rétreint à la matrice

OBS: rétreint tampon : terme obtenu d'un spécialiste du domaine.

CONT: There are three main types of necking technology ... The first is die-necking, where the diameter of the can body can be reduced at one end or at both ends simultaneously. A necking ring - a kind of drawing ring whose ring diameter equals the outer diameter of the unnecked body on one side, and the desired necked diameter on the other side - is pushed axially onto the body. The neck geometry is thus shaped to the profile formed by the two ring diameters. An inner core prevents wrinkling and calibrates the exact neck diameter.