What is 3D Printing?
3D printing or additive manufacturing is a process of making three dimensional objects from a digital file.
The creation of a 3D printed object is achieved using additive processes. In an additive process an object is created by laying down successive layers of material until the object is created. Each of these layers can be seen as a thinly sliced cross-section of the object.
There is one exception though, and it’s called volumetric 3D printing. With volumetric printing entire structures can be formed at once without the need for layer-by-layer fabrication. It’s worth noting, however, that as of now, volumetric technology is primarily in the research phase.
3D printing is the opposite of subtractive manufacturing which is cutting out / hollowing out a block of material with for instance a milling machine.
3D printing enables you to produce complex shapes using less material than traditional manufacturing methods.
How Does 3D Printing Work?
It all starts with a 3D model. You can opt to create one from the ground up or download it from a 3D library.
There are many different software tools available. We’ve created an overview on our 3D software page.
We often recommend beginners to start with Tinkercad. Tinkercad is free and works in your browser, you don’t have to install it on your computer. Tinkercad offers beginner lessons and has a built-in feature to export your model as a printable file e.g .STL or .OBJ.
Now that you have a printable file, the next step is to prepare it for your 3D printer. This is called slicing.
Slicing: From file to 3D Printer
Slicing basically means slicing up a 3D model into hundreds or thousands of layers and is done with slicing software.
When your file is sliced, it’s ready for your 3D printer. Feeding the file to your printer can be done via USB, SD or Wi-Fi. Your sliced file is now ready to be 3D printed layer by layer.
3D Printing Industry
Adoption of 3D printing has reached critical mass as those who have yet to integrate additive manufacturing somewhere in their supply chain are now part of an ever-shrinking minority. Where 3D printing was only suitable for prototyping and one-off manufacturing in the early stages, it is now rapidly transforming into a production technology.
Most of the current demand for 3D printing is industrial in nature. Acumen Research and Consulting forecasts the global 3D printing market to reach $41 billion by 2026.
As it evolves, 3D printing technology is destined to transform almost every major industry.
Examples of 3D Printing
3D printing encompasses many forms of technologies and materials as 3D printing is being used in almost all industries you could think of. It’s important to see it as a cluster of diverse industries with a myriad of different applications.
A few examples:
- – consumer products (eyewear, footwear, design, furniture)
- – industrial products (manufacturing tools, prototypes, functional end-use parts)
- – dental products
- – prosthetics
- – architectural scale models & maquettes
- – reconstructing fossils
- – replicating ancient artefacts
- – reconstructing evidence in forensic pathology
- – movie props
Rapid Prototyping & Rapid Manufacturing
Companies have used 3D printers in their design process to create prototypes since the late seventies. Using 3D printers for these purposes is called rapid prototyping.
Why use 3D Printers for Rapid Prototyping?
In short: it’s fast and relatively cheap. From idea, to 3D model to holding a prototype in your hands is a matter of days instead of weeks. Iterations are easier and cheaper to make and you don’t need expensive molds or tools.
Besides rapid prototyping, 3D printing is also used for rapid manufacturing. Rapid manufacturing is a new method of manufacturing where businesses use 3D printers for short run / small batch custom manufacturing.
Car manufacturers have been utilizing 3D printing for a long time. Automotive companies are printing spare parts, tools, jigs and fixtures but also end-use parts. 3D printing has enabled on-demand manufacturing which has lead to lower stock levels and has shortened design and production cycles.
Automotive enthusiasts all over the world are using 3D printed parts to restore old cars. One such example is when Australian engineers printed parts to bring a Delage Type-C back to life. In doing so, they had to print parts that were out of production for decades.
Aviation loves additive manufacturing, largely due to the promise of lightweight and stronger structures offered by 3D printing. We’ve seen a whole bunch of innovations in the domain of aviation lately, with the appearance of more critical parts being printed.
Turbine Center Frame
One such large component printed this year was the turbine center frame which was printed by GE as part of the EU Clean Sky 2 initiative.
