EDITED: SEPTEMBER 02, 2013We no longer recommend doing business with Dan Terry and Associates and Paramount Extrusions, due to their failure to deliver parts that meet print for three shipments in a row. We almost lost our business over this supply chain issue.
We have since moved our extrusion supplier to a far more competent supplier overseas. As it took us a lot of resources to find and qualify this new supplier, I am not willing to publish their name here. If you need aluminum extrusions, please send me an email off line.
Don't worry. They'll straighten it out. :-P
The extrusion press is running at about 510C (950F). Aluminum is heated and forced through the die plate under high pressure. The blocks are carbon blocks to withstand the hot aluminum coming out of the extrusion press.
The entire process is actually very similar to a pasta press - just a much larger scale. Here's a picture of the extrusion die. Because of the small geometry, the die runs two extrusions at the same time.
Once on the carbon block table, the extrusions are cooled a little bit (by massive cooling fans for a T5 temper, and water spray for a T6 temper part). Then giant hydraulic jaws are used to grip the extrusion and stretch the extrusions straight. Finally, the extrusions undergo the final heat treatment process, where the aluminum develops its full mechanical properties.
The resultant bars are then cut to length (1 meter, in our case) and anodized.