Contour crafting

Contour crafting is a building printing technology being researched by Behrokh Khoshnevis of the University of Southern California's Information Sciences Institute (in the Viterbi School of Engineering) that uses a computer-controlled crane or gantry to build edifices rapidly and efficiently with substantially less manual labor. It was originally conceived as a method to construct molds for industrial parts. Khoshnevis decided to adapt the technology for rapid home construction as a way to rebuild after natural disasters, like the devastating earthquakes that have plagued his native Iran.

Using a quick-setting, concrete-like material, contour crafting forms the house's walls layer by layer until topped off by floors and ceilings set in place by the crane. The notional concept calls for the insertion of structural components, plumbing, wiring, utilities, and even consumer devices like audiovisual systems as the layers are built.

Features
The technology consists in the extrusion (extrusion) of a layer after a layer of special concrete along the path laid down by the program, growing walls of the building, therefore the technology got this name. In this, it is very similar to conventional 3D printing using Stratasys FDM® technology (layering of the heated thermoplastic filament in accordance with the working file).

A feature of the technology is to connect an additional tool of the machine - a manipulator that installs into the design position the supporting and supporting structural elements, engineering communications (jumpers, floor beams / cover beams, truss structures, trays, chimneys, ventilation channels, etc.).

Building material for the construction of supporting structural elements (walls, floors) is a fast-hardening reaction-powder concrete, reinforced with steel or polymer microfiber. A feature of the reaction-powder concrete is the absence of coarse aggregate without loss in the ratio of binders / solid component, as well as the highest performance characteristics. Cheaper types of concrete can also be used, such as fine-grained and sandy concrete modified with additives (hyperplasticizers, hardening accelerators, fiber).

The reinforcement technology can be applied innovative technology woven volume mesh frameworks. In theory, such frameworks can be tied into a single structure during construction.

The advantage of technology lies in the speed of construction. According to the car, it can build a residential building with an area of 150 sq.m. in 24 hours.

The disadvantage is the complexity and, in some cases, the impossibility of building open-plan buildings and complex architectural forms because of the need to create supporting structures.

History
Caterpillar Inc. provided funding to help support Viterbi project research in the summer of 2008.

In the early 2000s the theoretical principles and first feedback are available, and many authors are testing or planning for the future of automatic building systems of entire buildings by robots or a single multitasking robot.

In the years 2002 to 2004 the development of automation in construction has been slower than in other areas (automotive and industrial robotics in particular), but based rapid prototyping by adding material used in other branches of industry, and after improvement of extrusion heads and adaptation of materials (cement, plaster, uncured ceramics, using the principle of Adobe, Plastic, resin, polymers or blends...) it is now theoretically advanced enough to allow the additive construction, including the moon and other planets according Khoshnevis from the University of Southern California.

In 2007, an alternative to the overhead traveling crane is under consideration: the use of a print head oriented in space by the movements of the cables to which it is suspended, these movements being controlled by the computer; this option is being studied by Bosscher and his colleagues in Ohio and improved in 2008.

In 2008, the company Caterpillar Inc. decided to provide funds to support research projects Viterbi (summer 2008).

In 2009, graduate students from Singularity University (an unofficial Silicon Valley University) set up an ACASA project, with Khoshnevis as project director, to commercialize the "Contour Crafting" (CC) technique..

In 2010, Khoshnevis says thus be able to build a robot (House-Bot) a full house in one day with a crane or electric gantry (can be powered by a clean energy source, safe and renewable for electricity green) by producing very little waste of building materials. If this challenge is met, this technique could then strongly limit the environmental impact and the carbon footprint and the ecological footprint of the construction of houses.

That same year 2010, Khoshnevis announces that NASAis evaluating the possibility of using the Contour Crafting for the construction of bases on the planet Mars and / or Moon, which also requires the ability to collect, transport and prepare the lunar material at reasonable costs, a question studied two years earlier by Zacny et al. and Zeng al (2007).

In 2013, based on earlier work (2005) and in view of a possible construction in situ of a lunar laboratory, NASA control a small study at the University of Southern California to refine this 3D printing technique by considering, among potential applications, the construction of structures or infrastructures that could be built on the moon in ISRU mode (in-situ resource utilization), that is to say with a material containing at least 90 % of lunar materials and not more than 10% of material imported from the Earth.

