Characterisation of aqueous ferric chloride etchants used in industrial photochemical machining

June 2005 Dr. David M. Allen and Dr. Heather J.A. Almond, School of Industrial and Manufacturing Science, Cranfield University, Bedford, UK Characterisation of Aqueous Ferric Chloride Etchants Used in Industrial Photochemical Machining Ferric cbloride (FeCI3) is the most commonly used etchant for photochemical machining (PCM) but there is a great variety in the grades of the commercial product. This paper aims at defining standards for industrial etcbants (that are not chemically pure) and methods by which they are analysed and monitored.