Aluminiumwerk Unna AG is specialised in the production of Aluminium tubes. The Aluminium tubes are extruded on site using two possible methods. These are either Seamless extrusion or Porthole extrusion.
It is quite simple to distinguish between the two extrusion methods. In seamless extrusion, a mandrel is positioned and fixed inside the extrusion die, creating the inner contour of the tube. In porthole extrusion, the mandrel is fixed and is supported by a number of integral bridges affixed to the outer portion of the extrusion die.
Which production method is appropriate is dependent on alloy and application. High-strength alloys, for example, can only be produced by seamless extrusion.