Extrusion die for aluminium ladder, 1996.
© Science Museum / Science & Society Picture Library
The various parts of an aluminium ladder are made by extruding, or squeezing aluminium through holes in a die. Extrusion is useful for producing such complex shapes which would be difficult to make by other methods. The aluminium is heated to around 500 degrees Celsius, which makes it soft enough for it to be pushed through the die under a presure of over 1800 tonnes. Made by Tridex Die Ltd.