Investigation on Innovative Dynamic Cutting Force Modelling in Micro-milling and Its Experimental Validation

Abstract

In this paper, an innovative cutting force modelling concept is presented by modelling cutting forces against micro-cutting processes such as micro-milling, ultraprecision turning and abrasive micromachining, and also taking account of microcutting dynamics. The modelling represents the underlying micro-cutting mechanics and physics in micro-milling in an innovative multi-scale manner, i.e. the specific cutting force at the unit length, unit area and unit volume by considering the size effect, cutting fracture energy, the material modulus, and the cutting heat and temperature partition. A novel instantaneous chip thickness algorithm is introduced to analyse the real chip thickness by taking account of the effects of the micro-tool geometry change brought up by the tool run-out and further contribute to the force model through a numerical iterative algorithm. The measured cutting forces are compensated by a Kalman filter to achieve the accurate cutting forces. This is further utilized to calibrate the model coefficients using least square method. The cutting force modelling is evaluated and validated through well-designed micro-milling trials, which can be used for optimizing the cutting process and tool cutting performance in particular.

Precision micro-milling process: state of the art

“…Micro-milling raises significant issues when removing material at the microscale owing to the effect of scaling, otherwise known as size effect. It has been shown that the size effect modifies the mechanism of material removal in conventional milling [ 55 , 56 ]. However, the characterization and exact cause of this effect remain a point of contention among researchers, indicating that many factors influence chip formation and material removal mechanisms at the microscale.…”

Improved dynamic cutting force modelling in micro milling of metal matrix composites part II: Experimental validation and prediction

“…As a result, the predicted chip thickness, that significantly affects the dynamic cutting forces, needs to be further modified by considering the tool run-out. 14–16 In order to accurately predict the dynamic cutting forces, a novel instantaneous chip thickness algorithm is integrated to determine the real chip thickness, tool position and tool tip trajectory by taking account of the effects of the micro-tool geometry change resulted from the tool run-out.…”

Analysis of characteristics of arc shape caused by intermittent cutting force and dynamic vibration in ultra-precision cutting processes

“…They also investigated the influences on the machined surface profile of the spindle vibration. Cheng and colleagues 4,5 proposed an innovative dynamic cutting force model that considered instantaneous chip thickness and revealed the relationship between process dynamics and micro-cutting mechanics. Lu et al 6 adopted a transfer matrix method to establish a multi-rigid-flexible-body dynamics model of an ultra-precision fly-cutting machine tool, and he concluded that the stiffness of the aerostatic bearing spindle has a significant influence on the surface.…”