考虑曲率与加工变形的薄壁叶片测点规划与补偿方法

Sampling Point Planning and Compensation Method for Thin-walled Blades Considering Both Curvature and Processing Deformation

薄壁叶片易发生加工变形,传统的在机检测测点规划未考虑加工变形,导致测点不能准确反映加工情况。为此,提出了综合考虑叶片曲率特征与加工变形的分区域测点规划与镜像补偿方法。首先,对叶片进行截面划分,确定截面数与截面线位置;预测叶片的加工变形,并根据变形大小对截面线进行区域划分。然后,根据各区域的曲率和加工变形设置对应的弦偏差值和测点数,并利用弦公差法确定各区域测点,综合提取各区域测点并进行实验验证。最后,利用镜像补偿法来提高叶片加工精度。实验结果显示,与传统的弦公差法相比,本方法可在测点总数减少18.8%的前提下,使得叶片整体拟合的最大偏差减小37.5%,平均偏差减少16.3%,补偿后叶片的整体偏差减小了65.2%。本方法符合叶片曲率特征的分布,且与加工变形分布相匹配,有效提高了叶片在机检测的效率和加工精度。

The thin-walled blades are prone to machining deformation,and the traditional on-machine inspection method does not consider the machining deformation,resulting in the sampling points not being able to truly reflect the machining situation.Therefore,this paper proposes a sub-regional sampling point planning and image compensation method considering both curvature characteristics and machining deformation.First,the blade is divided into sections,and the number of sections and the position of the section line are determined.Second,the processing deformation of the blade is predicted,and the section line is divided into regions according to the deformation size.Then,the chord deviation value and the number of sampling points are set according to the corresponding curvature and processing deformation of each region,and the chord deviation method is used to determine the sampling points,the measuring points in each region are comprehensively extracted,and the experimental verification is carried out.Finally,the image compensation method is used to improve the blade machining accuracy.The experimental results show that compared with the traditional chord deviation method without considering the processing deformation,the maximum deviation of the overall ftting of the blade is reduced by 37.5%and the average deviation is reduced by 16.3%when the total number of sampling points is reduced by 18.8%.After compensation,the overall deviation of the blade is reduced by 65.2%.The proposed method not only conforms to the blade curvature characteristics,but also matches the processing deformation,which improves the efficiency and accuracy of blade on-machine inspection.