The Advanced Additive Integrated Turbine Centre Frame (TCF) is a 1 meter diameter part printed in nickel alloy 718 by GE and a consortium from Hamburg University of Technology (TUHH), TU Dresden (TUD) and Autodesk. It is one of the largest single metal parts printed for aviation.
Typically components like this are manufactured using casting, and consist of multiple parts. In the case of the 3D printed version, it was reduced from an assembly of 150 parts down to just 1 single piece. The printed version also benefits from a reduction of both cost and mass by 30%, and a reduction in lead time from 9 months to just 10 weeks.
Metal Parts Certified by EASA
Back in June 2022 it was reported that Lufthansa Technik and Premium AEROTEC had created the first load-bearing metal part that had been approved for use in aviation.
The new A-link was produced using LPBF and had demonstrated higher tensile strength compared to the traditionally-forged version.
The part was made at Premium AEROTEC’s facility in Varel, Germany, and a large number of test parts were printed and tested to ensure quality and repeatability for certification.
Printing the part represented a cost saving for the component and set the stage for using this manufacturing method for creating structurally important metal parts in the future. It was also used to test the process and to demonstrate the certification process of load-bearing AM parts.
Hypersonic Fuel Injector
This next printed item was never destined to be fitted to an aircraft, but rather it was designed to be installed in a facility for testing flow conditions at hypersonic speeds.
When flying in the hypersonic flight regime above (Mach 5), the air passing around the vehicle becomes incredibly hot, and the pressure increases significantly. These conditions can cause the air itself to become chemically reactive, which causes issues for fuel burning vehicles.
Simulating flow conditions with computational flow diagnostics (CFD) is computationally expensive (if not impossible), and so to replicate the flow conditions, researchers at Purdue fabricated a giant burner to recreate the hot, fast, high pressure experienced in hypersonic flight. In short, they basically built a rocket nozzle and they placed the test components in the exhaust plume to see how they performed.
The injectors that they printed feed fuel and air into the combustion chamber to create specific turbulent flow fields and a stable flame.
The injectors were printed with Hastelloy X, which is a superalloy with superior temperature resistance. The team printed multiple different injectors in rapid time, and tested them all in the burner to see which performed the best.
Now they are able to replicate the hypersonic conditions for flight on Earth at a fraction of the cost (and risk) associated with doing it miles above the Earth’s surface. This can benefit fast aircraft such as scramjet powered vehicles as well as space vehicles.
US-based rocket printing company Relativity Space has a super large metal printer, dubbed the “Stargate”. The 4th gen Stargate 3D printer is capable of printing objects measuring 120ft long and 24ft in diameter.
This AI-assisted robotic printer has been able to achieve fast print speeds thanks to its innovative multi-wire print head. This print head allows for multiple metal feedstock wires to be fed into it at the same time, resulting in higher deposition rates.
The company has made their first LEO test flight of the printed Terran-1 rocket in 2023, so we just thought we would give them an honorable mention in this article as a reminder.
You can see the Terran-1 undergoing a hot fire test in the video below.
Is it possible to print walls? – yes it is. 3D printed houses are already commercially available. Some companies print parts prefab and others do it on-site.
Most of the concrete printing stories we look at on this website are focused on large scale concrete printing systems with fairly large nozzles for a large flow rate. It’s great for laying down concrete layers in a fairly quick and repeatable manner. But for truly intricate concrete work that makes full use of the capabilities of 3D printing requires something a little more nimble, and with a finer touch.
When we first started blogging about 3D printing back in 2011, 3D printing wasn’t ready to be used as a production method for large volumes. Nowadays there are numerous examples of end-use 3D printed consumer products.
Adidas’ 4D range has a fully 3D printed midsole and is being printed in large volumes. We did an article back then, explaining how Adidas were initially releasing just 5,000 pairs of the shoes to the public, and had aimed to sell 100,000 pairs of the AM-infused designs by 2018.
With their latest iterations of the shoe, it seems that they have surpassed that goal, or are on their way to surpassing it. The shoes are available all around the world from local Adidas stores and also from various 3rd party online outlets.
