Basically, Additive Manufacturing is the action of depositing or adhering material, eventually forming a solid object – sounds simple but with all the wonderful 3D printing (Additive Manufacturing) possibilities available (and growing!) this versatile manufacturing method may seem complicated or even daunting. A short overview of the basic principles and options, like the one below, can help make it more approachable and handy. The technologies, processes, and materials vary, allowing different functions and uses. When choosing between the various 3D printing options, how do you select the best fit for your designs? We will try to give some examples that can help. Here is a cheat sheet post summarizing the main 3D printing options, their capabilities, and design possibilities.
Extrusion / FDM / FFF
Want to quickly and affordably create a plastic object or tool? Extrusion might be your solution. Extrusion, in a nutshell, refers to extruding fluid or viscous material through a nozzle onto a surface, the 3D printed, extruded lines are placed one layer at a time, onto a platform according to the 3D data supplied to the printer. Each layer hardens (usually by cooling after the hot nozzle) as it is deposited and bonds to the previous layers. The video below shows an unusual analog ceramic 3D printer designed by Daniel de Bruin – due to the bare nature of this printer it’s easy to see the essence of how layers are deposited and an object is built. Commercial FDM (Fused Deposition Modelling) 3D printers have a larger capacity, resolution, and more capabilities than this one, of course, but the deposition principle is the same.
3D printing by extrusion usually refers to FDM and FFF (FreeForm Fabrication) which started from thermoplastics but today many other materials can be used in this way: ceramics (as in the video above), and many composites such as wood (fine wood chips mixed with adhesives), and even bronze (mixed with adhesives that are then cooked away in an oven). The 3D printers, as well as the resulting products, can span the gamut from completely amateurish to commercial.
The affordability of lower end FDM 3D printers makes them a favorite among many young designers and DIY enthusiasts in projects such as Martin Zampach’s Wave collection or in Of instruments and Archetypes by Unfold (both above). Extrusion is also diverse in scale, using a robotic arm can lead to constructions such as Joris Laarman’s bridge for example, or 3D printing concrete constructions (below). FDM prints have a layered texture that can range from very rough (as in the picture below) to almost nonexistent (on high-end, high-resolution 3D printers from Stratasys, for example), and the thermoplastics can be biodegradable (PLA) making them environmentally very friendly. The part strength can vary in different dimensions (with or perpendicular to the layers, for example) and they can only be water tight in higher resolutions (available resolutions vary a lot, as we mentioned). For a nice toy or decoration or handy cookie-cutter, this can be a great choice.
SLA and DLP
Here’s the jewelry designer’s favorite: high detail casting. How can you achieve it? Stereolithography (SL/SLA) and Digital Light Processing (DLP) – these are both based on laser technology which cures photopolymer resin. The photopolymer resin is held in a container, the difference is in the light source that cures the material and because of the light application in DLP it is a faster production method. The results produced are highly accurate parts with excellent resolution, but usually aren’t very durable over time – they are light sensitive. However, even though they are not optimal for producing end products directly, they are perfect for lost wax models for investment casting (below is an example of a ring made in a resin called WaxCast by MakerJuice). For jewelry, your needs would normally be a very high level of accuracy, small scale detailing, and a smooth surface – these methods tick all the boxes. The durability of the 3D printed part, on the other hand, isn’t a factor as it will be melted in order to make room for the casted metal. More about the lost wax method and 3D printing here.
Looking for speed and willing to pay for it? Continuous Liquid Interface Production technology is a Carbon3D development, using light and oxygen to quickly and smoothly 3D print objects from a pool of resin. The methods mentioned above produce the 3D printed form layer by layer, while CLIP 3D prints continuously – the light pattern changes like a movie. In addition, Carbon3D’s material and method balance the interaction of UV which triggers photo-polymerization, and oxygen that inhibits the reaction in this material. This balance makes it possible to 3D print even smoother surfaces and achieve consistent and persistent mechanical properties with a broad range of materials appropriate for end products. The best thing about it is that it looks like magic (see video below), then, of course, there is the drastic decrease in printing times and the high performance of the material. CLIP does require post processing for final curing, similar to other resin printers. Another aspect to consider is that it is priced for industrial use, at a basic lease rate of $40,000 per year (before material costs) which means it isn’t the most affordable option.
Ford, for example, is using CLIP technology and researching new materials not only for the speedy development of prototypes but also for finished parts that can be integrated directly into their vehicles (in the image above a 3D printed bumper piece for a Ford Transit van and electrical grommet for a Focus).
Because of its versatility and availability, SLS is frequently used by designers in creating on-demand production for items such as these 3D printed vases by DesignLibero (below). Selective Laser Sintering works with powder material. The laser traces over the tightly compacted powder, sintering or fusing the particles into a solid object. After every layer the bed of the material shifts down making room for the following layer. When the process is completed the excess material is removed exposing the 3D printed parts. The printing resolution is higher than FDM but the texture produced isn’t completely smooth, the layers are barely visible, if at all, and the result can be further polished to be smoother and dyed to a required color.
Another benefit of SLS is the powder bed which serves as a support structure during the process, allowing production of complicated shapes without additional structures. With SLS the object can be printed in one piece without the need to assemble afterwards, a perfect example is the frame for PQ eyewear by Ron Arad (below).
Selective Laser Melting (SLM) and Electron Beam Melting (EBM) work in a similar way, but with metal powder. These methods are used by Siemens for example in the production of gas turbines in order to achieve accuracy and surface finish. In these objects, the high quality of the materials and their durability are critical in providing optimal operational performance of the parts. Using metal as a 3D printed material opens a wide range of uses: fuel nozzles, watch cases or anything in-between.
What do ceramics, sugar, and plaster have in common? They can all be 3D printed using a binder. Binder Jetting, in simple terms, refers to a method where the material being jetted is a binder, which is selectively sprayed onto the powder material, fusing it one layer at a time. Like SLS, the powder material provides support while 3D printing, a further advantage is the range of different materials that can be used, including ceramics and food. The 3D printed parts, however, are not as strong as the parts produced with SLS and require post-processing to ensure some durability. If we strip it down to basics the ChefJet Pro by 3D Systems explains it well: in this case, the powder material is sugar and the binder is water with food coloring and flavoring, the result is a sugary surface which isn’t completely smooth like melted sugar would be, but isn’t grainy either (example below). Of course, this technology is aimed at much more advanced materials such as ceramics leading to a wide range of possible outcomes.
Specifically, Polyjet by Stratasys (Objet), is a method where the actual build materials are selectively jetted through multiple jet heads, in the form of droplets, and cured with a UV light after each layer. This technique is very precise, producing accurate parts with a very smooth finish, on top of that the material possibilities range from rigid to rubber-like, transparent to opaque and a mix of materials can be jetted in one print. Meaning a single part can be produced from multiple materials with different characteristics and properties and even colors.
Earlier this year HP released their new Multi Jet Fusion 3D printer. The new printer doesn’t quite fit to one category of 3D printing, it is a combination of binder jetting, material jetting and powder bed fusion. The binding chemical agents actually don’t exactly bind, they fuse, allowing for detailing, coloring, and transforming the printed material. The HP printers are highly industrial with a large capacity and much faster speed of production. Initial users of the technology include companies such as Nike and BMW, both known for widening their manufacturing capabilities with 3D printing.
Of course, there are more methods and adaptations of various 3D printers to various needs, this is just a taste of what’s out there. For more follow us on Pinterest or subscribe to our newsletter for weekly updates.