Fundamentals of metal working

objectives

Classifying Forming Processes

Forming processes involve the INTERACTION of a WORKPIECE (the starting material) with some form of TOOLING to produce a change in shape: based on the ability of some materials to FLOW PLASTICALLY in the solid state

- Little or no waste

- Large machines, expensive tooling

- Large production quantities are normally necessary to justify forming as a production route

A FIRST CLASSIFICATION is based on the GEOMETRY of the WORKPIECE: 3D or 2D or:

BULK DEFORMATION PROCESSES: the workpiece is subjected to triaxial stresses which are usually compressive in nature, hindering failure processes and improving formability. Examples: forging (card F1), rolling (F3) and extrusion (F4)

SHEET DEFORMATION PROCESSES: the workpiece surface area to thickness ratio is relatively high. Both the workpiece and the imposed stresses can be considered 2D. Examples: sheet metal forming (F2), vacuum forming (F6) and blow molding (F7).

Sheet material is usually produced first by continuous bulk processes such as rolling followed by “blanking“ and only then the material is pressed into closed dies.