The market of 3D printed eyewear is forecasted to reach $3.4 billion by 2028. A rapidly increasing section is that of end-use frames. 3D printing is a particularly suitable production method for eyewear frames because the measurements of an individual are easy to process in the end product.
But did you know it’s also possible to 3D print lenses? Traditional glass lenses don’t start out thin and light; they’re cut from a much larger block of material called a blank, about 80% of which goes to waste. When we consider how many people wear glasses and how often they need to get a new pair, 80% of those numbers is a lot of waste. On top of that, labs have to keep huge inventories of blanks to meet the custom vision needs of their clients. Finally, however, 3D printing technology has advanced enough to provide high-quality, custom ophthalmic lenses, doing away with the waste and inventory costs of the past. The Luxexcel VisionEngine 3D printer uses a UV-curable acrylate monomer to print two pairs of lenses per hour that require no polishing or post-processing of any kind. The focal areas can also be completely customized so that a certain area of the lens can provide better clarity at a distance while a different area of the lens provides better vision up close.
There are two ways of producing jewelry with a 3D printer. You can either use a direct or indirect production process. Direct refers to the creation of an object straight from the 3D design while indirect manufacturing means that the object (pattern) that is 3D printed eventually is used to create a mold for investment casting.
It’s not uncommon these days to see headlines about 3D printed implants. Often, those cases are experimental, which can make it seem like 3D printing is still a fringe technology in the medical and healthcare sectors, but that’s not the case anymore. Over the last decade, more than 100,000 hip replacements have been 3D printed by GE Additive.
The Delta-TT Cup designed by Dr. Guido Grappiolo and LimaCorporate is made of Trabecular Titanium, which is characterized by a regular, three-dimensional, hexagonal cell structure that imitates trabecular bone morphology. The trabecular structure increases the biocompatibility of the titanium by encouraging bone growth into the implant. Some of the first Delta-TT implants are still running strong over a decade later.
Another 3D printed healthcare component that does a good job of being undetectable is the hearing aid. It is estimated that 99% of hearing aids manufactured are made with the use of additive manufacturing, and it’s clear to see why.
In the dental industry, we see molds for clear aligners being possibly the most 3D printed objects in the world. Currently, the molds are 3D printed with both resin and powder based 3D printing processes, but also via material jetting. Crowns and dentures are already directly 3D printed, along with surgical guides.
As of the early two-thousands 3D printing technology has been studied by biotech firms and academia for possible use in tissue engineering applications where organs and body parts are built using inkjet techniques. Layers of living cells are deposited onto a gel medium and slowly built up to form three dimensional structures. We refer to this field of research with the term: bio-printing.
Additive manufacturing invaded the food industry long time ago. Restaurants like Food Ink and Melisse use this as a unique selling point to attract customers from across the world.
Educators and students have long been using 3D printers in the classroom. 3D printing enables students to materialize their ideas in a fast and affordable way.
While additive manufacturing-specific degrees are fairly new, universities have long been using 3D printers in other disciplines. There are many educational courses one can take to engage with 3D printing. Universities offer courses on things that are adjacent to 3D printing like CAD and 3D design, which can be applied to 3D printing at a certain stage.
In terms of prototyping, many university programs are turning to printers. There are specializations in additive manufacturing one can attain through architecture or industrial design degrees. Printed prototypes are also very common in the arts, animation and fashion studies as well.
Types of 3D Printing Technologies and Processes
Below we discuss six types of 3D printing. These are:
- Vat Photopolymerisation
- Material Jetting
- Binder Jetting
- Material Extrusion
- Powder Bed Fusion
- Directed Energy Deposition
A 3D printer based on the Vat Photopolymerisation method has a container filled with photopolymer resin. The resin is hardened with a UV light source.
SLA was invented in 1986 by Charles Hull, who also at the time founded the company, 3D Systems. Stereolithography employs a vat of liquid curable photopolymer resin and an ultraviolet laser to build the object’s layers one at a time. For each layer, the laser beam traces a cross-section of the part pattern on the surface of the liquid resin. Exposure to the ultraviolet laser light cures and solidifies the pattern traced on the resin and fuses it to the layer below.
