On the Acceleration Limits for Sliding and Detachment Between Contacting Rough Surfaces for Micropart Manipulation in a Dry Environment

Abstract

Micropart manipulation is an active research area encompassing a wide array of fields and applications. As the size of the parts to be manipulated by an automated system decreases, the dominant forces are different compared to macroscale ones. Thus, for accurately modeling and evaluating the motion dynamics of a micropart, microscale forces and their effects must be considered. This manuscript employs a nanomicroscale friction model based on the Kogut–Etsion model that along with microscale forces considers surface roughness and material hardness properties to identify the acceleration threshold that would cause a micropart to start sliding on a carrier surface or vertically detach from the carrier surface during gripperless manipulation in a dry environment. The microscale forces change significantly as a function of the surface roughness of the two contacting surfaces. The results indicate that there will always be critical acceleration values below which no sliding or detachment takes place. Also, for the same model parameters, the sliding acceleration is smaller than the detachment acceleration for softer materials and larger for harder materials. The sliding acceleration threshold is more sensitive to hardness changes at smaller surface roughness values as compared to larger surface roughness values. The material hardness has no effect on the detachment acceleration for the same surface roughness values. The knowledge of the acceleration thresholds and their relative magnitudes could be advantageously employed for the development of gripperless manipulation approaches for microcomponent or microdevice handling or for the development of microconveyor platforms for controlled micropart translocation.