How does metal 3D printing work?
Metal 3D printing makes it possible to manufacture the most complex rocket parts using flame-retardant materials. While 3D printing is not new, how has the technology evolved to face more extreme space conditions?
From plastic to metal
Since the first 3D printers appeared in the 1980s, its applications have been constantly evolving. Initially, this technology was relatively unknown, according to Live Science, but gained popularity in the 21st century. In the early years of 3D printing, it was used primarily for rapid prototyping, and available filament was limited to plastics. This flexible material is the simplest choice for 3D printing because it can be easily melted and shaped.
At room temperature, the metal does not naturally allow printing as a liquid. However, this is exactly what today’s machines allow. To create small shapes in metal, 3D printing is a much faster method than cutting metal. Then a subtraction process, the book Introduction to Plastic Engineering (2018) This, explained, involves carving into blocks of metal that are roughly the same shape, and it can be extremely expensive and time consuming. Instead, 3D printing is an additive process that uses carefully selected dimensions to build 3D layer by layer.
Some metallographic printing methods have more steps than others, based on the printing method. Selectively sintering metal prints metal by combining it with resin. This makes the printing process similar to the plastic printing process. The difference is that when removed from the machine, it is still not a completely metal piece. The next steps strengthen the printed part and remove the unwanted plastic.
Related: Relativity Space announces fully reusable 3D printed Terran R rocket
Space application
Metal printing is favored by many engineers tasked with fabricating space-based components such as metal parts for rocket. Because rocket engines need to be able to withstand very high temperatures, Inconel copper superalloy powders are often chosen. Inconel is a special superalloy recognized for its resistance to corrosion and oxidation.
Instead of incorporating plastic into a metal filament, printing for space applications is better suited to Direct Metal Laser Sintering. To produce dense rocket parts, bulk metal powders are formed into several layers. Between each layer placed, a laser is shined on the metal powder. The laser traces out the exact shape dictated by the digital file, melting and bonding the metal in the process. This is repeated for each layer, until the solid metal shape is submerged in the excess metal powder.
Soon, metal 3D printing could take place in space to create tools, instead of sending devices with rockets. This will reduce the time it takes to receive replacement parts for repair as well as the cost of flying them from Earth to the International Space Station (ISS). NASA currently funding metal 3D printing research in low gravity. Depending on the success of manufacturing in space, the future could include printing a base on the moon.
Molten metal
From the digital file to the metal part, follow the steps of the metal printing process in the following interactive images.
Additional sources
What’s next for metal 3D printing in space? You can read about the progress towards automated 3D printing in space in NASA article. Or, learn more about how 3D printing can help Space Station Research.
https://www.space.com/metal-3d-printing How does metal 3D printing work?
