Geometric Theory And Process Method Of Cuttingaxial-flow Blisk By Largest Tool

As an important component of high performance aero engine,a blisk is complex in shape.The pressure and suction surfaces of the blisk blades are designed with free-form surfaces,and the space between two adjacent blades varies significantly.Usually,the blisk's material is difficult-to-cut material,such as high-strength stainless steel,titanium alloy,superalloy.The cutting force and temperature in roughing the blisks are high,and thus,the machine tool should be rigid and the cutters should be as larger as possible.However,due to complex shape of the blades,it is quite difficult to automatically optimize the largest cutter size and tool orientation with no interference.Therefore,the main work of this paper is as fellow:(1)Establish optimization model of the largest radius of the theoretical cutter.Analyze the relationship between the blisk's channel and the cutting tool during the four-axis machining,then a theoretical tool model based on point constraints and allowable cutter model based on the constraints of channel is established.Finally,a simplified optimization model of the largest allowable diameter of the theoretical cutter at a cutter contact(CC)point is established.(2)An effective solver to the optimization model.The classical optimization algorithm,such as Particle Swarm Optimization,is easy to converge to the local optimal solution and slow convergence speed in solving the optimization model.Through investigate the law of the constraint of largest cutter on the blisk's channel.Thus,this optimization model can be simplified and solved using a linear searching method.Finally,an efficient and reliable solver is proposed,which named linear search algorithm based on the constraint of largest tool on the blisk's channel.(3)Multiple largest tools cutting blisks patch by patch in the blisks' four-axis rough machining.In order to maximize the advantages of largest cutters and to increase the machining efficiency in roughing.A new process of blisk rough machining is proposed.Based on the calculation results of the largest tool size,several cutting tools are selected.Following the principle of machining with using large tool cutting first and small tool cutting later,and based on the group of selected cutters and their corresponding patches,the tools paths can be generated.(4)Test verificationIt is proved that the geometric theory of the largest cutting tool and this new process of roughing blisks are correct and practicable.And its advantages of this new process of roughing blisks is demonstrate that using this new process can improve the efficiency in roughing.