Supports in FDM
Fused Deposition Modeling (FDM) extrudes a melted filament onto a build surface along a predetermined path. As the material is squeezed, it cools, forming a solid surface that provides the foundation for the next layer of material.This will be repeated layer by layer until the object is complete.
SLA & DLP support structures
Stereolithography (SLA) and Digital Light Processing (DLP) create 3D printed objects from a liquid (photopolymer) resin by using a light source to solidify the liquid material.
Material Jetting support structures
Material Jetting (Stratasys PolyJet and 3D Systems MultiJet Modeling) technologies are similar to inkjet printing, but instead of dropping ink onto paper, these printers spray layers of liquid photopolymers onto the building tray and then instantly solidify using ultraviolet light.
SLS support structures
Selective Laser Sintering (SLS) fuses powdered material in a chamber using a laser.
For SLS, you don't need support structures, because powder ACTS as support when objects are built layer by layer.This gives the design a lot of freedom, but also increases the cost and time of printing parts.
Binder jetting support structures
Binder jetting is similar to SLS in the way that the printer uses thin layers of powdered material to build up an object, but instead of using lasers to sinter the powder together, these printers use a binder extruded from a nozzle to hold the powder together.
Metal printing support structures
Metal printing USES a support structure to hold the model to a floor during construction, but cantilevers with an Angle greater than 35 degrees can be built without support.