Rapid Prototyping SLS SLA Plastic
Technical principle: SLS (Selective Laser Sintering).
The technique uses a powder layer to lay a layer of powder material on the upper surface of the formed part and heats it to a temperature just below the sintering point of the powder, and the control system controls the laser beam to follow the cross-sectional profile of the layer on the powder layer. Scanning, the temperature of the powder is raised to the melting point, sintered and bonded to the underlying formed portion. After the completion of one layer, the workbench is lowered by a layer thickness, and the paving roll is coated with a uniform dense powder to perform a new layer of sintering until the entire model is completed.
Advantages of SLS technology:
1) A variety of materials are available. The usable materials include a variety of powder materials such as polymers, metals, ceramics, gypsum, and nylon. In particular, metal powder materials are one of the most popular development directions in current 3D printing technology.
2) The manufacturing process is simple. Due to the large amount of materials available, the process can directly produce complex shape prototypes, cavity mold 3D constructions or components and tools, depending on the material.
3) High precision. Generally, tolerances of (0.05-2.5) mm over the entire range of the workpiece can be achieved.
4) No support structure is required. The suspended layer that occurs during the lamination process can be supported directly by the unsintered powder.
5) High material utilization rate. Since there is no need for support, there is no need to add a base, and the material utilization rate is the highest among several common 3D printing technologies, and the price is relatively cheap.
Disadvantages of SLS technology:
1) Surface roughness. Since the raw material is powdery, the prototype is constructed by layer-by-layer bonding of the material powder layer by heating and melting. Therefore, the surface of the prototype is strictly granular and the surface quality is not high.
2) There is an odor in the sintering process. In the SLS process, the powder layer needs a laser to heat it to a molten state, and the polymer material or the powder particles volatilize the odor gas during laser sintering.
3) High-performance metal box ceramic parts cannot be directly formed, and warping deformation is likely to occur when forming large-sized parts.
4) Long processing time. Before processing, there must be 2 hours of warm-up time; after the parts are built, it takes 5 to 10 hours to cool before they can be taken out of the powder cylinder.
5) Due to the use of high-power lasers, in addition to the cost of the equipment itself, many auxiliary protection processes are required. The overall technical difficulty is high, and the manufacturing and maintenance costs are very high. The ordinary users cannot bear.