What are the Processes and Materials Used in 3D Printing ?

WineGlass Printed using 3D PrinterIn our earlier Article, we discussed how 3D printing has the potential to rewrite the rules of global manufacturing, with an impact that could be as significant to the industrial sector as the now pervasive adoption of the principles of the Toyota Production Systems and Lean Manufacturing. We’d like to enlighten on the actual Process and the Material used in the 3D printing Job.

The different print processes are typically tied to specific materials and produce varying material properties such as strength and surface finish that can better suited for certain applications. The print consumables address nearly the entire spectrum of materials currently being used in the manufacturing process with plastics, glass, paper, ceramics and even metals.

Fused deposition modeling (FDM) / Material extrusion
The process involves plastic filament being forced through a heated nozzle that traces the desired shape over a build platform that is lowered as each section of the model (“slice”) is completed. Layer by layer the material is extruded until the object is completed. The process typically requires the use of two materials; build and support. The support material is meant to hold up overhanging features and is easily removed during the post-production finishing process. The build materials are traditionally thermoplastic filaments such as ABS, ABSi, etc

Material jetting
As the name implies, the process uses ink jet head (much like 2D printers) to deposit build materials. With material jetting, photopolymer resins are distributed onto the build platform and then immediately cured with a UV light that is positioned
by the print head. Like FDM, material jetting requires the use of a secondary support material to retain structural integrity during the process. Post production finishing is required to smooth the surface area. Build materials are most commonly photopolymer plastic or wax resins that harden when exposed to UV light.

Stereolithography (SLA)
SLA technology uses an ultraviolet laser guided by mirrors to cure the liquid surface. The build platform is then lowered or raised before the process is repeated again until the completed product is complete. Post production finishing is required to remove excess resins and to smooth the surface area.

Digital light processing (DLP)
Digital light processing adheres to many of the same principles as stereolithography. However, DLP uses a high powered lamp or LEDs instead of a laser to cure the liquid surface. The build platform is then lowered or raised before the process is repeated again until the completed product is complete. Post production finishing is required to remove excess resins and to smooth the surface area.

Selective laser sintering (SLS) / Powder bed fusion
The selective laser sintering process like powder binding uses powdered plastics, metals and sand as the build material. But instead of a liquid bonding agent, SLS uses a laser to fuse powder materials. Once the bonded surface hardens, another layer of materials is spread over the build platform and the process is repeated until the object is completed. Powdered plastics, sands, ceramics and metals are most commonly used in the SLS process.

The Proof of concept has already happened. It is now common in Industrial Towns for a business lunch 3D printing demonstration to include the while-you-watch fabrication of a customized trinket.