Direct Extrusion || Indirect Extrusion

Direct Extrusion

• Direct extrusion is a manufacturing process used to create various products with a continuous cross-sectional profile.
• It is a type of extrusion process where a billet (a cylindrical or rectangular metal workpiece) is forced through a die to form a specific shape and size.
• The term “direct” refers to the fact that the billet is pushed directly through the die without any intermediate steps or additional manipulation. 

The process of direct extrusion typically involves the following steps:

Billet preparation:

• The raw material, usually a metal or metal alloy in the form of a cylindrical or rectangular billet, is heated to a specific temperature to improve its plasticity and reduce deformation resistance.

Container and die assembly:

• The billet is placed into a container that holds it in place during the extrusion process. The container is often referred to as a “container” or “chamber.” At the end of the container is a die with a specially designed opening through which the material will be extruded to form the desired shape.

Extrusion process:

The billet is pushed through the die using a ram or a screw mechanism. As it passes through the die, it takes on the shape of the opening in the die. The pressure exerted by the ram forces the material to flow through the die, giving it the required cross-sectional shape.

Cooling and cutting:

• Once the material has passed through the die and formed the desired shape, it is cooled using water or air to maintain its structural integrity. After cooling, the extruded product is cut to the desired length.
• Direct extrusion is commonly used to produce a wide range of products, including rods, bars, tubing, and other linear profiles. It is a cost-effective and efficient method for manufacturing products with a consistent cross-sectional shape and excellent mechanical properties. The process can be performed with various metals and alloys, such as aluminum, copper, steel, and brass.

Direct Extrusion and Indirect Extrusion

Indirect extrusion

• Indirect extrusion, also known as backward extrusion or reverse extrusion, is a manufacturing process that is the opposite of direct extrusion. In indirect extrusion, the billet is held stationary while the die moves towards it, forcing the material to flow in the opposite direction. 

The process of indirect extrusion typically involves the following steps:

Billet preparation:

• Similar to direct extrusion, a billet of metal or metal alloy is prepared by heating it to a suitable temperature for plastic deformation.
  

Container and die assembly: 

• The billet is placed into a container, often referred to as a “container” or “chamber.” The container has a specially designed die attached to it. The die consists of an opening through which the material will be extruded, but unlike direct extrusion, it moves towards the stationary billet.