The ingenious idea behind 3D printing is that adding up lots of 2D layers, from the bottom upward, one will eventually get a 3D model. So how does a 3D printer achieve that?
First, a 3D CAD drawing is “sliced” into 2D layers. In this step, a G-code file is produced to provide tailored instructions for the printing process. Then, connected to power, the 3D printer begins to work. One of the 3D printing technologies is called Fused Deposition Modeling. In this case, plastic filament is unwound from a coil and supplies material to the extrusion nozzle. The extruder is attached to a motor, two gears and a hot end to form a complete tool head. This design enables the heated extruder to melt the material before extruding them on the printing bed. Just past their glass transition temperature so that it quickly cools down to form a solid at room temperature.
The material also needs to be on the exact spot and this is where the file comes in handy. It instructs the tool head and the printing bed simultaneously. The tool head, driven by the connected rubber belt, moves across the hanging aluminum rods, or the “rails” horizontally, while the printing bed, attached to the sliding structure at the base of the frame, moves in a perpendicular direction horizontally. Both cooperate with one another to mark the exact x and y coordinates of each point to paint. When one layer is done, the printing bed lowers a little, thus moving on to the next layer. It continues in this way until the whole model is finished.
