Papers by Author: Shoichi Tamura

Abstract: The demand of carbon fiber reinforced plastics (CFRP) has been increased in aircraft and automobile industries. In milling of CFRP, the cutting parameters should be determined to finish the machining surfaces without delamination. The tool wear is also a critical issue to finish good surfaces. The paper presents a force model to study the milling process of CFRP. In order to investigate the anisotropy in milling of CFRP, the cutting tests were conducted for unidirectional CFRPs with changing the feed direction of the milling tool. The cutting force and the surface finish depend on the feed direction with respect to the fiber orientation. A force model based on the minimum cutting energy is applied to milling of CFRP. The orthogonal cutting data used in the force model is associated with the relative angle of the cutting edge rotation angle to the fiber orientation. The model was verified in comparison between the predicted and the measured cutting forces. The model also estimates the effect of the feed direction with respect to the fiber orientations on the cutting force in terms of anisotropy in the orthogonal cutting data.

Abstract: The paper presents a predictive cutting force model in drilling of anisotropic materials. Three dimensional chip flow in drilling is interpreted as a piling up of the orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities. The cutting models in the chip flow are determined to calculate the cutting energy using the orthogonal cutting data. Then, the chip flow direction is determined to minimize the cutting energy. The cutting force can be predicted in the determined chip flow model. The cutting force with anisotropy in the material is modeled as the change in the shear stress on the shear plane. The shear stress changes with the rotation angle of the cutter. The cutting force prediction is verified in drilling of a titanium alloy. The anisotropic parameters are identified to minimize the model error between the measured and the predicted cutting forces. The periodical oscillation of the cutting force is also predicted by anisotropy in the shear stress.