Almonti Daniele, Ucciardello Nadia
Dipartimento di Ingegneria dell'Impresa "Mario Lucertini", Università di Roma "Tor Vergata", Via del Politecnico 1, 00133 Rome, Italy.
Materials (Basel). 2019 Jul 13;12(14):2261. doi: 10.3390/ma12142261.
Additive manufacturing (AM) processes are used to fabricate three-dimensional complex geometries. There are several technologies that use laser or electron beam over metal powder beds. However, the direct AM processes have inconveniences such as specific set of materials, high thermal stress traced, high local energy absorbed, poor surface finish, anisotropic properties, high cost of material powder, and manufacturing with high-power beams. In this paper, an alternative process was developed. An indirect additive manufacturing (I-AM) combining a 3D print of castable resin and metal casting in order to obtain a cellular structure similar in shape to commercial metal foams but completely definable as design features was developed. Design of the cellular structure was made by the graphical algorithm editor Grasshopper. Designed structures were realized by a lost-wax casting process and compared with commercial foam specimens by a system designed for this work. The designed metal foams showed a performance superior to that of commercial metal foam; in particular, the heat thermal coefficient of designed metal foams in the better case was 870 W/m·K, almost doubled in comparison with the commercial foam tested in this work.
增材制造（AM）工艺用于制造三维复杂几何形状。有几种技术是在金属粉末床上使用激光或电子束。然而，直接增材制造工艺存在一些不便之处，如特定的材料组合、较高的热应力、高局部能量吸收、表面光洁度差、各向异性性能、材料粉末成本高以及使用高功率光束进行制造等。本文开发了一种替代工艺。开发了一种间接增材制造（I-AM）方法，它将可铸造树脂的3D打印与金属铸造相结合，以获得一种形状与商业金属泡沫相似但可完全作为设计特征定义的多孔结构。多孔结构的设计由图形算法编辑器Grasshopper完成。通过失蜡铸造工艺实现设计的结构，并通过为此工作设计的系统与商业泡沫样本进行比较。设计的金属泡沫表现出优于商业金属泡沫的性能；特别是，在较好情况下设计的金属泡沫的热系数为870W/m·K，与本文测试的商业泡沫相比几乎翻倍。
