3D Printing, a technology originally envisaged to merely make prototyping quicker in the product development process, has grown over the decades to become the phenomenon that it is today. Desktop 3D printing units is something that still continues to amaze and astonish.
But another format of 3D Printing that often gets overlooked, is when the “Print bed” stops being limited to a few square feet and is increased many times to allow not only manufacturing of small to medium objects, but also construction of small habitable buildings to large scale luxury homes.
In this in-depth guide, we will be taking a look at 3D printed houses, the materials they can be built from, their qualities, advantages, disadvantages, costs, the technology that makes them possible, as well as if and how you could potentially buy one.
- Quality and size of 3D printed houses
- Durability and sustainability of 3D printed house
- Costs of 3D printed houses
- Time savings offered by 3D printing a home
- Where to buy 3D printed houses
- Construction 3D printing companies, the homes they build and the cost
- 3D printed house construction – How 3D printed houses are made
- Modular/off-site 3D printed houses
- Advantages of off-site 3D printed houses
- Disadvantages of off-site 3D printed houses
- On-site 3D printed houses
- Advantages of on-site 3D printed houses
- Disadvantages of on-site 3D printed houses
- 3D printed house materials
- Future outlook of 3D printed houses
- Construction 3D printing technology
- Gantry style construction 3D printers
- Robotic arm construction 3D printer
- D-shape construction 3D printing technology
Quality and size of 3D printed houses
One area where houses built with current construction 3D printers fall short of conventional construction methods is the quality of the exterior due to the persistent layer lines being visible. This requires further smoothing (by plastering for example) to allow for a flat paintable surface.
Newer models have a higher resolution with less visible layers, or a square extruder nozzle that lays the material to look like a square brick. This is especially true for newer mechanized arm or robotic arm construction 3D printers such as the Apis Cor’s line of construction 3D printers. Still this is something to keep in mind when considering a 3D printed house versus a conventional one.
Where 3D printed house construction technology leave conventional construction in the dust however is the extent of design freedom they afford to architects and designers with walls curving and zigzagging, something conventional construction will cost you an arm and a leg for.
The biggest limitation of 3D printed house technology by far is scalability. The problem is alleviated when construction 3D printers are used offsite to build the house in parts. Buildings can also be especially engineered to withstand external forces. At which point 3D printing construction methods can fuse with conventional construction techniques to create a full-scale home. Fully 3D printed houses cannot be taller than a certain height due to the lack of metal reinforcements.
With the new 3D printing construction techniques being used to print new homes and offices, 3D printed buildings have been getting bigger and bigger.
Durability and sustainability of 3D printed house
Traditional homes generally last from 100-years, all the way up to the 300-year mark. However, for a house to last long, it must be well-built and properly maintained.
So how long will a 3D printed house last?
As with most things, the house will only begin to fail in part. If the failing parts are properly repaired, a house can last for several hundred years. The durability and sustainability of 3D printed houses largely depends upon the choice of materials used for the construction.
Concrete is no doubt, going to provide durability. Concrete blocks for example, typically last at least 100 years. Depending on the mixture used, 3D printed houses can be expected to last about the same as a house made with concrete blocks.
Even with specific mixtures that have a lower overall environmental impact, concrete remains an environmentally unfriendly choice. Alternate concrete blends such as Mirreco’s hemp-based hempcrete are being developed that are only part cement. These new substrates largely depend on other substances, hemp fiber in this case, for the additional strength.
Alternatively, construction 3D printing may be done with whatever building material is available locally such as clay, mortar, sand or dirt (as WASP did). However, this sustainable approach is clearly going to make the resulting houses less durable and less likely to survive in the face of a calamity.
Conspicuous by its absence in this discussion, is of course, wood. It simply is not possible yet to utilize the benefits of additive manufacturing with wood on a construction scale. Which is quite a shame as wood has been lauded by many experts as possibly the least environmentally damaging building material.
