Utilisation of FIB/SEM Technology in the Assembly of an Innovative Micro-CMM Probe

Abstract

The measurement of features from the micro-and precision manufacturing industries requires low uncertainties and nano-scale resolution. These are best delivered through ultra precise co-ordinate measuring machines (CMMs). However, current CMMs are often restricted by the relatively large and insensitive probes used. This paper focuses on the assembly challenges of a novel micro-CMM probe. The probe is comprised of a 70 µm glass sphere, attached to a solid tungsten-carbide shaft of diameter less than 100 µm, joined to a piezoelectric flexure structure. The assembly requirements are for positional accuracy of ± 0.5 μm, angle between the shaft and flexure of 90° ± 0.29° and that the components be undamaged by the process. A combined Focused Ion Beam and Scanning Electron Microscope machine (FIB/SEM) with integrated nanoresolution manipulators was used. The investigation has evaluated potential assembly and joining solutions, identified modifications to existing equipment and product design and produced a set of prototypes.

Assembly of a novel MEMS-based 3D vibrating micro-scale co-ordinate measuring machine probe using desktop factory automation

“…The assembly of the flexure chip and the sphere-tipped stylus, to produce the vibrating micro-CMM probe presents a number of challenges [8]. These include, but are not limited to, the delicate nature of the flexures (nominally 20 µm thick), the difficulty in handling millimetre-sized parts, the change of forces dominant on the operation and the limited view of the operation.…”

“…These include, but are not limited to, the delicate nature of the flexures (nominally 20 µm thick), the difficulty in handling millimetre-sized parts, the change of forces dominant on the operation and the limited view of the operation. The ideal physical requirements of the assembly of the stylus onto the chip are a positional accuracy of ± 0.5 µm and that the angle between the two be 90º ± 0.29º [8].…”

Biomimetic whisker transducer for vibrissal tactile sensing

“…20 Assembly of a micro-sphere (70 µm ) onto the shaft using a FIB/SEM machine[127]. Effect of scaling on the fluid load According to Equation (6.2), both the fluid induced damping and mass are functions of the radius of the sphere.…”