Accurate Measurement of High-Bandwidth Nanomilling Forces

This paper presents a novel technique for accurate measurement of high-bandwidth nanomilling forces. Nanomilling has recently emerged as a viable mechanical nanomanufacturing technique for creation of three-dimensional nano-scale features on engineering materials. Accurate measurement of nanomilling forces is paramount to advancing the fundamental understanding of nanomilling and to enhancing the process outcomes. However, to date, no effective approach has been described for obtaining accurate measurement of nanomilling forces that exhibit micro/nano Newton range amplitudes and a broad frequency bandwidth. In this paper, we introduce a new in situ microcantilever-based technique for accurate measurement of nanomilling forces within a 10 kHz bandwidth without compromising its high-stiffness configuration. To this end, a microcantilever is designed and fabricated as a sensing element. The sensor possesses the processing and sensing locations close to its fixed and free ends, respectively to enable high stiffness at the processing location and high sensitivity at the sensing location. The sensor is then integrated into our custom-made nanomilling system as a force measurement device (FMD), and its dynamic calibration is achieved through an AFM-probe based dynamic testing approach. The calibration approach relates the measured displacements at the sensing location to the applied forces at the processing location. Subsequently, the accurate in situ nanomilling force measurements are obtained within a broad frequency range using the calibrated force sensor. It is concluded that the presented technique provides an effective means of accurate measurement of nanomilling forces within 0-10 kHz frequency range towards realizing essential advances in nanomilling.