Extrusion is a typical manufacturing
process where a billet of material is gradually pushed and/or drawn via a
die for creating a shaped rod, pipe or rail. The process generally creates
a long length of the final product and may be of the types continuous or
semi-continuous. While some materials may be hot drawn others may be cold
drawn.
Different cross-sections can be produced from the extrusion process. The
shapes of the Extruded Profiles can vary from regular shapes like
rectangular, solid round, to Tubes, L and T shapes. A typical extrusion
process works like this. A material, mostly a billet is either pushed and/or
drawn through a die. This die turns the billet into desired profile shape. A
hydraulic or mechanical process can be used for such a process. The
following image shows a typical extrusion process irrespective of material.
To extrude a Hollow section, a pin or piercing mandrel is placed inside a
die, some times positive pressure is applied through the pins to the
internal cavities. A typical Extrusion process for metal is shown below:
As
is seen a block of metal known as billet is transformed to a cross section
by forcing it under high pressure to flow through a die orifice.
Types of Extrusion Process
Extrusion processes for our discussion here has been broadly divided into
three categories. Irrespective of the material a perfect extrusion process
would be the harmony of the material and the extrusion process resulting in
enhanced performance of the extruded profiles and cut in costs. The
following image very well describes what should be an ideal combination in
case of Polymer extrusion.
