Effect of fixture design variables on fixture-workpiece conformability and static stability

A parametric study of the effect of fixture design variables on fixture-workpiece conformability and static stability is presented. Conformability is defined as the geometric similarity between the workpiece surface and the smallest polyhedron fit over all contacts. Two conformability metrics are introduced to account for global and local conformability. The design variables of interest are: the number and position of fixture elements, fixture element length, clamping intensity, fixture element orientation, static coefficient of friction, fixture element tip radius and the direction of the fixture principal stiffnesses. Both force-controlled and displacement-controlled fixtures are considered The static stability was found to increase with the static coefficient of friction and with the fixture element tip radius. Clamping intensity and the principal stiffness directions were found to have opposing effects on the stability of force-controlled and displacement-controlled fixtures.