哪种技术将主导 3D 打印？

随着 3D 打印（也称为增材制造）日益成为先进制造的关键组成部分，进一步推动 3D 打印变得十分重要。

3D printing, also known as additive manufacturing, is rapidly becoming a crucial component of advanced manufacturing processes. As 3D-printed parts and components are frequently utilized in highly demanding applications, such as automotive engines, rockets, and military equipment, any failure in a single component can have catastrophic consequences.

3D 打印，也称为增材制造，正在迅速成为先进制造工艺的重要组成部分。由于 3D 打印零部件经常用于要求很高的应用，例如汽车发动机、火箭和军事设备，因此单个组件的任何故障都可能造成灾难性后果。

To mitigate this risk and pave the way for 3D printing to become the dominant manufacturing method, surpassing traditional techniques like melting metal in casts and machining, continuous optimization of the 3D printing process is paramount.

为了降低这种风险并为 3D 打印成为主导制造方法铺平道路，超越铸造和机械加工中熔化金属等传统技术，持续优化 3D 打印工艺至关重要。

Among the various 3D printing techniques, laser powder bed fusion is particularly suited for precision manufacturing. Researchers at the University of Wisconsin-Madison and Argonne National Laboratory have recently employed advanced X-ray imaging to analyze this process meticulously, uncovering promising avenues to drastically reduce defects during manufacturing. Their findings were published in the International Journal of Machine Tools and Manufacture, under the title “Revealing mechanisms of processing defect mitigation in laser powder bed fusion via shaped beams using high-speed X-ray imaging”.

在各种 3D 打印技术中，激光粉末床熔融特别适合精密制造。威斯康星大学麦迪逊分校和阿贡国家实验室的研究人员最近采用先进的 X 射线成像来仔细分析这一过程，发现了大幅减少制造过程中缺陷的有希望的途径。他们的研究结果发表在《国际机床与制造杂志》上，标题为“通过使用高速 X 射线成像的成形光束揭示激光粉末床熔合中加工缺陷缓解的机制”。

The Mechanics of Laser Powder Bed Fusion

激光粉末床熔融的力学原理

In powder bed 3D printing, a layer of powder containing the material used for additive manufacturing is spread out in a container. A laser then selectively melts/fuses the powder in the zone that will eventually form the 3D-printed item.

在粉末床 3D 打印中，含有用于增材制造的材料的粉末层铺展在容器中。然后，激光选择性地熔化/熔合区域中的粉末，最终形成 3D 打印物品。

Following this, another layer of powder is deposited on top, and the portions that need to be melted and added to the item are once again targeted by the laser. By repeating this process over time, even highly complex shapes and relatively large items can be produced.

随后，另一层粉末沉积在顶部，需要熔化并添加到物品中的部分再次被激光瞄准。通过随着时间的推移重复这个过程，甚至可以生产高度复杂的形状和相对较大的物品。

You can observe laser powder bed fusion in action in this video, along with examples of items that can be made using this technique.

您可以在此视频中观察激光粉末床融合的实际情况，以及可以使用该技术制造的物品的示例。

This method is not limited to plastics; it can also be used to create items made of metals, including titanium, steel, cobalt-chromium, aluminum, and more.

这种方法不仅限于塑料；它还可用于制造金属制品，包括钛、钢、钴铬、铝等。

The advantages of this method lie in its ability to create precise geometry, with tolerances of +/- 0.2mm, which are comparable to metal injection molding, and its efficiency in material usage, as the unused powder can be collected back and reused.

该方法的优点在于能够创建精确的几何形状，公差为 +/- 0.2 毫米，可与金属注射成型相媲美，而且其材料使用效率高，因为未使用的粉末可以回收并重复使用。

Moreover, by simultaneously using multiple lasers, which is typically found in more advanced 3D printer designs, larger parts can be printed quickly.

此外，通过同时使用多台激光器（通常在更先进的 3D 打印机设计中使用），可以快速打印更大的零件。

It's important to note that laser powder bed fusion encompasses several sub-techniques, including:

值得注意的是，激光粉末床融合包含多种子技术，包括：

Revealing Mechanisms to Prevent 3D Printing Failures

揭示防止 3D 打印失败的机制

In theory, additive manufacturing of metal parts should yield results equivalent to those obtained from traditional casted parts. However, in practice, issues can arise, such as pores, or “voids,” on the surfaces, and large spatters.

