A prediction model for net cutting specific energy in computer numerical control(CNC)turning based on turning parameters and tool wear is developed.The model can predict the net cutting energy consumption before turni...A prediction model for net cutting specific energy in computer numerical control(CNC)turning based on turning parameters and tool wear is developed.The model can predict the net cutting energy consumption before turning.The prediction accuracy of the model is verified in AISI 1045 steel turning.The comparative experimental results show that the prediction accuracy of the model is significantly improved because the influence of tool wear is taken into account.Finally,the influences of turning parameters and tool wear on net cutting specific energy are studied.With the increase of cutting depth,the net cutting specific energy decreases.With the increase of spindle speed,the additional load loss power of spindle drive system increases,so the net cutting specific energy increases.The net cutting specific energy increases approximately linearly with tool wear.The results are helpful to formulate efficient and energy-saving CNC turning schemes and realize low‑carbon manufacturing.展开更多
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supported by the Project of Shandong Province Natural Science Foundation of China (No. ZR2016EEM29)the Project of Shandong Province Key Research Development of China (No.2017GGX30114)。
文摘A prediction model for net cutting specific energy in computer numerical control(CNC)turning based on turning parameters and tool wear is developed.The model can predict the net cutting energy consumption before turning.The prediction accuracy of the model is verified in AISI 1045 steel turning.The comparative experimental results show that the prediction accuracy of the model is significantly improved because the influence of tool wear is taken into account.Finally,the influences of turning parameters and tool wear on net cutting specific energy are studied.With the increase of cutting depth,the net cutting specific energy decreases.With the increase of spindle speed,the additional load loss power of spindle drive system increases,so the net cutting specific energy increases.The net cutting specific energy increases approximately linearly with tool wear.The results are helpful to formulate efficient and energy-saving CNC turning schemes and realize low‑carbon manufacturing.
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.
