A shield machine with freezing function is proposed in order to realize tool change operation at atmospheric pressure. Furthermore, the transformation project of freezing cutterhead and tool change maintenance method ...A shield machine with freezing function is proposed in order to realize tool change operation at atmospheric pressure. Furthermore, the transformation project of freezing cutterhead and tool change maintenance method are put forward. Taking the shield construction of Huanxi Power Tunnel as an example, a numerical analysis of the freezing cutter head of the project was carried out. The results show that when the brine temperature is-25 °C, after 30 d of freezing, the thickness of the frozen wall can reach 0.67 m and the average temperature drops to-9.9 °C. When the brine temperature is-30 °C, after 50 d of freezing, the thickness of the frozen wall can reach 1.01 m and the average temperature drops to-12.4 °C. If the thickness of the frozen wall is 0.5 m and the average temperature is-10 °C, as the design index of the frozen wall, the brine temperature should be lower than-28 °C to meet the excavation requirements in 30 d. Analyzing the frozen wall stress under 0.5 m thickness and-10 °C average temperature condition, the tensile safety factor and compressive safety factor are both greater than 2 at the most dangerous position, which can meet the tool change requirements for shield construction.展开更多
针对五轴加工机床存在程序编制复杂,人工检查困难,加工过程中易碰撞等问题,以Mikron HEM 500U五轴加工中心机床为例,研究了双摆台五轴加工中心结构,提出了应用NCSIMUL软件构建虚拟机床的方法,搭建了虚拟加工环境,通过叶轮零件仿真加工,...针对五轴加工机床存在程序编制复杂,人工检查困难,加工过程中易碰撞等问题,以Mikron HEM 500U五轴加工中心机床为例,研究了双摆台五轴加工中心结构,提出了应用NCSIMUL软件构建虚拟机床的方法,搭建了虚拟加工环境,通过叶轮零件仿真加工,完成了APT刀位源文件到NC代码的自动转换,实现了零件五轴联动加工,验证了NC代码的正确性,检验了加工工艺合理性,保障了机床安全性,减少了零件试切时间,缩短了加工周期,仿真结果验证了虚拟五轴加工中心仿真加工的可靠性。展开更多
基金Project(2014FJ1002)supported by the Science and Technology Major Project of Hunan Province,ChinaProject(2012AA041803)supported by National High Technology Research and Development Program of China。
文摘A shield machine with freezing function is proposed in order to realize tool change operation at atmospheric pressure. Furthermore, the transformation project of freezing cutterhead and tool change maintenance method are put forward. Taking the shield construction of Huanxi Power Tunnel as an example, a numerical analysis of the freezing cutter head of the project was carried out. The results show that when the brine temperature is-25 °C, after 30 d of freezing, the thickness of the frozen wall can reach 0.67 m and the average temperature drops to-9.9 °C. When the brine temperature is-30 °C, after 50 d of freezing, the thickness of the frozen wall can reach 1.01 m and the average temperature drops to-12.4 °C. If the thickness of the frozen wall is 0.5 m and the average temperature is-10 °C, as the design index of the frozen wall, the brine temperature should be lower than-28 °C to meet the excavation requirements in 30 d. Analyzing the frozen wall stress under 0.5 m thickness and-10 °C average temperature condition, the tensile safety factor and compressive safety factor are both greater than 2 at the most dangerous position, which can meet the tool change requirements for shield construction.
文摘针对五轴加工机床存在程序编制复杂,人工检查困难,加工过程中易碰撞等问题,以Mikron HEM 500U五轴加工中心机床为例,研究了双摆台五轴加工中心结构,提出了应用NCSIMUL软件构建虚拟机床的方法,搭建了虚拟加工环境,通过叶轮零件仿真加工,完成了APT刀位源文件到NC代码的自动转换,实现了零件五轴联动加工,验证了NC代码的正确性,检验了加工工艺合理性,保障了机床安全性,减少了零件试切时间,缩短了加工周期,仿真结果验证了虚拟五轴加工中心仿真加工的可靠性。