Blow for blow – so to speak – there is little difference in the durability of a 3D printed house versus a conventional house made from similar building materials.
Costs of 3D printed houses
3D printed houses bring the benefits of additive manufacturing to the construction space. The material costs incurred by construction 3D printing are usually an order of a magnitude less when compared to conventional methods. This is while we take into account the fact that 3D printing concrete tends to be more expensive than normal construction concrete.
As for labor costs, they drop down basically to the daily wages of at most two or three operators. And that too is for a much shorter length of time as the 3D printed house would be ready for finishing and furnishing in days instead of months.
The cost to build an average sized 3-bedroom house with conventional building methods is from $250,000 to $320,000. Building the same home with 3D printing technology would cost from 20 percent to 40 percent less to build. So that same 3-bedroom house would presumably cost between $140,000 to $240,000 to build with 3D printing technology.
It should be noted at this point, that most construction 3D printers will not build, or 3D print the foundations, nor would the construction 3D printer be of any cost-saving benefit when it comes to roofing the house.
All those things: the roof, the windows, the doors, electrical wiring, paint and finishing – all of these costs remain the same as with a conventional house, as all this fall outside the scope of what a construction 3D printer is capable of.
Time savings offered by 3D printing a home
While costs are often the most quoted benefits of shifting to construction 3D printers. The time scale benefits are one of the most staggering numbers.
As a matter of fact, most 3D construction projects never need more than a month to 3D print even the most complex designs.
The Future Foundation Office of Dubai took a total of 3 months to go from idea to operational office.
Europe’s first 3D printed office, The BOD, only took 22 days on their first attempt, and this was reduced to just 3 days when COBOD reperformed the construction 3D printing of the building as a test 2 years later.
And of course, ICON’s 500 sq. foot houses take only a day each to go from nothing to a completely finished and ready-to-move-in house.
The mere thought of constructing an entire house in a single day is nothing short of amazing.
Compare this with conventional construction, and it is normal to expect ANY house to take at least several months to be ready to move in.
Where to buy 3D printed houses
As it stands, consumers in most cases would be unable to commission a 3D printed house construction directly. The printers themselves are expensive investments for any local construction company. 3D construction printer generally starts at $39,000 for the small basic models, to the upwards of $100,000 for the larger models.
Apart of from the cost of equipment and materials, there’s another major hurdle in purchasing a 3D printed house depending on where you are located. Only a handful of construction permit have been handed out for 3D printed houses, in special experimental cases, in select areas.
The mass of 3D printed houses is currently being developed in more technologically primitive areas. However, for anyone interested, a good place to start would be to contact the large-size local construction companies first. And then, as option B, contact the construction 3D printer makers themselves.
One exception of course, is Haus.me. The luxury prefabricated home maker readily sells its houses conveniently online via both monthly installments plans as well as outright cash purchases.
Others such as COBOD (www.cobod.com) provide construction 3D printing services, albeit in limited areas of Europe.
Another potential website to check out is www.weprinthouses.com. However, they are currently only taking requests and not orders. Additionally, at a cost of $100 per square foot for the construction alone, there is not much of a cost saving benefit transferred to the customers.
The company based out of Austin Texas has been awarded the first commercial permit to build a 3D printed house that can appraised and sold in the U.S. The construction project has been given the code name the Genesis. Construction begins February of 2020.
See our post, when will 3D printed houses finally become available where we look at the viability of 3D printed houses, plus when and where 3D printed houses will be commercially available to begin with.
Construction 3D printing companies, the homes they build and the cost
University of Nantes researchers designed and constructed a full-size single-family house via construction 3D printer in France at a cost of $232,000 in 2018. Which was twenty percent less than what a similar sized building would have cost to construct via conventional means.
Haus.me – the business that sells the PassivDom highly insulated prefabricated houses, charges $210,000 for a ready to move in luxury 3D printed smart house that is entirely self-sufficient and filled to the brim with smart features.
