D printing in construction

3D printing was first developed in the 1980's, but at that time it was a difficult and expensive operation and so had few applications. (1)___.

A 3D model of the item is created by computer aided design (CAD). The printer then reads the design and lays down successive layers of printing material. 3D printing can be used to create small complex components or to 'print' entire buildings. (2)___ . It may also enable construction to be undertaken in dangerous environments not suitable for human beings.

Fig. 30. 3D Printer

Professor Behrokh Khoshnevis at the University of California has developed a process of 'contour crafting' and is testing a giant transportable 3D printer that can build the walls of a house in 24 hours. The robotic system requires a flat ground slab with underground services in place. Rails are installed near the footprint to take a gantry crane that builds the house. (3)___ . The layers form an inner and outer skin for each wall, leaving them to be filled later with insulation or concrete.

Fig. 31. 3D Printed Apartment Building by Winsun, 2015

A Chinese company Winsun used large 3D printers to build a group of ten small houses in one day. To achieve this, big segments of the structures are 3D printed on their factory using a mixture of concrete and construction waste. Each 3D printer is 6 meters tall, 10 meters wide and 40 meters long. Once all the components have been fabricated, they are shipped in and assembled together, just as if they were Lego bricks. According to the company, this method allows them to save up to 60% of the materials usually needed with traditional building methods and requires 80% less labor, leading to more affordable housing. Winsun believe it will be possible to use the technique to build even skyscrapers in the future. (4)___ .

However, at present none of these systems can handle major elements of the building, such as electrical services, plumbing, doors, windows and finishes. (5)___ . Also, studies on structural stability against earthquakes and winds are yet to be done before anyone can safely live in a 3D printed house.

Exercise 15. Is it True or False?

1. 3D printing was invented in 2000.

2. A 3D model of the house is created by CAD.

3. This technology decreases labour costs, but produces more waste.

4. The process of 'contour crafting' was developed by a Chinese company Winsun.

5. 3D printed walls can be filled with insulation or concrete.

6. It will never be possible to use this technique to build skyscrapers.

7. There are no 3D printers that can create plumbing, doors, windows and finishes.

8. Studies on structural stability have shown that 3D printed houses are very safe.

Exercise 16. What do these numbers refer to?

i. 2015.

ii. 6.

iii. 60.

iv. 2000.

v. 2014.

vi. 5.

vii. 24.

viii. 1980s.