Which one should we choose: SLA, DLP, or LCD? To answer this question, we first need to research and compare the individual technologies used in 3D printing services.
In this article, we examine stereolithography (SLA), digital light processing (DLP), and liquid crystal display (LCD) 3D printing technologies. They are characterized by the fact that the printing process is carried out using a liquid photopolymer resin, which is stored in a small tank, instead of being injected through a special nozzle.
The distinction between the different methods exists both in the sources of light that serve to harden the resin and in the way the material is stored and distributed during 3D printing. There are also significant differences in the speed, precision, and accessibility of the 3D model printing process.
What is SLA 3D printing - Stereolithography
Stereolithography is the best-known method for resin 3D printing. A laser directed by galvanometers is used to cure the material. This approach makes SLA printing an extremely precise process.
What does an SLA 3D printer consist of?
A SLA 3D printer consists of a tank that contains the resin, a build platform, a lift, a light source, and a pair of galvanometers. The build platform is located above the tank and is attached to the lift, which raises and lowers it during printing.
The galvanometers are located under the transparent bottom of the tank. They consist of two movable mirrors through which the laser beam is directed.
How do SLA 3D printers work?
Most SLA 3D printers operate with a laser as the light source. Every point of the resin in the tank that the laser reaches hardens instantly. When the laser finishes hardening the entire layer, the build platform rises to start constructing the next one. This process is repeated until the 3D printing of the given object is complete.
What are the advantages and disadvantages of SLA technology?
The advantages of this 3D printing method are the smooth surfaces of the final product and the high precision throughout the entire working process.
On the other hand, a drawback is the significant slowdown in speed when increasing the area of the object being printed. There is also a risk of distortion with larger flat surfaces, which can lead to defects in the final product.
DLP - Digital Light Processing
What is the difference between DLP and SLA technology?
Instead of a laser, DLP 3D printers use a digital projection surface as a light source. This surface reflects images of entire layers onto the bottom of the tank where the resin is located.
Unlike SLA printing, where the laser hardens only one point at a time, in DLP an entire layer hardens in the same amount of time.
What does the DLP 3D printer consist of?
The main component of DLP 3D printers is the digital micromirror device (DMD - digital micromirror device). It contains hundreds of thousands of micromirrors that direct light and create a pattern in the layer. It is through this process that the solidification of an entire layer at once becomes possible.
How do DLP 3D printers work?
DLP projectors create an image on a given layer by passing light through a lens to the DMD device.
"After constructing a complete layer, the building platform moves to the necessary height to design a new image on a new surface. This continues until a complete 3D element is built."
What are the advantages and disadvantages of DLP technology?
"Just like with SLA technology, DLP also creates elements with extremely smooth surfaces. The difference is that DLP operates at a much higher speed."
However, the quality of processing significantly decreases with the increase in the printing area. Larger elements have lower accuracy than those with a smaller area. This means that with more extensive models, there is a higher risk of pixel distortion.
LCD 3D Printing - Liquid Crystal Display
How do LCD printers work?
For a light source, LCD 3D printers use a set of UV liquid crystal displays. They emit light parallel to the build area of the elements. This significantly reduces the risk of pixel distortion compared to the risk in DLP 3D printing.
In this case, the print quality depends on the LCD density. The more pixels there are, the better the print quality.
What makes the technology of LCD 3D printing different?
LCD technology is often confused with DLP, as the two methods of operation are quite similar. However, there is one significant difference between them.
"As we have already explained, DLP 3D printers require a DMD device to direct the light from the projector to the bottom of the resin tank. In LCD, such an additional device is not necessary."
"3D printers that operate with this technology emit UV light through numerous LEDs shining through an LCD screen. This screen acts as a mask, displaying only the specific pixels for the selected layer."
What are the advantages and disadvantages of LCD technology in 3D printing?
3D printing using resin as the main material is becoming much more accessible precisely due to the invention of LCD technology. The reason is that with this method, the individual components for printing are much more cost-effective.
"Moreover, LCD 3D printers build a given element in a much shorter time compared to those using SLA. Also, the risk of pixel distortion is minimal, unlike 3D printers that use DLP."
In this case, a disadvantage can be noted that the lifespan of an LCD screen is shorter than that of a DLP chipset, which means that more frequent maintenance is required.
Which one should we choose: SLA, DLP, or LCD?
SLA technology is recommended when you aim to build parts with very high precision and smooth surfaces, and the build time is not of particular importance.
DLP is a suitable method when you aim to achieve high precision in building individual details in a short time.
If you choose LCD technology, you get elements with smooth surfaces in a short time, with minimal risk of distortion, at an affordable price. If you are a beginner in 3D printing with liquid photopolymer resin, LCD would be a great choice for your first steps in the field.
If you still have questions, the engineers at 3DLarge will be happy to answer you.
