The present invention relates to a method for removing powder from a component or part produced by a powder bed additive manufacturing system. The method comprises the steps; providing a part, the part having at least one internal cavity with at least one external opening, the at least one cavity being at least partly filled with powder grains, the powder grains being connected to each other and to the walls of the cavity by mechanical, frictional, electrical, physical or chemical forces; adding medium in liquid phase to the at least one cavity of the part, the liquid having the property that it expands in phase transition from liquid to solid phase; transforming added medium to solid phase to loosen and break up at least a fraction of the powder grains connections from each other; and removing powder from the at least one internal cavity.