3D printing SLS (laser sintering process)

3D printing SLS (laser sintering process)

Nowadays, with the increasing innovation of 3D printing technology, materials are also evolving. At this stage, the main materials are photosensitive resin materials used in SLA technology, ABS and SLA wires used in FDM technology, and PA nylon powder materials used in SLS technology and MJF technology.

SLS (selective laser sintering process), the process was proposed by C.R. Dechard of the University of Texas in 1989, and then C.R. Dechard founded DTM and released the Sinterstation, an industrial grade commercial 3D printer based on SLS technology, in 1992.

Process Principle
SLS uses the principle of sintering of powder material under laser light, and computer-controlled layer-by-layer stacking to form a model.SLS technology also uses layer-by-layer stacking to form a model, but the difference is that it first lays a layer of powder material, preheats the material to near the melting point, then uses a laser to scan the cross-section of the layer to raise the temperature of the powder to the melting point, then sintering to form a bond, and then repeats the process of laying powder and sintering until the entire model is completed. until the entire model is formed.

Process Advantages
White nylon (SLS)
Wide range of materials available and low price. As long as the viscosity of the material is low after heating, it can be used as a material for SLS. A wide variety of powder materials including polymer, metal, ceramic, gypsum, nylon, etc.
The process is relatively simple. The process can directly produce complex shapes of prototypes, cavity mold 3D builds or parts and tools by material.
No support structure is required. The unsintered powder can be used as a support structure.
High material utilization, as there is no support structure or base and all materials are available.
High precision. The accuracy is generally between 0.05mm and 2.5mm, depending on the type of powder and the size of the powder particles.

Small deformation rate Process disadvantages
Slightly rough surface. Since the raw material is powdered, the prototype construction is realized by layer-by-layer bonding of the material powder layer through heating and melting.
Warping and deformation tend to occur when forming large size parts.
Long processing time. Before processing, there is a 2-hour preheating time. After the part is constructed, it takes 5 to 10 hours to cool down before it can be removed from the powder cylinder.
Due to the use of high-power lasers, in addition to the cost of the equipment itself, many auxiliary protection processes are required, and the overall technical difficulty and manufacturing and maintenance costs are very high.