There are many technologies for 3D printing. Now I would like to introduce several common 3D printing technologies.
FDM
Fused deposition rapid prototyping technology, the main materials are ABS and PLA. The materials used in the melt extrusion molding (FDM) process are generally thermoplastic materials, such as wax, ABS, PC, nylon, etc., which are supplied in filament form. The material is heated and melted inside the nozzle. The nozzle moves along the cross-sectional contour and filling trajectory of the part while extruding the molten material. The material solidifies rapidly and bonds with the surrounding materials. Each layer is stacked on the previous layer, which positions and supports the current layer. It is the traditional heated extrusion method, the simplest and most common 3D printing technology, and is often used in desktop-level 3D printing equipment.
SLA
Light curing molding technology, the main material is photosensitive resin. Light-curing molding is the earliest rapid prototyping process. Its principle is based on the photopolymerization principle of liquid photosensitive resin. This liquid material can rapidly undergo photopolymerization reaction under the irradiation of ultraviolet light of a certain wavelength (x=325nm) and intensity (w=30mw), the molecular weight increases sharply, and the material changes from liquid to solid.
Light curing molding is currently the most studied method and the most technically mature method. Generally, the layer thickness is 0.1 to 0.15mm, and the precision of the formed parts is high. It is the earliest commercialized 3D printing technology, but it cannot print metal parts.
3DP
Three-dimensional powder bonding technology, the main material is powder material, such as ceramic powder, metal powder, plastic powder. The principle is similar to traditional two-dimensional inkjet printing, and gypsum powder is usually used as the molding material. This technology is currently mainly used in full-color 3D printing and sand mold casting.
SLS
Selective laser sintering technology, the main material is powder material. Spread the material powder on the upper surface of the formed part and scrape it flat; use a high-intensity CO2 laser to scan the cross-section of the part on the newly laid new layer; the material powder is sintered together under high-intensity laser irradiation to obtain the cross-section of the part,then is bonded to the formed part below; when one layer of cross-section is sintered, a new layer of material powder is spread and the lower cross-section is selectively sintered. The principle of action is similar to SLM technology and is usually used for 3D printing of polymers.
LOM
Layered entity manufacturing, the main materials are paper, metal film, and plastic film. It operates on the principle of fusing plastic or paper layers through heating and pressure, and a computer-controlled blade or laser cuts the object into the desired shape. The cost of consumables is low and the printing speed is fast.
LMD
Laser cladding molding technology. The material powder is gathered on the work surface through the nozzle, and the accumulated cladding entity is obtained after the powder is melted and cooled.
PCM
Moldless mold manufacturing technology applies rapid prototyping technology to the traditional resin sand casting process. First, the casting CAD model is obtained from the part CAD model. The STL file of the casting CAD model is layered to obtain the cross-sectional profile information, and then the layer information is used to generate control information.
DLP
Laser molding technology, the material is liquid resin, and DLP projection technology is used to project the entire plane and achieve full-layer printing with fast printing speed and high precision.
SLM
Selective laser melting molding technology. At present, the most commonly used technology in metal 3D printing molding uses finely focused light spots to quickly melt pre-set metal powder, directly obtaining parts of any shape and with complete metallurgical bonding.