In order to implement cost-effective machining of gr anite materials with diamond impregnated tools, we should realize low tool w ear, low energy consumption, and high cutting efficiency, while the accuracy of the wor...In order to implement cost-effective machining of gr anite materials with diamond impregnated tools, we should realize low tool w ear, low energy consumption, and high cutting efficiency, while the accuracy of the workpiece surfaces are maintained to be satisfactory. It is understood that the main factors affecting the tool wear, the energy, and the efficiency during the machining process are related to the tribological interactions that occur at the interface between the diamond tool surface and the workpiece. Based on this consideration, we propose a new machining method to machine granite materia ls to achieve improved cost effectiveness. In the proposed method, the tribologi cal interactions are maintained to a minimum. Based on the analyses of the experimental results, the following conclusions can be drawn: The wear performance is greatly dependent on the machining parameters and their combination. Therefore, optimum machining parameters must be set up at first in order to optimize the tribological characteristics of segments and thereby sawbl ade performance. These may be realized by balancing the energy expended by frict ion and the mechanical load on diamond crystal. The geometry and structure of diamond segments are another important criterion f or the diamond saw blade. Using a seven-layer structure for multi-blades sawin g and applying segments with side slots for trimming application had greatly red uced the frictions in the sawing processes. The wetting and bonding between diamonds and matrix alloys have been considered as the prerequisite for high wear performance of the segments. Diamonds coated w ith Ti-Cr alloy by a unique technique can effectively improve its wetting c apability and provide more storage space for debris, thereby reducing friction i nteractions.展开更多
Law level of RRO(Repeatable Run Out), NRRO(Non Repe at able Run Out), and lightweight construction are a major trend in the high-speed HDD(Hard Disk Drive) sytem to reduce track misregestration and to achieve high tra...Law level of RRO(Repeatable Run Out), NRRO(Non Repe at able Run Out), and lightweight construction are a major trend in the high-speed HDD(Hard Disk Drive) sytem to reduce track misregestration and to achieve high track density, which lead to succeed in the market. However, it is not easy to r educe RRO, NRRO, and the weight of the spinning disk spindle system efficiently because lightweight construction and or bearing stiffness changes often yields a decrease in the static and dynamic stiffness of the system, and consequently hi gh vibrations may be generated as a results. Therefore, it is of importance to e valuate in advance the accurate dynamic behavior of the high speed spinning disk spindle system of a HDD sysem. This study introduces an optimum design of the high speed spinning disk spindle system of a HDD for minimum RRO, NRRO, and lightweight construction using a gene tic algorithm. The spinning disk, hub, and bearing components of a HDD system ar e modelled as appropriate finite elements respectively and their equations of mo tion are derived to construct the system equations of the whole spinning disk sp indle system of the HDD system. The RRO and NRRO responses of the spinning disk, due to exciting forces arised from ball bearing faults and rotating unbalance, are analyzed. In the design optimation, the hub thickness, the disk thickness, bearing positio ns (or bearing span) and bearing stiffness were set as design variables. The uni que objective function is obtained by multiplying an appropriate weighting facto r by multi-objective functions, such as RRO, NRRO, and the total weight of HDD the system. The constraints are maximum RRO limit, maximum weight linit, and the critical speed limit of the HDD spindle system. Results show that the RRO, NRRO, and weight are reduced by 6%, 66.7% and 28% r espectively compared with the initial design of the HDD system. Therefore, thi s present study can be used for an optimum design of the spinning disk spindle s ystem of a HDD for lightweight construction and low vibrations.展开更多
文摘In order to implement cost-effective machining of gr anite materials with diamond impregnated tools, we should realize low tool w ear, low energy consumption, and high cutting efficiency, while the accuracy of the workpiece surfaces are maintained to be satisfactory. It is understood that the main factors affecting the tool wear, the energy, and the efficiency during the machining process are related to the tribological interactions that occur at the interface between the diamond tool surface and the workpiece. Based on this consideration, we propose a new machining method to machine granite materia ls to achieve improved cost effectiveness. In the proposed method, the tribologi cal interactions are maintained to a minimum. Based on the analyses of the experimental results, the following conclusions can be drawn: The wear performance is greatly dependent on the machining parameters and their combination. Therefore, optimum machining parameters must be set up at first in order to optimize the tribological characteristics of segments and thereby sawbl ade performance. These may be realized by balancing the energy expended by frict ion and the mechanical load on diamond crystal. The geometry and structure of diamond segments are another important criterion f or the diamond saw blade. Using a seven-layer structure for multi-blades sawin g and applying segments with side slots for trimming application had greatly red uced the frictions in the sawing processes. The wetting and bonding between diamonds and matrix alloys have been considered as the prerequisite for high wear performance of the segments. Diamonds coated w ith Ti-Cr alloy by a unique technique can effectively improve its wetting c apability and provide more storage space for debris, thereby reducing friction i nteractions.
文摘Law level of RRO(Repeatable Run Out), NRRO(Non Repe at able Run Out), and lightweight construction are a major trend in the high-speed HDD(Hard Disk Drive) sytem to reduce track misregestration and to achieve high track density, which lead to succeed in the market. However, it is not easy to r educe RRO, NRRO, and the weight of the spinning disk spindle system efficiently because lightweight construction and or bearing stiffness changes often yields a decrease in the static and dynamic stiffness of the system, and consequently hi gh vibrations may be generated as a results. Therefore, it is of importance to e valuate in advance the accurate dynamic behavior of the high speed spinning disk spindle system of a HDD sysem. This study introduces an optimum design of the high speed spinning disk spindle system of a HDD for minimum RRO, NRRO, and lightweight construction using a gene tic algorithm. The spinning disk, hub, and bearing components of a HDD system ar e modelled as appropriate finite elements respectively and their equations of mo tion are derived to construct the system equations of the whole spinning disk sp indle system of the HDD system. The RRO and NRRO responses of the spinning disk, due to exciting forces arised from ball bearing faults and rotating unbalance, are analyzed. In the design optimation, the hub thickness, the disk thickness, bearing positio ns (or bearing span) and bearing stiffness were set as design variables. The uni que objective function is obtained by multiplying an appropriate weighting facto r by multi-objective functions, such as RRO, NRRO, and the total weight of HDD the system. The constraints are maximum RRO limit, maximum weight linit, and the critical speed limit of the HDD spindle system. Results show that the RRO, NRRO, and weight are reduced by 6%, 66.7% and 28% r espectively compared with the initial design of the HDD system. Therefore, thi s present study can be used for an optimum design of the spinning disk spindle s ystem of a HDD for lightweight construction and low vibrations.
