We just developed a new technique to centre and clamp turbine blades.
Turbine blades are mounted on their turbine wheel by means of a “fir tree” foot. This foot must precisely be machined and during this machining operation the blade has to be firmly positioned by tooling that holds on the spiralling surface of the turbine blade. Different systems are in use, like for instance the temporary molding of the blade in lead or zinc, in order to obtain a firm clamping without damage to the blade surface.
We used our present experience with the centring and clamping of objects of about any shape to develop a practical system consisting of mechanical clamping claws that adapt to the surface of the blade. It distributes the surface pressures to avoid any damage to the blade and it allows an accurate positioning of the blade while being operated by a simple on- off action.
Our method takes all the pain away:
– the mechanical claws distribute the clamping pressure over a large surface to avoid any damage
– it creates a very strong and stiff clamping
– it is activated by an instantaneous on-off clamping action