Abstract: 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.

Key words: aero-engine, blade edge, profiling grinding, tool path planning, belt enveloping