The Dubai Future Foundation office that was 3D printed off-site by Winsun cost $140,000 at the time for the entire structure. With the fit and finish of this luxury office, a hundred and forty thousand dollars is quite a bargain seeing as how by using construction 3D printing technology, the government estimates that it saved almost 50% on the total (assembly, electrical, and technical) labor costs.
All three of the above are examples of luxury or large-sized 3D printed houses that cost a sizably less amount than what an equivalent construction done via conventional methods would cost.
On the other end of the scale are the small size houses that have been making headlines and have successfully been 3D printed at a fraction of conventional costs.
COBOD’s construction 3D printing services provide an online project cost calculator based on various factors such as the square meter area of all the walls, labor cost and number of operators, and the cost per unit of 3D printing concrete.
The cost of construction comes out to be around $15,000 for a small sized house (single bedroom). $20,000-25,000 for a medium sized house (two bedroom). And around $50,000 for a large sized 4 bedrooms house.
Compare this with the fact that building one’s own house can cost anywhere between $95 to $150 per square foot and it quickly becomes clear that even construction 3D printing services have a lot to offer in terms of cost savings.
On the extreme end of affordable housing of course, stand ICON and WASP’s efforts.
ICON and New Story’s 500 sq. Foot houses 3D printed on-site in El Salvador cost around $4,000-5,000 per house.
And WASP’s earthen house village made with their construction 3D printer. The average raw material cost per house came out to only 48 euros per house.
3D printed house construction – How 3D printed houses are made
Construction 3D printing has come a long way in the last decade from being just a pipe dream to an actual available service. Construction 3D printing has thus far flourished by and large in the prefabricated houses market.
Slowly and surely, mobile construction 3D printers are gaining both the stability as well as the quality needed to cope with printing on-site, and on-location in a variety of construction conditions.
Based on the method of construction, 3D printed houses right now fall into two categories:
- Modular/Off-site 3D Printed Houses
- On-site 3D Printed Houses
Modular/off-site 3D printed houses
With the accuracy and resolution of construction 3D printing comes the ability of 3D printing a complete house, in parts, off-site and then later transporting and assembling the same onto the final location.
Many 3D construction printer companies, most notable Winsun, have made this into a viable business model.
Advantages of off-site 3D printed houses
The advantages that come with 3D printing off-site include:
- Much greater control over the 3D printing process: Printing off-site allows the manufacturer to treat building the house the same as manufacturing any other good. That is, the factory can be tailored to the exact needs of the construction 3D printing process. Temperature and humidity control are just the tip of the iceberg.
- Less risk of damage to the expensive construction 3D printing equipment: While the 3D construction printer itself is not a multi-million-dollar investment, it still is a very capital-intensive move for any construction company to invest hundreds of thousands of dollars in a construction 3D printers. 3D printers are sensitive and precise computerized machines. Printing off-site ensures that the construction 3D printers never leave the safe confines of a suitably large hanger.
- Permanently installed construction 3D printers: Large-scale gantry style construction 3D printers can be used instead of expensive robotic or mechanized arm-based ones. Gantry-style construction 3D printers are both faster and much easier to maintain than more advanced robotic construction 3D printers. Thereby further reducing construction times for the customer.
- Increased worker safety: Worker safety has long been one of the biggest concerns of large-scale construction projects. Labor workers on-site are exposed to a variety of hazardous situations and oftentimes life-threatening levels of work-related risks. Construction 3D printing done off-site alleviates a lot of these risks and allows for the company to always have necessary medical facilities on-hand too.
- Greater design freedom: On-site construction 3D printing can quickly devolve into simply a battle with mother nature. Especially in trickier climate and/or terrain conditions. 3D printing inside factory premises allows for much greater flexibility in both design as well as the allowed versatility. The Future Foundation Office of Dubai serves as a prime example.
- Cost Savings: From economies of scale, to lower failure rates, to savings in transportation of raw material costs—off-site construction 3D printing considerably brings down the costs of construction. This in turn makes construction 3D printing that much more viable and brings down housing costs as a result.