The first French building printed in 3D (YHNOVA, social housing, announced in March 2017 should be born in Nantes, on the basis of a technique "Batiprint3D", patented by the University of Nantes, and conceived with the CNRS, the School Centrale, Inria and IMT Atlantique, and patented by the University of Nantes).

Khoshnevis stated in 2010 that NASA was evaluating Contour Crafting for its application in the construction of bases on Mars and the Moon. After three years, in 2013, NASA funded a small study at the University of Southern California to further develop the Contour Crafting 3D printing technique. Potential applications of this technology include constructing lunar structures of a material that could be built of 90-percent lunar material with only ten percent of the material transported from Earth.

In 2017 the Contour Crafting Corporation (of which Khoshnevis is the CEO) announced a partnership with and investment from Doka Ventures. In the press release, they claim that they "will start delivery of the first printers early next year"

Principle
The house is designed on the computer and the data is then forwarded to the 3D printer. The 3D printer is a fully automatic gantry robot that is larger than the building; The fast-hardening special concrete and normal concrete are supplied via concrete containers.

First, the gantry robot pours a frame layer by layer using the fast-hardening special concrete. Its computer-controlled spray nozzle places thin traces of the concrete on the ground, which are brought to their final shape by two side-mounted trowels. Then the frame is filled with normal concrete. Furthermore, finished steel frameworks or the like can be introduced with. Thus, a building is created exactly after computer drawing.

This principle of rapid prototyping was developed by the US researcher Behrokh Khoshnevis, a professor at the University of Southern California, Los Angeles.

Methods
In general, automated systems allow additive, formative or subtractive management of the material. They can also combine - in situ - these 3 approaches.

The CC (Contour crafting) method adapts to the needs of a large construction software and hardware tools created to machine or produce molds to produce industrial parts for foundries, glass or plastics and then for 3D printers.

Since the mid-1990s, Khoshnevis has been gradually adapting these technologies to a rapid home construction project, which could be implemented, for example, after devastating natural disasters (tsunamis, earthquakes) such as the earthquake. hit his homeland, Iran) or even on other planets in the context of space exploration with human presence. In Europe, the Italian Enrico Dini has created his own machine called D-Shape which deposits layers of sand hardened by an inorganic binder to produce objects up to six meters high (in 2014).

In the first case, a fast-setting material such as concrete from sand and cement used with a "set accelerator" shape - layer by layer - the walls and elements of a home, to floors, ceilings and roof set up by the gantry crane or crane.

The voids necessary for the insertion of plumbing, electrical and computer wiring, ventilation or insulating materials are provided upstream in the computerized plan, but the robot and its gantry can theoretically also install pipes or some secondary elements of the structure, or decorative and protective elements such as tessellations, tiles, plaster, paints, etc.

Alternatives or ecological variants
They seek to use basic materials that are widely available and have a small ecological footprint (sand, gravel, clay, etc.) and to use a free and safe source of energy such as solar energy (transformed into electricity and in the form of heat)..

Recently (2012-2013), artistic and / or technical experiments have used machines constructing objects or decorations in sand, sometimes of large size. This is the case for example of:

sets or elements of printed architecture (or "computational architecture") produced by architects Michael Hansmeyer and Benjamin Dillenburger, with the Architecture Department of ETH Zurich 36. In this case, the 3D printer manufactured large objects (columns, walls, rooms) made from sand. The pieces were formed from algorithms aiming at rapidly producing complex and decorative architectural objects that are almost impossible to achieve by the means of classical sculpture, which should be exhibited in France at the FRAC in Orléans in 2014

Sculptures or utility objects built by a computer-controlled " Stone Spray Robot" capable of printing in multiple directions at a time (in two planes, vertical and horizontal) to produce complex, possibly self-supporting shapes (furniture, walls, sculptures... built on sand agglomerated by a glue (ecological binder LEEED certified (Leadership in Energy and Environmental Design), with a power supply which is a photovoltaic panel. This robot was produced by Shergill, Anna Kulik and Petr Novikov, supervised by Jordi Portell, Marta Male Alemany and Miquel Iloveras of the IAAC (Catalan Institute for Advanced Architecture (Institute for Advanced Architecture of Catalonia;

Objects in melted sand; fusion is produced by concentrating a solar light beam on a renewed layer of desert sand; It was Markus Kayser who developed the first very simple prototype, successfully tested in the Sahara desert, using a simple fresnel lens driven by a computer powered by solar panels ("Solar Sinter Project"). The lens concentrates the heat of the sun on sand added in the machine layer by layer, the shape being programmed as a digital model.

