photoetched

Photoetching, also known as photochemical machining, is a subtractive metalforming process that uses light to pattern a metal sheet. A photosensitive resist is applied to the workpiece and then exposed to ultraviolet light through a mask that defines the desired geometry. After development, the resist protects selected areas while the unprotected metal is exposed for etching. The metal is removed by a chemical etchant, leaving behind the formed profile. Depending on the resist, the exposed areas may be dissolved (positive resist) or the unexposed areas may be removed (negative resist). The resist is then stripped and the finished part cleaned and finished as required.

Typical process steps include cleaning the metal surface, applying and drying the photoresist, aligning the mask, exposing the resist, developing and hardening the image, etching in a chemical bath, rinsing, stripping the remaining resist, and finishing. Etchants vary with material; ferric chloride or cupric chloride are common for copper and brass, while ammonium persulfate or other oxidizing solutions may be used for other alloys. Etch depth is controlled by time, temperature, agitation, and solution composition.

Materials and capabilities: photoetching is used on copper, brass, phosphor bronze, nickel, stainless steel, aluminum, and other alloys, with typical thicknesses ranging from a few micrometers up to several tenths of a millimeter. It excels at producing precise outlines, complex internal features, and fine details with relatively low tooling costs, making it popular for printed circuit boards, microfilters, stencils, jewelry components, and rapid-prototyping of small to medium runs.

Safety and environmental considerations are important due to chemical handling and waste treatment.