Shearing is the process of mechanically cutting sheet metal with the application of shear force. When the cutting blades are straight, the process is called shearing. When the cutting blades are curved, the process can be known by different names such as punching, blanking, notching, and trimming. Flange bending or flanging is a forming operation in which a narrow strip at the edge of a sheet is bent down along a straight or curved line. Bends are made in sheet metal to gain rigidity and produce a part of desired shape to perform a particular function. Presses are classified by one or a combination of characteristics that include the source of power and the number of slides. The most common sources of power for press operation are manual, mechanical, and hydraulic. Press tooling consists of several components such as the punch holder, punch, stripper, die, die shoe, bolster, guide pins, and blank.