Exploring sustainable micro milling: Investigating size effects on surface roughness for renewable energy potential

Abstract

Abstract. Micromilling is a helpful process empowering the fabrication of small-scale components characterized by complex geometries, heightened precision, and superior surface integrity. Widely embraced across aerospace, biomedical, and electronics sectors, it characterizes efficiency and sustainability in modern manufacturing paradigms. However, fundamental instabilities emerge during the cutting phase, particularly when the size effect diminishes below a critical threshold termed the minimum chip thickness, a parameter linked to the cutting-edge radius and feed rate dynamics. The micro-milling process enables the production of small-scale parts with complex geometries, high precision, and optimal surface quality. It stands as a preferred production method not only in the aerospace, biomedical, and electronics industries but also in the renewable energy sector, where its ability to create intricate components with precise dimensions and superior surface quality is crucial for optimizing efficiency and sustainability in energy harvesting and storage technologies. Instabilities are observed in the cutting process when the size effect falls below a critical value known as the minimum chip thickness. This critical value is related to the cutting-edge radius and feed rate. This study investigates the effect of size on surface roughness in micro-milling of Al6061-T6 workpiece. The results show that surface roughness is high at feed rates below the minimum chip thickness due to the ploughing mechanism. The shear mechanism is active at feed rates above the minimum chip thickness, but the ploughing effect is still observed at the 100µm edge of the cutting channel. The study revealed that surface roughness and height differences were high at feed rates significantly below or above the minimum chip thickness. However, surface quality was optimal at feed rates near the minimum chip thickness. Nevertheless, the study highlights an optimal peak in surface quality achieved at feed rates close to the minimum chip thickness, explaining a relationship between operational efficiency and sustainability in micro-milling endeavours.