NC Machining Toolpath Planning For Large Size Blade Surface With Partition

Aeroengine is the core component of aviation equipment,and blade disk is an important part of aeroengine.With the increasing requirements of national economy for transportation capacity,large-size bladed disks are more and more used in aeroengines.For the integral blade disc with large size and large distortion,the traditional surrounding method is adopted for processing,and a longer cutter is required.After processing,the blade is easy to deform and affect the product quality.It is a new method to process large-size blades by using short cutting tools.However,there are some new problems in blade zonal processing.First,how to divide the processing area.Second,zonal processing is easy to produce tool receiving traces at the boundary of the partition.Therefore,this paper studies the tool path planning for sub regional NC machining of large-scale blade surface,in order to reduce the tool mark of sub regional machining.The specific research contents are as follows:Firstly,the cutting force model of ball head cutter is established,and the influence of tool attitude on cutting force is analyzed.Starting from the influence of tool attitude on micro elements of cutting edges,the relationship between tool attitude change and cutting force is analyzed,and the cutting force model of ball head tool under tool attitude change is established.Secondly,the blade partition method is proposed.Starting from the equal residual height and tool walking step,the tool contact coordinate position of the whole blade is obtained,and the tool contact trajectory is generated.Then,considering the direction of surface normal vector,surface curvature and the machinable position of tool,the region of large-size blade is divided.Then,the cutter axis vector is determined and the deformation at the blade machining boundary is analyzed.The Gaussian sphere projection method is used to eliminate the tool axis interference,and then the initial tool axis at the key tool contact is obtained according to the principle of small normal cutting force.The other tool contacts are interpolated by quaternion spherical interpolation method to obtain the tool axis path of blade zonal machining,and complete the tool path planning of NC machining.Extract the tool position data at the boundary of the feed on both sides of the blade,and analyze the deformation at the boundary of the blade partition.Finally,the simulation and experiment of blade zonal NC machining are carried out.Use UG software to generate the NC track of rough machining and semi finishing machining.The NC program is generated by rough machining,semi finishing machining and post-processing of blade partition tool position file in this paper,which is imported into VERICUT software for simulation verification.Finally,the tool path calculated by the blade partition method in this paper and the tool path generated by the blade partition method in UG are processed by NC respectively.The results show that the tool trace at the boundary is reduced by 68.69% on average,which verifies the effectiveness of the method proposed in this paper.