Research On The Key Technology Of Precision Flatness Measurement For Miniature Parts

Such as hydrostatic guideway in floating components,semiconductor wafer,these parts are all characterized with high flatness precision and small plane size.When the size of the part is small and the flatness is better than 0.5 microns,it is difficult to quantitatively detect the conventional optical flat.Precision measuring devices as nano three coordinate measuring machine and profilometer can meet the measuring requirements of the flatness for the micro parts.However,because of high price,they demand high requirements for the environment and are difficult to be applied to engineering.Therefore,it is necessary to explore a convenient method for measuring the flatness of micro parts with reasonable cost.Based on the good guiding characteristics of flexible guiding mechanism,a system plan for measuring the flatness of micro parts is put forward in this paper.The two dimensional coplanar double composite flexible guide mechanism is used as the scanning motion platform of the system,and one dimension parallel quadrilateral flexible guide is combined with the LVDT sensor as the measuring head,and the precision measurement system is formed.Based on the energy conservation principle,the static characteristics of the double composite flexible guide mechanism are analyzed.The influence of the asymmetry of the flexible guide rail structure and the load asymmetry on the guidance precision is numerically calculated by the finite element method,and the robustness of the guidance precision of the double composite flexible guide rail is verified.The design,processing and testing of the micro plane measuring system are completed,and the uncertainty of measurement is analyzed.The standard flat crystal is used as the plane reference for the preliminary test.In the range of20 mm x 20 mm,the flatness of the experimental data is evaluated by the least square method,andthe flatness error is 0.36 microns.