Investigations into collar drawing using urethane pads

Collars were drawn from aluminium blanks by applying the Maslennikov's technique: frictional traction between an annular urethane pad and an annular sheet metal blank is used to repeatedly draw the sheet metal to form the collar. Substantially larger tubular lengths are formed by this technique compared with traditional collar drawing methods. Experiments were conducted with blanks of thickness 0.5, 0.7 and 1 mm; internal diameters of 18, 20, 22 and 25 mm; and an outer diameter of 95 mm. Collars were drawn by subjecting the blanks to a maximum of six loading cycles. Heights of the tubular part formed on the product were measured for various blank dimensions and load cycles. The maximum force was measured for each cycle of loading. Inner lip diameter on the product formed after each loading cycle and the strains were measured. The results from the investigations are presented and discussed in this paper.