Photochemical Etching or Photochemical Milling / Machining is a high quality, fast turn-around, economical way of manufacturing precision fabricated metal parts such as screens, shields, grids, washers and gaskets, RFI/EMI Shielding, Spring Contacts, and other precision metal fabricated parts. Photochemical etching can be used for components in electronic, medical, aerospace, small appliance, semi-conductor and consumer product industries.
Photochemical etching starts when a negative image of thin metal parts (the parts are shown as transparent and areas to be removed from the metal are black) are printed on two sheets of photographic film. This film is referred to as the “phototool” and is laminated on both sides of a metal sheet which will ultimately be the part itself. When the phototool and the metal plate are exposed to ultraviolet light, the clear part of the photoresist allows light to contact the metal and harden it, while preventing light from accessing the metal that is blocked by the photoresist. After cleaning and removing unexposed photoresist, the metal is etched by presure spraying both sides with a heated solution of acid and ferric chloride that reacts with the unprotected metal and corrodes it rapidly. The etchant is then rinsed off and the parts are neutralized, cleaned and dried.
