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直接金属激光烧结（DMLS）是一种3D印刷金属的奇特方式，是航空航天工程的新趋势。DMLS使用YTTerbium光纤激光灭火到粉末金属床中，将材料焊接在一起以产生固体结构。对于您无法使用传统制造技术构建的复杂金属部件非常棒。
On April Fool’s Day in 2016, SpaceX sent out a company-wide email claiming they were going to 3D print the entire Falcon 9 rocket. While the technology is not ready to print the entire rocket in one build, it’s definitely capable of printing many of its components.
This article will explain the details of DMLS, the benefits and drawbacks associated with the technology, and how it is helping the aerospace industry.
How DMLS works
DMLS使用精确的高瓦数激光至微焊接粉末金属和合金以形成全功能性金属部件。由于加工限制，DMLS能够产生极其困难的部分，以前是不可能制造的复杂几何形状。零件通过层加热层，通常为20微米厚。
这个过程很容易媲美SLS 3D Printing Technology，使用高功率激光器烧结粉末材料，将其结合在一起以产生固体结构。
History of DMLS
DMLS was developed by theEOSfirm in Munich, Germany. In 1995, EOSINT M 250 launched a DMLS system for additive manufacturing of metal tools for plasticsinjection molding, and that was the start of rapid tooling. In 2001, EOS created a 20 micrometer layer thickness for the DMLS process, improving part quality. The EOSINT M 270 launched in 2004, which was the first commercial DMLS system with fiber laser, an optical fiber doped with rare-earth elements, and in 2007, EOS introduced EOS Titanium Ti64, the first commercial DMLS process for titanium.
DMLS系统
EOS now has 5 DMLS systems: EOS M 100, EOS M 290, EOS M 400, EOSINT M 280, and PRECIOUS M 080.
- 这EOS M 100是一种高端系统，可快速高效地生产复杂的金属部件。
- 这EOS M 290.是高品质金属部件的工业3D打印机，具有增强的质量管理功能。
- 这EOS M 400.is for the industrial production of high-quality large metal parts.
- 这Eosint M 280.is capable of metal products directly from CAD data.
- 这PRECIOUS M 080is a high-end system capable of producing precious metal products designed for the jewelry and watchmaking industries.
DMLS材料包括不锈钢17-4 pH，不锈钢316L，铝ALSI10MG，INCOLEN 625和718，钛TI64和钴铬COCRMO。这些材料总结在下表中，以及其一些材料特性。可以找到更多材料属性信息here. These materials are strong, durable, heat-resistant, and denser than investment-casted metal parts.
DMLS具有大量的益处，从设计自由到快速，功能部件。它允许人们构建难以或不可能与其他制造过程制造的复杂金属部件。这些件包括带空腔，底切和拔出角度，工具，固定装置，夹具，转子和叶轮的零件。DMLS还允许通过整合设计和优化值，并将多个部件（如架构，紧固件和切片部分）集成到单个部件中的多个组件。
摘要也有一些局限性,最大的cost. The cost of a machine starts at around $500,000 and the machine requires a lot of maintenance and upkeep. Furthermore, the surface finish of DMLS pieces are very grainy and the metallic support structure removal and post processing is time consuming and requires machining. Lastly, the pieces are not always built to spec and it is difficult to qualify if they meet the specified tolerances.
Even with its limitations, DMLS has been taking over the aerospace industry. GE is 3D printing fuel nozzles for their new LEAP and GE9x engines and have performed successful test flights with the 3D printed parts. The 3D printed fuel nozzles give the engines stronger thrust, reduced fuel consumption, and higher durability.
Spacex还使用3D打印技术，拥有多个DMLS打印机。它们在九个Merlin 1D发动机之一和2014年1月6日之前用主氧化剂阀体3D打印，成功地将火箭发射到太空中。
Spacex也使用DMLS来生产其再生冷却的SuperDraco发动机室, which will be used on the crewed spaceflight program and the龙版本2.vehicle. In 2013, the SuperDraco engine successfully fired at full thrust using the 3D-printed engine chamber.
DMLS是一项惊人的技术，真正有助于航空航天行业的创新。当每磅或毫米的物质事项时，由于加工限制，之前无法制造之前的印刷件，这是革命性的。航空航天3D印刷有空间改善，特别是在完成和后处理，但看到潜力非常令人兴奋。与此同时，由于成本，可用性和提前时效，塑料和传统制造方法足以满足大多数应用。
