Hierarchical alignment of 3D print with tool path based on microstructure

Using a 3D scanner to inspect a 3D print is becoming more significant as the spectrum of applications for fused filament fabrication expands. We use the tool path, which describes the 3D printing process, as the nominal data to evaluate the manufacturing errors. However, since the 3D print's coordinate system in the scan data is unknown, the 3D print must be aligned with the tool path before the nominal-actual comparison. Therefore, we present a novel alignment based on the 3D print's microstructure. The proposed method first estimates the build direction and then aligns the 3D print with the tool path along the build direction. Finally, each layer of the 3D print is aligned with its corresponding layer of the tool path in the horizontal direction. The alignment result can be confirmed through the slice view. In addition, the performance, extension, and applications of the proposed method are discussed.