An analytical micro-milling force model based on the specific cutting pressure-feed dependence, in presence of ploughing and tool run-out effects

The growing request of extremely accurate small parts in the last decades led to the disruptive employment of micro-milling processes. Despite conventional milling knowledge is widespread in the industrial field, its application at micro-level remains a big effort because of phenomena usually neglectable at macro-scale, such as the so-called size-effect and tool run-out. Therefore, to correctly evaluate micro-milling forces, a model able to consider these effects is mandatory. In this paper a mechanistic model for predicting cutting forces in micro-milling of Ti-6Al-4V specimens, considering ploughing and tool run-out effects, is presented. The proposed model concerns the introduction of a dedicated coefficient for considering ploughing and shearing effects on tangential and radial components of the cutting forces. Differently from the previous scholars, the coefficients related to ploughing regime have been considered as a function of the specific cutting pressure. In turn, this latter has been characterized by a regression power law dependent on the feed rate since, in this regime, it has a significant influence. The good agreement between analytical and experimental results enforces the proposed model capabilities.