Search

Monolayer brazed diamond wheel can be precisely dressed by the plate wheel dressing method. The contour of grits is improved and the quality of the ground surface is enhanced. In order to investigate the influence of the dressing method on the material removal mechanism, a theoretical model about the influence of the dressing depth on the maximum undeformed chip thickness is proposed. Besides, a monolayer brazed diamond wheel is dressed through plate wheel dressing. During the dressing procedure, a serial of grinding experiments are carried out on SiC ceramics. The material removal mechanism of the ground surface on SiC ceramics is studied in terms of the morphologies of grits and the ground surfaces. The results show that the number of the dynamic effective grits on the diamond wheel is increased when dressing the monolayer brazed diamond wheel with the plate wheel, leading to the decrease of the maximum undeformed chip thickness. The material removal mode changes from brittle rupture to plastic deformation. The ductile-regime grinding of SiC ceramics is realized finally. [ABSTRACT FROM AUTHOR]

To study the thread milling of superalloy, the definition and expression of uncut chip thickness are proposed, and the expression method of section area between two passes is introduced. On the basis of these concepts, the thread milling cutting force and torque of superalloy are studied. The result shows that thread milling cutting force and torque are positively related to section area. In the process of superalloy thread milling, the radial depth of cut is optimized by the same section area at every cutting step. The optimization method of cutting force and torque can improve part precision and tool life, and can be the theoretical basis for processing technology of thread milling of difficult-to-machine material. [ABSTRACT FROM AUTHOR]

The milling experiments of C/SiC composite with PCD tools are conducted, and surface formation mechanism is analyzed by observing surface/subsurface damages. The effect of milling parameters on surface topography and surface roughness is discussed with the analysis of cutting force. The results show that C/SiC composite is removed in the mechanism of brittle fracture. Laminated fracture, pull-out and fracture in bundle of carbon fiber can be observed on the machined surface. The effect of milling parameters on surface roughness is basically the same with that on surface topography. The higher cutting speed can improve the surface quality, the bigger axial depth of cut will worsen the surface quality and the feed per tooth has no significant influence on surface quality. [ABSTRACT FROM AUTHOR]

During the grinding process, once the coolant comes into film boiling state, the vapor film on the work piece surface will impede the coolant to exchange heat. Consequently, more coolant will not helpful when high heat flux exceeds critical value. The workpiece surface will also burn immediately if there is no measure for this. A new conception of using heat pipe to enhance heat transfer in the grinding zone is put forward combining with the heat transfer technology of thermal engineering. A new type grinding wheel named the loop heat pipe wheel is developed for greatly increasing the critical heat flux. Finally, the measuring experiments of grinding temperature are carried out with loop heat pipe wheel and normal grinding wheel respectively to verify the great potential of the heat pipe for removing grinding heat and decreasing grinding temperature, thus increasing the material removal rate. [ABSTRACT FROM AUTHOR]