Abstract: Aerospace parts require high precision and a qualified rate of 100 %.Three-coordinate measurement is commonly adopted to improve the measurement precision and reduce the error caused by personnel measurement. High-precision and thin-wall shaft sleeve as a connecting part playing an axial positioning and radial fastening role in the work,plays an important role in mechanical transmission. In order to ensure the measurement precision and qualified rate of the parts,it is necessary to control the measurement process error within 1/3 of the part tolerance,including positioning error,clamping deformation error,etc. The experiment used SLA prototyping flexible fixture to clamp the shaft sleeve to reduce the deformation and damage caused by the metal clamp and eliminate the deformation error. Using the repeated measurement of the same shaft sleeve parts,the standard uncertainty caused by the positioning error combined with the process ability calculation was obtained to determine the feasibility of the measurement method.

Key words: flexible fixture, three-coordinate measurement, perpendicularity, uncertainty, probability, process capability