You have probably heard more about 3D printing lately; now that there are models for consumer use, you may see more items created using a 3D printer. Now it is beginning to enter the construction industry, which is both exciting and a little uncomfortable, depending on your viewpoint.
First, a quick lesson in 3D printing…
What is 3D printing?
3D printing (additive printing or additive manufacturing) is a production technique for creating solid objects from a digital file uploaded to a 3D printer. The printer reads the file and lays down successive layers of materials, such as plastics, resins, concrete, sand or metals, until the entire object is created.
Like an inkjet printer, a 3D printer has containers of a raw material, often plastic based, that it extrudes in a precise pattern to lay down layers. Think of it as the inkjet printer reprinting the same spot over and over until a column of ink is built up.
Currently, they have only been used to create 3D models of a structural design, prototypes, and smaller non-structural elements such as landscaping bricks or decorative components. Viatechnik, however, is showing how the industry is moving beyond that.
3D printers in construction
Extremely large 3D printers have already been built that can use concrete-like materials to fabricate a variety of large structural components and even entire buildings, such as emergency huts and residences.
Raw materials tested include:
- Recycled plastic
- Synthetic stone-like material made of sand and chemicals
Most printers can only extrude one type of material at a time, but more advanced printers have been built that can extrude multiple materials, providing a level of speed and flexibility that was not present before.
The printers may fabricate wall sections that snap together like Legos® onsite or they may print structural scaffolding that can be filled to create full-size walls. Reinforced concrete beams have already been fabricated using a 3D printer.
It’s thought that components can be printed offsite and shipped to the jobsite where they will be erected with steel reinforcement. Alternatively, the printer can be transported to a jobsite to fabricate on demand.
New material development
Within the last year, some new materials have been developed for use in construction printers.
One is a special concrete and composite mixture that is thicker than regular concrete, allowing it to support itself as the concrete sets and cures. Another is from the University of California at Berkeley. It is dry powder based cement printed in thin layers, then sprayed with water to begin the hardening process.
Architects from Amsterdam are experimenting with bio-based renewable materials. These are a bioplastic mix of plastic fibers and 80% plant oil. The architects have already printed wall components that interlock.
Benefits of 3D printing in construction
The benefits of 3D printing include:
- Reduced materials usage
- Increasing the ability to design a larger variety of customized homes and buildings
- Savings of 30%-60% in construction waste
- Reduction of production time by 50%-70%
- Reduction of construction labor costs by 50%-80%
Building designers will escape some of the constraints of current construction methods. For instance, 3D printing makes curvilinear construction practical; no longer will designs be limited by cost and process to rectangular forms.
Being able to use round shapes will impart more strength and stability to the structure because curvilinear shapes are some of the strongest while rectilinear shapes are some of the weakest of structures.
In addition to being stronger, curvilinear design will require a minimum of material to create shapes with a consistent curve. Another benefit is that structures can be designed and printed with hollow components for the easy insertion of service utilities like electricity and plumbing.
The pros and cons of 3D printing
- Lower costs for customized design. It costs no more to design for a single item than it does thousands.
- Construction will be faster and more accurate. The printer directly transfers the digital design into the physical; therefore, the only errors will be due to materials or poor design.
- Labor costs will be decreased because the printer does most of the work.
- Less waste will be generated. Components are printed to order, or on-demand, during the construction phase. Any unused construction components can be recycled.
- Health and safety risks are reduced because many of the dangerous parts of the construction process will be eliminated.
- It is environmentally friendly. Recycled products can be used to produce construction materials for the printer.
- 3D printing can be used to create lower cost housing or to create designs not possible with traditional construction.
- There will be less demand for labor, impacting erectors, and builders.
- Producers of conventional manufacturing products will also see a drop in demand, as will those who rent construction equipment.
- Of those workers needed, there will be a change in the type of skills and labor required.
- Currently, the types of materials available for use in these printers are rather limited. In addition, many printers may be limited to a single type of material.
- Transporting printers to and from site could be problematic as could safe onsite printer storage.
- Construction risks may be higher because any errors in the digital model could result in problems onsite that will need special handling or rework.
- The printers are not necessarily faster than traditional construction. More time may be required for onsite component production.
Is 3D printing for construction ready for prime time?
Wellll….the technology has been developed to the point where full sized testing can be accomplished; however it is going to require a high initial capital investment to build more and larger printers. Right now there are few in existence.
The “Big Delta” printer in Italy has been used for the World’s Advanced Saving Projects (WASP) program. This printer is capable of producing a complete shelter using mud, clay, and natural fibers. The hope is to print emergency housing in areas struck by disaster.
Berok Khoshnevis, a researcher at the University of Southern California, is testing a fabrication process called contour crafting. This is a method that could automate the construction of complete structures as well as subcomponents. With contour crafting, Khoshnevis hopes to print an entire building, such as a house, in a single print run. It would include conduits for electrical, plumbing, drywall, and insulation. He thinks it realistic to expect widespread use in the residential market by 2020 and for high rise construction by 2025.
Remaining printing challenges must be resolved.
Due to the high cost of the printers and the lack of experienced operators and designers, 3D printing is still substantially more expensive than traditional construction. The upfront costs are also high for designing a safe, cost-effective building.
These printers, as mentioned before, are limited in the materials they can use although there are some printers now available that can use multiple materials simultaneously to produce complex structures and assemblies.
Finally, 3D printers are currently very slow, even when operated 24/7.
Is 3D printing right for your construction company?
While challenges remain, most of the problems can be resolved as the technology advances. Nobody would pass up the chance to save money. You don’t need to rush out to get a printer, but you do need to monitor its advance in the industry.