Basic Research On CNC Abrasive Belt Grinding Process Of Aero Engine Precision Forged Blade

As one of the key parts of aero-engine, blades have a critical influence on theperformance of aero-engine. Functional mission and work characteristics of blades inthe engine, determines its complex shape, large span of size, complex stress, largebearing capacity. Operation in high temperature, high pressure and high-speed state,usually require blades made of titanium and other high temperature alloy materials, andin order to meet the engine performance, job security, reliability and life requirements,the blades must have precise dimensions, accurate shape and strict surface integrity.The new generation of aero-engine blade is usually manufactured by usingprecision forging process, quality of blade surface is guaranteed by the forging die,moulding precision is high, and the body surface does not need the secondaryprocessing, but because of the large changes of the edges curvature, machiningallowance of the leading and trailing edges are uneven and precision forging is difficultto meet the processing requirements. At present, milling forging flash first, then polishedges of blade by hand is the processing methods in domestic, it is easy to cause bladechord deviation, section line variation, lead to higher rejection rate and poor consistency.In order to achieve high efficiency and high machining precision requirements of theblade edges, this paper proposed the CNC abrasive belt grinding as the processingmethod for leading and trailing edges.The main contents and research results are as follows:①Analyzed the grindability of difficult-to-machine materials(titanium and nickelbased high temperature alloy) used to make aero-engine blade.②According to the processing requirements and current processing status ofaero-engine blade, put forward a new grinding process which can realize the processingof leading and trailing edges. Based on six axis belt grinding of free-form surface,through the single grain vertical contact pressure model analysis, proposed a method byadding normal vector axis to control grinding pressure, studied the contact pressurecontrol strategy. Afterwards，analyzed the NC belt grinding process of blade edges,determined the processing positioning reference and tool path, simultaneously analyzedthe contact wheel, belt and the selection of grinding parameters.③Established an uneven grinding margin model of blade edges, extracted relevantdata of the margin value. Through the grinding experiment of leading and trailing edges, obtained the prediction model of the grinding material removal of the edges, and thengot the grinding parameters control model, afterwards calculated the grindingparameters with the data files extracted from the blade edges.④Completed the correlative experiment, verified the edge grinding materialremoval quantity prediction model and the quantitative grinding parameters controlmethod of uneven margin, and optimized the grinding parameters control model andgrinding process. Based on the prototype measurement, put forward the processing errorcompensation method, through experimental verification, proved the feasibility andvalidity of the method.