New technical revolution

3D printing is becoming more and more widespread every year. According to research group CONTEXT, the 500,000th 3D printer was shipped in 2015, and more than 8 million devices have been sold by 2020. 3D printing is already being introduced as a manufacturing technology. For example, in 2016, General Electric began selling aircraft engines with 3D-printed fuel injectors. Atlas-5 rockets with parts printed with the same technology were launched into space. Under Armor and New Balance have launched small batches of partially 3D printed athletic shoes, and Organovo has launched commercial bioprinting of human kidney tissue.

For now, this is just the foundation. There have been several technological revolutions in the history of mankind, each of which went through three phases. The first is ‘conceptualization’, when visions and ideas are formed that determine the further path. Then ‘realization’, during which previously seemingly impossible plans begin to be partially realized. And the third phase is ‘mass commercialization’, when enterprises master the production and application of new technology.

And what phase is 3D printing in? The use of a 3D printer to turn a digital file into a physical object is already widespread. For example, in areas such as engineering, law, economics, business, geography and art. There is already a debate about the consequences of exchanging digital objects over the Internet in order to immediately print them on a printer (let’s say a firearm). Obviously, we are still a long way from the day when personal 3D printers will end capitalism by placing manufacturing in the hands of the majority. However, there is no doubt that the 3D printing revolution has reached its second phase – implementation.

By this time, enough methods have been invented for the manufacture of solid objects by printing them in many thin successive layers. In fact, the most common 3D printing technologies have been around for decades.

Although the technology continues to evolve, the last revolutionary phase – mass commercialization – is about ten years away. The pioneers of 3D printing are already using it to make a variety of things. However, this market is still niche and limited in commercial applications. In particular, these are companies that are engaged in small-scale, piece production or goods that cannot be manufactured using traditional methods.

Notwithstanding the above, we must remember that ten years ago, no industrial sector reported the sale of products made in whole or in part with a 3D printer. Therefore, what is happening now is impressive. As 3D printing techniques evolve and new ones emerge, and older processes become faster and cheaper, expect 3D printing to move towards a phase of mass commercialization in the late 2020s or early 2030s. The innovators in this field plan to take advantage of the technology well before that.

3D printing technology

So how does 3D printing work? To a large extent, it is an evolution of 2D printing already used ubiquitous in offices and homes.

Most of us are familiar with inkjet or laser printers that allow us to print documents or photographs. They create them by controlling how ink or toner is applied to the surface of a sheet of paper. Similarly, 3D printers produce objects by controlling the placement and adhesion of successive layers of ‘building material’ in three-dimensional space. For this reason, 3D printing is also known as ALM – ‘Additive Layer Manufacturing’ or AM – ‘Additive Manufacturing’.

To print an object on such a printer, you need a digital model on a computer. It can be created using a computer-aided design system or other software for three-dimensional modeling. Also, a digital model can be captured by scanning a real object with a 3D scanner and processing using CAD or other programs.

The model then needs to be run through another “slicer” program that will split the digital object into multiple cross-sectional layers — typically about 0.1 mm thick. These digital ribbons are sent to a 3D printer, which builds them one on top of the other until the real object is formed.

3D model in Cura
3D model in Cura
desktop 3D printer prints
The same model that the Ultimaker desktop 3D printer prints
Finished 3d printed toy
Ready-made 3D toy ‘elephant’.

Varieties of 3D printers

How a 3D printer builds an object layer by layer depends on the technology it is built on. There are several methods of 3D printing and they can be divided into 4 categories:

  1. The first category includes printers that create objects by extruding molten semi-liquid material from a printhead nozzle. Most often it is a thermoplastic that hardens quickly after leaving the print head. Other extrusion-based 3D printers produce objects by outputting molten metal or chocolate icing (for printing culinary creations). There are also printers that use concrete, ceramic paste, or clay.
  2. The second category of 3D printers creates layers of objects by selectively solidifying a liquid resin known as ‘photopolymer’ that solidifies when exposed to a laser or other light source. Some of these machines create layers of objects inside a fluid reservoir. Others release a layer of resin from the printhead and use ultraviolet light to cure it before applying the next layer. There are appliances that mix several different photopolymers in a single print job, allowing them to output colored objects made from multiple materials. In particular, one such printer – the J750 from Stratasys – offers a palette of 360 thousand shades and can produce objects from a mixture of different materials.
  3. The third and most common category of equipment creates layers by selectively bonding granules of very fine powder. This ‘bonding of granular materials’ is achieved by applying glue to the powder layers or by melting the granules with a laser or other heat source. There are many types of powder adhesion based on different materials. These include nylon, wax, bronze, stainless steel, cobalt chrome, and titanium.
  4. The last category of 3D printers is built around lamination. Successive layers of cut paper, metal, or plastic are glued together to form a solid object. If sheets of paper are used as a building material, they are cut with a blade or laser, then glued together. They can be sprayed with ink during printing to create inexpensive, full-color 3D objects.