Selective laser agglomeration: about the Equipment method
Selective laser sintering (SLS) – selective laser agglomeration (SLS), equipment of additive production, is used for malekhanky production of models of prototypes and functional a component.
Selective laser agglomeration (SLS) developed and запатентировал doctor Charles Dekard, also scientific managing director, doctor Joe Biman from Ostinsky Institute of the State of Texas among the 1980th, with assistance of DARPA (Defense Advanced Research Projects Agency – agencies of the advanced defensive research projects). Descartes and Biman participated in development of the DTM company based for the purpose of development and production SLS-mashin. In 2001 3D Systems, the most powerful competitor of DTM and SLS technology, took control of the company. Similar process was patented, without being commercial, R. F. Housholder in 1979.
Additive development of level-by-level production, SLS, means introduction of very bulky laser (for example, the laser on carbon dioxide) to connect small particles of a powder of plastic, metal (direct laser agglomeration of metal), ceramics or flew down, way of scanning of the sections generated from digital 3D of the description of details (for example, from the CAD file or from picture data), over a powder layer of base. After scanning of each section the powder flooring (base) falls by one layer at thickness, the new layer of a material is atop imposed, process repeats until the model will not be complete.
Because the density of model depends on laser capacity, instead of duration of influence of the laser, SLS-ustroystva are almost always equipped with the pulse laser. SLS the device warms up previously a loose powder material of base before when it actually begins will melt, thus, to the laser simpler to increase temperature in the chosen sites and to melt into their material up to the end.
Unlike other technologies of additive production, such as stereolithograph (SLA) and modeling by a method of a naplavleniye (FDM), SLS development does not mean introduction of supporting structures because during production the model is surrounded all the time with an unfused material. Thus, becomes possible to create earlier impossible forms.
Materials and introductions
Some SLS-ustroystva work at base of a unicomponent powder, for example, direct laser agglomeration of metal. After all, the most part of SLS of devices works at base of two-componental powder materials – usually, either the covered powder or powder mixes. At unicomponent mixes the laser melts only an external surface of particles (surface fusion), thus, firm unfused particles stick together in common and with the previous layer.
In comparison with other methods of additive production, by means of SLS it is possible to produce rather vast richness of models from available materials on sale. Including polymers, such as nylon (filled with fiber glass, or with other fillers) or polystyrene, metals, including steel, the titan, alloys and connections, also green sand. Physical process can mean complete melting, partial melting or zhidkofazny agglomeration. It is dependent on a material, it is possible to achieve to 100 % of density in materials, whose physical properties are comparable with what are used in ordinary development. In many cases the descent can create to a meeting some models that essentially increases efficiency.
Development of SLS is widely used worldwide in connection with possibility simply and quickly to create models of very difficult form directly from CAD figures. At first it was the way to create models on a raneshny step of a cycle of modeling, and now this method is widely used in production of final products. Now SLS-tekhnologiyu start to use in art.