Disadvantages of off-site 3D printed houses
While prefab construction 3D printed housing certainly has plenty of positives going for it, certain drawbacks have kept it from becoming the housing revolution that is so needed in today’s world.
These disadvantages include:
- Unpredictable durability: While it is easier to 3D print off-site, 3D printed house done without considering the exact ambient conditions that the 3D printed house will face may cause some serious question marks over how long the resulting 3D printed house would last after being moved to the site.
- Costs of Assembly: The biggest promise of construction 3D printing, like its smaller desktop sibling, is the cost savings that come with additive manufacturing. The cost of transporting and assembling the 3D printed house then, becomes both counter-intuitive to the tenet of this technology, and, from a practical point of view, it diminishes the materials and labor costs saved during the construction process. Transporting many tons of solid concrete, or other material, even when done in parts, adds up to quite a hefty transportation cost. This is exacerbated further still if the parts have to be shipped overseas or trans-nationally.
- Increased Lead Times: Construction 3D printing is fast. A 3D printed house can be ready in days, as opposed to the months-long wait. But if you are going to be transporting and assembling a whole house to a location, this adds a good deal of additional lead time to a project.
- Risk of Damage On the Road: While any self-respecting business would try its best to ensure that the shipping and transport of the 3D printed house or building are safely secured during the move, the reality is that accidents do happen and worse still is when a part gets damaged in an imperceptible way. This runs the risk of the house getting assembled only for the structure to fail later on. The last thing anyone wants is for an assembled house to be structurally unsound, be it the manufacturer, or the people that are going to occupy it.
- Limited reach:There will inevitably be limits to how multiple tons of concrete could feasibly be transported for the purpose of on-site assembly. While cost and time are two factors, the inability to 3D print on-site means that for persons who do not have the money and time to bear the carriage costs, or even those who live too far away for off-site prefabrication of a 3D printed house to be considered feasible would automatically be stuck with the costly and inefficient conventional methods of construction.
- The “Mobile Home” Stigma: Ever since manufactured homes became a viable housing solution, there has persisted a stigma that prefabricated housing is only purchased by those of a lower income class who cannot afford a constructed home. This stigma alone, is an extremely strong adversary to overcome for off-site construction 3D printing companies. It is unreasonably difficult to convince and overcome the psychological barriers of the masses, who would love the cost savings of construction 3D printing but would quickly flinch and leave at hearing the word “prefab”.
On-site 3D printed houses
On-site 3D printed houses promise far greater disruption in the housing and construction industry than off-site ones. The primary reason is that on-site construction 3D printing actively takes business away from conventional construction technology.
The savings in labor cost, and just the sheer amazement of seeing an entire habitable house get constructed in a matter of days instead of months means that on-site 3D printed houses have a bigger audience to cater to before even completely hitting the market.
Advantages of on-site 3D printed houses
On-site construction 3D printing is now being hailed as the future of construction as a whole by a lot of industry experts, its advantages include:
- Increased Apparent Durability: On-site constructed 3D printed houses have to be drawn from the foundation to the top roof. This means that the entire construction 3D printing apparatus needs to be set-up such that it can effectively, reliably and accurately deal with whatever conditions that the site may present, which sometimes could even include earthquakes and other violent acts of mother nature. Clearly while this is a more challenging construction landscape, the fact remains that if a 3D printed house is successfully 3D printed in such an environment, the questions regarding its durability and strength should be far fewer than with an off-site constructed 3D printed house.
- Adaptable Design: Unlike off-site construction of 3D printed houses, on-site construction 3D printing can be adapted to the specific needs of the customer as the construction process is on-going. Maybe they would prefer the boundary wall to be twice as thick, or they would like to add a curved corner to the front of the house. Such last-minute requests simply cannot be entertained when the house has been prefabricated and is only going to be assembled on-site.
