| By means of a wide variety of techniques, sheet | | | | the shearing of a metal blank from the sheet ), |
| metals can be given all sorts of complex hollow | | | | piercing ( the cutting of a hole in the metal article |
| shapes and sections. The equipment used for this | | | | with tools fitted in the machine ) and clipping ( the |
| type of work ranges from simple hand tools to | | | | removal of surplus metal). |
| elaborate power operated automatic machinery. | | | | A wide range of shaping operations coming under the |
| Sheet metal work usually starts with a basic | | | | heading of folding and bending are done on presses |
| preliminary operation such as cutting, slitting, | | | | and similar machines, as well as such operations as |
| perforating, etc., performed with tools that exercise | | | | stamping, crimping, beading, seaming and grooving |
| a shearing action. Many kinds of shearing devices are | | | | etc. These processes are used for the shaping or |
| available for these purposes. These may be simple | | | | stiffening of metal sheets, the forming of tubular |
| hand shears, which are scissor like cutting tools of | | | | sections of circular or other shape and numerous |
| various shapes and sizes, or hand operated bench | | | | other purposes. |
| shears for heavier gauge materials. | | | | Cylindrically shaped items such as tubes can be |
| There are several kinds of power driven shearing | | | | produced on a roll forming machine. Press forming |
| machines. In general, such machines comprise of a | | | | operations include cupping, which is the conversion of |
| fixed blade and a moveable blade. The term 'punching' | | | | a blank into cup form, and embossing, by which a |
| refers to operations performed with the aid of a | | | | particular design can be produced on a partly finished |
| punching machine or press, and comprising blanking ( | | | | component. |