Abstract: A vacuum-metallizing machine including a metal platter base (17) having an obverse side and a face side. A substrate-receiving platter (2) is resiliently disposed (3, 3b) in a recess on the face side of the platter base (17). The platter (2) receives a substrate to be metallized. A circumferentially-arranged rigid ring (27) of predetermined dimensions and location is disposed on the face side and mates with a ring (29) around a port (11) on the wall of the vacuum chamber which surrounds an opening in the wall. Engagement of these rings aligns the platter base (17) relative to the port (11, 12, 13 and 14). A compliant ring (42) is disposed between the wall and the platter base (17).

Abstract: An electrolytic reduction cell for the production of aluminium has current collector bars running across the floor of the cell unitarily or in separate sections. Deformation of the molten metal/electrolytic bath interface is reduced by leading current out of the collector bars or bar sections at positions remote from their ends by connector bars connected to said positions.