To investigate the vibration principle in machining thin-walled components, a dynamic model for end milling of flexible structures is built based on considering the variations in the dynamic chip thickness and the dif...To investigate the vibration principle in machining thin-walled components, a dynamic model for end milling of flexible structures is built based on considering the variations in the dynamic chip thickness and the differences between up-milling and down-milling. Two milling experiments verify the model. Experimental results show that the model can predict the milling force and displacements simultaneously in the dynamic milling process.展开更多
This paper studies the influence of cutting parameters on deformation and residual stress of the workpiece with small-aperture deep holes in the process of drilling for the purpose of obtaining the variation law of th...This paper studies the influence of cutting parameters on deformation and residual stress of the workpiece with small-aperture deep holes in the process of drilling for the purpose of obtaining the variation law of the cutting force and residual stress with different cutting parameters.Based on the analysis of cutting technology,using finite element simulation software ABAQUS,selecting appropriate material model and failure criterion and setting multiple groups of cutting parameters,the 3D drilling model is established for the simulation of drilling process.The results show that the suitable cutting parameters can be selected according to the simulation results and the cutting force can be predicted,which provides a theoretical basis for actual drilling technology..展开更多
Tool wear and breakage of the micro-milling tool is an important problem for high speed machining of hardened steel die and mould. Dry milling of S136 hardened steel is carried out using TiAlN coated carbide micro-end...Tool wear and breakage of the micro-milling tool is an important problem for high speed machining of hardened steel die and mould. Dry milling of S136 hardened steel is carried out using TiAlN coated carbide micro-end mill (2 mm).The effect of cutting speed, feed per tooth and radial depth of cut on cutting force is analyzed. Cutting parameters adapting to dry machining and strategy optimized for higher rate of material removal with lower cutting force are attained. Results of SEM observation show that the main failure patterns of micro-end mill are breakage of tool tip, wear and drop-off of surface coating, micro-chipping, and breakage of flank.展开更多
Grooving method can restrain the deformation and destruction of surrounding rock by transferring the maximum stress to deep rock,bringing about the effective control for floor heave in soft rock roadway. Based on this...Grooving method can restrain the deformation and destruction of surrounding rock by transferring the maximum stress to deep rock,bringing about the effective control for floor heave in soft rock roadway. Based on this important effect,and to discuss the relationship between cutting parameters and pressurerelief effect,this paper carried out a numerical simulation of grooving along bottom slab and two sides of gateway with finite difference software FLAC^（2D）.The results show that the control effect on floor heave in soft rock tunnel can be improved by selecting appropriate cutting parameters.Appropriately increasing the crevice depth in the middle of the floor can improve the stress state of bottom slab by stress transfer. So the floor heave can be more effectively controlled.To lengthen the crevice in the corners of roadway can simultaneously transfer the maximum stresses of bottom slab and two sides to deep rock,and promote the pressure-relief effect.Extending the crevice length and crevice width on both sides within a certain range can decrease the stress concentration in the corners of roadway,and reduce the deformation of two sides.The cutting position beneficial to restrain the floor heave is close to the bottom slab.展开更多
文摘To investigate the vibration principle in machining thin-walled components, a dynamic model for end milling of flexible structures is built based on considering the variations in the dynamic chip thickness and the differences between up-milling and down-milling. Two milling experiments verify the model. Experimental results show that the model can predict the milling force and displacements simultaneously in the dynamic milling process.
基金Shanxi Province Scientific and Technological Research Program(No.20140321008-03)
文摘This paper studies the influence of cutting parameters on deformation and residual stress of the workpiece with small-aperture deep holes in the process of drilling for the purpose of obtaining the variation law of the cutting force and residual stress with different cutting parameters.Based on the analysis of cutting technology,using finite element simulation software ABAQUS,selecting appropriate material model and failure criterion and setting multiple groups of cutting parameters,the 3D drilling model is established for the simulation of drilling process.The results show that the suitable cutting parameters can be selected according to the simulation results and the cutting force can be predicted,which provides a theoretical basis for actual drilling technology..
文摘Tool wear and breakage of the micro-milling tool is an important problem for high speed machining of hardened steel die and mould. Dry milling of S136 hardened steel is carried out using TiAlN coated carbide micro-end mill (2 mm).The effect of cutting speed, feed per tooth and radial depth of cut on cutting force is analyzed. Cutting parameters adapting to dry machining and strategy optimized for higher rate of material removal with lower cutting force are attained. Results of SEM observation show that the main failure patterns of micro-end mill are breakage of tool tip, wear and drop-off of surface coating, micro-chipping, and breakage of flank.
文摘Grooving method can restrain the deformation and destruction of surrounding rock by transferring the maximum stress to deep rock,bringing about the effective control for floor heave in soft rock roadway. Based on this important effect,and to discuss the relationship between cutting parameters and pressurerelief effect,this paper carried out a numerical simulation of grooving along bottom slab and two sides of gateway with finite difference software FLAC^（2D）.The results show that the control effect on floor heave in soft rock tunnel can be improved by selecting appropriate cutting parameters.Appropriately increasing the crevice depth in the middle of the floor can improve the stress state of bottom slab by stress transfer. So the floor heave can be more effectively controlled.To lengthen the crevice in the corners of roadway can simultaneously transfer the maximum stresses of bottom slab and two sides to deep rock,and promote the pressure-relief effect.Extending the crevice length and crevice width on both sides within a certain range can decrease the stress concentration in the corners of roadway,and reduce the deformation of two sides.The cutting position beneficial to restrain the floor heave is close to the bottom slab.
