Extrusion refers to the method of shaping material, such as aluminum, by forcing it to flow through a pre-designed opening in a die. Extruded materials emerge as an elongated piece with similar shape to the die opening.

You can understand the aluminum extrusion process by examining the Play-Doh(r), Fun Factory. Consider the Fun Factory as the extrusion press, the handle as the shape bar as the ram, the ram as the die, and the Play-Doh(r) as the aluminum billet. First, choose the desired shape or color. Consider the shape as a die and the color as the alloy needed and the temper. Next, the Play-Doh(r) is placed into the holding chamber , and pressure is applied to the handle which forces Play-Doh(r) into the shape. In an extrusion presses, pressure is applied to the billet by the ram, where the dummy block will be attached to the top of the stem. The billet is “extruded” when Play-Doh(r) appears. Extrusions from aluminum billets follow the same principles, but Tamilnadu Aluminium Company makes use of more sophisticated technology.

The size of the press determines the amount of an extrusion could be made. The longest dimension of an extrusion is its length across the cross-section, i.e. it’s circumscribed circle. A circumscribed circle is the smallest circle that covers the entire part of the cross-section that is extruded in shape.

The temperature is the primary aspect to be considered when extruding aluminum. The temperature is crucial as it imparts aluminum the desired attributes such as hardness and finish.

STEPS OF THE ALUMINUM EXTRUSION ALUMINUM EXTRUSION SYSTEM

1. Billets should be heated to approximately 800-925deg F.
2. Once a billet has reached the desired temperature when it reaches the desired temperature, it is sent to the loader, where an smut-like film or lubricant is poured on the billet as well as to the ram. The smut is a lubricant that acts as a splitting agent that prevents the pieces from sticking.
3. The billet then transferred to the cradle.
4. The ram is used to apply pressure to the dummy block. This, then, pushes the billet until it’s within the container.
5. The billet is compressed against the die under pressure, becoming smaller and longer until it is able to touch the walls of the container. As the aluminum is moved through the die, liquid nitrogen flows through certain areas of the die in order to cool it. This helps to reduce the life span of the die and keeps the extruded shape from forming oxides. Sometimes, nitrogen gas can be used instead of liquid nitrogen. While nitrogen gas does not chill the die, it does provide an inert atmosphere.
6. Due to the pressure that is applied to the billet the solid, but soft metal begins to squeeze the die’s opening.
7. After an extrusion has left the press, its temperature is measured using a True Temperature Technology (3T) device mounted on the platen for the press. The 3T monitors the temperature of exit of the aluminum extrusion. The main purpose of knowing the temperature is to maintain maximum press speeds. The alloy is what determines the extrusion’s exit temperature. For example, the target exit temperature for the alloys 6063 6463 6063, 6063A, and 6101 is 930deg F (minimum). The desired temperatures for the alloys 6005A, 6005A and 6061 is 6005A and 6061 is 950deg F (minimum).
8. Extrusions are pulled out of the die into the leadout table and the puller that guides metal down the run-out table during the extrusion. The extrusions are cooled with the series of fans that span along the length of the table and run-out. (Note: Alloy 6061 is water quenched and air quenched.)
9. You aren’t able to use all of the billet. The butt (remainder) is composed of oxides extracted from the billet skin. As the butt is being removed an additional billet is loaded. The the welded billet will then be used to extrude.
10. When the extrusion is at the length desired the extrusion can be cut with a profile saw or shear.
11. Metal is moved (via belt or walking beams systems) from the run-out table to the cooling table.
12. After aluminum has cooled, it can be moved on the cooling tables and stretched. Stretching straightens extrusions and is a process of ‘work hardening’ (molecular re-alignment which gives aluminum more hardness and increased strength). Aluminium extrusion manufacturers in india
13. The next step is sawing. After extrusions have been stretched, they can be transferred to a sawtable , and then cut to lengths of your choice. The cutting tolerance on saws is 1/8 inch or more according to the length of the saw.

After the pieces have been cut to size, they can then be loaded onto a transport device and transferred to age ovens. The process of heat-treating or artificial aging ages the material by speeding up the maturing process in a controlled temperature environment for an amount of time.