Punching is a separation process in which a sheet is perforated by a single stroke of the machine. Individual hits can produce shapes such as circular holes or outer contours.
Shearing punches does not overlap, resulting in a faster process but sometime unwanted small edge protrusion.
Sloting punches does overlap, resulting in a slower process, but essential, when smooth edges are desired
Nibling is a process when curved contours or bigger holes are desired, therefore changing the punch head with either a circular one or a crescent one to perform the process.
The additional of forming capabilities greatly increases the versatility of punch presses. No longer just machines for making holes in sheet metal. punch presses have been used for years to produce common formed features such as extrusions, beads, and louvers. The tools are designed so that the workpiece is formed between the punch and die.
Extrusion is a forming process that forms material outward that is sometimes used to increase surface grip or used as a process before tapping, to increase the tap length.
Pre - Tapping
Punch presses can be equiped with tapping tool to produce threads, reducing post process work. Threads are made by first punching a hole and then forming the threads on the inside of the hole.
Circular, flat elevation on the sheet. A hole is punched only partially through the sheet, causing the slug to protrude from the other side.
Assembly / Fastening aid
End stop for inserted elements
Oblong opening in the sheet resembling a gill. The punch cuts and forms the louser in one stroke.
Ventilation slots in housings
A strip projects from the sheet surface in a bridge-like fashion. The bridge is cut and formed in one stroke.