Optimizing the Properties of Polymers and Composites Made by Additive Manufacturing

拟议的研究计划集中于对使用数字加法制造的材料的加工、结构和机械性能之间的关系进行分析和建模。术语“添加制造”，也称为“3D打印”，描述了许多不同的工艺，其中固体组件是通过沉积非常薄的材料层来构建的，这些材料层熔合或结合到先前沉积的层的材料上。商业机器已经被用来以这种方式沉积各种材料：聚合物、金属、陶瓷、复合材料，甚至生物兼容的人体组织支架。在所有情况下，各个层(最终是整个部分)都是直接从数字文件渲染的。这允许在零件的构思和实际三维对象的创建之间进行非常快速的转变。因此，加法制造也被广泛地称为“快速成型”。 对于非功能原型，材料性能通常不是很重要，然而，目前从添加原型到添加制造的过渡表明，理解制造参数、材料和部件完整性之间的关系将成为未来十年的关键问题。 熔融纤维的制备是一项关键的添加剂技术，它涉及到热塑性塑料熔融细丝的层层沉积。已知所得到的机械性能取决于材料、温度、打印速度、填充图案和孔隙率。我们正计划启动一项研究计划，重点是使用各种技术对FDM零件和断口表面进行结构分析。我们将发现结构和最终性能之间的关系，并将就数字印刷材料的最佳结构提出建议。我们还将学习加工条件如何控制结构，以便我们能够找到最佳方法，以低成本快速打印可用于结构应用的部件。

The proposed program of research centers on the analysis and modeling of the relationship between processing, structure, and mechanical properties of materials made using digital additive manufacturing. The term “additive manufacturing”, also known as “3D printing”, describes a number of different processes in which a solid component is constructed by depositing very thin layers of material that fuse or bond to the material of the previously deposited layer. Commercial machines have been made to deposit a variety of materials in this way: polymers, metals, ceramics, composites, and even biocompatible human tissue scaffolds. In all cases, the individual layers (and eventually the entire part) are rendered directly from a digital file. This allows for a very quick turnaround between the conception of a part and the creation of the actual three-dimensional object. Hence additive manufacturing has also been widely referred to as “rapid prototyping”. For a non-functional prototype, material properties are often not very important, however the current transition from additive prototyping to additive manufacturing suggests that an understanding of the relationship between manufacturing parameters, materials, and component integrity will become a critical issue over the next decade. Fused filament fabrication is one of the key additive technologies, and involves the deposition of thin molten filaments of thermoplastic, layer by layer. The resultant mechanical properties are known to be dependent on material, temperature, print speed, fill pattern, and porosity. We are planning to initiate a research program centered on the structural analysis of FDM parts and fracture surfaces using a variety of techniques.  We will discover relationships between the structure and final properties, and will make recommendations about the optimal structures for digitally printed materials.  We will also learn how the processing conditions control structure, so that we can find best way to make low-cost rapid prints of parts that can be used in structural applications.