Structured Filaments for High Performance 3D Printed Plastic Objects

该资助将支持研究，为一种常见的3D打印方法的原料设计提供新的基础知识，为改进的塑料部件提供指导，以实现从快速原型到制造的转换。增材制造从数字计算机模型中生成几乎任何形状的近净形状物体，对于发展对国家生产力至关重要的新制造方法至关重要。增材制造通常被称为3D打印，它为个人消费者的大规模定制提供了革命性的可能性，因此符合人体工程学。然而，几乎所有塑料零件的增材制造工艺都会导致零件的固有弱点，使其不如传统制造的塑料。该资助支持基础研究，通过对一种称为熔丝制造的3D打印的原料进行可扩展的改变，为提高增材制造塑料部件的性能提供所需的知识。新材料将与现有的打印机兼容，包括普通大众可用的消费者打印机，但将在获得更好地匹配所需尺寸和提高韧性的部件方面取得重大改进。塑料部件的增材制造随着医疗保健的应用而增长，以帮助医生计划手术和定制植入物用于颅面修复，以减少非关键部件的重量。通过提高塑料零件的性能，本研究将通过扩展增材制造塑料零件的潜在应用，使美国经济和社会受益。本研究涉及制造业、材料科学、机械工程等多个学科，将为参与本研究的学生提供独特的教育体验。此外，所生产的材料将与许多商业3D打印机兼容，包括一些K-12学校的3D打印机，因此，与这些学校的接触将为学生提供一个机会，通过动手的方式了解增材制造和材料设计。结构细丝的设计假设克服了机械性能和尺寸精度之间的内在权衡与挤压聚合物增材制造相关。一般来说，由于温度限制了聚合物链的相互扩散，打印过程中层间强度较差，打印温度升高会导致打印部件流动和变形。本研究试图通过芯-壳结构来克服这种权衡，其中芯提供机械增强以抑制流动，而壳在较低温度下固化以提供层间强度。然而，对于增材制造中的核壳材料，与材料选择和打印加工相关的基本要求知之甚少。本研究将通过系统的实验研究，填补在固化温度、力学性能和核壳聚合物混相关系方面的知识空白。研究团队将建立工艺参数、聚合物的固有材料特性、打印部件的尺寸精度和机械性能之间的关系，以深入了解基于挤出的塑料物体增材制造的局限性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This grant will support research that will contribute new fundamental knowledge related to the design of the feedstock for one common method of 3D printing to provide guidance for improved plastic parts to enable the translation from rapid prototyping to manufacture. Additive manufacturing generates near net shape object of virtually any shape from a digital computer model and is critical to the development of new manufacturing approach essential for the national productivity. Additive manufacturing is commonly called 3D printing and offers revolutionary possibilities in terms of massive customization for the individual consumer, so the fit is ergonomically perfect. However, almost all additive manufacturing processes for plastic parts lead to inherent weaknesses in the parts that make them inferior to traditionally manufactured plastics. This grant supports fundamental research to provide needed knowledge for the development of improved performance of additive manufactured plastic parts through scalable changes in the feedstock for one type of 3D printing called fused filament fabrication. The new materials will be compatible with existing printers, including consumer printers that are available to the general public, but will enable significant improvements in obtaining parts that better match the desired dimensions and with improved toughness. Additive manufacture of plastic parts is growing with applications from healthcare to assist doctors with planning surgery and custom implants for craniofacial restoration to aerospace parts to decrease the weight of non-critical components. Through improving the performance of plastic parts, this research will benefit the U.S. economy and society by extending the potential applications for additively manufactured plastic parts. This research involves several disciplines including manufacturing, materials science, and mechanical engineering, which will provide a unique educational experience for the students involved in this research. Additionally, the materials produced will be compatible with many commercial 3D printers, including those found in some K-12 schools, so outreach to these schools will provide the students with an opportunity to learn about additive manufacturing and design of materials with a hands-on approach. The design of structured filaments is hypothesized to overcome the intrinsic trade-off between mechanical properties and dimensional accuracy associated with extrusion-based polymer additive manufacturing. Generally, there is poor interlayer strength during the print as the interdiffusion of polymer chains is limited by the temperature and increasing the printing temperature leads to flow and deformation of the printed part. This research seeks to overcome this trade-off with a core-shell structure to the feedstock filament, where the core provides mechanical reinforcement to inhibit flow, while the shell solidifies at lower temperature to provide interlayer strength. However, the fundamental requirements associated with the materials selection and the print processing are poorly understood for the core-shell materials in additive manufacturing. This research will fill the knowledge gap on the relationships between solidification temperature, mechanical properties and miscibility of the core and shell polymers through systematic experimental investigation. The research team will establish relationships between process parameters, intrinsic material properties of the polymers, the dimensional accuracy of the printed part, and mechanical properties to provide insights into the limitations of extrusion-based additive manufacturing for plastic objects.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.