After each change of alloy, and also after every shift, a clean-out block should be used to remove the build-up of oxide skin from the liner of the container
Clean-out block is pushed through a heated container by the dummy block. It should remove all the aluminum left on the inner bore of the liner after repeated extrusion cycles.
A dummy block that is working properly will leave approximately .005” (.25 mm) of aluminum on the inside of the liner. The clean out block should remove this, having zero clearance with the liner in the heated condition.
Relatively safe to handle – hollow/light and room temperature
Because it is quite long, it can sit on the billet loader and also enter the liner bore without skewing
When properly sized, most of the alloy left in the container bore is removed