This technology uses powder spreading to spread a layer of powder material on the upper surface of the molded part and heat it to a temperature just below the sintering point of the powder. The control system controls the laser beam to be on the powder layer according to the cross-sectional profile of the layer Scanning, the temperature of the powder rises to the melting point, sintering and bonding with the molded part below. After the first layer is completed, the worktable drops a layer of thickness, and the spreading roller spreads a layer of uniform and dense powder on it, and sinters the section of the new layer until the entire model is completed.
Advantages of SLS
1) A variety of materials can be used. The available materials include polymers, metals, ceramics, gypsum, nylon and other powder materials. Especially metal powder materials are currently one of the most popular development directions in 3D printing technology
2) The manufacturing process is simple. Because there are more materials available, this process can directly produce complex-shaped prototypes, three-dimensional construction of cavity molds or parts and tools according to different materials.
3) High precision. Generally, the tolerance of (0.05-2.5) mm within the entire range of the workpiece can be achieved.
4) No supporting structure is required. The suspended layer during the lamination process can be directly supported by the unsintered powder.
5) High material utilization rate. Since there is no need for support, no need to add a base, it is the most commonly used 3D printing technology, and the price is relatively cheap
Disadvantages of SLS technology:
1) The surface is rough. Since the raw material is powdery, the prototype is built by heating and melting the material powder layer to achieve layer-by-layer bonding. Therefore, the surface of the prototype is strictly powdery, so the surface quality is not high.
2) There is a peculiar smell during the sintering process. In the SLS process, the powder layer needs to be heated by a laser to reach a molten state, and polymer materials or powder particles will volatilize peculiar smell gas during laser sintering.
3) It is impossible to directly form high-performance metal box ceramic parts, and it is easy to warp and deform when forming large-size parts.
4) Long processing time. Before processing, there must be a preheating time of 2 hours; after the part is built, it will take 5 to 10 hours to cool down before it can be taken out of the powder tank.
5) Due to the use of high-power lasers, in addition to the cost of its own equipment, a lot of auxiliary protection processes are required. The overall technical difficulty is very high, and the manufacturing and maintenance costs are very high, which ordinary users cannot afford.
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