SLA and FDM are two different 3D printing technologies. The main difference is the material and the process. FDM printers use thermoplastic filaments, which are melted and extruded to lay down layers. SLA printers use liquid resin that is cured by a laser to cure each layer. SLA is usually at a better resolution, and the surfaces are smoother, so it's very fit for the designs with much detail and very intricate. FDM is more suitable for functional prototypes and bigger parts because it's stronger and cheaper. Generally, FDM is also cheaper compared to SLA printers and their materials.