1, Light cured stereolithography (SLA)
Stereolithography Apparatus (SLA) is the earliest and most mature form of rapid prototyping technology. SLA technology is based on the photopolymerization principle of liquid photosensitive resin. Through computer-controlled laser beam scanning on the surface of the liquid resin, the resin undergoes photopolymerization reaction where the laser is irradiated, transforming from liquid to solid and stacking layer by layer to form a three-dimensional solid.
working principle:
The working process of SLA technology includes model preparation, laser scanning, layer by layer curing, lifting platform, and post-processing steps. Firstly, convert the 3D model into an STL format file, which approximates the original model with a series of small triangular planes. Then, under computer control, the laser beam scans the surface of the liquid resin according to the cross-sectional profile information in the STL file, and solidifies the resin layer by layer. After each layer of curing is completed, the lifting platform drives the workbench to descend one layer, and then applies liquid resin on the new layer for scanning and curing of the next layer. Repeat this process until the entire model is manufactured.
Material application:
The commonly used materials for SLA technology are thermoplastic epoxy resins, such as ABS, PP/PE, PBT, etc. These resin materials can quickly cure under laser irradiation, forming solid models with high precision and strength.
Advantages and disadvantages:
The advantages of SLA technology are high forming accuracy, short processing cycle, and the ability to manufacture complex three-dimensional geometric entities. However, SLA technology also has some limitations, such as the need for supporting structures to maintain the stability of the model, and the shrinkage effect of resin materials during the curing process, which affects the molding accuracy. In addition, UV cured resin materials have certain toxicity and require appropriate protective measures.
Applicable scenarios:
SLA technology is suitable for manufacturing display models, transparent or semi transparent parts, as well as parts with complex cavities and surfaces. Due to SLA technology's ability to manufacture high-precision and high surface quality models, it is also commonly used for prototyping in fields such as jewelry, art, and medical devices.
2, Selective Laser Sintering (SLS)
Selective Laser Sintering (SLS) is another important rapid prototyping technique. SLS technology uses laser beams to sinter powder materials layer by layer, forming three-dimensional entities. Unlike SLA technology, SLS technology uses a wider range of materials, including plastic powder, metal powder, and ceramic powder.
working principle:
The working process of SLS technology includes steps such as model preparation, powder spreading, laser sintering, layer by layer stacking, and post-processing. Firstly, convert the 3D model into an STL format file. Then, a layer of powder material is spread on the workbench, and the laser beam is controlled by the computer to sinter the powder according to the cross-sectional profile information in the STL file. After sintering is completed, the lifting platform drives the worktable to descend one layer, and then spreads the powder on the new layer for the next layer of sintering. Repeat this process until the entire model is manufactured.
Material application:
The commonly used materials for SLS technology are nylon powder, metal powder, and ceramic powder. Nylon powder has good mechanical properties and thermal stability, making it suitable for manufacturing functional prototype models and product development testing. Metal powder and ceramic powder are used to manufacture prototypes and molds for metal and ceramic materials.
Advantages and disadvantages:
The advantage of SLS technology is its ability to manufacture complex three-dimensional geometric entities, with a wide range of material choices and no need for supporting structures. However, SLS technology also has some limitations, such as relatively low molding accuracy and inferior surface quality compared to SLA technology. In addition, the sintering process of metal powder and ceramic powder requires higher temperatures and longer times, which increases manufacturing costs and cycles.
Applicable scenarios:
SLS technology is suitable for manufacturing functional models of products, product development testing, as well as prototypes and molds of metal and ceramic materials. Due to its ability to manufacture parts with complex shapes and structures, SLS technology is also commonly used for prototyping in fields such as aerospace, automotive, and medical devices.
3, Direct Sintering Rapid Prototyping (DMLS)
Direct Metal Laser Sintering (DMLS) is a specialized technique in rapid prototyping for manufacturing metal parts. DMLS technology uses laser beams to sinter metal powders layer by layer, forming metal parts with high precision and strength.
working principle:
The working process of DMLS technology is similar to SLS technology, including model preparation, powder spreading, laser sintering, layer by layer stacking, and post-processing steps. However, the metal powder and sintering process used in DMLS technology are different from those used in SLS technology. DMLS technology typically uses high-performance metal materials such as copper nickel alloys and steel alloys, and the sintering process requires higher temperatures and more precise control.
Material application:
The commonly used materials for DMLS technology include high-performance metal materials such as copper nickel alloys, steel alloys, titanium alloys, and aluminum alloys. These materials have excellent mechanical properties, thermal stability, and corrosion resistance, making them suitable for manufacturing high-precision and high-strength metal parts.
Advantages and disadvantages:
The advantage of DMLS technology is that it can manufacture high-precision and high-strength metal parts, with a wide range of material choices and no need for supporting structures. However, DMLS technology also has some limitations, such as high manufacturing costs and the sintering process requiring higher temperatures and longer times. In addition, parts manufactured using DMLS technology are limited in size and shape by equipment dimensions.
Applicable scenarios:
DMLS technology is suitable for manufacturing metal parts in fields such as aerospace, automotive, medical devices, and precision instruments. Due to its ability to manufacture metal parts with complex shapes and structures, as well as high precision and strength, DMLS technology is also commonly used in the production of metal molds and fixtures.
