In this article, you’ll learn about the common types of 3D printing technologies. If you are beginner, you will have a good understanding of what is 3D printing and how it works by the end of this article.
This article does not claim to be scientific. Instead, it is a small introduction to 3D printing for beginners.
What is 3D Printing?
In the early 1980s, new methods used in the production of parts began to develop. These methods were not based not on the removal of material, like is the case with traditional machining technologies, but on the layer-by-layer addition of materials.
Products were produced based on 3D models obtained from CAD software, by adding materials in the form of plastic, ceramic, metal powders and others. These materials were bonded through thermal, diffusion or adhesive methods.
What does this mean in practice? This simply means that it became possible to create physical objects in a completely new way.
The first person who patented this technology was Chuck Hull, back in 1984. Hull also created 3D Systems in 1986, which is still one of the industry leaders.
The first commercial 3D printer, the 3D Systems SLA-1, was introduced in 1987.
We won’t go deeper into the history of 3D printing as we’ve already covered the topic before. But if you are interested in a quick rundown, watch the video below:
Types of 3D Printing Technologies
With that introduction, we come to the first and possibly the most promising 3D printing technology, i.e., photopolymer resin printing. Initially, the technology was called SLA. However, over time, this name has turned out not to be entirely correct.
Photopolymer Printing
Photopolymer 3D printing involves the hardening of a liquid photopolymer resin under the influence of light to form a 3D model. Initially, a laser acted as a light source and the technology was called SLA or stereolithography.
Despite its apparent simplicity, 3D Systems spent over 10 years to bring the first full-fledged commercial product to market. This required shifts in other technological products, such as solid-state lasers, which use a solid-state substance as the active medium.
Without going deep into the technological jungle, we can say that it took about 25 years of gradual development of this technology until 2013-2014. At this time, SLA 3D printers cost hundreds of thousands of dollars and were available only to large companies. Their usage was also very limited due to their high cost as well as expensive materials.
In 2011, a startup called FormLabs reimagined Chuck Hull’s ideas and developed the first desktop SLA 3D printer. The printer was unveiled on the market at a price of $3,000. This low-cost printer made it possible for many consumers to get started in 3D printing.
Over the years, FormLabs has delivered tens of thousands of its printers to the market. The company became the first unicorn in 3D printing with a market capitalization value of over $ 1billion. This story marks one of two turning points in the breakthrough made in 3D printing technologies in recent years.
However, other companies were also doing research and development. Some companies realized that using a laser as a light source for illuminating a photopolymer resin was not the only solution. They suggested another way of forming a model. This method was named DLP (Digital Light Processing).
Without going into technical details, the advantages of this technology lie in higher productivity due to illumination of the entire layer at once. This is in contrast to a laser, which must physically illuminate the entire model, which means the model must be constantly moved.
It is easy to explain this 3D printing technology with a simple example.
Let’s say you want to print a ring. This task will take about the same time on both SLA and DLP 3D printers. However, if you need to print 10 rings at once, DLP technology will have an advantage because you can print all the rings at the same time. On the other hand, an SLA printer will spend a certain amount of time printing each ring one at a time, although their quality will be much higher.
Let’s compare some numbers.
The Form2 SLA printer will take 11 hours 22 minutes to print 55 ring models. This means that each ring prints in 12.4 minutes.
The Uniz Slash Plus 3D printer, which is based on DLP technology, takes only 3 hours 51 minutes to print 60 rings. This means each ring is printed in just 3.8 minutes .
DLP technology started gaining popularity and began to compete with the traditional SLA 3D printer. However, before it became mainstrem, a new revolution happened; LCD 3D printers appeared on the scene .
LCD 3D printing technology make 3D printing models even simpler. With this technology, a powerful LED lamp that is reinforced by a lens system shines on an LCD matrix. The matrix then projects the desired image onto a bath with resin, where the 3D model is formed.
When this technology was perfected in 2016, the price of 3D printers reduced by 10 times compared to the hit FormLabs Form 2 printer of that time. The price of budget LCD 3D printers started at about $300. This dramatic cost reduction has significantly expanded the range of buyers and has given home users and small print studios the opportunity to try this technology for their needs.
