DLP and SLA 3D printing technologies, both, belong to the Vat Photopolymerization type of 3D printing. And though they are quite similar, they do have significant differences. With this article, we present you with a basic guide to understand both the technologies along with their major difference between DLP and SLA.
DLP 3D Printing Technology
DLP stands for Digital Light Processing. The DLP process shares some similarities with the Stereolithography 3D printing process where photopolymers are used. The DLP 3D printing technology uses a conventional light source like an arc lamp with a liquid crystal display panel. In DLP printing, the vat of liquid polymer is exposed to UV light in safe conditions. The process starts with loading the 3D model to the printer. An in-built projector that sits under the resin container projects slices of the 3D image on the resin layers. The first layer of polymer that is exposed to the UV light hardens and the process continues to the 2nd and all successive layers in the photopolymer. The process continues until the 3D model is built.
SLA 3D Printing Technology
SLA stands for Stereolithography. It is the oldest 3D printing technology that is still used today. Unlike DLP, the SLA 3D printer uses a laser beam to harden the polymer. The SLA 3D printer directs UV laser to two galvanometers which directs them to correct X and Y coordinates that are traced out to a cross-section of the model. The UV laser beam moves continuously across the print are hardening the photopolymer as it goes. The 3D printing process breaks the 3D design into multiple sets of coordinates for each layer along the lines that are sent to two galvanometers.
Difference between DLP and SLA
- Light Source: SLA uses a UV laser beam while the DLP uses UV light from a projector.
- Light Movement: In DLP, the UV light source remains stationary and it cures the complete layer of resin at a time. In SLA, the laser beam moves from point to point tracing the geometry.
- Light Intensity: In DLP 3D printer, the operator can control the intensity of UV light source and thereby control its effect on the resin. In SLA, the intensity of the laser beam cannot be adjusted and you have to change the laser light completely for different resin effect.
- Curing: Since the curing (hardening) of the resin is done from point to point, SLA 3D printing is more accurate and the quality of the print is also better in comparison to DLP 3D printing.
- Printing Time: The DLP 3D printer works faster and cuts down the 3D printing time significantly.
- Cost: The UV light source in DLP is cheaper compares to the lasers used in SLA
- Application: DLP is more suitable to build one-off small and intricate part while SLA is more suitable for printing several intricate parts in one
From the above points it is must be fairly clear to you on the difference between DLP and SLA 3D printing technology. By understanding these technologies well enough, you will also be able to take better decisions on which technology to use for your next 3D printing project.
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