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.

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.