SLA (Stereolithography) technology (also known as light curing rapid prototyping technology) is based on the principle of photopolymerization of liquid photosensitive resin. This liquid material can rapidly undergo photopolymerization under the irradiation of a certain wavelength and intensity of ultraviolet light (such as λ=325nm), the molecular weight increases sharply, and the material changes from liquid to solid. Its core technology is computer technology and material technology. The laser forming technology abandons the traditional machining method. According to the geometric information of the part generated by CAD, the three-dimensional numerical control forming system is controlled, and the part is formed by stacking the materials with the laser beam. Molding in this way eliminates the need for time-consuming and costly mold or special tool design and machining, which greatly improves production efficiency and manufacturing flexibility.
The principle of SLA laser molding: First, the liquid tank is filled with liquid light-curing resin, and the laser beam can be scanned on the liquid surface under the action of the deflecting mirror. The scanning trajectory and the presence or absence of light are controlled by the computer, and the light spot is printed. Wherever it arrives, the liquid solidifies. At the beginning of molding, the working platform is at a certain depth below the liquid surface, and the focused light spot scans point by point on the liquid surface according to the instructions of the computer, that is, it solidifies point by point. When one layer is scanned, the unirradiated area is still liquid resin. Then the lifting platform drives the platform to drop one layer of height, and the formed layer is covered with a layer of resin. The leveling device will scrape the liquid surface of the resin with greater viscosity, and then scan the next two layers to form a new solidified layer. Stick it firmly to the previous layer and repeat this process until the entire part is manufactured. A three-dimensional solid model is obtained. The part formed by the SLA process has a higher precision. Years of research have improved the cross-section scanning method and resin forming performance, so that the processing accuracy of this process can reach 0.05mm.
Features of SLA rapid prototyping:
1. The machining accuracy is high, which can reach 0.05mm;
2. It can manufacture parts with complex shapes (such as hollow parts) and particularly fine (such as jewelry, handicrafts, etc.). It is suitable for making mobile phones, radios, walkie-talkies, mice and other fine parts and toys, as well as high-tech electronics industry casings, home appliances casings or Models, motorcycles, auto parts or models, medical equipment, etc.;
3. The manufacturing speed of the parts is fast, and the layered scanning of 0.1-0.15mm can be carried out;
4. The surface quality is good, it can produce very fine detail and thin wall structure, and the post-processing is easy;
5. The processing is in place, and many details that cannot be processed by CNC can be processed, thereby reducing the workload of post-processing;
6. Shortcomings: The photosensitive resin material selected for laser molding is relatively single, and the toughness and strength of SLA prototypes are not as good as CNC prototypes, and the buckle position is easy to break.
Features of SLA rapid prototyping material (photosensitive resin):
Similar to traditional engineering plastic ABS, it is a transparent or beige liquid with a certain viscosity. The workpieces made are translucent or beige. The strength is good. It can be assembled, tapped screws, painted, and silk screened. The disadvantage is that it is not resistant. high temperature.
Shenzhen Kaiao Mould Co., Ltd. (formerly Yinhua Company), as the earliest national rapid prototyping service center in China, has accumulated rich experience in laser forming. The laser forming machine used by 3D SYSTEMS of the United States and the laser forming machine provided by HUNTSMAN of the United States are used. The photosensitive resin RenShape SL7810 has a manufacturing accuracy of up to ±0.1mm.