Pressworking includes a wide variety of chipless processes by which workpieces are shaped from rolled metal sheets.A general term,stamping,is used almost interchangeably with pressworking .
Stampings are produced by the downward stroke of a ram in a machine called a press.The ram is equiped with special punches and moves toward and into a die block ,which is attached to a rigid bed.The punches and the die block assembly are generally referred to as a “die set”or, more simply,as the “die”.Pressworking operations are usually cold-worked at room temperature that does not exceed the annealing temperature or in some cases hot-worked at an elevated temperature that does not exceed the annealing temperature of the metal.
Parts produced by pressworking operations can be as small as a shoe eyelet or as large as the end of a freight car.Compared to other metalworking processes,pressworking techniques offer an almost unlimited choice of metals and design versatility and can be produced in extremely large quantities.Metal stampings are lightweight,strong,and have a superior strength-to-weight ratio.It is estimated that the average household contains products in which there are over 100000 pressworked items.
Skillful designers are often able to redesign parts previously made by forging or by casting,with significant saving in time, labor,and materials.Because it is pratical to produce parts to close limits of accuray,interchangeability is assured.
Pressworked parts are used for internal components on business machines, machine tools,household equipment,aircraft and small engines,and for locks,various other hardware items,and countless other functional applications.It is estimated that approximately half the weight of an automobile consists of pressworkd parts:formed parts are widely used as containers of various kinds,ranging from household pots and pans,to pails,buckets,and bins.sheet-metal forms are also widely used for heating,exhaust,and ventilating equipment,medical and food processing equipment,for buildings and structures,household appliances(stoves,refrigerators,freezers,washers,and dryers),bathroom and plumbing and electrical articals,highway vehicles,farm equipment,office furniture,and for many other applications too numerous to mention.