It’s an easy thing to understand how 3D printing plastics works. A term known as additive manufacturing, it’s as simple as understanding that a layer of plastic is laid on top of another layer of plastic over time. Of course initially the plastic is going to be hot, to allow it be flexible and as it is printed it cools and solidifies – which leaves us with our 3D printed object.
As you will remember from your science days, metals are molten at a particular temperature, but that temperature is quite high, making this an untenable proposition in terms of safety or creating nozzles that could withstand this temperature. The process of 3D printing metal involves using powdered metals, which use a laser to either sinter or melt the power. Here’s a good definition from Wikipedia:
Selective Laser Sintering (SLS) is an additive manufacturing technique that uses a laser as the power source to sinter powdered material (typically metal), aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure.
There are various differences in technology, outcomes and techniques, but this gives you a good idea of how 3D printing metal might work. 3D printing materials in this way has been of interest to automotive and aviation industries, to develop new designs and for spare parts. The question has been whether the quality of these parts can stand up to the high specifications required for the aviation industry – would you be the first person in a fully 3D manufactured plane?
But the technology and the quality of the products have been developing to the point where Monash University have manufactured a small jet engine using 3D printed parts! Amazing, check out the video below