Punching

Punching is often the cheapest method for creating holes in sheet materials in medium to high production volumes.

A die is located on the opposite side of the workpiece and supports the material around the perimeter of the hole and helps to localize the shearing forces for a cleaner edge.

The hole walls will show burnished area, rollover, and die break and must often be further processed.

Major components of this mechanical press are the frame, motor, ram, die posts, bolster, and bed.

These machines use hydraulic as well as pneumatic power to press the shape with enough force to shear the metal.

The punch force required to punch a piece of sheet metal can be estimated from the following equation:[4] Where t is the sheet metal thickness, L is the total length sheared (perimeter of the shape), and UTS is the ultimate tensile strength of the material.

A beveled punch helps in the shearing of thicker materials by reducing the force at the beginning of the stroke.

Other processes such as stamping, blanking, perforating, parting, drawing, notching, lancing and bending operations are all related to punching.

Other blow molding equipment, such as rotary wheel machinery, requires the use of downstream trimming.