Extrusion is the process of confining the metal in the
closed cavity and then allowing it to flow from only one
opening so that the metal takes the shape of the opening.
Extrusion is a process used to create objects of a fixed,
A material is pushed or drawn through a die of the desired
The long straight metal parts of solid ,round ,T-shaped ,
L-shaped cross- sectional products can be manufactured.
The extrusion process is often likened to the
squeezing of tooth paste from a tube, as is
The top of the tube represents the die and determines
the shape of the extrusion, while the paste may be
considered to be the billet.
In general, extrusion process is used to
produce long part of same cross-section.
The billet is the starting stock for the extrusion
operation.Extrusion billets may be a solid or hollow
form, commonly cylindrical, and is the length charged
into the extrusion press container.
Extrusion operations typically take place with billet
heated. However during the extrusion, the billet is still
Dies are the cutting tools used in the extrusion
Also called as forward extrusion process.
The flow of metal in the forward direction that is same as
that of direction of ram/plunger.
Hot metal billet is loaded in cylinder.
The plunger compresses metal billet against the
die and forces it to flow through die opening and
produces extruded product Extruded product
acquires the shape of opening.
In this process, the problem of friction is more because of
relative motion between the heated metal billet and the
Also called as indirect extrusion process.
In order to completely overcome the friction, the
backward extrusion process I used.
The hot metal billet is confined fully by the
The ram which have die, compresses the metal
against the container, forcing it to flow backward
through the die opening in the hollow plunger or ram.
It is termed as backward because of the opposite direction
of the flow of metal to that of ram movement.
The billet in the container remains stationary and hence no
Indirect extrusion does not requires as much force as
Impact extrusion is a manufacturing process
similar to extrusion and drawing by which
products are made with a metal blank. The blank
is pressed at a high velocity with extreme force
into a die/mold by a punch.
In the hydrostatic extrusion process the billet is
completely surrounded by a pressurized liquid, except
where the billet contacts the die.
Containing the fluid under high pressures can be difficult.
Limited use due to complex tooling, high pressures, special
equipment, and long cycle times.
No friction between the container and the billet reduces force
requirements. This ultimately allows for faster speeds, higher
reduction ratios, and lower billet temperatures.
Usually the ductility of the material increases when high
pressures are applied.
Large billets and large cross-sections can be extruded.
Extrusion often minimizes the need for secondary
machining,and as a result could result in financial
savings. However extruded objects are not of the same
dimensional accuracy or surface finish as machined