The reason of bubble flaw in aluminium extrusion

Aluminium is a environmental-friendly raw material in packing industry. More and more package in food, drinks, pharmaceuticals, personal care industries choose aluminium to be raw material because it's good appearance, perfect protection to its contents and recyclable characters. Impact extruded aluminium aerosol can and aluminium collapsible tube are typic application of these area. Cold impact extrusion aluminium cartridge or can is a kind of one piece can extruded from aluminium slugs, used for food packaging, pressed air package.

During the production of aluminum aerosol can or aluminium tube, 

sometimes the surface of workpiece after extrusion or painting bears bubbles,

which creates uneven or visible slim profile on the surface of can and lead to

quality rejection and economic loose. The left illusion shows aluminium cans 

with extrusion bubble flaw.

Main Causes

1. The melting furnace temperature is too high and integrate more H2 than normal temperature.

2. The purity of N2 is not as pure as required level.

3. Wet weather contains more moisture and moisture immerged into aluminium liquid also caused the flaw.