Deep drawing is basically a sheet metal forming process in which a sheet metal blank is progressively formed into a three-dimensional shape by the mechanical action of a punch. The process work hardens the metal and the result is a seamless finished part which is much stronger than the base material. Deep Drawing is a manufacturing process that is extensively used in the forming of pots and pans for cooking, gas tanks, panels, just to name a few. It is important to pay attention to the fact that this sheet metal forming process is not similar to the bulk deformation process of drawing. On the contrary, the process implies shape transformation with material retention and the whole reason why the process is considered deep is that the depth of the drawn parts exceeds its diameter.
The Deep Draw process is made up of many components and steps. The fact is that many different metals can be used for sheet metal forming, including stainless steel, brass, copper, aluminum, HSLA and others. Companies with experience like National Manufacturing Company, Inc. begin the process begins with performing a punch and die. The punch represents the preferred shape of the base of the part, one drawn. On the other hand, the die cavity is in tune with the punch and it is deeper so as to allow for its passage. As for the setting, it resembles the sheet metal cutting operations. Clearance is the lateral distance between the die edge and the punch edge. The blank is placed over the die opening, after which the blankholder begins to apply pressure to the surface of the blank. After the punch contacts the work, the sheet of metal is forced into the die cavity and consequently forms its shape.
Commercial applications involve even more complex geometries with straight sides and radii. Here stamping is used to make the difference between the deep drawing and stretch-and-bend components. This type of sheet metal forming process is accompanied by other forming techniques within the press. To be more precise, it can include blanking, drawing, piercing and trimming. Blanking refers to the process of cutting the initial sheet into shaped flats for deep drawing. The process is generally the first station in the press and it implies a much simpler punch and die in order to cut out the initial metal blank. Drawing is the process of forming sheet metal with the help of a punch and die, which is at the heart of the deep drawing process. It is frequently realized with smaller series of dies that minimize the shape and increase the depth of the die. Piercing literally means piercing holes in the metal stock which are required for the end product. Last but not least, trimming is necessary to cut the excess metal.
More often than not, components are partially deep drawn with the purpose of creating a series of diameters throughout the components. Therefore, it is worth considering cost – saving alternatives to turned parts which demand raw material.