What are the advantages of LCD 3D printing technology over others, apart from the price?
LCDs, like DLP printers, light up the layer immediately. This gives them a performance advantage. However, initially, the quality of models produced by LCD 3D printers was not very good. But in 2019, 3D printers with a 2K LCD matrix were introduced. These were followed later by those with 4K matrix. The 2K and 4K LCD 3D printers solved the problem of low quality prints.
Today, LCD printers surpass both DLP and SLA in terms of print speed and minimum layer thickness.
Some good examples of printers with 2K resolution include: Elegoo Mars , Anycubic Photon S , Wanhao GR1 , Phrozen Shuffle Lite , Phrozen Shuffle 2019 , Phrozen Shuffle XL 2019 , Phrozen Sonic , with 4K resolution – Phrozen Shuffle 4K , and Phrozen Transform .
The introduction of 8K matrices, as well as the use of special monochrome matrices that increase printing speed, have make this technology dominant in the 3D printer market. A good example of an LCD 3D printer with 8K matrix is the Phrozen Sonic Mega 8K.
TECHNOLOGIES OF PHOTOPOLYMER 3D PRINTING:
And that is the differences between these 3D printing technologies.
Now, in this section, we’ll discuss why SLA/DLP/LCD 3D printing is popular. Before we begin, we have to divide the 3D printers into industrial and desktop ones.
Industrial 3D Printers
Industrial 3D printers are mainly used for large-scale prototyping as well as small batch production and casting molds. With a fairly high productivity and good quality end products, these units are used in the automotive and aerospace industries.
The printers are also used for printing massive objects, such as this mammoth bone that printed by Materialize in cooperation with the Royal Belgian Institute of Natural Sciences in Brussels.
Desktop 3D Printers
Desktop SLA/DLP/LCD printers have become widespread and are mainly used in dentistry, jewelry making, shipping industry and aircraft modeling. The printers are also used in the manufacture of unique gifts and souvenirs. You can read more about their applications in the guides below:
- Guide to 3D Printing Dental Crowns
- 3D Printing in Prototyping
- How to 3D Print Jewelry
- Small Batch Production 3D Printing
High detail and high-quality finishing surface makes this 3D printing technology excellent for solving many problems that previously had to be solved in much more time-consuming and expensive ways.
FDM 3D Printing Technology
The second father of 3D printing is S. Scott Crump. In 1988, Crump patented the FDM (Fused Deposition Modeling) technology. In 1989, together with his wife, he created Stratasys, which is still one of the leading companies in the industry.
The abbreviation FFF (Fused Filament Fabrication) is also often used to refer to this technology. However, don’t let this mislead you. The essence of the technologies is the same, but the names are different in order to avoid patent disputes.
So, what was really invented?
The idea was that the filament is fed into an extruder, where it melts at a high temperature and forms a model in layers through a small nozzle.
Based on this invention, Stratasys began to produce industrial 3D printers. The printers were mainly used in the same way as the first SLA machines. Their application was mainly in the automotive and aerospace industries in the advent of various durable types of plastics, such as polycarbonate (PC), polyether ether ketone (PEEK), polyetherimide (PEI, Ultem), and polyphenylsulfone (PPSF/PPSU). The printers were mainly used for functional prototyping.
The technology did not become widespread until more than 20 years later when the RepRap (Replicating Rapid Prototyper) project appeared. RepRap is a self-replicating mechanism for rapid prototyping.
The original idea of RepRap was to create a 3D printer that could be printed by another 3D printer. In the above photo, all the plastic parts of the “child” printer are printed on the “parent” printer.
Well, something completely different happened. A group of enthusiasts was able to create a budget 3D printer for home or office use using RepRap technology. The idea was quickly picked up by three New York geeks who formed MakerBot and commercialized desktop FDM 3D printers.
This was the second turning point in the modern history of 3D printing.
The cost of Makerbot FDM 3D printers was about $1000. This price was quite affordable for many 3D printing enthusiasts and technologists passionate about the idea of 3D printing engineers and students.
In 2013, MakerBot was acquired by Stratasys for a record $400 million. The result of all this was that the world received a very interesting technology for creating physical objects.
