Aiming at the approximate error of commonly used methods on calculation of hydrostatic pressures of closed hydrostatic guideways with multiple pockets, a more accurate solution is proposed. Taking design of beam ＆ sl...Aiming at the approximate error of commonly used methods on calculation of hydrostatic pressures of closed hydrostatic guideways with multiple pockets, a more accurate solution is proposed. Taking design of beam ＆ slide-rest guideways for a heavy duty CNC vertical turning mill as an example, under an assumption that stiffnesses of guideways and their jointing structure are sufficiently large, the pressures of the pockets can be attained by adding a co-planarity equation that constrains pocket centers. Then, an optimization model is built to minimize the highest pocket pressure under additional constraints that are posed on the highest seal margin pressure, the highest levitating pressure of the pockets, and the maximum deformation of the guideways. The optimization problem is solved sequentially by using the methods of design of experiments and adaptive simulated annealing on iSIGHT software platform. The results show significant improvements to the original design. Optimized maximum hydrostatic pressure meets the requirement of hydraulic system.展开更多
Residual stresses induced during turning processes can affect thequality and performance of machined products,depending on its direction and magnitude.Residual stresses can be highly detrimental as they can lead to cr...Residual stresses induced during turning processes can affect thequality and performance of machined products,depending on its direction and magnitude.Residual stresses can be highly detrimental as they can lead to creeping,fatigue,and stress corrosion cracking.The final state of residual stresses in a workpiece depends on its material as well as the cutting-tool configuration such as tool geometry/coating,cooling and wear conditions,and process parameters including the cutting speed,depth-ofcut and feed-rate.However,there have been disagreements in some literatures regarding influences of the abovementioned factors on residual stresses due to different cutting conditions,tool parameters and workpiece materials used in the specific investigations.This review paper categorizes different methods in experimental,numerical and analytical approaches employed for determining induced residual stresses and their relationships with cutting conditions in a turning process.Discussion is presented for the effects of different cutting conditions and parameters on the final residual stresses state.展开更多
基金This project is supported by National Natural Science Foundation of China(No.60573178)Provincial Natural Science Foundation of Hubei China(No.2006ABA074).
文摘Aiming at the approximate error of commonly used methods on calculation of hydrostatic pressures of closed hydrostatic guideways with multiple pockets, a more accurate solution is proposed. Taking design of beam ＆ slide-rest guideways for a heavy duty CNC vertical turning mill as an example, under an assumption that stiffnesses of guideways and their jointing structure are sufficiently large, the pressures of the pockets can be attained by adding a co-planarity equation that constrains pocket centers. Then, an optimization model is built to minimize the highest pocket pressure under additional constraints that are posed on the highest seal margin pressure, the highest levitating pressure of the pockets, and the maximum deformation of the guideways. The optimization problem is solved sequentially by using the methods of design of experiments and adaptive simulated annealing on iSIGHT software platform. The results show significant improvements to the original design. Optimized maximum hydrostatic pressure meets the requirement of hydraulic system.
文摘Residual stresses induced during turning processes can affect thequality and performance of machined products,depending on its direction and magnitude.Residual stresses can be highly detrimental as they can lead to creeping,fatigue,and stress corrosion cracking.The final state of residual stresses in a workpiece depends on its material as well as the cutting-tool configuration such as tool geometry/coating,cooling and wear conditions,and process parameters including the cutting speed,depth-ofcut and feed-rate.However,there have been disagreements in some literatures regarding influences of the abovementioned factors on residual stresses due to different cutting conditions,tool parameters and workpiece materials used in the specific investigations.This review paper categorizes different methods in experimental,numerical and analytical approaches employed for determining induced residual stresses and their relationships with cutting conditions in a turning process.Discussion is presented for the effects of different cutting conditions and parameters on the final residual stresses state.
