- FDM (ABS, PLA,…)
A filamentous plastic is heated by a movable nozzle which places the material layer by layer on the work surface. After each layer the work surface lowers before the next layer is added. This way an object is built up in hight. On parts which have no direct support on the work surface, suppot material is printed. This can be removed manually afterwards. - SLS (Polyamide, Alumide, Metals, …)
SLS uses a highly specific laser that sinters thin layers of polyamide powder together one layer at a time. After each round of lasering, the printing bed is lowered and another layer of powder is evenly swept across the top for another round of sintering. This proces is repeated until the object is completed. For plastics no support material is needed because the object supports in the previous layers of powder. For metal prints pieces of metal powder are heated to built support material. Without this support the object would sink into the non-lasered powder. If the print is finished the non-used powder will be blown away or vacuumed for re-use. For prints of hollow objects an ‘escape hole’ must be provided to clean out the non-lasered powder. - Binder Jetting (Composite : colour)
The material in powder form is rolled out and a printhead sprays a binder mixed with colour ink on the layer of powder. This way the powder parts stick to one another. With this technique full colour 3D objects can be created. Once the full 3D object is finished heated air is blown in the building chamber to harden the powder and binder. The excess of powder will be blown away or vacuumed for re-use. To give the 3D object a certain strength and to improve the colours the object is soaked in colourbond. With this action causes new hardning and dryingproces. If required, after that another coating with UV-filter can be applied. This makes your object water-resistant and scratch-resistant. - SLA (stereolithography)
In this proces a UV curable liquid photopolymer is lighted with a UV-laser. The surfaces of the liquid photopolymer wich is shined by the laser hardens immediately. The excess of liquid photopolymer can be rinsed off. The 3D object can harden further under UV light after it is printed. These type of printers are very accurate. Though support material needs to be printed. This can removed manually after the print. - Poly/multi-jetting
With this technique UV-curing drops of resin are placed on the printing surface. Then these drops are lighted with UV-light wich makes them harden immediately. Around surfaces that need support, another printhead drops pieces of liquid wax wich hardens immediately. Once the full 3D print is ready it is placed in a ultrasone bath of 60 degreeds to let the excess of wax melt away. These printers can proces different materials with different hardness charachteristics. Because of the accuracy, resolution and fully removable supports these printers can produces very detailed objects.
