Video Transcript

Welcome to the Metal Additive Manufacturing lab at the Air Force Institute of Technology. The metal additive manufacturing lab does what is called 3D printing. So those terms, metal additive manufacturing, or metal 3D printing are synonymous. In this lab, we have two machines, a smaller one and a larger one and they each have different capabilities, as far as the laser that is used to accomplish the 3D printing. Talking about 3D printing, you’re probably used to a plastic 3D printer, which you’ve likely seen in your home, in a library or in a school. A plastic 3D printer uses a heated nozzle and a plastic filament to follow instructions or vectors to build a part layer after layer. Where a head will move around on some bill plate of glass or metal and depositing some plastic filament. The metal 3D printers operate by much the same principal, but instead of a plastic filament, they are wiping a layer of powder across a metal plate, like this one here. So this a solid piece of metal, the laser will follow the same sorts of instructions or vectors, and melt with a laser on this plate; essentially welding to it. And then layer after layer, a wiper will move a layer of powder onto the plate and build up successive layers constructing a part. In the video, you see a wiper moving across that metal carriage that just went across the screen, that was the wiper which moves the powder across the bed. Now, you see the laser, which is melting areas of the bed, shown by this sort of burst of light. That’s actually a laser moving very, very quickly in a back and forth, or squiggly, meandering pattern. You see it’s kind of slowly solidifying various areas on the plate and those are the areas in this particular layer which are the sort of vertical slice in the part for this layer. After this layer finishes, the wiper, or that metal carriage that we saw at the beginning of the video, will wipe across again, just like your windshield wipers will, but instead of pushing water on your windshield, this is pushing powder. Notice how you can see the metal parts and those metal parts are now disappearing as the wiper moves across. That’s because they’re buried under a layer of powder. And so, this is the working principal for metal 3D printers which operate by selective laser melting or laser powder bed fusion. There are other types of metal 3D printers, which operate by a filament type or they’ve got metal particles inside of a plastic filament. But those have issues because the plastic has to be melted out afterwards to allow those metal particles to come together and form a solid part. There are issues there with solidifying and shrinkage of the part, and so it is very difficult to make a useful part. The selective laser melting, or laser powder bed fusion process essentially creates a one-to-one shape of the part you are trying to make. So the preferred, or most promising technology for creating air craft parts and other parts which will have engineering and technical relevance. So in my hand, I have a finished 3D printed part from the video you watched on the 3D printer. You can see it has a fully built up structure and after it was done building, it had to be removed from the bill plate, or that metal piece that I showed you earlier, with various machining tools. So, set that aside. That is just one example of things that can be 3D printed. That one has special relevance and interest because it is something that couldn’t be manufactured any other way than with a 3D printer. We’re using our 3D printers for lots of different types of research, like developing new materials, things to try to make new materials that could be 3D printed to enable new applications for the Air Force. Thank you for coming by the metal additive manufacturing lab and I hope you enjoyed your visit!