What is 3D printing?

3D printing technologies

3D printing is a technique of manufacturing solid objects, in three dimensions. 3D printing is a technique known as additive manufacturing (or AM for Additive Manufacturing in English). In 3D printing, the final object is built by depositing layers of material on top of each other, in superposition. Each layer, deposited by the 3D printer, is very thin and solidifies quickly, to form the desired object, layer by layer. There are different 3D printing technologies to be able to build a 3D model.

What is 3D printing?

To create a solid object, the 3D printer deposits material on the print bed following the model contained in a 3D file, often in STL format. The most common printing material is molten plastic (PLA or ABS in general) used as a consumable in the form of a coil of filament by 3D printers with molten filament deposition (say FFF for Fused Filament Deposition or FDM for Fused Deposition Modeling ).


3D printing technologies

Many 3D printing technologies are already available in the market, and a number are under development. Each of these technologies requires a different type of 3D printing material: plastic filaments in coils (PLA, ABS…), photosensitive liquid resins, powders (metal, plastics…), etc.

 

Each 3D printing technology has advantages and is suitable for particular applications.

There are three main categories of 3D printing technologies:

Wire deposition or extrusion (FFF and FDM): a plastic filament is melted by the print head of the 3D printer and deposited on the printing platform of the 3D printer to create the desired object, layer by layer.

Resin (SLA and DLP): a liquid photosensitive resin is polymerized (solidified) very precisely by a laser or a projector, thus forming the desired object directly in the tank of the 3D printer containing the resin. The most common technology using photo polymerization (solidification of the photosensitive resin by light) is 3D printing by stereolithographic (SLA).

Powder (SLS, SLM, DMLS…): a material in powder form is placed in a tank of the 3D printer. An energy source, usually a laser, fuses the powder grains to form a solid structure. We speak mainly of 3D printing by laser sintering or powder sintering (SLS for Selective Laser Sintering), even if variants of this technology exist (SLM for Selective Laser Melting in particular).


3D printing technologies

Many 3D printing technologies are already available in the market, and a number are under development. Each of these technologies requires a different type of 3D printing material: plastic filaments in coils (PLA, ABS…), photosensitive liquid resins, powders (metal, plastics…), etc.

 

Each 3D printing technology has advantages and is suitable for particular applications.

Freeing itself from the constraints of traditional manufacturing techniques, 3D printing is the technology for rapid prototyping, for example (one of its most common uses). There are also more advanced industrial 3D printers used for manufacturing finished objects and operational parts.

 

The development of 3D printing is already impacting design and production methods and cycles in many sectors.


Extrusion and deposition of molten wire (FDM, FFF)

Fused Deposition Modeling: FDM (Fused Deposition Modeling) and FFF (Fused Filament Fabrication)

Fused wire deposition 3D printing technology, also called extrusion, uses plastic filaments (PLA or ABS) as a consumable. The filament is heated and melted in the print head (also called a nozzle) of the 3D printer. The nozzle moves in two axes (the X and Y axes) at the same time as the print platform moves on a vertical Z axis. 3D printers using molten wire deposition technology are commonly referred to as FFF or FDM 3D printers. .

The 3D printer deposits the molten filament in successive layers, one on top of the other, to form the 3D object. When a layer is complete, the print bed lowers slightly on the Z (vertical) axis and the extrusion process resumes by depositing a new layer of molten filament on top of the first. The layers thus created are fused together by the plastic, which solidifies quickly. The stack of layers of material forms the final object.

 

COMPARE 3D PRINTERS TO EXTRUSION

The precision and quality of the final result depend among other things on the minimum layer thickness offered by the 3D printer (the thinner the layers, the greater the resolution and the more precise the result).

3D printing materials compatible with wire deposition 3D printers are plastic filaments in the form of coils (usually PLA or ABS).  There are also filaments for so-called exotic 3D printers, containing a certain percentage of metal or wood, or specific properties (flexible, transparent, phosphorescent, etc.). The vast majority of desktop 3D printers are extrusion 3D printers and use plastic filament in spools as consumables.

 

Directed Energy Deposition (DED)

3D printing by direct energy deposition or “Directed Energy Deposition”, sometimes referred to as “Direct Energy Deposition” (DED) is an advanced 3D printing technique used only by a few industrial 3D printers.

We chose to categorize it as extrusion 3D printing technology because with this technology, the printing material is pushed to a powerful source of energy (usually a laser) to be melted and fused, thus forming the 'object.

A classic DED 3D printer consists of a nozzle mounted on a multi-axis arm (up to 5 axes), which deposits molten material on a surface where it solidifies. The process is similar in this to extrusion, the difference being that the nozzle moves in multiple directions and not just along two axes. The printing material can be deposited at any angle and is melted at the same time as it is deposited by a laser or electron beam.

DED technology can be used with polymers or ceramic materials but is most often used with metal powders. 3D printing is typically used to repair or add components to existing parts.

 

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