Printing in 3D may seem bizarre. In fact it is similar to clicking on the print button on a computer screen and sending a digital file, say a letter, to an inkjet printer. The difference is that the “ink” in a 3D printer is a material which is deposited in successive, thin layers until a solid object emerges.
The layers are defined by software that takes a series of digital slices through a computer-aided design. Descriptions of the slices are then sent to the 3D printer to construct the respective layers. They are then put together in a number of ways. Powder can be spread onto a tray and then solidified in the required pattern with a squirt of a liquid binder or by sintering it with a laser or an electron beam. Some machines deposit filaments of molten plastic. However it is achieved, after each layer is complete the build tray is lowered by a fraction of a millimetre and the next layer is added.
The printing of parts and products has the potential to transform manufacturing because it lowers the costs and risks. No longer does a producer have to make thousands, or hundreds of thousands, of items to recover his fixed costs. In a world where economies of scale do not matter any more, mass-manufacturing identical items may not be necessary or appropriate, especially as 3D printing allows for a great deal of customisation. Indeed, in the future some see consumers downloading products as they do digital music and printing them out at home, or at a local 3D production centre, having tweaked the designs to their own tastes.