ECM - Drilling
Winbro’s offers two ECM (electro chemical) drilling processes – STEM and Capillary.
STEM (Shaped Tube Electrolytic Machining) drilling is used in two main gas turbine applications: axial cooling holes in large IGT blades where the depth to diameter ratio makes it the only viable process, and IGT trailing edge holes where either metallurgical requirements or depths make EDM not viable. The process produces no recast layer or heat affected zone as with EDM or laser machining and can achieve much better surface finishes. STEM drilling produces holes by anodic dissolution using titanium tubular cathodes that have an insulating exterior coating. Very high depth-to-diameter ratio holes can be drilled and many holes (and components) can be drilled simultaneously without slowing of the drilling rate.