Question

(a) If you want to extrude a Y-shaped profile, what is the maximum allowable branch length you can obtain if you use a 4” billet? The Y-shaped profile has a design that contains three equal length of branches, 30° angle between the top two branches, and a wall thickness of 4 mm throughout.

(b) If the Y-shaped profile is extruded from “easy” aluminum alloys with an exiting speed of 60 m/min, how long does it take to finish one extrusion process using a 6 feet long billet? (Hint: Make assumptions on when extrusion starts and stops.)

Answer 1

a)If we are considering the volume of material before and after extrusion is same.

Volume of billet is given as area of billet × length

π/4(0.102²)×1.83=0.0149m³

Extrusion ratio of aluminium 'R' is~ 400:1

The area of extrusion = Area of billet /R

= 8.17×10^-3m² / 400

=2.04×10^-5m²

Volume of extrusion = volume of billet

Area of extrusion × length= 0.0149m³

Length of extrusion = 0.0149/area of extrusion

=0.0149/(2.04×10^-5)=730.4m

But around 10% to 15% is lost as butt thickness

Taking 10%of extrusion length

Therefore actual length =730.4-73.04= 657.4m

b) the exiting velocity is 60m/min

time taken for extrusion of 6feet (1.83m)long billet in minutes

=657.4m/ 60= 10.95 minutes.