DMLS vs SLM 3D Printing for Metal Manufacturing

3D printing is revolutionizing the world of 制造业, 允许公司以相对较低的成本快速生产原型和专用组件. Most applications of 3D printing use molten plastic to produce objects in a wide variety of designs; 然而, 金属3D打印也正在成为金属锻造和制造im体育平台app下载的流行技术. 

用于进行金属增材制造的技术与用于打印塑料的技术略有不同. The two main techniques are direct metal laser sintering and selective laser melting. 

Direct Metal Laser Sintering 

One of the most effective additive 制造业 techniques for metal is direct metal laser sintering, also known as DMLS. This process can be used to build objects out of almost any metal alloy, unlike other 3D printing techniques, which only work with polymer-based materials or specific metal alloys. 

直接金属激光烧结包括在要打印的表面上扩散一层非常薄的金属粉末. A laser is slowly and steadily moved across the surface to sinter this powder, which means that the particles inside the metal are fused together, even though the metal is not heated enough to allow it to melt completely. Additional layers of powder are then applied and sintered, thus “printing” the object one cross-section at a time. 通过这种方式，DMLS通过一系列非常薄的层逐渐建立一个3D对象. 

Once the DMLS process has been completed, the printed object is left to cool. Excess powder can be recovered from the build chamber and recycled. 

DMLS的主要优点是，它产生的对象没有残余应力和内部缺陷，可以困扰传统制造的金属部件. 这对于在高压力下工作的金属部件是极其重要的, such as aerospace or automotive parts. 传统制造的金属部件需要在制造后进行热处理，以消除可能导致部件失效的内应力. 

The main downside of DMLS is that it has so far been very expensive, which has limited its use to very high-end applications, such as 制造业 metal prototype parts in the aerospace industry. 然而, 密歇根理工大学的科学家们已经开发出一种只需1美元的3D金属打印机,建造500座. 相比之下，大多数商用金属3D打印机每台的成本超过50万美元. The printer is still very early in development; however, this breakthrough could make DMLS technology much more affordable in the future. 

Selective Laser Melting

Another method of 3D metal printing is selective laser melting (SLM), 高能激光将每一层金属粉末完全熔化，而不仅仅是烧结. Selective laser melting produces printed objects that are extremely dense and strong. 

Currently, selective laser melting can only be used with certain metals. The technique can be used for the additive 制造业 of stainless steel, 工具钢, 钛, 钴铬合金, and aluminum parts. 研究人员希望SLM有一天能被用来制造其他金属制成的零件, but there are difficulties that still need to be resolved. 许多其他金属不具有适合SLM所需的正确流动特性. 

Selective laser melting is a very high-energy process, as each layer of metal powder must be heated above the melting point of the metal. 在SLM制造过程中发生的高温梯度也会导致最终产品内部的应力和位错, which can compromise its physical properties. 

美国国家航空航天局正在研究使用选择性激光熔化技术为其航天器生产高度专业化的部件. 2013年8月, 美国宇航局发布了一份新闻稿，描述了它是如何使用SLM生产3D打印火箭发动机喷射器的. 3D打印部件在8月22日进行的发动机点火测试中成功运行, 2013. 

美国宇航局表示，SLM提供的一大优势是，它允许工人制造金属设备作为一个整体, 而不是生产单个部件并将它们组装起来以创造最终产品. 例如, the engine injector that was tested in August 2013 was made up of just two parts, compared to 115 parts in a similar injector that was previously tested. Having fewer parts means that complex equipment is easier to assemble. 

SLM在金属制造中的应用也由德国公司SLM Solutions率先推出. This company produces SLM machines for use in factories. 该公司的3D金属打印机被工业集团西门子(Siemens)用于生产燃气轮机的替代叶片. 使用SLM Solutions的3D金属打印机生产涡轮叶片所需的时间可以缩短到短短四周, compared to 44 weeks using current technologies. 

3D printing could significantly speed up metal 制造业, 当重要设备发生故障时，减少企业等待更换金属部件的停机时间. 这可能会产生多米诺骨牌效应，减少许多使用金属工具和机器制造产品的不同im体育平台app下载的延误. 

Electron Beam Melting 

电子束熔化(EBM)是一种与选择性激光熔化非常相似的增材制造工艺. Like SLM, it produces models that are very dense. 这两种技术的不同之处在于EBM使用电子束而不是激光来熔化金属粉末. 

Currently, electron beam melting can only be used with a limited number of metals. Titanium alloys are the main starting material for this process, although 钴铬合金 can also be used. The technique is used primarily to manufacture parts for the aerospace industry. 

The Future of 3D Metal Printing 

发展s in laser technology, such as the introduction of the femtosecond laser, 是否可以扩大增材制造技术的使用范围，使其可以与更大范围的金属和金属合金一起使用. 飞秒激光器对于3D金属打印非常有用，因为它们可以提供非常短的高能激光脉冲, allowing them to fuse metal powders with a greater-than-ever level of precision. 

随着金属3D打印技术的不断发展和技术成本的进一步下降, 3D printing could play an ever-greater role in metal 制造业. 3D printing techniques avoid many of the typical pitfalls of metal 制造业, 如需要后期热处理和专用机器铣削和精加工金属物体. 金属3D打印还可以显著加快许多金属领域的生产速度 制造业.

For more information on Direct Metal Laser Sintering (DMLS), Selective Laser Melting (SLM) or Electron beam melting (EBM), 请 立即im体育APP.