TABLE OF CONTENTS Sheet-metal parts are usually made by forming material in a cold condition, although many sheet-metal parts are formed in a hot condition because the material when heated has a lower resistance to deformation.
Strips or blanks are very often used as initial materials, and are formed on presses using appropriate tools. The shape of a part generally corresponds to the shape of the tool.
Sheet-metal forming processes are used for both serial and mass-production. Their characteristics are: high productivity, highly efficient use of material, easy servicing of machines, the ability to employ workers with relatively less basic skills, and other advantageous economic aspects. Parts made from sheet metal have many attractive qualities: good accuracy of dimension, adequate strength, light weight, and a broad range of possible dimensions, - from miniature parts in electronics to the large parts of airplane structures.
All sheet-metal forming processes can be divided into two groups: cutting processes - shearing, blanking, punching, notching, piercing, and so on; and plastic deformation processes - bending, stretch forming, deep drawing, and various other forming processes.
The first group of processes involves cutting material by subjecting it to shear stresses usually between punch and die or between the blades of a shear. The punch and die may be any shape, and the cutting contour may be open or closed.
Shearing; involves the cutting of flat material forms from sheet, plate or strip. The process may be classified...
