FDM or Fused Deposition Modelling is a polymer filament-based 3D printing technology which uses thermoplastics to print strong, resilient, functional, and dimensionally accurate products in an additive layer-by-layer process.
These products can be simple prototypes, surgical models, architectural models, gifting items, cosplay items, production-grade manufacturing tools, and even end-use parts.
FDM technology is also popularly known as FFF technology which is Fused Filament Fabrication. FDM & FFF are different names for the same technology.
FDM technology operates on coordinated movements of three axes wiz. X, Y & Z. Most commonly, the Extruder moves in X & Y direction whereas the print bed (build platform) moves in the Z direction.
DLP or Digital Light Processing is a popular 3D printing technology which uses thermosetting polymers. These are specially formulated for specific applications like dentistry (dental resin), jewelry (castable resin), flexibility (elastic resins), tough or strength applications (tough resin), and lots more.
DLP 3D printing produces parts which have a very fine resolution or around 25 microns. This means that features as small as 25 microns can be printed in this technology. The printing is pretty fast and products are aesthetically appealing, smooth and with specific properties needed for use.
The products manufactured through DLP process are generally aesthetically appealing products, jewelry models, dental models, products with minute features less than 100 microns, gifting products, etc.
This process also follows the principle of additive manufacturing where the object is printed in a layer-by-layer process.
This process is very similar to SLA (Stereolithography) 3D printing technology and has certain advantages and disadvantages over it.