T-slot milling is one of the most common milling processes in industry. Despite recent advances in machining technology, productivity of T-slot milling is usually limited due to the process limitations such as high cu...T-slot milling is one of the most common milling processes in industry. Despite recent advances in machining technology, productivity of T-slot milling is usually limited due to the process limitations such as high cutting forces and stability. If cutting conditions are not selected properly the process may result in the poor surface finish of the workpiece and the potential damage to the machine tool. Currently, the predication of chatter stability and determination of optimal cutting conditions based on the modeling of T-slot milling process is an effective way to improve the material removal rate（MRR） of a T-slot milling operation. Based on the geometrical model of the T-slot cutter, the dynamic cutting force model was presented in which the average directional cutting force coefficients were obtained by means of numerical approach, and leads to an analytical determination of stability lobes diagram（SLD） on the axial depth of cut. A new kind of SLD on the radial depth of cut was also created to satisfy the special requirement of T-slot milling. Thereafter, a dynamic simulation model of T-slot milling was implemented using Matlab software. In order to verify the effectiveness of the approach, the transfer functions of a typical cutting system in a vertical CNC machining center were measured in both feed and normal directions by an instrumented hammer and accelerators. Dynamic simulations were conducted to obtain the predicated SLD under specified cutting conditions with both the proposed model and CutPro~. Meanwhile, a set of cutting trials were conducted to reveal whether the cutting process under specified cutting conditions is stable or not. Both the simulation comparison and experimental verification demonstrated that the satisfactory coincidence between the simulated, the predicted and the experimental results. The chatter-free T-slot milling with higher MRR can be achieved under the cutting conditions determined according to the SLD simulation.展开更多
因为传统波导魔T体积较大,所以不利于集成。为了使魔T体积更小更利于集成,基于基片集成波导(SIW)理论,设计了Ka波段平面魔T。下层结构为H-T分支,上层结构为使用耦合缝实现的E-T分支。所设计的SIW魔T较传统波导魔T,不但体积小、易于生产...因为传统波导魔T体积较大,所以不利于集成。为了使魔T体积更小更利于集成,基于基片集成波导(SIW)理论,设计了Ka波段平面魔T。下层结构为H-T分支,上层结构为使用耦合缝实现的E-T分支。所设计的SIW魔T较传统波导魔T,不但体积小、易于生产和集成,而且E臂、H臂具有天然的隔离特性,方便调谐。利用仿真软件HFSS可以看出,在28.6~30.4GHz,得到的各端口的回波损耗均优于-20 d B,E臂、H臂的隔离优于-43 d B,性能良好。展开更多
基金supported by National Science and Technology Support Program of China (Grant No. 2006BAF01B09-03)the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 200800060010)Hunan Provincial Educational Department Scientific Research Project of China (Grant No. 08D096)
文摘T-slot milling is one of the most common milling processes in industry. Despite recent advances in machining technology, productivity of T-slot milling is usually limited due to the process limitations such as high cutting forces and stability. If cutting conditions are not selected properly the process may result in the poor surface finish of the workpiece and the potential damage to the machine tool. Currently, the predication of chatter stability and determination of optimal cutting conditions based on the modeling of T-slot milling process is an effective way to improve the material removal rate（MRR） of a T-slot milling operation. Based on the geometrical model of the T-slot cutter, the dynamic cutting force model was presented in which the average directional cutting force coefficients were obtained by means of numerical approach, and leads to an analytical determination of stability lobes diagram（SLD） on the axial depth of cut. A new kind of SLD on the radial depth of cut was also created to satisfy the special requirement of T-slot milling. Thereafter, a dynamic simulation model of T-slot milling was implemented using Matlab software. In order to verify the effectiveness of the approach, the transfer functions of a typical cutting system in a vertical CNC machining center were measured in both feed and normal directions by an instrumented hammer and accelerators. Dynamic simulations were conducted to obtain the predicated SLD under specified cutting conditions with both the proposed model and CutPro~. Meanwhile, a set of cutting trials were conducted to reveal whether the cutting process under specified cutting conditions is stable or not. Both the simulation comparison and experimental verification demonstrated that the satisfactory coincidence between the simulated, the predicted and the experimental results. The chatter-free T-slot milling with higher MRR can be achieved under the cutting conditions determined according to the SLD simulation.
文摘因为传统波导魔T体积较大,所以不利于集成。为了使魔T体积更小更利于集成,基于基片集成波导(SIW)理论,设计了Ka波段平面魔T。下层结构为H-T分支,上层结构为使用耦合缝实现的E-T分支。所设计的SIW魔T较传统波导魔T,不但体积小、易于生产和集成,而且E臂、H臂具有天然的隔离特性,方便调谐。利用仿真软件HFSS可以看出,在28.6~30.4GHz,得到的各端口的回波损耗均优于-20 d B,E臂、H臂的隔离优于-43 d B,性能良好。
