Deep Drawing

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Deep Drawing Mathias Liewald Institute for Metal Forming Technology, University of Stuttgart, Stuttgart, Germany

Synonyms Stamping

Definition Deep drawing is a sheet metal forming process by which a sheet metal blank is slightly clamped along its perimeter by a blank holder and radially drawn into a forming die by use of a punch.

Theory and Application According to DIN 8584–3 (2003), deep drawing is a tensile compression metal forming process, which shapes a sheet metal blank as a hollow body open on the one side or of a projected hollow body to one with a smaller cross section, without intentionally modifying its wall thickness. Such categorization of deep drawing within this process group is done due to radial tensile acting and tangential acting compression stresses mainly

acting in the forming zone when the punch is drawing the part. The deep drawing process basically can be divided into three different kinds of load application (Fig. 1): deep drawing using tools (most commonly used method), deep drawing using active media, and deep drawing by means of active energy. In the most simple case during the ﬁrst draw, a hollow body or a cup shape is produced from a plane sheet metal blank (irregular or circular outline of blank, Fig. 2). The deep drawing tool ever consists of three major components: deep drawing punch, draw ring or die or matrice, and a blank holder. During deep drawing, ﬁrst the blank is located between die and blank holder. Forming process starts when a blank holder linked to controllable component of drawing press clamps the sheet metal and applies required blank holder force. Normal compression distribution applied by the blank holder ﬁrst induces retracting force onto sheet metal surface by friction and second prevents wrinkling (of the ﬁrst degree) in the ﬂange area of the workpiece. Basically the forming procedure starts when biaxial stresses are applied to the bottom area of the workpiece by the drawing punch. In Fig. 2 deep drawing is depicted as so called “hat proﬁle”, where the drawing punch is ﬁxed on the lower platen, die is ﬁxed to the ram and blank holder is supported by cushion. When travel of die (driven by ram of press) proceeds,

# CIRP 2017 The International Academy for Production Engineering et al. (eds.), CIRP Encyclopedia of Production Engineering, DOI 10.1007/978-3-642-35950-7_6502-3

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Deep Drawing

Deep Drawing, Fig. 1 Categorization of the deep drawing processes according to DIN 8584–3 (2003) with kind permission of e.V

bottom blank s0

rd rp

flange

sidewall drawing ring (die) blank holder

Fbh Fbh

(drawing) punch Fbh

Fp d0 D0

Fp

Fbh

Deep Drawing, Fig. 2 Fundamentals of deep drawing during the ﬁrst draw. D0 diameter of blank, d0 diameter of (drawing) punch, s0 initial thickness of blank, rd radius of drawing ring (die), rp radius of (drawing) punch, Fbh force of blank holder, Fp force of (drawing) punch (Reprinted with permission # IFU Stuttgart)

bottom and part sidewall region get hardened due to tensile load and ﬁrst material starts to ﬂow into the cavity b

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