Forming, metal forming, is the
metalworking
Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scale ...
process of fashioning metal parts and objects through mechanical deformation; the workpiece is reshaped without adding or removing material, and its mass remains unchanged. Forming operates on the
materials science principle of
plastic deformation
In engineering, deformation refers to the change in size or shape of an object. ''Displacements'' are the ''absolute'' change in position of a point on the object. Deflection is the relative change in external displacements on an object. Strain ...
, where the physical shape of a material is permanently deformed.
Characteristics
Metal forming tends to have more uniform characteristics across its subprocesses than its contemporary processes,
cutting
Cutting is the separation or opening of a physical object, into two or more portions, through the application of an acutely directed force.
Implements commonly used for wikt:cut, cutting are the knife and saw, or in medicine and science the scal ...
and
joining.
On the industrial scale, forming is characterized by:
* Very high loads and
stresses required, between 50 and ()
* Large, heavy, and expensive machinery in order to accommodate such high stresses and loads
* Production runs with many parts, to maximize the economy of production and compensate for the expense of the machine tools
Forming processes
Forming processes tend to be categorised by differences in effective stresses. These categories and descriptions are highly simplified, since the stresses operating at a local level in any given process are very complex and may involve many varieties of stresses operating simultaneously, or it may involve stresses which change over the course of the operation.
Compressive forming involves those processes where the primary means of plastic deformation is uni- or multiaxial compressive loading.
*
Rolling
Rolling is a type of motion that combines rotation (commonly, of an axially symmetric object) and translation of that object with respect to a surface (either one or the other moves), such that, if ideal conditions exist, the two are in contact ...
, where the material is passed through a pair of rollers
*
Extrusion
Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex c ...
, where the material is pushed through an orifice
*
Die forming, where the material is
stamped by a
press around or onto a die
*
Forging
Forging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer (often a power hammer) or a die. Forging is often classified according to the temperature at which ...
, where the material is shaped by localized compressive forces
*Indenting, where a tool is pressed into the workpiece
Tensile forming
Tensile forming involves those processes where the primary means of plastic deformation is uni- or multiaxial tensile stress.
*Stretching, where a tensile load is applied along the longitudinal axis of the workpiece
*Expanding, where the circumference of a hollow body is increased by tangential loading
*Recessing, where depressions and holes are formed through tensile loading
Combined tensile and compressive forming
This category of forming processes involves those operations where the primary means of plastic deformation involves both tensile stresses and compressive loads.
*Pulling through a die
*
Tandem rolling mill
*
Deep drawing
Deep drawing is a sheet metal forming process in which a sheet metal blank is radially drawn into a forming die by the mechanical action of a punch. It is thus a shape transformation process with material retention. The process is considered "de ...
*
Spinning
Spin or spinning most often refers to:
* Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning
* Spin, the rotation of an object around a central axis
* Spin (propaganda), an intentionally ...
*
Flange
A flange is a protruded ridge, lip or rim (wheel), rim, either external or internal, that serves to increase shear strength, strength (as the flange of an iron beam (structure), beam such as an I-beam or a T-beam); for easy attachment/transfer of ...
forming
*Upset bulging
Bending
This category of forming processes involves those operations where the primary means of plastic deformation is a bending load.
Shearing
This category of forming processes involves those operations where the primary means of plastic deformation is a shearing load.
Notes
References
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See also
*The
Forming section of
List of manufacturing processes
*
Ferrous metallurgy
Ferrous metallurgy is the metallurgy of iron and its alloys. The earliest surviving prehistory, prehistoric iron artifacts, from the 4th millennium BC in Egypt, were made from meteorite, meteoritic Iron–nickel alloy, iron-nickel. It is not know ...
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Moulding
*
Pressing
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Metalworking
Metal forming