical body (11) comprises a side wall (12), a bottom (13), and an open end (14) opposite the bottom (13), [0073] applying a coating (15) on the inside of the cylindrical body (11) of the metal container (10), [0074] deforming the open end (14) of the metal container (10) to obtain a neck (16) at the open end (14), [0075] curving the neck (16) outwardly to obtain a curled portion (17) at the open end (14), and [0076] obtaining a flat surface (18) in the curled portion (17), to obtain the flat surface (18), the process comprises: [0077] a first sub-step wherein the curled portion (17) is pressed to obtain the flat surface (18) in a plane (N) normal to the main axis (X) of the cylindrical body (11) of the metal container (10), and [0078] a second sub-step wherein the curled portion (17) that has been previously pressed is machined to remove the coating (15) from the curled portion (17), leaving the metal of the metal container (10) exposed.

[0079] Clause 2. Process according to clause 1, wherein in the second sub-step, the curled portion (17) is machined at an angle comprised between 5 and 5 with respect to the normal plane (N).

[0080] Clause 3. Process according to clause 2, wherein the curled portion (17) is machined at an angle of 0 with respect to the normal plane (N).

[0081] Clause 4. Process according to any of the preceding clauses, wherein in the first sub-step, a first flat surface (18) is obtained in the upper part of the curled portion (17) and a second flat surface (18) is obtained in the lower part of the curled portion (17), which is parallel to the first flat surface (18), wherein the thickness of the curled portion (17) before and after pressing the curled portion (17) is the same.

[0082] Clause 5. Process according to any of the preceding clauses, wherein the excess material of the coating (15) removed from the curled portion (17) is aspirated.

[0083] Clause 6. Process according to any of the preceding clauses, wherein the side wall (12) of the metal container (10) has a thickness of between 0.5-0.7 mm and in the second sub-step, the curled portion (17) is machined with a depth of less than 0.1 mm.

[0084] Clause 7. Process according to any of the preceding clauses, wherein in the second sub-step, the coating (15) is removed from the curled portion (17) that has been pressed and part of the metal is removed from the metal container (10).

[0085] Clause 8. Process according to any of the preceding clauses, wherein the flat surface (18) is formed in a necking machine (200) comprising a clamping table (210) with clamping stations (220) for clamping the metal containers (10) by the bottom (13), and a tool table (230) with tool stations (240) to form the open end (14) of the metal containers (10), with the clamping table (210) facing the tool table (230), and the clamping stations (220) and the tool stations (240) are movable with respect to the others to form the metal containers (10).

[0086] Clause 9. Process according to the preceding clause, wherein the first sub-step is performed with a first tooling (241) of one of the tool stations (240) of the necking machine (200), and the second sub-step is performed with a second tooling (242) of another one of the tool stations (240) of the necking machine (200).

[0087] Clause 10. Installation for manufacturing metal containers according to the process of any of clauses 1 to 9, comprising: [0088] a feeder (101) for supplying metal discs (1), [0089] an extrusion press (102) for extruding the metal discs (1) and forming metal containers (10), with each metal container (10) having a cylindrical body (11) with a main axis (x), the cylindrical body (11) comprises a side wall (12), a bottom (13), and an open end (14) opposite the bottom (13), [0090] an internal varnishing machine (106) for applying a coating (15) on the inside of the cylindrical body (11) of the metal containers (10), and [0091] a necking machine (200) comprising a clamping table (210) with clamping stations (220) for clamping the metal containers (10) by the bottom (13), and a tool table (230) with tool stations (240) to form the open end (14) of the metal containers (10), with the clamping table (210) facing the tool table (230), and the clamping stations (220) and the tool stations (240) are movable with respect to the others to form the metal containers (10), [0092] one of the tool stations (240) has a first tooling (241) for pressing the curled portion (17) and obtaining a flat surface (18) in a plane (N) normal to the main axis (x) of the cylindrical body (11) of the metal containers (10), and another one of the tool stations (240) has a second tooling (242) for machining the curled portion (17) and removing the coating (15), leaving the metal of the metal containers (10) exposed.

[0093] Clause 11. Metal container obtained according to the process of any of clauses 1 to 9.

[0094] Clause 12. Aerosol product comprising a metal container according to the preceding clause and a sprayer (21) arranged in the metal container (10).