Shaped tube electrochemical drilling of good quality holes

This paper is concerned with the shaped tube electrochemical drilling (STED) of small diameter cooling holes in turbine blades. Following an initial identification of the common defects occurring in STED, a partial factorial design of experiments (DOE) was carried out to identify the more important process parameters that affect hole quality. For these process parameters, a full factorial design of experiments was conducted to study their effects not only on hole diameter but also on hole taper. Guidelines and equations for determining appropriate operating conditions to drill a good quality hole are presented for one drill diameter.