One big advantage of FDM technology is its low cost and a large selection of printing materials to use. The materials began to appear in large quantities after the spread of 3D printing. FDM printers primarily spread among home users, who began numerous experiments with printing at home. For more details, see the article 3D printing as a hobby .
In addition, FDM printing has found its main professional application in prototyping. Once 3D printed in this process, it will never be the same again.
Prototyping has become significantly cheaper and faster. This has enabled engineers to try many ideas to create high quality and detailed products. Find out more about this in our article 3D printing in prototyping .
There are also active attempts to introduce FDM 3D printing into small-scale production. This attempt was seen during the COVID-19 epidemic, when doctors urgently needed to produce spare parts for ventilators, as well as mask holders for doctors who are forced to spend whole days wear them.
FDM 3D printing was able to fully demonstrate its main advantages compared to classic production. Its advantages were fast modeling a new parts and launching it into a series in the shortest possible time, usually in less than a day.
Another major advantage of FDM printing is the wide variety of materials available for printing. The materials range from biodegradable PLA to PEEK that can be sterilized at high temperature and pressure.
In the near future, we expect the widespread introduction of so-called “3D printing farms”, which will be able to implement the concept of “flexible production”. In flexible production, a farm can produce any available product, and not specialize in the manufacture of any specific products as happens in classic production. Today, you could print spare parts for old models of railway cars, and tomorrow, holders of medical masks or souvenir cups for competition winners.
In the meantime, let’s continue our story about the different types of 3D printing that arose together with the development of the two mainstream technologies, i.e., SLA/DLP/LCD and FDM.
Many engineers and entrepreneurs in different countries realized that they can start using the principles of 3D printing using different materials and methods of forming models. And so, they did.
Other Types of 3D Printing Technologies
Here are some of the other 3D printing technologies that have emerged.
Selective Laser Melting
Selective laser melting is also called DMLM and LPBF. The principle of 3D printing here is that under the influence of a powerful laser, metal powder melts and forms a 3D model. This allows you to create models of complex shapes and high strength.
This technology has been applied in aerospace and medicine. A rocket is not a mass product and some elements are much more convenient and profitable to 3D print than to mill or cast.
In medicine, metal 3D printing began to be used to create individual titanium implants made directly for a specific patient. This significantly increases the chances of recovery.
EBM (Electronic Beam Melting)
EBM (Electron Beam Melting) is is a technology similar to SLS/DMLS. However, with this technology, the object is formed by melting a metal powder with an electron beam in a vacuum.
SLS (Selective Laser Sintering)
Selective laser sintering is another interesting technology. The process of forming the model is the same as in SLM. However, instead of metal powder, polyamide or nylon powder is used. This makes it possible to form very strong, wear-resistant products of complex shapes. The models can be primarily used as functional prototypes of future metal or durable plastic products.
MJF (Multi Jet Fusion)
MJF (Multi Jet Fusion) is an original technology developed by HP that essentially repeats the SLS principle, but does not use a laser. This gives a definite advantage in the performance of the printer compared to laser technology, because it bakes the layer immediately, just like it happens with LCD 3D printers.
As one of the world’s technology giants, HP quickly broke into the small 3D printing market and quickly took a large share in the industrial segment of equipment. Unfortunately, as of 2020, HP has not started shipping its 3D printers worldwide.
PolyJet
PolyJet is a technology similar to conventional inkjet printing. With this technology, liquid polymer is shot through many tiny nozzles onto the surface of the print bed. After this, it is hardened using ultraviolet light. U
sing this technology, you can create high-quality full-color mockups and prototypes with the highest level of detail and finish quality comparable to commercial production samples. Unfortunately, the high cost of equipment and materials does not allow for a wider introduction of this technology.
MJM (Multi Jet Modeling)
MJM (Multi Jet Modeling) is a multi-jet modeling technology similar to PolyJet. However, wax can also act as a material here. The technology was developed by 3D Systems and therefore has a different name for patent protection.
Wax printing is widely used in jewelry for making individual models to order and creating master models. There are also specialized printers from SolidScape that print with two-component wax and then melt the support material in hot water.
