April 15, 2008 Die design and building is a critical part of a
successful extrusion process. ironing—vertically squeezing the
metal between the punch and the die to increase the surface
area—helps refine the extruding process, as does preforming.
Click to view image larger A good extrusion die design. Editor's
Note:This is Part II of a two-part series. Part I explored the
effects of the working material as well as the edge condition of
the prepierced hole. This article discusses the effects of die
design and the use of ironing and preforms. Die design and build
is a critical part of a successful extrusion process (see Figure
1). Extrusion Punch. The extrusion punch should be made of
highly wear-resistant tool steel—powdered metal (PM)
preferably—or solid carbide material. The punch should be
polished linearly to a mirrorlike surface finish. Relieve the
punch after extruding the straight section to allow for
lubricant to settle into the negative portion of the punch. This
will help to lubricate the punch on th