1, SLA photocuring 3D printing.
SLA technology is the earliest 3D printing technology and the most mature 3D printing technology widely used in the industry. This technology has been patented by 1986, and is the co-founder of 3D system, Inc., a leader in 3D printing industry. At present, large-scale industrial photocurable 3d printers are mainly based on SLA technology.
Generally, the wavelength of the lamp used in SLA machine is 355nm laser beam. On the resin tank, the exposure direction is above, and the liquid resin hardens when the laser beam scans. Reduce the breakeven of the platform. Therefore, the surface of the platform is the thickness below the resin surface. Then, the laser beam tracks the boundary and fills the two-dimensional cross section of the model. After the resin is cured layer by layer, the formation of the platform layer by layer is controlled by the movement of the laser beam before the three-dimensional object is generated. Theoretically, the laser beam can move in a large space. So SLA printing technology can print large models.
Advantages and disadvantages: SLA is the earliest rapid prototyping technology with high maturity, stable printing process and many machine suppliers. So far, SLA is the only photocurable 3D printer technology that can print large models. In addition, there are restrictions on cationic photopolymerization resins. Due to the different sizes of lasers, the resolution of SLA is lower than other photocuring technologies. Nevertheless, SLA technology is accurate enough for printing objects with complex structure and fine size. So far, SLA is still an important printing technology available in dentistry, toys, molds, automobiles, aerospace and other fields.
2.DLP photocuring 3D printing.
The core technology of DLP3D printing is DLP technology which determines the image formation and printing accuracy. DLP technology has existed for 20 years. The core of DLP technology is the optical semiconductor or digital microscope equipment or DLP chip invented by Dr. LarryHornback in 1977, which was commercialized by Texas Instruments in 1996. DLP chip can be said to be the most advanced optical switching equipment in the world today, including a micro microscope composed of 2 million rotating shafts. Each microscope is only about one-fifth the size of human hair. Therefore, the printing resolution of DLP3D printing is very high, and the minimum printable size is 50m.
Advantages and disadvantages: Accuracy is the biggest advantage of DLP3D printing. But in order to ensure high accuracy, the projection size is limited. So DLP3D printing can only print small-sized objects. DLP3D printing technology can only print models with high precision and small size, so it is mainly used in gem casting and dentistry.
3.LCD photocuring 3D printing
From laser scanning SLA to digital projection DLP to the latest LCD printing technology, there is a great difference between lighting and imaging system, but there is almost no difference between control and stepping system. The biggest difference between DLP and LCD3D printing technology is the imaging system. Applying an electric field to liquid crystal will change the molecular arrangement and prevent light from passing through. Due to the advanced LCD technology, the resolution of LCD screen is very high. However, in the process of electric field conversion, a small number of liquid crystal molecules cannot be rearranged and the light becomes weak.
Advantages and disadvantages: LCD machine is cheap and has good resolution. However, the LCD screen has a short life and needs to be replaced regularly. The brightness of LCD 3D printing is very weak, only 10% of the light passes through the LCD, and 90% of the light is absorbed by the LCD. In addition, as mentioned earlier, local water leakage will expose the photosensitive resin of the floor, so the sink should be cleaned regularly. At present, LCD light-cured 3D printers have applications in dentistry, jewelry, toys and other fields.
4. Edit photo-curing 3D printing
2065438+On March 20th, 2005, the CLIP technology developed by Carbon3DCorp appeared on the cover of Science. The core of this technology is the invention of oxygen-permeable membrane, which is helpful for continuous printing of oxygen-permeable, thus inhibiting free radical polymerization. CLIP technology is the frontier technology of DLP. The basic principle of editing technology is not complicated. UV projection at the bottom hardens the photosensitive resin, and the liquid resin at the bottom of the tank maintains a stable face value due to oxygen barrier, thus ensuring the continuity of hardening. Special windows below allow light and oxygen to pass through. The most important advantage of this technology is that it can subversive make objects at a speed of 25 ~ 1000 times faster than that of DLP light-cured 3D printer-the theoretical potential printing speed can reach1000 times that of DLP technology, and the layering can be infinitely good. At present, 3D printing needs to cut the 3D model into multiple layers similar to the superposition of slides, so the roughness will not be deleted. The image projection of editing technology can be constantly changed, just as slides evolve into superimposed videos. This is a great progress of DLP projection technology.
Advantages and disadvantages: CLIP technology is true 3D printing. This is a destructive technology for the current 3D printing technology. Undoubtedly, the biggest advantage of CLIP technology is its fast printing speed. Nevertheless, there are still some technical problems to be solved. Up to now, in order to print quickly, it is necessary to use low viscosity resin and blank model through CLIP technology. The first two methods can make the resin quickly replenish to the printing area, and the latter can reduce the amount of each layer. Therefore, the effect of CLIP process on high viscosity resin and solid model is not good.
5.MJP photocuring 3D printing
MJP technology, also known as PolyJet, was patented by Israeli Objet company in 2000. MJP3D printing can effectively print models, and multiple groups of nozzles work together. According to the model slice data, hundreds of nozzles spray liquid photosensitive resin on the platform in layers, and the printing nozzles move along the XY plane. After the photosensitive resin is sprayed on the workbench, the surface of the sprayed resin is smoothed by a roller, and the photosensitive resin is cured by a UVD lamp. After one layer of printing hardening is completed, the built-in workbench of the equipment reduces the thickness of one layer very accurately, and the nozzle continues to spray photosensitive resin for the next layer of printing hardening. Repeat this operation until the whole workpiece is printed.
Advantages and disadvantages: For MJP3D printing, there are many nozzles, which can spray a variety of materials. This allows you to print a variety of materials and multi-color materials at the same time to meet the requirements of materials, colors, hardness and so on. Up to now, MJP3D printing is the only technology that can print multi-color models. MJP3D printing has extremely high machining accuracy, and the thickness of printable layer is as low as 16 micron. The support material is easy to melt or dissolve, so the process of removing the support is non-destructive and easy. Therefore, the printed model surface is smooth. Finally, theoretically, the printing size is infinite. But MJP printers are expensive. These materials are also expensive and have low viscosity. MJP technology can be applied to fields that need high machining accuracy. Now it is often used in gem casting, precision medicine and so on.