Non-fill Scanning Path Planning With Nonnegative Machining Allowance

One of the main directions of additive manufacturing is to print functional components directly using metal powder materials. In order to improve the functionality of the component, this thesis focuses on a kind of non-fill path planning instead of the traditional fill scanning. When the metal powder is melted with the traditional scanning path and solidified, warping and even cracking may appear in the formed layers. One target of this research is to suppress the warping and cracking.Meanwhile, the staircase effect is a fundamental disadvantage and could not be avoided for all 3D printing techniques. Additional sandblasting, grinding, etc. are generally needed for 3D printed components. It is therefore necessary to leave enough allowance to guarantee the accuracy of the final components. In this thesis, a method guaranteeing the allowance of obtained components to be non-negative has been proposed. This thesis is divided into five chapters:In the first chapter, related works with an emphasis on slice processing and scanning path planning are reviewed. The significance of this research is also analyzed. Finally, the main contents of this thesis are introduced.In the second chapter, the methods to analyze the STL file structure, read the file as well as display the model are introduced. The topology of the mesh is constructed to get the adjacency of triangular facets.In the third chapter, the slicing of mesh models is realized. The intersections between the model and a series of evenly spaced planes parallel to the X-Y plane are computed to get a series of cross-sectional contours of the model. The topological relationship of the contours in each slice is constructed to determine the correct filling area;In the fourth chapter, a regular triangle template is trimmed by the contours in each slice with respect to the filling area to get three groups of parallel scanning hatches, respectively. And all hatches constitute a path of triangular mesh shape, and the path is ultimately saved in a CLI format file executable in a 3D printer;The thesis was concluded with a summary and prospect in the fifth chapter.