All 3D printers, regardless of the technology employed, construct 3D objects according to a basic set of operations. The first step is to produce a 3D digital representation of the object in software. The digital version of the object can be a 3D scan of a physical model or a model created in a computer aided design (CAD) package such as SolidWorks. For printing purposes, the digital model is sliced into thin layers. The number and thickness of the layers depends on the technology being used and on the desired printing resolution. In general, thinner layers produce smoother surfaces, sharper corners and edges, and a higher level of detail in the printed object. The details of each layer are fed in sequence to the electronic systems that control the printer. An object is created by printing one layer of the object at a time. A building table is used to support the bottom layer of the object, and this table must be properly leveled and positioned. Each layer is constructed on top of the previous layer, which acts as a support for the next layer. For many objects, parts of the object do not extend all the way to the bottom of the object, or cannot be created by extending out from a previous layer. In these cases supporting posts are built up from the building surface and end where they meet the object. The main differences among existing 3D printers are the materials used, the method used for printing each layer, the software used for each aspect of the process, and the precision and speed with which the object can be constructed.
In the present landscape of the 3D printer market, there are three primary technologies used to create 3D objects.
- fused-filament fabrication (FFF).
- DMD-based resin printers.
- laser sintering printers.