Image a robot-controlled hot glue gun that uses plastic instead of glue, and you have the basics of a 3D printer. Strings of plastic are fed into a printhead that is heated to melt the material. The printhead moves very precisely in three dimensions and releases lines of plastic on the print bed ̵1; the table where it is printed. The printer does it over and over again, build plastic plastics until it forms a 3D part.
Everything begins with 3D models
Each item printed on a 3D printer begins with a 3D model. These are usually done in a CAD program that is designed to work on 3D models in reality, such as TinkerCAD, Fusion360 or Sketchup. This is a little different than how 3D models can be made for movies or games, but you can certainly print very detailed numbers from traditional 3D modeling software.
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An advantage of a 3D printer is that it can print almost anything. Some models are so complex that they are impossible to do with traditional manufacturing techniques such as casting or CNC routing, and that's where 3D printers take a clear lead. But they are not only used to make beautiful geometric shapes, as it is usually much cheaper for a large-scale R & D department to print a plastic model instead of rigging the entire factory to make the actual part. This is called prototype, which makes a rough draft to help test the final copy without wasting valuable time and material.
Slicing the Model Printing
Since a printer does not understand how to compile a complex 3D network and turn it into a print model, the 3D model must be decoded to information that the printer can understand. This process is called slicing because it takes scans of each layer of the model and tells the printer how to move the print head to create each layer in turn. It is done using a disk, a program that manages all of this for you, such as CraftWare or Astroprint.
The slider manages the model's "fill", creating a lattice structure in a solid model to provide extra stability. This is an area where 3D printers light up – they can print very strong materials with very low densities by strategically creating pockets of air inside the model and making it much easier.
Another thing that disk handles are about are support columns. Because the printer can not lay down plastic on thin air, support columns must be created to allow the printer to bridge the gap. These are removable but are used in the printing process to ensure that it does not collapse.
When the disc is finished, it sends data to the 3D printer to start the printing process.
Waiting For A Long Time
When the printer starts, you notice the biggest problem with 3D printing today: it's terribly slow. While a 2D printer can print a whole book in a few minutes, most 3D prints take several hours, if not days, to complete the print job. And if you destroyed the settings, failed the disc, or just encountered it, you could lose the entire printout.
There are a few faster technologies that make splashes in the industry, like the Carbon M1, using laser shots into a bed of liquid and pulling out the pressure out of it, which speeds up the process significantly. But these types of printers are many times more complicated, much more expensive and only work with plastic so far.
So should I buy a 3D printer?
If you are not interested in designing and printing parts, then, surely, they will not replace your boring 2D printer anytime soon.
The printers most consumers will buy usually print in plastic, but there are exotic (and expensive) printers used in the industry that can print as much as possible. There is even a 3D printer that can print artificial meat. The technology goes very fast and has significant consequences for many industries. Certainly one day you can print gourmet food from an edible food printer, but until then it's still a hobbyist and industrial unit.
Still, with prices coming down all the time it can be a fun hobby – especially if you build something where small plastic models are used.
Image Credits: Kaca Skokanova / Shutterstock