3D printing (sometimes referred to as Additive Manufacturing (AM)) is the computer-controlled sequential layering of materials to create three-dimensional shapes. It is particularly useful for prototyping and for the manufacture of geometrically complex components.
It was first developed in the 1980s, but at that time was a difficult and expensive operation and so had few applications.
It is only since 2000 that it has become relatively straightforward and affordable and so has become viable for a wide range of uses including product design, component and tool manufacture, consumer electronics, plastics, metalworking, aerospace engineering, dental and medical applications, and footwear.
The sales of AM machines, or '3D printers' has grown rapidly and since 2005, the home use of 3D printers has become practical.
3D printing systems developed for the construction industry are referred to as 'construction 3D printers'.
A 3D digital model of the item is created, either by computer-aided design (CAD) or using a 3D scanner. The printer then reads the design and lays down successive layers of printing medium (this can be a liquid, powder, or sheet material) which are joined or fused to create the item.
The process can be slow, but it enables almost any shape to be created.
Depending on the technique adopted, printing can produce multiple components simultaneously, can use multiple materials and can use multiple colours.
Accuracy can be increased by a high-resolution subtractive process that removes material from an oversized printed item. Some techniques include the use of dissolvable materials that support overhanging features during fabrication.
Materials such as metal can be expensive to print, and in this case it may be more cost-effective to print a mould, and then to use that to create the item.
In the construction industry, 3D printing can be used to create construction components or to 'print' entire buildings.
Construction is well-suited to 3D printing as much of the information necessary to create an item will exist as a result of the design process, and the industry is already experienced in computer aided manufacturing.
The recent emergence of building information modelling (BIM) in particular may facilitate greater use of 3D printing.
Construction 3D printing may allow, faster and more accurate construction of complex or bespoke items as well as lowering labour costs and producing less waste. It might also enable construction to be undertaken in harsh or dangerous environments not suitable for a human workforce such as in space.