基于工业 CT 的零件内外曲面形位误差分析

针对具有复杂内腔结构零件的内部曲面形位误差分析困难的问题,提出了一种基于工业 CT 技术的零件复杂内腔的形 位误差分析方法。 首先,使用工业 CT 对零件进行扫描并重建为测量 STL 模型。 然后将设计 IGES 模型离散为 STL 模型与测量 STL 模型进行配准。 其次,利用设计 IGES 模型作为引导,判定测量 STL 模型中的点和 IGES 模型各曲面的归属,自动分割测量 STL 模型中的所有曲面。 最后,选取设计 IGES 模型的曲面并对曲面对应的点云簇进行形位误差分析。 选取百万级测量点云的 阀体模型进行实验,完整地分割点云模型所有曲面,选择任意曲面进行形位误差分析,测得选定内部曲面的圆柱度为 1. 11 mm、 平面度为 0. 61 mm、平行度为 1. 92 mm。 本文方法只需输入零件测量 STL 模型和零件设计 IGES 模型,再选取设计 IGES 模型待 测曲面就可以自动地完成零件内外曲面的形位误差分析。

Form and position error analysis of inner and outer surface of parts based on the industrial CT

It is difficult to analyze the shape and position error of internal surface of parts with complex cavity structure. To address this issue, a method of analyzing the shape and position error of complex cavity of parts is proposed, which is based on industrial CT technology. First, the parts are scanned by using industrial CT and reconstructed into the measurement STL model. Then, the design IGES model is discretized into the STL model and the measurement STL model for registration. Secondly, by using the designed IGES model as the guide, the points in the STL model and the belonging of each surface of the IGES model are determined. And all the surfaces in the STL model are automatically segmented and measured. Finally, the surface of IGES model is selected and the point cloud cluster corresponding to the surface is analyzed. The valve body model of the million-dollar measurement point cloud is selected for the experiment. All the surfaces of the point cloud model are completely segmented. The cylindricity, flatness and parallelism of the selected internal surface are measured to be 1. 11 mm, 0. 61 mm, and 1. 92 mm, respectively. In this method, only the input STL model of part measurement and the IGES model of part design are required. The measured surface of IGES model is selected. The internal and external surface of part can be analyzed automatically.