Aluminum Extrusion Process Explain

Extrusion refers to the process of making material shape, like aluminum, by pushing it through a shaped opening in a die. Extruded material emerges as an elongated material with identical profile to that of the opening of the die.

You can get a better understanding of the extrusion process by examining the Play-Doh(r), Fun Factory. Think of the Fun Factory as the extrusion press with the handle acting as the mold bar, the ram as the die, and the Play-Doh(r) as the aluminum billet. The first step is choosing the desired shape and color. The shape is the die, and the color the temper or alloy. The Play-Doh(r) is introduced into the holding chamber and it is pressed against the handle which forces Play-Doh(r) through the form. In an extrusion presses, pressure is applied to the billet via the ram at the point where the dummy block is attached to the end of the ram stem. When Play-Doh(r) appears to be forming, it has effectively been “extruded”. The same principles apply to extrusions from aluminum billets, but much more sophisticated and precise technologies are involved that used by tamilnadu aluminium company.

Press size determines how large of an extrusion can be produced. Extrusion size is measured by its longest cross-sectional dimension, i.e. the circumscribed circle. A circumscribed circle is the smallest which completely covers the cross section of an extruded form.

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

STEPS OF THE ALUMINUM EXTRUSION PROCESS

1. The temperature of the billets is around 800-925 deg F.
2. When a billet reaches the temperature desired, it’s transferred to the loader. Then, a fine layer of smut (lubricant) is applied to the billet and the ram. The smut is a parting agent (lubricant) that keeps both parts from sticking together.
3. The billet is moved to the cradle.
4. The ram is used to apply pressure to the block that is dummy, which in turn forces the billet into the container.
5. The billet under pressure is broken against the die and then becomes smaller and larger until it has full contact with the walls of the container. In order to chill the aluminum, liquid nitrogen is circulated through the die as it moves through. This improves the lifespan of the die and creates an inert atmosphere which keeps oxides from developing on the design being extruded. In some cases, nitrogen gas may be used in place of liquid nitrogen. Although nitrogen gas doesn’t chill the die, it can create an inert atmosphere.
6. The billet gets compressed by the additional pressure and the soft, solid metal begins to squeeze out the opening of the die.
7. The temperature of the extrusion as it exits the press can be recorded using True Temperature Technology (3T), which is mounted on the platen. The 3T monitors the temperature at which an aluminum extrusion exits. The main purpose of knowing the temperature is to maintain the highest speed of press. The alloy determines the extrusion’s final temperature. The recommended exit temperature for 6063A, 6463A, 6063A and 6101 is 930deg F (minimum). 6061 and 6005A are respectively the temperatures of 950 and 950 degrees F.
8. Extrusions are then pushed from the die, and are then transferred to the table for leadout and then the puller that guides metal down the run-out table during extrusion. When pulled, the extrusions are cooled with the use of a series of fans across all the length of the run-out and cooling table. (Note: Alloy 6061 is water quenched, as well as air quenched.)
9. It isn’t possible to use the entire billet. The remainder (butt) includes oxides formed from the billet skin. While the butt is being removed the other billet is loaded. The welded billet will be used to extrude.
10. Once the extrusion has reached a desired length, the extrusion will be cut with a profile saw or a shear.
11. Metal is transferred (via belt or walking beams systems) from the run-out table to the cooling table.
12. After aluminum has cooled, it can be moved along the cooling tables and stretched. Stretching straightens the extrusions , and does ‘work hardening’ (molecular aligning, giving aluminum greater hardness and enhanced strength). Make sure to check Aluminium extrusion manufacturers in india.
13. The next step is sawing. After extrusions are stretched, they are moved to a saw table and cut to certain lengths. The cutting tolerance on saws is 1/8 inch or greater, depending on saw length.

Once the pieces have been cut to size, they can then be transported on a device and taken to age ovens. Artificial aging or heat treatment hardens the material by speeding up the maturing process in a controlled temperature environment for the specified amount of time.