Recent developments in friction-assisted sheet metal forming processes

Direct and inverted redrawing of cups at a draw ratio of 3 was accomplished by repeated squeezing of a urethane pad placed on top of the blank seated on a die-frictional traction helps redraw the first-stage deep-drawn cup into a very deep cup. Collar drawing is the most recent development in which friction enhances the forming of a collar from annular sheet metal blanks. Using this method collars can be drawn with desirable flange diameters or tubular lengths. Results from investigations into the above techniques are presented in this paper.