近净成形叶片作为一种高效低成本的新型工艺方法,越来越广泛地被应用在航空发动机叶片毛坯制造上。航空发动机近净成形叶片其叶型复杂且属于薄壁类零件,无法保证所有区域一次成形且满足设计精度要求,需要对进/ 排气边区域进行自适应加工。自适应加工中进/ 排气边曲面通常为重构曲面,因为测量数据、缘头形状约束、毛坯变形等因素影响,重构曲面会出现曲率变化大、边界不齐等问题。针对上述问题,本文通过分析刀心轨迹与加工曲面几何关系,以光顺偏置曲面为基础,建立光顺刀心轨迹规划线规划算法,实现了重构曲面光顺刀心轨迹的高效自动化生成。在某型精锻叶片上进行了数控加工试验,试验结果显示进/ 排气边曲面轮廓公差控制在(–0.02~+0.039) mm范围内,满足图纸设计公差(–0.03~+0.05) mm 的要求,证明了所提算法的有效性和实用性。
Abstract
As an efficient and cost-effective new process method
near-net shape blade is increasingly being used in the manufacture of aero-engine blank. For aero-engine near net-shape blade
which is complex and thin-walled part
it is not possible to ensure that all areas are formed at once and meet the design accuracy requirements
and adaptive machining of the leading/trailing edge areas is required. The leading/trailing edge surfaces in adaptive machining are often reconstructed surfaces that have large curvature variations and uneven boundaries due to measurement data
leading/trailing edge areas shape constraint
blank deformation and other factors. To address the above problems
this paper analyses the geometric relationship between tool centre path and machined surface
and establish a planning line planning algorithm for the smooth tool centre path based on the smooth offset surface to achieve efficient automatic generation of smooth tool centre path for reconstructed surface. The experimental results show that the surface contour tolerance is controlled within the range of (–0.02~+0.039) mm to meet the requirement of the design tolerance (–0.03~+0.05) mm
which proves the effectiveness and practicality of the proposed method.