- Cost Savings are transferred: While off-site construction 3D printing adds additional carriage and assembly overhead costs to be borne by the customer, the cost savings of on-site construction 3D printing are a lot more likely to be transferred to the new home owner since the construction company would still be able to keep a hefty profit margin despite the overall reduction in costs.
- Flexible Construction Materials: Off-site construction 3D printing is limited to the types of raw materials that are available to the construction 3D printing company. However, with on-site 3D construction printing, it is possible to choose the best material mix in terms of cost as well as environmental impact to ensure that the 3D printed house is sustainable both during its construction as well as when it is eventually going to be repaired.
- Time Savings: With on-site 3D construction printing, a 3D printed house may very well only take a matter of days including complete finishing and furnishing. These time savings are directly transferred to the customer since the absence of transportation lead times means less of a headache for the construction 3D printing company. That is more opportunity to 3D print more houses and not just have a backlog of orders that need to be shipped and assembled.
- Greater reach: On-site construction 3D printers are usually designed with mobility in mind. This means that the only transportation and carriage would be for the 3D construction printer itself, the raw and finishing materials, and the furnishings. It is far easier to transport a truckload of bags of 3D printing concrete, mortar or clay than it is to transport tons of prefabricated house parts. Inevitably this means that construction 3D printing companies can cater to a larger audience and even entertain projects in remote locations since the costs of transportation would in large part be reduced by sourcing the raw and finishing materials as well as the furnishings locally, closer to the actual site of construction.
Disadvantages of on-site 3D printed houses
While on-site construction 3D printing is poised as the future of home building, it still has some drawbacks that have yet to be overcome. These disadvantages of on-site construction 3D printing include:
- Loss of printing quality: While it is true that on-site construction 3D printing promises more durable 3D printed houses by tailoring the material mix as well as the design to the on-site requirements, another fact is that by focusing so much on battling the ambient conditions, the print quality both aesthetically and design-wise would have to face compromises in order to complete a successful on-site 3D construction print.
- More expensive failure: When a module of a modular off-site 3D construction print fails, only that specific module needs to be reprinted and replaced. However, when an on-site 3D construction print fails, the damage is usually far more expensive both in terms of material costs as well as the time it would take to repair the said failed area of 3D print. By design construction 3D printing on-site is broken into a number of major construction chunks. Usually building the walls of a single floor in one go. If a 3D construction print fails, then usually a very large part of the structure needs to be redone since the 3D printing materials are by their very nature designed to be quick setting.
- Higher risk to construction 3D printing equipment: Printing on-site would always pose a much greater risk to the 3D construction printer, needlessly causing damage to these high accuracy construction machines. This matter could further be exacerbated if the construction 3D printing company charges any abnormal damage to the customer. Construction costs are one thing but paying for damage to a 3D construction printer could easily take the project out of budget for any potential 3D printed house owner.
- Less Safety for Workers: On a normal on-site construction 3D printing project, only one or two operators are engaged to mind the 3D construction printer while it does its own thing and constructs up the gray structure. However, a lot of 3D printed houses are designed such that all the electrical as well as insulation work needs to be done alongside the 3D printing process. This may be done both to reduce construction time, but also to streamline the construction 3D printing process when using quick drying materials. This puts workers directly in a less safe working environment especially since with a computerized piece of equipment, there is little that can be done if something were to go wrong.
- Construction Regulations or lack therof: There is very little in the way of construction 3D printing regulations, leading to a case by case analysis for most construction 3D printing projects. You may simply not be allowed to employ construction 3D printers commercially on a piece of plot you own if it is in an area where specific construction permits are required. Consequently, the only work around would be to print off-site, if faced with such a hurdle.
- Site Preparation: A construction 3D printing site, much like its desktop counterpart, works best with a leveled “print bed”, what this means is even before the foundation can be laid, the site needs to be made perfectly flat and perfectly even. With off-site 3D construction printing, this is never an issue, and the foundations are used to straighten out the ground same as it is done in conventional construction. However, with on-site 3D construction printing, a leveled site is crucial for successfully 3D printing the structure. Any flaw here would potentially lead to a failed or undesired 3D print, which is a lot more costly if the failed print is the size of a house.