理论上，金属零件的增材制造应该产生与传统铸造零件相同的结果。然而，在实践中，可能会出现一些问题，例如表面上的孔隙或“空隙”以及大的飞溅。

Such structural imperfections can lead to the parts breaking, which is unacceptable in critical applications.

这种结构缺陷可能导致零件断裂，这在关键应用中是不可接受的。

“Because we understood the underlying mechanisms, we could more quickly identify the right processing conditions to produce high-quality parts using the ring-shaped beam.”

“因为我们了解基本机制，所以我们可以更快地确定正确的加工条件，以使用环形梁生产高质量的零件。”

Lianyi Chen – Associate professor of mechanical engineering at UW-Madison

Lianyi Chen – 威斯康星大学麦迪逊分校机械工程副教授

The Ring-Shaped Laser Beam

环形激光束

The first modification made by the researchers to their 3D printing setup was to replace the standard laser beam with a ring-shaped laser beam, which was provided by nLight, a laser company specializing in semiconductor lasers.

研究人员对其 3D 打印装置所做的第一个修改是将标准激光束替换为环形激光束，该激光束由专门从事半导体激光器的激光公司 nLight 提供。

This distinct shape facilitates better circulation of the melted metal within the melt pool overall and results in smaller waves on the surface of the freshly created item, reducing the size and distance traveled by the spatters.

这种独特的形状有利于熔化的金属在熔池内更好地循环，并在新创建的物品表面产生更小的波浪，从而减少飞溅的尺寸和传播距离。

Matching Model And Observations

匹配模型和观察结果

The researchers went on to verify these observations using the high-energy synchrotron X-ray facility at Argonne National Laboratory. They employed this facility to capture high-speed snapshots of the 3D printing process, which allowed them to check whether their mathematical model accurately simulated reality.

研究人员继续使用阿贡国家实验室的高能同步加速器 X 射线设备验证了这些观察结果。他们利用该设施捕获 3D 打印过程的高速快照，这使他们能够检查他们的数学模型是否准确地模拟了现实。

3D Printing At A Quicker Pace

更快的 3D 打印

Another achievement was the ability of the ring-shaped beam to penetrate deeper into the powder without causing more instability. This led to thicker layers without compromising the strength of the finished product.

另一项成就是环形光束能够更深入地穿透粉末，而不会造成更多的不稳定。这导致了更厚的层而不影响成品的强度。

As the production ultimately requires fewer layers, this speeds up manufacturing and increases the overall productivity of the machine.

由于生产最终需要更少的层数，这加快了制造速度并提高了机器的整体生产率。

An Example of Powder Bed Fusion in Practice

粉末床融合的实践示例

This line of work is far from being merely an academic demonstration; it has the potential to directly improve powder bed fusion machinery already used in the industry.

这项工作远非仅仅是学术演示；它有可能直接改进行业中已使用的粉末床熔融机械。

A prime example would be in aeronautics, with the fuel nozzle on General Electric’s GE9X engine, which is used on Boeing 777 aircraft.

一个典型的例子是航空业，通用电气 GE9X 发动机上的燃油喷嘴，用于波音 777 飞机。

The GE9X is the largest turbo-fan engine produced, and the additively manufactured nozzle is five times more durable than previous versions.

GE9X 是生产的最大的涡轮风扇发动机，增材制造的喷嘴比以前的版本耐用五倍。

It's worth noting that such developments are still very recent, with the GE9X design being approved by the FAA in 2020.

值得注意的是，此类发展仍然是最近才出现的，GE9X 的设计已于 2020 年获得美国联邦航空局 (FAA) 的批准。

Even a higher quality powder bed fusion process, as well as a quicker one, could improve the design further while at the same time reducing its costs.

即使是更高质量和更快的粉末床熔融工艺，也可以进一步改进设计，同时降低成本。

The Future of 3D Printing: Advanced Manufacturing Domination

3D打印的未来：先进制造占据主导地位

We have previously covered how 3D Printing is consolidating into the future of manufacturing.

我们之前介绍过 3D 打印如何融入未来的制造业。

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