Method for changing the shape of a can, and can shaped in this way

Abstract

The invention relates to a method for changing the shape of a can ( 2 ), which can has a can wall, such as a deep-drawn can or a wall-ironed can, the can being positioned in or around a die ( 1 ), which die is provided with a surface with, for example, a relief, embossings or thickened sections, after which the can wall is pressed into the shape of the die by means of at least one jet of a high-pressure medium which is moved along the can wall. According to the invention, a supporting layer ( 3 ), which supports the can wall during the deformation of the can wall, is arranged between the can wall and the die. The invention also relates to a can shaped using the method.

1 . A method for changing the shape of a can, which can has a can wall, such as a deep-drawn can or a wall-ironed can, the can being positioned in or around a die, which die is provided with a surface with, for example, a relief, embossings or thickened sections, after which the can wall is pressed into the shape of the die by means of at least one jet of a high-pressure medium which is moved along the can wall, characterized in that a supporting layer, which supports the can wall during the deformation of the can wall, is arranged between the can wall and the die.  
     
     
         2 . The method as claimed in  claim 1 , characterized in that the supporting layer is formed by a layer of a solid.  
     
     
         3 . The method as claimed in  claim 2 , characterized in that the supporting layer of a solid is arranged against the can wall.  
     
     
         4 . The method as claimed in  claim 2  or  3 , characterized in that a layer of deformable material with a thickness of at most approximately 3 mm is used.  
     
     
         5 . The method as claimed in  claim 4 , characterized in that a layer with a thickness of approximately 1 mm is used.  
     
     
         6 . The method as claimed in one of the preceding claims, characterized in that a layer of deformable material made from plastics or rubber is used.  
     
     
         7 . The method as claimed in one of the preceding claims, characterized in that a layer of deformable material with a hardness of less than 90 Shore D is used.  
     
     
         8 . The method as claimed in  claim 7 , characterized in that a layer of material with a hardness of between 40 Shore D and 70 Shore D is used.  
     
     
         9 . The method as claimed in  claim 8 , characterized in that a layer of material with a hardness of approximately 55 Shore D is used.  
     
     
         10 . The method as claimed in one of the preceding claims, characterized in that a layer of deformable material with a density of between 1000 and 7800 kg/m 3 , preferably between 2500 and 5000 kg/M 3 , is used.  
     
     
         11 . The method as claimed in  claim 10 , characterized in that a layer of material with a density of approximately 3500 kg/m 3  is used.  
     
     
         12 . The method as claimed in one of the preceding claims, characterized in that the jet of the medium is guided helically along the can wall.  
     
     
         13 . The method as claimed in  claim 12 , characterized in that the pitch of the helix is at least approximately 1 mm, preferably 1.5 to 3 mm.  
     
     
         14 . The method as claimed in claimed in  claim 12 , characterized in that the pitch is 1.5 to 2 mm.  
     
     
         15 . The method as claimed in one of the preceding claims, characterized in that the expansion of the can amounts to at most approximately 10%, preferably at most 5%.  
     
     
         16 . The method as claimed in  claim 15 , characterized in that the expansion amounts to at most 2%.  
     
     
         17 . The method as claimed in one of the preceding claims, characterized in that the medium used is a water jet at a pressure of between 3000 and 5000 psi.  
     
     
         18 . A can produced using the method as claimed in one of  claims 1  to  17 , characterized in that the can has a surface which is mirror-smooth to the naked eye.  
     
     
         19 . A can produced using the method as claimed in one of  claims 1  to  17 , characterized in that the roughness average of the can wall formed is lower than 0.5.