3D printed house materials
Construction 3D printing materials offer a lot less variety than their desktop counterparts. The most popular material by far is 3D printing concrete. However, this is just a very broad term for mixtures that involve cement, fibers and other ingredients mixed in with water. Other materials include castable clay, mortar, synthetic polymers, and even regular old plastic (recycled).
Concrete is by far the most popular construction 3D printing material. In large part this is due to the flexibility in its formulation. A number of construction 3D printer makers have also devised their own optimal formulation of 3D printing concrete that they claim is the best for use with their construction 3D printers. “Lavacrete” is one such example used with the Vulcan construction 3D printers by ICON.
Construction 3D printing concrete in many ways is similar to normal concrete, but with added fibers, super-plasticizers and other ingredients that make the concrete set in optimal time for layer adhesion between the construction 3D printing layers, as well as strength to allow for less need of steel re-enforcements.
The major advantage of using 3D printed concrete is obviously its strength, as well as its similarity to conventional concrete, which allows for transference of conventional construction material knowledge to 3D printed house construction as well.
The major drawback, however, is how environmentally unfriendly concrete itself is. Concrete production, or more specifically, cement production overall is responsible for more than 5% of total global CO2 emissions. Which is worse than even emissions by the airline industry.
While it is still the go-to material for construction 3D printing and 3D printed houses in general, 3D printed concrete is far from being an eco-friendly choice for the same.
In its defense however, 3D printing concrete is on a road to sustainability with research underway to make 3D printing concrete out of CO2 based binders as well as a shift to smartly designed concrete structures that would use less material for the same level of strength, thereby limiting the need for this eco-unfriendly building material.
Mortar, similar to concrete, is a mix made out of cement, sand and other minerals, designed to be used in construction. Traditional mortar is the stuff that is placed between bricks to bond them together. Construction 3D printing mortar is similar but is designed to be used to construct entire 3D printed houses.
Mortar tends to be easier to work with, and more flexible than concrete allowing for it to be made with a less environmentally damaging footprint. Mortar-based construction 3D printing is slowly falling out of practice in favor of concrete-based mixes mainly due to the added strength advantages of 3D printing concrete.
However, there are notable exceptions, such as CyBe Mortar, that is used by CyBe’s line of construction 3D printers.
Notably used by WASP in their Crane Wasp and BigDelta construction 3D printers, soil is simply the stuff we walk on. By engineering the material delivery pipe and nozzle of the 3D construction printer, WASP built the very first 3D printed earthen house, “Gaia”, with rice husk insulation in Italy in 2018.
If the environment comes first and foremost in your decision making, then using the on-site soil along with agricultural fiber waste like WASP used is an excellent way of making a 3D printed house with an almost nil environmental footprint.
More than just environmentally friendly, using the soil at any site is also cost and time effective. WASP later on went to build an entire village of 3D printed earthen houses, all smartly engineered to be able to provide modern amenities in Italy based on the same principle technology demonstrated in constructing “Gaia”.
The beautiful thing about 3D printing technology is the potential for innovation merely through using a specialized printing material. Similar to desktop 3D printing, construction 3D printing is also home to a large number of innovations in material sciences.
While most of these in the past have dealt with making more effective 3D printing concrete. A recent trend has been towards developing entirely new synthetic polymers that can be used to construct entire houses.
PassivDom is one such example whereby they have built an entire 3D printed prefabricated house using a special insulating polymer composite. The polymer composite is so good in fact that PassivDom’s prefabricated houses can be heated and cooled with only solar energy powered equipment inside the house. PassivDom has even went as far as to cheekily call their prefab houses “Zombie proof”.
