Experiment Investigation On Surface Residual Stress In Dry Machining And It’s

Under the condition of dry cutting, cutting heat is accumulated in cutting area and can’t release because lacking cutting fluid to reduce temperature, lubrication, washing and chip removal. So cutting temperature and tool wear is rise quickly due to lots of cutting heat. Residual stress is more easily get worse. The strength, corrosion resistance and service life, and geometrical dimension stability of the workpiece was effect by surface residual stress. It is an essential way to improve workpiece machined quality and efficiency that forecast even control dry cutting residual stress in machined surface.Based on cutting theory, The influence factors and law of machining surface residual stress is analyzed applying finite element modelling(FEM) and experimental method. The main research contents are as follows:(1) Influence of workpiece material, cutting parameter to residual stress is studied though this dry mill experiment. Residual stress is rule by indentation method. The results show that: in process of dry cutting, residual tensile stress is always distributed on surface of 45 steel and SKD11. Residual compressive stress is distributed on surface of 7075 Al. Residual stress increase with an increase of axial depth of cut, and reduce with an increase of feed in process of dry cut 45 steel at low cut speed. But in high cut speed, residual stress increase firstly and then decrease with an increase of axial depth of cut, but effect of feed on residual stress less is very small.(2) Influence of tool coat, tool geometrical parameter and tool wear to residual stress is studied though the dry mill experiment in this paper. The result show that: Abrasion performance of Ti Al N and Ti Al Si N coated tools are better, and which’s residual stress is very low by these coated tool. Surface residual stress is lower in 45° spiral angle of cutting tool at low speed, but in high cutting speed, surface residual stress is lower in 30° spiral angle of cutting tool. residual stress increase with an increase of speed in four flute end mill machined surface, and reduce in two and three flute end mill machined surface. Residual stress is increase with an increase of wear in initial stage, but decrease due to great wear later.(3) Influence of tool wear to residual stress is studied though dry milling experiment in different tool wear states. The result show that: Residual stress is increase with an increase of wear in initial stage, but decrease due to great wear later.(4) Finite element model(FEM) is built in Deform to predict the status and distribution of residual stress. Residual stress, temperature field, strain field is predict by this FEM in different materials and different cutting parameters. Influence of material physical properties and cutting parameters on the residual stress is studied. The result show that: residual tensile stress are easily form due to high cutting temperature which produce in cutting high strength and hardness material. the surface residual tensile stress is reduced by fast speed of the moving heat source because of improvement of cutting speed, surface residual tensile stress decreases, the residual stress distribution in depth due to the increase of cutting depth.