3D Printing Methods and Technologies Explained
3D printing, also known as additive manufacturing, is a process that uses 3D modeling software to print a 3D object by adding material layer by layer. There are several techniques for 3D printing, including melting material such as plastic, sandstone, or metal through a heated nozzle, fusing powders together to create an object, and depositing layers of resins, waxes, or other materials to build up a 3D object. Below is a list of several 3D printing technologies.
In 3D printing, the user first creates a 3D model in a 3D modeling program and saves it as an STL file or other 3D printable file. This file is sent to the printer’s interfacing software, which converts the file and slices the model into sections and determines how the layers will be printed
Here are some of the major technologies:
Binder Jetting (Also known as Powder bed or Inkjet Printing)
The object is printed by sticking successive layers of powder, sand, or metal material together. A glue or binder is jetted from an inkjet style print head to bind the layers together. A fresh layer of powder is spread across the top of the model and the process is repeated until the object is fully printed.
Digital Light Processing (DLP) (Also known as Vat Polymerization)
In this process, once the 3D model is sent to the printer, a vat of liquid polymer is exposed to light from a DLP projector under safelight conditions. The DLP projector displays the image of the 3D model onto the liquid polymer. The exposed liquid polymer hardens and the build plate moves down and the liquid polymer is once more exposed to light. The process is repeated until the 3D model is complete and the vat is drained of liquid, revealing the solidified model. DLP 3D printing is faster and can print objects with a higher resolution.
Direct Metal Laser Sintering (DMLS)
A layer of metal powder is deposited on a print bed and exposed to a laser. The laser fuses the powder into a solid, and then another layer of powder is deposited and exposed to the laser. This process continues until the part is complete.
Electron Beam Freeform Fabrication (EBF³)
Electron Beam Freeform Fabrication (EBF³) is an additive manufacturing process (3D printing) being developed by NASA to create metal parts in space.
EBF³ uses a focused electron beam in a vacuum environment to create a molten pool on a metal substrate. First, a model is created in CAD software and the file is translated into G-code. The G-code is sent to the printer. Metal wire is fed into the printer, forming a molten pool in a layer, which solidifies after the electron beam has passed. Once the layer has solidified, another layer is printed, until the process is complete and the part is created.
Electron Beam Melting (EBM)
Metal powder is extruded through a nozzle in layers. Each layer is melted by an electronic beam in the vacuum chamber. Another layer of powder is extruded and melted by the electronic beam. This process repeats until the part is complete.
Fused Deposition Modeling
By far the most common type of 3D printing, especially for home consumers, Fused Deposition Modeling (FDM) typically uses ABS or PLA plastic filament or other material that is extruded through a heated nozzle and deposited layer by layer.
Granular 3D Printing
Material, such as plastic or ceramic powder, is fused in a granular bed layer by layer. The part is surrounded by layers of powders, which eliminates the need for support material. The process repeats until the part is complete.
Inkjet Head 3D Printing
See Binder Jetting
Laminated Object Manufacturing (LOM)
The user places tape on the print bed so that the print material will stick. A sheet of paper, plastic, or metal laminate coated with polyethylene is rolled onto the print bed with a heated roller. The heated roller melts the polyethylene coating and causes it to stick. A laser traces the shape of the model. The laser cross-hatches the material not used for the part to act as support material. The platform moves downward and another sheet of material is rolled on top of the previous layer. The process is repeated until the part is complete. The part is then removed by shaking or chiseling away the support material. Lastly, the part is sanded and lacquered.
Light Polymerized 3D Printing
See Digital Light Processing or Stereolithography
See Binder Jetting
Nylon Extrusion 3D Printing
Similar to Fused Deposition Modeling, Nylon Extrusion uses nylon filament that is extruded through a heated nozzle in a layer that hardens. Another layer is added and the process repeats until the part is complete.
Layers of liquid photopolymer materials are deposited onto the print bed one layer at a time. Once each layer is deposited, the material is exposed to UV light, which hardens the layer. Another layer of liquid photopolymer material is deposited and exposed to UV light. Gel-like support material is printed and surrounds the part to hold the layers in place. This process repeats until the 3D model is complete.
Powder Bed Printing
Like other 3D printers that use laser sintering technology, a welding head moves across a thin cross section of the material, heating and bonding its layers together. Layers of powder build up as support material for the part.
Selective Deposition Lamination (SDL)
Sheets of standard business paper are fed into the 3D printer. Colored inks are deposited on each sheet of paper and then loaded into the section of the printer where the cutting and gluing occurs. A tungsten-tip blade cuts the shape of the part on the first sheet of paper that is fed into the printer. The blade also cross-hatches the material not used for the part. This allows for easier removal of the support material.
Adhesive is then deposited onto the sheet. Another sheet is fed into the printer. The platform moves upward and applies pressure to the newly added sheet of material. The platform is lowered and the blade cuts the shape of the part on the second sheet of paper. The process is repeated until the part is complete. The part is then removed by cutting it out of the support material.
Selective Heat Sintering (SHS)
A layer of ABS or PLA powder is deposited onto the print bead and the print head moves back and forth to apply heat to melt the powder that then hardens. Another layer of powder is added and the print head applies heat to melt and harden the layer. Unheated powder acts as support material around the part. The process of layering the powder and heating it is repeated until the part is complete. The part is removed from the powder and cleaned. The excess powder can be reused for the next print.
Selective Laser Sintering (SLS)
The powder is preheated in the powder bed. The printer prints a layer of powder which is fused together by the laser. The process is repeated until the part is complete.
A vat of liquid resin is exposed to an ultraviolet (UV) laser, which traces a layer of the 3D model image onto the resin. The exposure to light causes a layer of the resin to harden. The build platform rises and the resin is again exposed to the laser. This process repeats until the part is complete.