This study was performed to investigated the mechanism and stability prediction of flat-end milling process of SKD11 hard steel. The static milling force (MF) model, dynamic milling force (DML) model, milling vibration (MV) model, stabilily loble diagram (SLD) model were developed and proposed in this study. The values of milling force coefficients (MLCs) and dynamic structure parameters (DSPs) were determined based on the combination of theoretical and experimental method. In static analysis, the relationship was very close to the linear regression with high determination coefficients (R^2>97%) in all three x, y, z directions. In milling process the SKD11 hard steel using flat-end mill cutter, with each dynamic system, the natural frequencies in different directions were quite close to each other but different. The natural frequency of machine-tool system was almost half of natural frequency of machine-workpiece system. The width of the stability region increased when the spindle speed increased. The machining processes were almost at the stable conditions with the axial depth of cut to be smaller than 0.3 mm at all values of spindle speed. The stable and unstable conditions in milling processes were verified with high precision for almost milling tests. With the points at the border between stable and unstable zones, the verified results had small different point between the predicted results using the proposed model and the analyzed results from experimental processes.

Milling mechanism, milling forces, Milling vibration; Dynamic Structure