Photoelectropolishing Of Stainless Steel

December 2003

Dr.-Ing. M. Buhlert, University of Bremen, Dr. K. Meier, HTP HiTech Photopolymere AG, and Prof. Dr. P.J. Plath, MIR-Chem GmbH

Herein we present a study on the photoelectropolishing of stainless steel sheets. The advantage of this manufacturing process is that a smooth surface finish is achieved where removal takes place. The areas being protected against removal by photoresist are not removed. Therefore. structuring takes place. This makes the process one of the electrostructuring processes. Electrochemical removal processes are characterized by the combination of electropolishing and structuring by the use of any resist that prevents metal from electrochemical removal. Different from photoetching, spray etching and PCM (photochemical machining), the removal takes place without build-up of local cells.[III The electrochemical removal process occurs when a current now is applied to the system by use of an outer power supply. The metal components of the alloy are oxidized al the unprotected areas of the anodic workpiece.

In contrast to PCM, it is quite easy to achieve shiny and smooth surfaces between the embossed structures.  By using differ­ent photomasks, different structures can be produced in a flexible and easy way. Using lithographical techniques, the etching stencil is made with the help of the photomask. After exposure, development and rinsing, the work­piece, now partly coated with the etching sten­cil, is placed in a special electrolytic solution. Switching on the current starts the anodic re­moval process. The metal is dissolved at the uncovered areas of the sheet surface.