SLA (Stereolithography) and DLP (Digital Light Processing)
SLA (stereolithography) or stereolithography is the oldest complete 3D printing technology. It has exists since the early 80s of the last century. It continues to be widely used today due to its precision and the ability to produce very small details and fine details.
How does it work?
SLA technology has a remarkable way of working. As with most of the other 3D printing methods, the first step is to create a 3D model using CAD software, then splits it into layers and generates an STL file. The layers are so thin that one millimeter can contain up to ten layers. After that an extremely precise laser begins to create their physical copy from the liquefied source material. When this layer hardens, the 3D printer platform moves vertically at a distance of less than a millimeter, and the next layer of liquid polymer is applied. The laser then begins to work on it. This process is repeated until the end of the printing work is completed. It is possible to dip the product into water after that to remove residual materials or to undergo other secondary treatment.
The Stereolithography method allows the creation of detailed, fine and smooth elements, including elements with very small dimensions, which significantly extends its applications compared to other 3D printing technologies. In addition, with the SLA, the manufacturing time is less, and the cost may be lower than other methods.
The technology is widely used in the field of prototyping, both, for large objects and very small details, the creation of conceptual models, designer works, as well as small series of marketing and advertising materials. It can also successfully create tools, spare parts and other customized parts for the end users in a short time, as well as architectural models. SLA is used relatively rarely to create whole end products. However, the technology has been widely used in areas such as medicine and dentistry, automotive and other engineering, as well as architectural modeling. It is also used in finishing processes such as painting, grinding, galvanizing and vacuum metallisation.
Digital Light Processing (DLP) or Digital Light Processing is a 3D printing technology that has some similarities with the SLA method. However, it was created much later – in the late 80s. One of the differences between them is that this technology works with significantly larger printers.
Way of working
DLP also uses photopolymers, but it treats the source material with a different light source, such as an arc lamp. Like other 3D printing methods, this technology also uses a CAD model that has to be cut into layers to create the final print object. A liquid polymer is used in the process.
Printing with a DLP machine is very fast – a layer of the hardened material can be created in just a few seconds. The resolution and robustness of the resulting elements is also impressive. In addition, DLP uses less materials compared to other technologies, including SLA, which results in lower cost for production and less environmental pollution.
Digital Light Processing technology is for easy and quick creating and testing of prototypes, conceptual models, spare parts, and marketing materials. It is also used in the medicine, dentistry, jewelry and other areas requiring the creation of precise details, as well as for the production of end products in limited series.