US Egypt Cooperative Research: Freeform Fabrication of Porous Metallic Structures

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。德克萨斯大学奥斯汀分校的Bourell博士和Khalid M. Elghany，Central Metallurgical R D Institute，Egypt，以评估和优化多孔金属结构的自由成形制造工艺。多孔金属结构有几个重要的应用，例如直接从电子设计（CAD）数据快速制造人体定制的植入物和特殊形状的过滤器。对于这项研究，选择的自由成形制造技术是选择性激光烧结/熔化（SLS）。制造过程（直接和间接）的优化将基于最终部件的相对密度以及与用于创建部件的CAD实体模型相比的尺寸精度。间接加工涉及使用瞬时粘合剂和后处理，而直接加工涉及在自由成形制造机中构建最终部件。将对试样的机械性能进行表征，以预期服务应用。将进行详细的成本分析，以比较间接和直接SLS零件生产的效用。最后，可持续性问题将通过评估整个生命周期对环境的影响来解决每个过程。智力优点：在快速制造领域，直接与间接自由成形制造的整体效用正在进行辩论。该项目是通过选择性激光烧结（SLS）制造铁合金的这些方法的第一次“头对头”竞争。鉴于直接SLS加工集中在欧洲和中东，而间接SLS加工集中在美国，因此国际合作是可取的。更广泛的影响：从技术上讲，SLS的商业化仅限于金属的间接加工，因为商业机器不具有直接熔化粉末的能力。有几个外国实体开发具有直接熔化金属粉末能力的商用机器。这些努力主要集中在德国、比利时和联合王国，但在埃及也很明显。在美国，商用聚合物机器适用于通过间接SLS进行金属加工。本文所述的工作将产生直接的商业影响，因为它提供了一个明确的成本和环境影响的直接和间接的方法，为商业上重要的金属正在考虑快速制造的比较。一名研究生将参与美国的研究，从代表性不足的群体中招募。PI每年组织的国际固体自由成形制造研讨会将是一个国际性的演讲和出版场所。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This collaborative research project is being undertaken by Dr. David L. Bourell, University of Texas at Austin, and Dr. Khalid M. Elghany, Central Metallurgical R&D Institute, Egypt, to evaluate and optimize freeform fabrication processes for porous metallic structures.Porous metallic structures have several important applications such as rapidly fabricated human-body-tailored implants and specially shaped filters direct from electronic design (CAD) data. For this research, the freeform fabrication technology of choice is Selective Laser Sintering/Melting (SLS). Optimization of fabrication processes (direct and indirect) will be based on the resulting relative density of the final parts and the dimensional accuracy compared to the CAD solid model that is used to create the parts. Indirect processing involves the use of a transient binder and post-processing, whereas direct processing involves building of the final part in the freeform fabricator. Test specimens will be characterized for mechanical behavior in anticipation of service applications. A detailed cost analysis will be performed to compare the utility of indirect and direct SLS for part production. Finally, sustainability issues will be addressed for each process by assessing the total life cycle environmental impact.Intellectual Merit: There exists in the rapid manufacturing field an ongoing debate on the overall utility of direct versus indirect freeform fabrication. This project is the first "head-to-head" competition of these approaches for a ferrous alloy by Selective Laser Sintering (SLS). The international collaboration is desirable given that the concentration of direct SLS processing is in Europe and the Middle East, whereas indirect SLS processing is centered in the US. Broader Impacts: Technically, commercialization of SLS has been limited to indirect processing for metals since commercial machines do not have the capability to directly melt the powder. There are several foreign entities developing commercial machines with capabilities for melting metal powder directly. The efforts are centered in Germany, Belgium and the United Kingdom, but this focus is evident in Egypt as well. In the United States, commercial polymer machines are adapted to metal processing by indirect SLS. The work described here will have direct commercial impact as it provides an explicit cost and environmental-impact comparison of the direct and indirect approach for commercially important metals under consideration for rapid manufacturing. A graduate student will be involved in the USA research with recruitment from underrepresented groups. The International Solid Freeform Fabrication Symposium organized annually by the PI will be an international venue for presentation and publication.