Precision Compensators Using Giant Superelasticity Effect

Elastic compensators for overconstrained precision devices can be separate components or integrated, e.g. as in HSK toolholders. The latter require precision complex surfaces and are expensive, the former require small springs allowing large deformations. The paper describes a recently discovered Giant Superelasticity Effect (GSE), wherein wires or tubes made from a NiTi superelastic material demonstrate 15-20% recoverable deformation when compressed radially. They are mildly nonlinear and exhibit significant damping. An effective method of attaching elastic tubes is developed. Application of GSE to toolholder-spindle interfaces, with significant reduction of runout, increased stiffness and damping is described.