Process variables in Direct Extrusion The die angle Reduction in cross-section Speed of Extrusion Billet temperature Lubrication.

Direct extrusion is also known as forward extrusion. Direct extrusion is one of the most critical as well as common method for making extruded profiles. Here the position of the die is stationary, while the metal gets pushed through the orifice. Here the billet is placed properly in the container and pushed along the die by using ram pressure. Direct extrusion has very popular applications. They are typically used in the manufacture of solid rods, bars, hollow tubes, solid sections etc. In direct extrusion, the direction of metal flow is in the identical direction as that of ram travel. In this process, the billet is slided relative to the walls of the container. The ensuing frictional force increases the ram pressure substantially. Conventionally, the process of direct extrusion has been described as having three distinct phases or regions:

• Billet is upset, and the pressure rises quickly to its peak value
• The pressure decreases, and the 'steady state” extrusion commences
• As the pressure attains its minimum value it is followed by a acute rise as the “discard” gets compacted.

However one of the main disadvantages of this process is the creation of frictional forces between the walls of the container and the metal. A typical Direct Extrusion process is shown below: This efficient process of direct extrusion saves a substantial amount of raw material and simultaneously provides improved product properties as compared to the traditional machining processes.

Advantages of Direct Extrusion
A Direct extrusion gives the following advantages:

• Complex Integral Shapes
• Cost-Effective
• Design Flexibility
• Simple fastening and assembly
• Easy fabrication
• Low Tooling Costs
• Good Machinability
• Precision Tolerances
• Shorter Lead Times
• Versatility in Joining
• Virtually Seamless