Guestblog by Joris Peels, 3D printing strategy consultant.
3D printing is the popular term used to describe any technology that manufactures things by building them layer by layer. There are many different 3D printing technologies. The most popular are Fused Deposition Modeling (FDM), Stereolithography (SLA), Selective Laser Sintering (SLS) & Direct Metal Laser Sintering. I hope that by reading this article I can clear up a lot of the confusion about the definitions and nomenclature surrounding 3D printing.
Works by melting a thin plastic wire which is then deposited on a build plate. This plate is then lowered and another layer is built on top of the first. FDM parts are strong and dimensionally accurate but less appealing than other parts. FDM is the most popular technology by far outselling all the others in numbers of system’s used in industry and powering over 400,000 desktop 3D printers. FDM is also routinely referred to as Fast Filament Fabrication or FFF by people who wish to avoid any legal issues with Stratasys who invented the technology. Officially according to ASTM 42 (a standards setting subcommittee) this is called Material Extrusion but no one really uses the term.
Uses a laser to harden an object inside a bath of resin. SLA is officially called Vat Polymerization, I don’t think I’ve ever heard anyone say this. This produces highly detailed objects. These however often have to be post processed by hand and are more delicate than parts made by other technologies. SLA is used to make millions of customized In the Ear hearing aids each year. 3D Systems and Formlabs make SLA machines.
Hardens fine loose powder on a bed using a laser. A new layer of powder is laid down and then a block of powder emerges. The hardened parts are then taken from this block. SLS is porous and may absorb dirt. But, it produces strong flexible parts and is a highly productive technology. SLS has been used to make over a 100,000 customized surgical guides. These are made based on a scan of a patient and then temporarily implanted in the body to assist surgeries. SLS and similar technologies are also called Powder Bed Fusion. Eos & 3D Systems make SLS machines.
Works in the same way as SLS but instead of plastic powder titanium and steel powders are sintered. DMLS is used to make tens of thousands of implanted hip cups each year as well as other orthopedic implants and aircraft parts. Eos, Concept Laser and Realizer sell machines that use DMLS or similar technologies.
With 3D printing an inkjet head deposits a binder on a bed of powder. This technology is officially called Binder Jetting. A new layer of powder is added and the head travels over it hardening the parts that will become your model. 3D printing was invented at MIT and the „MIT 3D printing patent” covers any powder that is 3D printed. The patent is used by ExOne to 3D print in metal, 3D Systems to 3D print in color and Voxeljet to 3D print in sand used for casting. 3D printing is therefore only really a term that describes but one technology.
The correct term is actually Additive Manufacturing (AM) as defined by the ASTM 42 subcommittee on Additive Manufacturing. Additive Manufacturing is defined as „process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies.” The industry used many different terms for itself over the last 3 decades ranging from Free Form Fabrication, Rapid Prototyping to Rapid Manufacturing. Because the term 3D printing appealed to journalists it has become the term used to incorrectly describe any and all 3D printing technologies as well as the industry as a whole. The terms are generally used interchangeably. The only real difference is the quality of your Google search results. Search for 3D printing and you’re likely to find a lot of media articles about desktop 3D printers. A search for Additive Manufacturing is likely to turn up more scholarly articles and articles related to industrial uses for the technology.