Recycled and other plastics
That’s right, houses made from plastic! Recycled plastic that is. Born out of a collaboration between DUS Architects and Ultimaker, the duo jointly designed and constructed a small plastic house as a means of demonstrating the viability of construction 3D printing with recycled material.
The aim of the project was to demonstrate how making plastic houses could serve as a solution to housing needs in the wake of a crisis or a natural calamity.
Likewise, there is work ongoing in 3D printing buildings with bioplastics.
Future outlook of 3D printed houses
Dubai has committed to law that at least 25% construction components of new buildings constructed by 2025 and beyond must be 3D printed. D-Shape and the European Space Agency are inching closer to 3D printing a Moon Base on our planet’s largest satellite. And back here down on Earth, ICON’s Vulcan II just recently finished churning out a house per day in El Salvador for impoverished families living in inadequate shelters.
These are just some of the promises of construction 3D printing in the present day and age.
The future is poised to be even brighter. New patented technologies, such as Armatron System’s slipform molding and casting of long bricks via construction 3D printing robots, are set to provide even more diversity in design and freedom in crafting architectural masterpieces that are energy efficient and space optimized.
Projects such as Eindhoven’s future 3D printed house community, increased government spending on construction 3D printers such as the BOD construction 3D printer delivered by COBOD to Saudi Arabia, and the world’s first ever construction 3D printing conference held in 2019; all highlight one simple fact: construction 3D printing is only going to become more and more common.
With prefabricated 3D printed houses available now, and greater interest and investment in on-site construction 3D printing by both new disruptive entrants as well as existing construction industry veteran corporations, construction 3D printing is here. And it is here to stay.
Construction 3D printing technology
Construction 3D printing, surprisingly, has been in the making for almost as long as other forms of 3D Printing technology. With automated bricklaying technologies being experimented with as early as the 1950s, Construction 3D printing has always had a strong focus on making the arduous process of construction more streamlined.
It should be noted, however, that almost all current construction 3D printing technologies are only able to construct the gray structure i.e. the walls, the floor and in some cases, able to lay the roof as well as pump in the foundation.
As it stands, the rest of the components that make the skeleton of a building inhabitable such as windows, doors, electrical wiring etc. all have to be done manually. This can be likened to how a 3D printer can only 3D print the required shape, but all the other bells and whistles have to be added afterwards via post-processing.
Unlike Desktop 3D printing or even factory production-grade 3D printing, all but one construction 3D printing technology are based on the tried and tested extrusion type 3D printing technique.
While there are variants as to the formulation of the mixture extruded, as well as the extrusion nozzle design, the biggest differentiating factor comes in the form of how the 3D printing nozzle of the construction 3D printer is suspended.
Broadly speaking, this classification is:
- Gantry Style construction 3D printers
- Robotic/Mechanised Arm Based construction 3D printers
Gantry style construction 3D printers
Gantry Style construction 3D printers get their name from the gantry-like overhead rails that are used to mount the construction 3D printing extrusion nozzle.
The earliest, and perhaps the most touted of gantry style construction 3D printing technologies, is the patented Contour Crafting technique by Professor Behrokh Khoshnevis.
Originally conceived as a way to compete with the then-existing 3D printing technologies, namely FDM, SLA and SLS. Contour Crafting was patented originally in 1995. It was not until around 2000 that Professor Khoshnevis and his team began building up a single system of autonomous construction on the basis of the patented technique.
Contour crafting construction 3D printing technique
In a nutshell, Contour Crafting is basically the same as taking an extrusion type desktop 3D printer and increasing its size by many magnitudes. The flattened earth or foundation serves as the print bed. All the XY as well as Z Axis arms are made from suitably rigid and strong steel beams and rails.
As for the print head, a nozzle of a suitable diameter is connected directly with a liquid mix of concrete, that is pumped via a motor at the required rate for layer deposition. This allows for the walls of the structure to be constructed via construction 3D printing. This print head is mounted atop the gantry-style XYZ construct, allowing for complete three-dimensional freedom for 3D printer within the printable area.