After the pattern has been traced, the SLA’s elevator platform descends by a distance equal to the thickness of a single layer, typically 0.05 mm to 0.15 mm (0.002″ to 0.006″). Then, a resin-filled blade sweeps across the cross section of the part, re-coating it with fresh material. On this new liquid surface, the subsequent layer pattern is traced, joining the previous layer. Depending on the object & print orientation, SLA often requires the use of support structures.
Digital Light Processing (DLP)
DLP or Digital Light Processing refers to a method of printing that makes use of light and photosensitive polymers. While it is very similar to SLA, the key difference is the light source. DLP utilizes other light sources like arc lamps. DLP is relatively quick compared to other 3D printing technologies.
Continuous Liquid Interface Production (CLIP)
CLIP is a proprietary 3D printing technology developed by Carbon. CLIP uses an oxygen-permeable window which creates a “dead zone” (a thin liquid interface) of uncured resin between the window and the object. This prevents the part from adhering to the bottom of the print basin. This technology allows for a continuous printing process, which significantly speeds up production.
In this process, material is applied in droplets through a small diameter nozzle, similar to the way a common inkjet paper printer works, but it is applied layer-by-layer to a build platform and then hardened by UV light.
With Binder Jetting two materials are used: powder base material and a liquid binder. In the build chamber, powder is spread in equal layers and binder is applied through jet nozzles that “glue” the powder particles in the required shape. After the print is finished, the remaining powder is cleaned off which often can be re-used printing the next object. This technology was first developed at the Massachusetts Institute of Technology in 1993.
Fused Deposition Modeling (FDM)
FDM works using a plastic filament which is unwound from a spool and is supplied to an extrusion nozzle which can turn the flow on and off. The nozzle is heated to melt the material and can be moved in both horizontal and vertical directions by a numerically controlled mechanism. The object is produced by extruding melted material to form layers as the material hardens immediately after extrusion from the nozzle.
FDM was invented by Scott Crump in the late 80’s. After patenting this technology he started the company Stratasys in 1988.
Fused Filament Fabrication (FFF)
The exactly equivalent term, Fused Filament Fabrication (FFF), was coined by the members of the RepRap project to give a phrase that would be legally unconstrained in its use.
Powder Bed Fusion
Selective Laser Sintering (SLS)
SLS uses a high power laser to fuse small particles of powder into a mass that has the desired three dimensional shape. The laser selectively fuses powder by first scanning the cross-sections (or layers) on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness. Then a new layer of material is applied on top and the process is repeated until the object is completed.
Multi Jet Fusion (MJF)
Multi Jet Fusion technology was developed by Hewlett Packard and works with a sweeping arm which deposits a layer of powder and then another arm equipped with inkjets which selectively applies a binder agent over the material. The inkjets also deposit a detailing agent around the binder to ensure precise dimensionality and smooth surfaces. Finally, the layer is exposed to a burst of thermal energy that causes the agents to react.
Direct Metal Laser Sintering (DMLS)
DMLS is basically the same as SLS, but uses metal powder instead. All unused powder remains as it is and becomes a support structure for the object. Unused powder can be re-used for the next print.
Due to of increased laser power, DMLS has evolved into a laser melting process. Read more about that and other metal technologies on our metal technologies overview page.
Directed Energy Deposition
This process is mostly used in the metal industry and in rapid manufacturing applications. The 3D printing apparatus is usually attached to a multi-axis robotic arm and consists of a nozzle that deposits metal powder or wire on a surface and an energy source (laser, electron beam or plasma arc) that melts it, forming a solid object.
Multiple materials can be used in additive manufacturing: plastics, metals, concrete, ceramics, paper and certain edibles (e.g. chocolate). Materials are often produced in wire feedstock a.k.a. filament, powder form or liquid resin. Learn more about materials on our materials category.
Looking to implement 3D printing in your production process? Get a quote for a custom part or order samples on our 3D print service page.