Influence of punch shapes on the collar-drawing process of sheet steel

An analysis of forming limit in the elliptic hole-flanging process of sheet metal

“…To investigate the characteristics of wall thinning and the limitation of formability of blanks in the elliptic hole-flanging process, the outer diameter of the circular blanks with a machined hole at their center was fixed to be 130 mm, the sheet thickness chosen to be 0.6 mm and the initial (major radius, minor radius) of the inner elliptic hole being assigned a value of (20,9), (21,10), (22,11) and (23,12) mm. Here, the limiting forming ratio (LFR) is defined as C p /C h,min , where C p is the punch circumference and C h,min denotes the minimal initial hole circumference of the blanks that can be drawn by the punch without fracture.…”

“…Elliptic Hole-flanging and related processes have been investigated analytically and experimentally [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Yamada and Koide [1] studied the effects of initial yield stress and strainhardening on bore-expanding using the incremental theory of plasticity with a flat-headed cylindrical punch to determine the stress and strain distribution.…”

“…The neck characteristics in the flange deformation, which are of basic types -lip, petal, and plug -shed light on the detailed mechanics of the hole-flanging process and the reasons for petal and plug formation. Besides the plastic properties of material, such as strain-hardening and anisotropy, which affect of the formability in the hole-flanging process [9,10], other external influencing factors include the lubrication condition, the punch shapes and the clearance between the punch and die [11][12][13][14].…”

Investigations into collar drawing using urethane pads

“…Several experimental and theoretical investigations on holeflanging [1][2][3][4][5][6] carried out over the years include the influences of the punch shape, rotating and non-rotating punches, influence of punch profile, finite-element analysis, and formability in holeflanging.…”

Collar drawing using a urethane pad

“…In conventional collar drawing [1][2][3][4][5][6], also called hole-flanging, an annular sheet metal blank is forced into a radiused die cavity by a radiused steel punch in a manner similar to the drawing of cups. However, the inner contour of the blank becomes substantially stretched as the blank is drawn towards the die wall to form the tubular part.…”