Structured Filaments for High Performance 3D Printed Plastic Objects

该补助金将支持研究，这些研究将为一种常见的3D打印方法提供与原料设计相关的新基础知识，为改进塑料部件提供指导，从而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物体，对于开发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，为个人消费者提供了大规模定制的革命性可能性，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，使其劣于传统制造的塑料。该补助金支持基础研究，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，为开发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，包括向公众提供的消费者打印机，但将在获得更好地匹配所需尺寸和提高韧性的部件方面实现重大改进。塑料零件的增材制造随着医疗保健的应用而增长，以帮助医生规划手术和定制颅面修复植入物，以减少航空航天零件的非关键部件的重量。通过改善塑料部件的性能，这项研究将通过扩大增材制造塑料部件的潜在应用，使美国经济和社会受益。这项研究涉及多个学科，包括制造，材料科学和机械工程，这将提供一个独特的教育经验，为参与这项研究的学生。此外，生产的材料将与许多商业3D打印机兼容，包括一些K-12学校中的3D打印机，因此与这些学校的联系将为学生提供一个学习增材制造和材料设计的机会。 假设结构化长丝的设计克服了与基于挤出的聚合物增材制造相关联的机械性能和尺寸精度之间的内在权衡。通常，在印刷期间存在差的层间强度，因为聚合物链的相互扩散受到温度的限制，并且提高印刷温度导致印刷部件的流动和变形。本研究试图克服这种权衡与核-壳结构的原料长丝，其中核提供机械增强，以抑制流动，而壳在较低的温度下固化，以提供层间强度。然而，对于增材制造中的核壳材料，与材料选择和打印处理相关的基本要求知之甚少。本研究通过系统的实验研究，填补了核壳聚合物固化温度、力学性能和相容性之间关系的知识空白。该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，以深入了解塑料物体基于挤出的增材制造的局限性。该奖项反映了NSF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.