Research On Key Technologies Of The CNC Machining For Closed Impeller

Closed impeller, as a whole impeller,has a wide range of applications inaerospace engine field becuse of its good structural strength and high workefficiency. However, due to a large degree of closed impeller twisted, narrow spacebetween the blades and passageways, the cover plate rotary blade curvature cuttingenvironment is very harsh, it is easy to produce tool interference and make cuttinghardly.This article proposed a method which separate the upper and lower cavity inprocessing. Firstly, drilling First drill chip hole from both sides of them. Secondlyusing cavity milling or plunging milling to machining most allowance, and thenusing semi finish milling, finish processing. Finally, process the root clearance tofinish the processing procedure.In the computing programe, the part is processed layer by layer from outsideto inside of the impeller, along the cutting lines which are calculated between thehole and the surfaces. The cutting lines in semi-finish and finish milling arecalculated based on the parameter curves of the surfaces.Calculating and adjusting tool vector with sub-layer or surface. The simpleenveloping surface is used to calculate the adjusting direction and angle. All thesecompute algorithms ensure that no interference happen when machining, and lessadjusting distance.Realizing the algorithm through GRIP is the second development tool in UG,and translating cutting locations into CNC program tested in cutting simulationprogram to check the rationality. Results shows that the algorithms is feasible.