航空发动机叶片叶缘随形磨抛刀路规划

航空发动机叶片是整机核心零件，其制造量占到30%以上。叶片叶缘具有大弯扭复杂曲面、薄壁圆角半径微小渐变、精度要求苛刻等特征，末端工序磨抛的精度和品质直接决定整机的性能与寿命。人工仍然是叶片叶缘磨抛的主要手段，然而粉尘危害健康、经验依赖性强、零件一致性差等不足决定了自动化磨抛是必然趋势。叶片叶缘自动化磨抛多采用砂轮横磨或纵磨的刀路规划方式，存在刀路不连续且分行密集、力控制困难等不足，易造成叶缘局部过切，难以保证圆角轮廓创成。为此，建立了砂带包络叶缘的螺旋进给力控磨抛工艺，提出了面族与复杂曲面高阶切触的随形磨抛路径规划方法，实现了叶片叶缘的宽行高效磨抛。首先对叶缘区域进行横磨刀路规划，然后依照圆弧拟合曲线原理进行高阶切触式包络段再规划，最后进行横纵混合磨抛路径规划实现螺旋式连续进给。针对航空发动机叶片开展仿真和实验验证，结果表明所提出的方法相比于传统的横磨或纵磨方法，可将刀触点减少78.8%，轮廓精度由-0.06~+0.07 mm提高到-0.015~+0.05 mm，表面粗糙度由R_a>3.2 μm提高到0.175 μm，并且有效保证了叶缘轮廓形状，避免了过切现象。

Tool path planning for profiling grinding of aero-engine blade edge

Blades are the core part of aero-engines, with a manufacturing amount accounting for more than 30% of the total manufacturing. The blade edge with large curved and twisted surfaces, thin walls and small gradual changing in radius, demands rigorous precision. The precision and quality of grinding in the end process directly determine the performance and life span of the aero-engines. Despite the dominant role of manual work in blade edge grinding, its disadvantages of health hazard, strong dependence on experience and poor consistency of parts make automatic grinding an inevitable trend. Automatic grinding and polishing of the blade edge usually adopts the cutting path planning method for horizontal or vertical grinding of contact wheels, which is discontinuous and easily leads to local over-cutting. The spiral feed grinding process with force control is therefore established in this paper using the belt enveloping blade edge, and the path planning grinding method based on the shape of tool surfaces and complex curved surfaces with high order touching is proposed to realize the efficient grinding of the blade edge. The blade edge area is first planned for the horizontal grinding path, followed by planning of the high order touching envelope segment according to the principle of arc fitting curve. The horizontal and vertical coupling path is finally planned to realize the spiral continuous feed. Simulation and experimental results reveal that compared with the traditional horizontal or vertical grinding method, the proposed method reduces the tool point by 78.8%, improves the contouring accuracy from -0.06-+0.07 mm to -0.015-+0.05 mm and the surface roughness from R_a>3.2 μm to 0.175 μm, and effectively avoids overcutting.