CJP (Color Jet Printing)
CJP (Color Jet Printing) is a technology that features layer-by-layer gluing and coloring of gypsum-based or plastic-based powder. Using this technology, you can create full-color products.
The technology is most often used for printing architectural models and people figurines. The cost of printing in this case is lower than that of PolyJet technology, which gives more opportunities for its wider use.
LOM (Laminated object manufacturing)
LOM (Laminated object manufacturing) is a technology similar to CJP. However, here the building materials are paper. Each sheet of paper is glued to the previous one, painted with an inkjet printer and perforated. This produces a full color 3D model.
The technology is also well suited for architectural and decorative models.
Another technology with great prospects is the combined technology of 3D printing with metals. The technology combines 3 stages of creating a model:
- Printing on an FDM printer with a special composite filament, where metal and polymer are mixed in certain proportions
- The polymer melts
- Baking of a metal model
Based on this technology, the American companies DeskTop Metal and MarkForged have already created their commercial 3D printer models and began selling them both in America and Europe. However, so far the technology is very crude and does not guarantee good quality finished products. Still, its huge advantage is the significantly lower price of both printers and finished products.
We haven’t tested these systems yet. We are waiting for the opportunity to independently assess their quality and efficiency.
How it works:
Ceramic 3D printing is also a promising trend in various industries. There are a number of companies that produce equipment for printing ceramic models. Different manufacturers use DLP and SLA for this, as a slightly adapted Ceramic binder jetting (CBJ) multi-jet modeling technology .
This technology is used in dentistry, jewelry, as well as for creating high quality prototypes with the necessary functional properties. Also, based on FDM-printers, they create printers that print with clay to create ceramic products in a new way. For example, the Italian company WASP has been offering such systems for several years on the basis of its delta printers that print with filament.
Construction 3D printers also use the same construction principle as FDM printers. However, instead of the molten filament, these printers use liquid concrete. The printers can build the walls of a 100 square meter house in about 3 days. This is significantly faster than standard construction methods. Moreover, the printers can make objects of complex shapes.
Of course, this direction is promising. However, up to date, construction 3D printers have not not received widespread use. But in China, the printers were used in rapid construction of autonomous blocks for self-isolation of patients with mild coronavirus who did not get a place in hospitals, but they were at home.
An interesting fact is that the most promising housing project on Mars is also recognized as a 3D printing method.
Food 3D printing is another way to use FDM technology. However, here, edible raw materials act as a material. The most popular food 3D printers are those that print with chocolate. The chocolate is tempered, enters the extruder and forms a 3D model in layers through the nozzle.
Unlike plastic, chocolate is a very delicate material that is not easy to print. However, it makes it possible to quickly create customized culinary masterpieces or desserts of unusual shapes. In addition to chocolate, it is possible to print using mashed potatoes, dough or jam.
This technology is still at an early stage of development. Perhaps in the near future, we will see more advanced equipment that can be used widely. One of the best3D printers for printing chocolate is Choc Creator .
And the last, but far from the most important type of 3D printing, on which very high hopes are pinned in the future – 3D bioprinting.
In essence, this is a layer-by-layer print, where living cells act as a material. This is a relatively new type of 3D printing. The first experiments began in 2000 by bioengineer Thomas Boland, who modified conventional desktop printers to print DNA fragments.
Over the past 20 years, the industry has made great strides forward. Today, in addition to prototypes of human organs, they are successfully printing implants, vascular tubes, heart valves, auricles, cartilage, bone tissue and skin for subsequent transplantation.
This 3D printing is successfully used to create “simulators” for doctors, on which they can rehearse operations or for students for live practice. Of course, one of the main purposes of bioprinting is the printing of functioning internal organs for transplantation from the patient’s biomaterial.
At the moment, this direction is at the stage of development and testing and is not fully used for treating patients. However, but a large number of successful experiments have already been carried out. For example, the seal of the heart by Israeli scientists in 2019 is still very tiny in size, but the main thing is that it is capable of performing its functions.
Bioprinting also holds great promise in the experimental testing of pharmaceuticals manufactured by pharmaceutical companies.
Of course, I was not able to talk about all 3D printing technologies in this article. But after reading it, even without being a technical expert, you can get a first idea of 3D printing, its various technologies and methods of application.
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