Abstract: In one embodiment of a method for etching a bar code on a metal surface, a carrier web having elongated openings is prepared. These openings correspond in size and position to the dark bars of the bar code. The carrier web is adhesively attached to the metal surface so that fluid cannot seep between the web and the surface. The metal surface is then electrochemically etched through the openings in the web. In another embodiment, a conveyor belt moves supports for metal objects past a printer assembly which includes melted-resin printheads. These melted-resin printheads are similar to ink drop printers except molten droplets of resin are expelled rather than droplets of ink. The resin droplets harden upon contact with the metal to provide a resist pattern. A rectangular opening in a mask is positioned over the resist pattern, and etching is conducted through the opening and resist pattern. The etching employed is preferably electro-chemical etching.

Abstract: To etch a bar code on a metal surface, a sheet of transfer material having an adhesive layer of negative-acting photosensitive substance is exposed through a positive of the desired bar code. After development, the adhesive layer provides an etching mask having apertures which correspond in position and shape to the bars of the positive. The mask is sealingly affixed to the metal surface. The metal is then electrochemically etched through the apertures in the mask to provide tough, black bars which remain after the mask is removed. Since the mask adheres to the metal surface, etchant seepage at the edges of the apertures does not occur, which improves the readability of the bar code etched onto the surface.