Improved design of the ILC blade-tuner for large scale production

The ILC superconducting linacs ask for the use of a compact and cost effective tuner design with no interference with the cavity end group area. The integration of the piezo-assisted fast tuning option made the Blade-Tuner, successfully tested at DESY on the superstructures, the most viable candidate to be included into the ILC BCD. In the perspective of large scale production and on the basis of the experience acquired so far, two alternative prototypes have been recently designed and built. They mainly differ for the materials adopted (titanium or stainless steel) and have been optimized to minimize material and construction cost, while fulfilling the reviewed performances required for the high gradient cavity operation up to 35 MV/m or even higher. In this paper we discuss the rationales that brought us to the current solutions, together with a critical comparison of the two systems behavior and cost.