The tumbling of die-cast aluminium products is a finishing process often required following the moulding or casting of pieces. The purpose of tumbling of die-cast aluminium products is to remove what is commonly referred to as "burr", in other words, the residues of a metallic substrate.
The term tumbling comes from the name "tumble", barrel, which is actually the place for this surface finishing: the pieces, usually in a large number and small size, are rolled and bumped together by the rotation-vibration of the barrel, often with other abrasive materials (usually stones) to accelerate the results. In some cases, it is possible to add water, lubricants, detergents or special chemical solutions to the inside of the barrel to achieve burnishing, a special cleaning or special chemical treatment of the parts.