Finite-Element Simulation of Conventional and High-Speed Peripheral Milling of Hardened Mold Steel

Abstract

A finite-element model (FEM) with the flow stress and typical fracture is used to simulate a hard machining process, which before this work could not adequately represent the constitutive behavior of workpiece material that is usually heat treated to hardness levels above 50 Rockwell C hardness (HRC). Thus, a flow stress equation with a variation in hardness is used in the computer simulation of hard machining. In this article, the influence of the milling speed on the cutting force, chip morphology, effective stress, and cutting temperature in the deformation zones of both conventional and high-speed peripheral milling hardened mold steel is systematically studied by finite-element analysis (FEA). By taking into consideration the importance of material characteristics during the milling process, the similar Johnson-Cook's constitutive equation with hardened mold steel is introduced to the FEM to investigate the peripheral milling of hardened mold steel. In comparison with the experimental data of the cutting force at various cutting speeds, the simulation result is identical with the measured data. The results indicate that the model can be used to accurately predict the behavior of hardened mold steel in both conventional and high-speed milling.

Modeling and simulation of the high-speed milling of hardened steel SKD11 (62 HRC) based on SHPB technology

“…When the main cutting edge involved in the cutting process is much longer than the secondary cutting edge, the cutting role of the secondary cutting edge can be ignored. Moreover, when the ratio of the radial cutting depth and axial cutting depth is greater than or equal to 5, helical cutting can be approximated to orthogonal cutting, and the 3D problem can be converted to a 2D plane strain problem; similar simplified methods have been validated in the literature [14,18]. The cutting parameter conversions and equivalent modeling process proposed in the present study are shown in Fig.…”

“…According to stress-strain curves obtained from the literature [14] and shown in Fig. 2, the strain softening effect occurred at 10 5 s À 1 and 800°C.…”

“…This means that the conventional empirical J-C constitutive equation no longer fits the flow stress of SKD11 hardened steel in highspeed cutting, and the J-C constitutive equation should be modified. Furthermore, to reduce the simulation time and assist the investigation of the chip shape, cutting force, and stress and strain in deformation zones, because of the similar chip-sectional shapes and cutting characteristics in 3D peripheral milling and 2D orthogonal cutting [13][14][15][16], the present paper provides a simplified 2D FE model based on the modified J-C constitutive equation for chip formation during the high-speed milling of SKD11 hardened steel. The model will also benefit the prediction of the cutting force and cutting temperature and the evaluation of the cutting performance of cutting tools.…”

Adaptive Control of Active Magnetic Bearing against Milling Dynamics

“…Though the two types of AMB designs shown in Figure 1 have ever been applied in computer numerical control (CNC) machines [1,3,6], the current AMB design still cannot meet the requirements for milling applications, such as the overall size of AMB and the force intensity [25][26][27]. For the purposes of solving these troublesome issues against milling applications, a novel embedded cylindrical-array magnetic actuator (ECAMA) is proposed [28].…”

Investigation on the chip formation concerning tool inclination angles in ball end milling of H13 die steel

“…They used the NURBS helix to characterize the contact cutting edges between the cutter and workpiece and chip thickness curve, and the instantaneous uncut chip was built as ruled surfaces with the two special curves. Tang et al 6 investigated the effects of cutting speed on the chip morphology for peripheral milling process with conventional and high cutting speed, and cutting forces, effective stresses, and temperature in deformation zone were also discussed. Ekinovic et al 7 investigated the chip formation process and chip geometry of high-speed milling hardened steels in order to make a trade-off with regard to the machining performance and cost.…”