增材制造中耦合零件表面粗糙度及支撑面积的建造方向优化

以熔融沉积(fused deposition modeling, FDM)技术为基础,研究了建造方向对于零件表面粗糙度以及支撑的影响.通过实验测试新型聚乳酸(polylactic acid, PLA)材料零件不同建造方向下的表面粗糙度,结合理论及经验公式,建立符合实际情况的粗糙度综合预测模型.对于复杂多面体零件,通过选择功能性表面,建立建造方向集合,在有限的方向集合内选择最优建造方向,从而整体提升零件表面粗糙度.提出了基于光固化立体造型术(stereolithography, STL)文件格式的支撑面积数学模型,以支撑面积最小为优化目标,使用遗传算法(genetic algorithm, GA)进行单目标优化,搜寻最优建造方向.针对不同建造方向下,表面粗糙度和支撑面积的耦合问题,建立多目标优化模型,使用遗传算法全局搜寻最优建造方向.

Optimization of Building Orientation Coupling Supporting Area and Surface Roughness in Additive Manufacturing

Based on the fused deposition modeling (FDM) technology, the influences of building orientation on surface roughness and supporting area are studied. The surface roughness of parts made by polylactic acid (PLA) at different building orientations is tested in experiments, and combined with the theoretical and empirical formula, a novel model for surface roughness prediction is established which conforms to the actual situation in manufacturing. Through the determination of functional surface, the set of building orientations is established in which the best building orientation can be found aiming at improving the surface quality of a complex multiple-surface part. Based on the stereolithography (STL), a mathematical model for the supporting area is established. The single objective genetic algorithm (GA) is used to optimize the building orientation to minimize the supporting area. Coupling surface roughness and supporting area, a multi-objective optimization based on GA is established to search for the global optimal solution.