Once the walls for a floor are all complete, an optional crane-like attachment alongside the print head is used to place the roof that would serve as the printing bed for the second story and so on.
It should be noted that to date, Contour Crafting has not been commercialized and has only been demonstrated as a Proof of Concept on a “lab” scale.
It should further be noted, then, that while Contour Crafting itself has not been commercialized. All the existing commercially available gantry-style construction 3D printers such as the BOD 1 and 2, Vulkan II, and especially the Winsun are basically a spin on this same technique.
The Winsun in particular was even controversially alleged to be patent infringing upon the Contour Crafting technique. The fact that it was Winsun that constructed the futuristic Dubai Future Foundation Office is a testament of equal measure to the financial viability and scalability of Contour Crafting, and gantry-style construction 3D printing Techniques in general.
Robotic arm construction 3D printer
While gantry-style construction 3D printers have taken the lead in terms of commercial projects, the sheer size of gantry-style construction 3D printers means that transportation, set-up and dismantling of the 3D construction printer requires a very large amount of financial as well as technical effort.
This is also one of the reasons why gantry-style construction 3D printers have become almost synonymous with prefabricated 3D printed houses.
Another competing style of construction 3D printer is the mechanized or robotic arm construction 3D printers such as Cybe line of construction 3D printers as well as the impressive Apis Cor construction 3D printer.
The Robotic Arm construction 3D printers all stem from one goal: to make the 3D construction printer more mobile, less cumbersome, and more compact. This allows construction 3D printers such as the Apis Cor to be transported on a flatbed truck instead of inside a container or containers part-by-part as would be the case with gantry-style construction 3D printers.
Benefit of Robotic arm construction 3D printer
Robotic arm-based construction 3D printers also benefit from a higher print “resolution” allowing for the finished structure to not have as apparent layer lines as Gantry-style construction 3D printers, such as COBOD’s the BOD 2, do. This makes finishing a much quicker process as well.
Drawback of Robotic arm construction 3D printer
The downside of-course is the fact that robotic arm construction 3D printers have limited reach as compared to gantry style construction 3D printers that could potentially be easily scaled up or down based on the size of the house or building to be 3D printed.
D-shape construction 3D printing technology
D-Shape was invented by Enrico Dini originally in 2005, and he was granted the patent for this in 2006.
But what exactly is D-Shape?
Just the only large-scale sand binder-jetting 3D printer ever conceived.
D-shape 3D Printing Technique
Dini specifically designed the 3D printer for being able to sinter together livable buildings made out of sand, seawater and epoxy. However, after running into issues with the epoxy in the mix for binding purposes, Dini reworked his 3D printing process to incorporate a patented magnesium-based binder. For which he was granted a patent in 2008.
The printer itself consists of a large 6 meter by 6 meter aluminum frame and tall aluminum beams upon which the binder jetting print-nozzles are attached.
A very large quantity of sand is placed that acts as both the foundation as well as the building material during the 3D printing process. Once the desired object has completely been 3D printed, it has to be manually excavated out of the excess sand with good old-fashioned shovels.
D-Shape stands uniquely due to both the process that it has upscaled, binder jetting, as well as due to it being the only 3D printing process that has been designed solely to 3D print actual houses and buildings with sand.
The resulting 3D printed structures have a sandstone-like finish and have a much smoother and higher resolution print quality. The resulting structures from binder-jetting are devoid of the visible layer-lines that basically all other extrusion construction 3D printing processes resultantly have.
All that being said, however, D-Shape also has yet to produce an actual livable 3D printed house. Still that has not reduced its inventor’s ambitions in any way as actual 3D printed houses made out of sand and water are very much what Monolite UK (founded by Dini) wishes to be able to do in the future.
D-Shape has also been chosen as the potential construction 3D printing partner of the European Space Agency for 3D printing moon-bases on the moon out of moon dust or lunar “regolith” as it is also known.