Abstract The performance of 3D printed sand molds with internal hollow structures was studied. The influence of the internal hollow structures (a single layer air cavity or multilayer air cavities) on heat flux was theoretically analyzed and numerically simulated using COMSOL software. Better insulation effect was achieved by reducing the cavity spacing, and multilayer air cavities performed better than a single layer air cavity. 3D printed sand molds with these hollow structures for a stress-frame casting and a bar-shaped casting were designed and poured with aluminum alloy A356 melt. The solidification time of the riser surrounded by three layers of air cavities was prolonged by over 30%, and its feeding function during solidification was significantly improved. The temperature difference within the stress-frame casting was decreased using three layers of air cavities surrounding its thin rods, resulting in a 40% reduction of the residual stress in the thin rods. Open air cavity structure was used for air blowing during the solidification process to increase the cooling rate of one thin rod of the cast specimen, and its secondary dendrite arm spacing was narrowed.

中文翻译：

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3D打印技术制造砂型中空心结构的影响

摘要 研究了具有内部中空结构的3D打印砂模的性能。利用COMSOL软件对内部中空结构（单层气腔或多层气腔）对热通量的影响进行了理论分析和数值模拟。通过减小腔体间距达到更好的保温效果，多层气腔的性能优于单层气腔。设计了具有这些中空结构的 3D 打印砂模，用于应力框架铸件和棒状铸件，并用铝合金 A356 熔体浇注。三层气腔包围的冒口凝固时间延长30%以上，凝固过程中的进料功能得到显着改善。应力框架铸件内的温差通过使用围绕其细棒的三层空气腔来降低，从而使细棒中的残余应力降低了 40%。在凝固过程中采用开放式空腔结构吹气，以提高铸件一根细棒的冷却速度，并缩小其二次枝晶臂间距。