The different types of 3D printing technology
There are various 3D printing methods which were developed to build 3D structures and objects. A number of them are prevalent nowadays, and a few have fallen by the wayside.
This guide focuses on the available 3d printing technologies, or in layman's terms, types of 3D printers. Below find a list of the most common technologies used in 3D printing today:
The seven different types of 3D printers
- Fused deposition modeling (FDM)
- Stereolithography(SLA)
- Digital Light Processing(DLP)
- Selective Laser Sintering (SLS)
- Selective laser melting (SLM)
- Laminated object manufacturing (LOM)
- Digital Beam Melting (EBM)
Fused deposition modeling (FDM)
FDM is the only 3D printing technology which uses production-grade thermoplastics, so items printed have excellent mechanical, thermal and chemical attributes.
3D printers which use FDM Technology construct objects layer by layer from the very bottom up by heating and extruding thermoplastic filament. The whole process is somewhat similar to stereolithography. Specialized programs or Slicers "cut" CAD models into layers and computes the manner printer's extruder would assemble each layer.
In addition to thermoplastic, a printer may extrude support materials too. Then the printer heats thermoplastic until its melting point and extrudes it throughout nozzle on a printing bed, which you may know as a build platform or a desk, on a predetermined pattern determined by the 3D model and Slicer software.
The Slicer software running on the computer connected to the 3D printer translates the measurements of an object into X, Y, and Z coordinates and controls the nozzle and the foundation follow calculated route during printing.
When the thin layer of plastic binds to the layer beneath it, it melts and hardens. When the layer is completed, the base is lowered (as shown in step 5) to accommodate the printing of the next layer, this is shown in steps 1 to 5 in the diagram below.
The full FDM process in 5 steps
Printing time depends upon size and complexity of your model.
Small objects can be completed relatively quickly, while larger, more intricate parts need more time.
When compared to SLA, FDM has a slower printing speed.
Overall printing time depends upon size and complexity of your model.
Small objects can be completed relatively quickly, while larger, more intricate parts need more time.
When the printing is finished supporting materials can readily be removed either by putting an object into a detergent and water solution or snapping the support material off by hand.
Nylon is typically used as a support material and can be dissolved in acetone. Read more about this process in our article about the various types of 3D printer filaments.
Then objects may also be painted, plated or even hammered afterward.
FDM technology is widely spread today, and used in industries such as automobile manufacturers, food producers, and toy manufacturers.
FDM is used for new product development, prototyping and even in end-product manufacturing. This technology is considered simple-to-use and environment-friendly. Through the use of this 3d printing method, it became possible to construct objects with complex geometries and cavities.
We can use many different types of thermoplastics with FDM printers. The most common of these are ABS (Acrylonitrile Butadiene Styrene) and PLA(Polylactic Acid) plastic You can read more about these 3D printer filaments here.
Additionally, there are several kinds of support materials such as water-soluble wax or PPSF (polyphenylsulfone).
Pieces printed with this technology have excellent mechanical strength and heat resistance, allowing you to use printed models as functional prototypes.
FDM is widely for the production end-user goods. We are specifically referring to small, detailed components and technical manufacturing tools. Some thermoplastics (such as PLA, which is non-toxic) may even be utilized in food and drug packaging, making FDM a favorite 3D printing method within the medical sector.
Stereolithography (SLA)
SLA is a 3d printing method which could be used to execute your projects that involve the 3D printing of items. Although this process is the earliest one in the history of 3D printing, it is still in use today.
The idea and application of this method are amazing. Whether you're a mechanical engineer, who wants to confirm whether the part can fit your design or creative individual who wishes to print a plastic prototype for a fresh upcoming project, Stereolithography can truly bring your 3D models to life.
SLA printing machines do not function like normal desktop printers that extrude some quantity of ink to the surface. SLA 3D printers operate with an excess of liquid plastic that after a while hardens and forms to a solid object.
Parts printed by stereolithography 3D printers usually have smooth surfaces, but its quality depends on the quality of SLA printer used.
After the plastic hardens a stage of the printer drops down in the tank a fraction of a millimeter and laser forms another layer until printing is finished. After all, layers are printed, the item has to be rinsed using a solvent and then put in an ultraviolet oven to complete processing.
SLA printing process explained
The time required to print an object depends upon the size of the SLA 3d printer utilized. Small items can be printed within 6-8 hours using a basic kid's 3D printer, while large 3d prints can be several meters in 3 dimensions and printing time could be up to several days long.
Digital Light Processing(DLP)
DLP is another 3D Printing process quite much like stereolithography. The DLP technology was made in 1987 by Larry Hornbeck of Texas Instruments and became well known for its use in the production of projectors.
It utilizes digital micromirrors laid out on a semiconductor chip. The technology is found in mobile phones, film projectors, and, of course, in 3D printing.
For 3D printing, both DLP and SLA functions with photopolymers. However, the difference between SLA and DLP technology is that DLA requires an additional source of lighting.
3D printing amateurs frequently use more traditional sources of lights like arc lamps for DLP printing.
The other important piece of the DLP puzzle is an LCD (liquid crystal display) panel, which gets applied to the entire surface of the 3D printed layer during a single run of the DLP procedure. The substance used for printing is a liquid plastic resin that's set in a transparent resin container.
The resin hardens quickly when exposed to a lot of photons, or more simply put, bright light.
The printing speed for DLP is the kicker. A layer of hardened material can be produced with this kind of printer in few seconds. After the layer is completed, it is transferred, and printing of the next layer is started.
Selective Laser Sintering (SLS)
SLS is a technique that uses a laser as power supply to form strong 3D printed objects. This technique was developed by Carl Deckard, a pupil of Texas University, and his professor Joe Beaman in the late 1980s.
Later on they participate in base of Desk Top Manufacturing (DTM) Corp., that was sold to its large competitor 3D Systems in 2001. As was mentioned previously, 3D systems Inc. developed Stereolithography (SLA), which per chance happened to be extremely simlar to Selective Laser Sintering (SLS).
The most notable difference between SLS and SLA is that it uses powdered material in the vat rather than liquid resin in a cube, like SLS does.
Schematic showing how SLS works
Unlike some other additive production processes, such as FDM and SLA, SLS does not have to use some other support structures as the object being printed is surrounded by unsintered powder.
Like the rest of the methods listed above the method begins with the creation of a computer-aided design (CAD) file, which then has to be converted into .stl format with special applications. The material used for printing can range from nylon, glass and ceramics to some metals such as aluminum, silver or steel.
Due to large selection of materials which may be used with this sort of 3d printer that the technology is quite popular for 3D printing customized goods.
SLS is more dispersed among manufactures instead of 3D amateurs at home as this technology requires using high-powered lasers, resulting in these printers being rather expensive.
That being said, there are quite a few startups working on cheap SLS printing machines. For example, recently Andreas Bastian has shared details about his SLS printer (in development) which uses wax and carbon for printing. Another fantastic example is the Focus SLS printer which can be easily used at home requirements and originally was presented at Thingiverse.
The rest - SLM, LOM and EBM
The last three types of 3D printing technologies are Selective laser melting (SLM), Laminated object manufacturing (LOM) and Digital Beam Melting (EBM). Through the last two decades, these technologies have either fallen out of fashion or proved to be economically unviable. As such, you will not find the 3D printers of today using SLM, LOM or EBM technologies, or mentioned in any beginners guide to 3D printing.