Papers by Author: Jing Shu Hu

Abstract: Tool wear plays an important part during cutting process, and wear loss has a close relationship with cutting condition, which affects machined surface mostly. In order to accomplish tool wear prediction in way of FEM, based on founding of cutting model under steady state, interrelated parameters needed for tool wear prediction, such as cutting temperature, contact pressure and raletive sliding velocity are extracted. By compiling Python subprogram and using Abaqus tool in hard cutting process PCBN tool wear is predicted, which provide foundation for optimizing cutting condition.

Abstract: In the cutting process, cutting force is one of the important physical parameters, which affects the generation of cutting heat, tool life and surface precision of workpiece directly. In this paper an orthogonal design of experiment and subsequent data is analyzed using high speed finish hard cutting GCr15 whose hardness is 65HRC. Cutting speed is 200-400m/min, to study the influence of cutting parameters on cutting force, cutting force empirical model has obtained from least square method.

Abstract: Air cooling is a near dry machining method, which cools cutting area and evacuates chips using low temperature cold wind instead of cutting liquid. It can decrease tool wear, increase tool life, reduce machining cost and bring no chemical pollution. In this paper, air cooling test was carried on, in which vortex tube was used for cooling and high hardness bear steel GCr15 was machined by PCBN tool. Experiment results indicated that cold air from vortex tube has a significant effect on cutting force, cutting temperature and chip formation process. This paper’s conclusions will have a great reference value for the practical application of air cooling technology.

Abstract: Through combining turning experiments and FE simulations, this paper studied the effects of force, temperature and residual stress of machined surface on high speed hard turning GCr15 bearing steel hardened to HRC60-62 with three kinds of ordinary edge preparation (sharp-edge, hone and chamfer). The experiment and simulation results indicated that the diathermanous proportion of chamfered edge preparation to tool and machined surface is less, and this distribution of cutting temperatures is useful for tool life and machined surface quality. The simulation results showed that cutting force had a descending tendency with increasing of cutting speed, which is in accordance with the change rules of machining general rigidity material, and it proved that FE simulations have good precision. The simulation results of residual stress of machined surface showed that residual tensile stress existed in machined surface using both honed and chamfered tools, and a highest compressive stress (about -200MPa) existed among 150-200μm of the depth into the workpiece surface. The difference was that the depth of superficial harden layer with honed tools is larger than that with chamfered tools.

Abstract: Air cooling is a near dry machining method, which cools cutting area and evacuates chip using low temperature wind instead of cutting liquid. It can decrease tool wear, improve tool life, reduce cost and produce no chemical pollution. In this paper, air cooling system is established, in which vortex tube is used for cooling. Air cooling test was carried on, in which high hardness bear steel GCr15 is machined by PCBN tool. Experiment results indicated that cold air from vortex tube has a significant effect on cutting force, cutting temperature and chip formation process. Cutting force and cutting temperature were simulated using Marc. Change rules that analysis results indicated are in accordance with experiment results. This paper’s conclusions have a great reference value for the practical application of air cooling technology.