Program a machine that applies acid to precision-etch metal and plastic.
Fits and secures multifocal lens parts together preparatory to fusing, utilizing adhesive compound or asbestos tape: Dips multifocal button in cleaning solution and wipes dry. Brushes button and countersink blank to remove dust and lint. Positions button on polished surface of countersink blank. Performs test to detect presence of foreign matter between button and countersink blank, using instrument that indicates foreign matter when pressure is applied to outside edge of button. Recleans surfaces and performs test until instrument indicates lens parts are free of foreign matter. Places spring clamp on blank to hold button in position. Inserts metal peg between button and blank to allow air to escape during fusing, using tweezers. Applies cement to surface contact points around edge of button, using needle applicator, or wraps asbestos tape around button and countersink blank assembly to hold button in place. Removes spring clip and metal peg after cement is set. Places assembled unit in tray for transfer to fusing room.