3D-printed vision-based micro-force sensor dedicated to in situ SEM measurements

Working at micro-scale efficiently requires accurate and integrated force feedback implemented with a sensor adapted to the scale. This paper presents a 3D-printed vision-based micro-force sensor intended to be used inside the chamber of a Scanning Electron Microscope (SEM). The combination of 3D printed elastic structures with a highly effective vision based measurement method allows to design integrated sensors at the cutting edge of the state of the art. Moreover the presented design respects the Abbe's alignment principle. The paper presents the general design, manufacturing and experimental characterization in SEM environment of the proposed sensor. Images of periodical patterns are used to measure the differential displacement between the two parts of the compliant structure. By the knowledge of its stiffness, the force applied on it is measured. The stiffness of the elastic structure has been measured to be 15.3 N.m
^-1
, leading to a force range of 25 μN.