There's no denying that 3D printing is a fast and effective way to build new objects, but most engineers are taking tentative steps to its mass adoption because the results aren't proven to be truly robust. Now, physicists hope to convince them once and for all. The most common form of 3D printing for real-world engineering applications is selective laser melting. The process sees a fine layer of metallic powder spread over a moveable platform. High-intensity laser or electron beams are then used to selectively melt certain areas of the layer, which rapidly cool and solidify. The platform is moved, more powder added and the process repeated, until a complete object is formed.
The resulting components can be produced more quickly, and with greater intricacy, than conventional techniques. No surprise, then, that the likes of GE, NASA and Boeing are all experimenting with the technique. But, as Wayne King from the Lawrence Livermore National Laboratory explains in a press release, "if we want to put parts into critical applications, they have to meet quality criteria" — and currently not everyone is convinced.
Now, King and fellow researchers from the Laboratory have published a paper in Applied Physics Reviews that lays down a series models to describe the precise physics of how the technique works. The idea is to develop a better understanding of how the process behaves at all scales, from microscopic melting and cohesion of the powdered metal to the bulk properties of the final object.
The models allow engineers to calculate the stress and heat generated during manufacturing, to help them understand what happens to the metal during the process. That should allow them to work out how subtle anomalies in the printing process can lead to parts that contain faults that can go on to cause failure — and, crucially, work out how to prevent it from happening in the future.
In turn, the researchers hope that the models will allow engineers to more carefully tune things like laser power, speed and beam size. That should help them to create products that they're as confident to use in hostile, real-world situations as conventionally manufactured parts. If engineers are convinced, we could see a step-change in the adoption of 3D printing in industries such as aerospace.
"We want to accelerate certification and qualification to take advantage of the flexibility that metal additive manufacturing gives us," explained King in a press release. "Ideally... plants would like to build a part on Monday that can be qualified and on the same machine on Tuesday build a different part that can also be qualified... We're talking about getting to the place of saying 'just press print' for metal."
Image by Sandia Labs