Effect of surface-active media on chip formation in micromachining

Abstract

Conventionally metal working fluids are employed to reduce tool wear and energy consumption in the metal cutting process. This paper presents a new method to achieve the same purpose by reducing chip thickness and cutting forces through introducing the mechanochemical effect, also referred to as Rehbinder effect, by applying the surface-active media on the workpiece surface before machining. Orthogonal cutting tests were conducted on the copper samples to understand the underlying mechanism of material deformation in the presence of surface-active media. Theoretical explanations for the mechanochemical phenomenon have also been provided. Moreover, the studies were extended to the face turning operation to examine the effectiveness of surface-active medium in a more general case study. It was found that the effectiveness of surface-active media is diminished with decrease in feed rate and enhanced with decrease in cutting velocity. A maximum of 60% reduction in cutting force can be achieved at the critical feed rate of 50 mm/min with low cutting speeds in face turning. This paper not only advances the understanding of the mechanochemical effect in micromachining but also for the first time correlates the surface effect with machining parameters and tool geometry. As validated, the significant reduction in cutting forces open new avenues for further development of new surface-active media for applications in machining processes.