The impact of rigid body workpiece displacement on the geometric errors of milled surfaces

Spherical–tipped locators and clamps are often used to restrain workpieces during machining. For structurally rigid workpieces, contact region deformation, slip and lift–off are the predominant modes of workpiece displacement. Experimental evidence obtained thus far indicates that this displacement is a significant source of geometric error. This paper describes a model that predicts the impact of clamp actuation and the end milling process on rigid body workpiece displacement and the geometric errors that result. This paper also describes an experimental study that was used to validate this model, and determine the impact of clamping induced workpiece displacement on the geometric errors of milled surfaces.