Research on the construction method of mechanical model for micro-hole drilling based on compression characteristics of contact area

The neglect of the compression deformation of the tool-workpiece contact area in the process of micro-hole drilling leads to the low precision of the mechanical model, which brings great challenges to the accurate characterization of the cutting force. Aiming at the above problems, this paper proposes a construction method of drilling mechanics model based on compression characteristics of contact area, and evaluates the credibility of the model. Firstly, according to the characteristics of the drill tool, the drilling process is decomposed, and the calculation method of cutting force of cutting unit is proposed. Then, according to the change rule of cutting force under the action of multi-cutting mechanisms, the influence mechanism of the cutting unit on the elastic deformation of the contact surface is studied, the main parameter affecting cutting force (undeformed chip thickness, UCT) is modified, the judgment criterion of different cutting mechanism is defined, so as to construct the more accurate mechanical prediction model. Finally, the credibility of the original model without considering compression deformation and the modified model with considering compression deformation is evaluated by the maximum entropy spectrum estimation method. The results show that compared with the original model, the credibility of the modified model for predicting axial thrust and torque is increased by 7.1 % and 5.8 %, respectively, which proves the applicability of the proposed method.