难加工薄壁类复杂曲面自适应加工的几何精确建模与工艺优化

Difficult-to-cut material and thin-wall sculpture surface part is common in aerospace field. Due to high-precision requirements, near-net allowance and complex shape of work-piece, it is a challenge for its adaptive machining. The promotion effect for adaptive machining optimization from geometry precision modeling is revealed in this research. 5-axis kinetic characteristic of on-machine measuring and radius compensation with accurate normal vector are imposed into preform surface recognition. The target machining surface is allowed to deform in tolerance area. With the influence rule between allowance distribution and machining deformation, the allowance optimization would be guided to guarantee precision requirements. In further, to solve the new proposition that the left tolerance of machining surface is occupied, a tool path compensation method is proposed to satisfy the continuous and inhomogeneous tolerance distribution. By above researches, the adaptive machining ability of high-precision blade is promoted in the wave of intelligent manufacturing.

航空航天领域广泛存在难加工材料的薄壁复杂曲面零件。由于加工精度要求高、近净余量且形状复杂，使其自适应加工成为一项挑战。本研究揭示几何精确模型对自适应加工优化的影响机理。引入在机测量的五轴运动特性和法矢精确的半径补偿方法提升预成型面识别精度。允许目标加工曲面在形位公差范围内做柔性变形，借助余量对加工变形的影响规律优化余量分布，使工件趋向于更能保证整体加工精度的要求。进一步，针对因占用设计公差空间而改变目标加工曲面允用公差的新命题，研究连续非均匀公差分布驱动的刀位规划补偿方法。最终提升复杂曲面类零件在智能制造浪潮中的高精度加工能力。

在航空航天领域, 广泛存在薄壁结构、且制造精度要求高的复杂曲面类零件,其材料多为高温合金、钛合金等难加工材料。这类难加工零件往往先采用精密热工艺成形毛坯，再采用精密数控加工保证最终加工精度。但受到热成形工艺的成熟度影响，精密加工前毛坯有可能不能覆盖加工特征，直接执行按照理论加工特征编制的数控加工程序，无法加工出合格的产品。研究了几何精确的复杂曲面毛坯建模与多轴在机测量的工艺优化。接着，借用形位公差空间的多层次目标加工曲面建模。然后，引入公差要求和切削变形的加工余量分布优化。最后实现了连续非均匀公差约束驱动的刀位路径规划补偿。多轴在机测量能帮助缩短测量路径用以提升测量效率，通过控制机床旋转轴的方向和变向频次，可以提升测量精度。借助测量结果拟合毛坯曲面，引入的拟合误差有上界，可以建立拟合误差上界与测量点分布的关系。面对复杂曲面类难加工件，建立形位尺寸约束下的多层次余量优化模型。实现了机床数控系统内切削路径的自适应补偿。揭示探针方向和毛坯曲面的几何约束关系，以精确识别毛坯曲面。对于难加工薄壁曲面结构，探索余量分布、切削力和工件变形之间的耦合机理，为保证曲面难加工零件的加工精度奠定了优化依据。

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