具有网格填充结构的自由曲面零件的多轴无支撑打印
Multi-Axis Support-Free Printing of Freeform Parts with Lattice Infill Structures
摘要：
在增材制造中，填充结构通常用于减少固体部件的重量和成本。目前，大多数填充结构生成方法都是基于传统的2.5轴打印配置，虽然能够满足填充物的自支撑条件，但会受到成品表面上众所周知的楼梯效应以及对悬垂特征的广泛支持的影响。本文基于新兴的连续多轴打印构型，提出了一种新的网格填充结构生成算法，该算法能够同时满足填充物的自支撑条件和零件边界表面的无支撑要求。该算法严重依赖于使用三个相互正交的测地线距离场，嵌入在四面体网格的实体模型。这三个测地距离场的等测地距离曲面之间的相交自然形成填充结构的所需网格，而填充的密度可以通过调整等值来方便地控制。每个弯曲切片层中的网格填充图案被修剪以符合欧拉图，从而生成连续的打印路径，这可以有效地减少打印过程中的喷嘴回缩。此外，为了满足无碰撞的要求，提高打印效率，本文还提出了一种打印顺序优化算法，以减少喷嘴的空气移动长度，从而确定连通网格填充的无碰撞打印顺序。在计算机模拟和物理打印中进行了大量的实验，结果初步证实了我们的方法的优越性。
英文摘要：
In additive manufacturing, infill structures are commonly used to reduce the weight and cost of a solid part. Currently, most infill structure generation methods are based on the conventional 2.5-axis printing configuration, which, although able to satisfy the self-supporting condition on the infills, suffer from the well-known stair-case effect on the finished surface and the need of extensive support for overhang features. In this paper, based on the emerging continuous multi-axis printing configuration, we present a new lattice infill structure generation algorithm, which is able to achieve both the self-supporting condition for the infills and the support-free requirement at the boundary surface of the part. The algorithm critically relies on the use of three mutually orthogonal geodesic distance fields that are embedded in the tetrahedral mesh of the solid model. The intersection between the iso-geodesic distance surfaces of these three geodesic distance fields naturally forms the desired lattice of infill structure, while the density of the infills can be conveniently controlled by adjusting the iso-values. The lattice infill pattern in each curved slicing layer is trimmed to conform to an Eulerian graph so to generate a continuous printing path, which can effectively reduce the nozzle retractions during the printing process. In addition, to cater to the collision-free requirement and to improve the printing efficiency, we also propose a printing sequence optimization algorithm for determining a collision-free order of printing of the connected lattice infills, which seeks to reduce the air-move length of the nozzle. Ample experiments in both computer simulation and physical printing are performed, and the results give a preliminary confirmation of the advantages of our methodology.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
