Study of static and dynamic ploughing mechanisms by establishing generalized model with static milling forces

• A generalized model is presented to study the static and dynamic ploughing and shearing effects.
• Shearing and ploughing force expressions are integrated into one unified form.
• The model can treat both mechanics and dynamics of milling process with process damping.
• A few milling tests rather than abundant turning cuts are needed to calibrate force coefficients.

Studies on ploughing mechanism were separately treated for static and dynamic cutting processes in the literature. In this paper, a generalized method, which is suitable for exploring the ploughing mechanism of both static and dynamic cuts, is presented by only using the static milling forces. Whether for static or dynamic cutting processes, a unified proportional form is used to express ploughing forces as function of the volume of the materials extruded under the clearance face of the tool, and the corresponding proportional scale is named ploughing force coefficient. To facilitate identifying the ploughing force coefficient, the total static milling force is decomposed into two parts, i.e. the shearing force component and the ploughing force component, and then the ploughing force coefficient is identified using the ploughing force component. It is observed that the relative error between the determined ploughing force coefficient and the one obtained by using dynamic signals in existing method is less than two percent. Besides, determination procedure is also specially developed to calibrate shear angle, shear stress and friction constant based on the separated shearing force component. Both static and dynamic milling tests are used to validate the proposed model.