SLA and SLM are two different printing technologies in the family of Additive Manufacturing. As we all know, SLA printing technology has been developed for the longest time, is the most mature, and is also the most widely used printing process. It has a fast manufacturing speed, the material is mainly photosensitive resin, and there are also many types of resin to choose from.
SLA works by focusing ultraviolet laser onto a vat of photo polymer resin. The resin is photo-chemically solidified and a single layer of desired 3D object is formed, the process of which is repeated for each layer until the model is completed.
Same with SLS 3D Printing, SLM is a powder molding printing technology. In contrast to SLA, which features a wide variety of printing materials, the SLM process can only use powdered metal as the printing material, with common materials such as stainless steel, aluminum alloys, and titanium alloys.
Under the control of the computer, the laser will be irradiated to the designated area, the metal powder will be melted, and the molten metal will rapidly cool and solidify. when finishing one layer, the forming substrate will lower by a layer thickness, and then a new layer of powder is applied by the scraper. The above process will be repeated until the work piece is formed.
According to the above brief introduction, it is not difficult to realize that SLA and SLM are very different, such as printing materials, the state of raw materials, printing speed and so on. In SLA, the printing material is mainly photosensitive resin, and the material is in liquid form; while SLM is powdered metal material.
Although both of SLA and SLM are layer-by-layer printing and molding process, the printing speed is very different. In SLA 3D printing technology, the UV laser will solidified the photosensitive resin in accordance with the settings, and this step will repeat until the desired object is finished. In SLM 3D printing technology, on the other hand, we need to melt the metal powder material through laser, and for each layer formed, it needs to be cooled and solidified quickly. From melting different metal materials to cooling and molding, all these processes take time, which is why it is not as fast as SLA printing technology.
Even so, SLM is one of the 3D printing technologies with a great prospect. It has no shape limitations, it is suitable for complicated and small parts, and it is being noticed by more and more fields and explored for more far-reaching potentials as the technology develops.