Equipment

There are many different variations of extrusion equipment. They vary by four major characteristics:

1. Movement of the extrusion with relation to the ram. If the die is held stationary and the ram moves towards it then its called "direct extrusion". If the ram is held stationary and the die moves towards the ram its called "indirect extrusion".
   
   
2. The position of the press, either vertical or horizontal.
   
   
3. The type of drive, either hydraulic or mechanical.
   
   
4. The type of load applied, either conventional (variable) or hydrostatic.

A single or twin screw auger, powered by an electric motor, or a ram, driven by hydraulic pressure (often used for steel and titanium alloys), oil pressure (for aluminum), or in other specialized processes such as rollers inside a perforated drum for the production of many simultaneous streams of material.

There are several methods for forming internal cavities in extrusions. One way is to use a hollow billet and then use a fixed or floating mandrel. A fixed mandrel, also known as a German type, means it is integrated into the dummy block and stem. A floating mandrel, also known as a French type, floats in slots in the dummy block and aligns itself in the die when extruding. If a solid billet is used as the feed material then it must first be pierced by the mandrel before extruding through the die. A special press is used in order to control the mandrel independently from the ram.[1] The solid billet could also be used with a spider die, porthole die or bridge die. All of these types of dies incorporate the mandrel in the die and have "legs" that hold the mandrel in place. During extrusion the metal divides and flows around the legs, leaving weld lines in the final product.