The P r Behrokh Khoshnevis, with the University of Southern California and the funding NASA and Cal-Earth Institute tests in 2014 a "giant 3D printer" with the project to build a house in 24 hours. The printer is here a robot that extrudes concrete according to a plan stored in the computer that controls it.

According to proponents of this technique, such robots could in the future build - with materials collected (or recycled) on site - civilian and military buildings, airstrips, roads, hangars or radiation walls as well as possibly habitable structures on the moon, march or other extraterrestrial environments. Tests are done in a laboratory located in the desert of NASA (D-RATS). This process is or has been tested on a small scale (project "House of the Future / Urban policy initiative" (2004) and is considered by industry for several years.

The project "3D Print Canal House" uses a printer of intermediate size, operating in a container, called "Kamermaker" easy to bring on site (test underway in the Netherlands 49), elements of walls that are then easily assembled on square; in this case, the plastic used is made of 75% vegetable oil, but other types of plastics are experimented.

Commercialization
The Caterpillar Inc. has funded the Viterbi School project since 2008.

Khoshnevis also says that NASA is evaluating outline construction as a method of building bases for the colonization of Mars and the Moon.

In 2009, undergraduate students from the University of Singularity established the ACASA project with Khoshnevis as CTO to market the construction by contours.

Anteriority
The concept of additive manufacturing exists among modelers who use clay, wax and architecture in craftsmen or decorators who use plaster or stucco. The construction of layered walls of adobe (banchage) consolidated or not by lime, straw, fibers, etc. has existed since antiquity, but it would now be potentially fully automated, accelerated and no longer require formwork.

Implementation
One of the most successful systems for contouring construction is D-Shape, the developer of which is Enrico Dini. D-Shape allows you to perform buildings without human intervention. In this case, D-Shape uses a special technology for converting sand into a mineral with microcrystalline characteristics, whose properties are superior to Portland cement. According to some claims, such material does not require reinforcement. It is noted that D-Shape allows you to speed up the construction process up to four times compared with traditional methods.

In 2009, the D-Shape system had already erected a building 3 meters high.

In 2014, a breakthrough began in the field of building construction using contour 3D printing with concrete.

During 2014, the Shanghai company WinSun announced, first the construction of ten 3D-printed houses, erected in 24 hours, and then printed a five-story house and a mansion.

The University of Southern California passed the first tests of a giant 3D printer that can print a house with a total area of 250 m² per day.

Prospective
Various more or less experimental models were created at the end of the xx th century and helped gradually producing parts increasingly large, usually single-material and of the same color.

The three-dimensional printer was initially science fiction (Arthur C. Clarke evoked a "replicating machine" in the 1960s, machine that would replicate objects as they printed books, which would have a profoundly positive effect on society: "humanity will adapt as in the past" or comics (in 1972, in the cartoon Tintin and Shark Lake, Professor Tournesol invents a three-dimensional photocopier immediately coveted by Rastapopoulos to manufacture of false by duplicating artwork stolen from major museums).

The technical solutions existing in the 1990s suggest the possibility of a rapid and fully automated construction of a building or a set of buildings, with automated painting, robotic installation of tiles and other decorative or functional elements such as piping water, gas, air conditioning or aeration, integration of electrical, electronic or fiber optic cabling, etc.

In 2014, robot surgeons exist, including brain surgery. Some medical robots can be remotely controlled (tele) and under development models can already adapt in real-time respiratory movements or reflexes of a patient. They suggest that the accuracy of 3D printing applied to architecture can progress further.

Similarly, typologies of materials are likely to increase in the future as technical progress. Reactive or "intelligent" materials structured to store or conduct or filter air, water, moisture, calories or frigories, information, etc. are also considered.

The biomimetic could inspire engineers and architects and offer new ideas for eco-housing with very low environmental footprint, without "water footprint" or carbon footprint, or likely to repay their ecological debt. Such constructions could for example be inspired by the constructive model of certain termite mounds, bioconstructive and / or photosynthetic organisms, etc. using micro-robots capable of possibly producing a nanotructured material with novel characteristics.

Source from Wikipedia