Patent ID: 7832075

Claim:
A method for producing aluminum metal caps, comprising: a) providing a flat blank cut by punching a metal coil or a metal sheet, the flat blank coated on both sides with a layer of drawing varnish, b) drawing, in one or more stages, the flat blank, using a drawing lubricant, so as to form a deep-drawn blank including a head and a skirt, having a rotational symmetry around an axial direction, c) degreasing the deep-drawn blank, so as to remove the remainder of the drawing lubricant, in order to form a degreased blank capable of being lacquered, and d) lacquering the degreased blank, wherein the deep-drawn blank is subjected during the degreasing step c) to an energy radiation emission treatment of selected intensity and duration so as to eliminate or break down the remaining lubricant, the treatment being carried out entirely at a metal temperature of less than 150° C., and for a time typically less than 1 second, so as to obtain, after the treatment, a surface tension equal to at least 33 dynes/cm.