For softer, easier to form metals such as aluminium and copper alloys continuous extrusion may also be performed using processes such as conform or continuous rotary extrusion. These processes use a rotating wheel with a groove around its circumference to drive the loose powder through a forming die. Through a combination of high pressure and a complex strain path the powder particles deform, generate a large amount of frictional heat and bond together to form a bulk solid. Theoretically fully continuous operation is possible as long as the powder can be fed into the process.