An Introduction to 3D-Printing
I recently came across a short book about Industry 4.0, “4 punto 0” by Temporelli, Colorni, Gamucci, 2017. As with many books and articles about Industry 4.0, the authors recognise the central role of the following technologies in the future industry development: Internet of Things (IoT), the Cloud, Artificial Intelligence and Machine Learning, Robot Process Automation and so on. These are all terms we’ve heard before, but according to the authors, another technology will heavily impact the future of manufacturing: 3D printing.
Compared to the technologies previously mentioned, few realise the impact that 3D printing could have on the industry, people’s lives and on the environment. Due to this, I’ve decided to write this article to shed some light on 3D printing; what it is, why we should care and the impact it will have on everyday life.
So, what is 3D Printing?
The idea of 3D printing is not new. The first 3D printer was implemented in 1986 by Chuck W. Hull, who created a method for printing physical objects by adding layers of light-activated resin (photopolymer) hit by light in the ultraviolet spectrum. Since then, this technology has improved a lot and many companies are now employing 3D printing at some stage in the manufacturing process.
The goal is to create physical objects starting from digital files, with the objects created through the addition of subsequent layers of matter. Therefore, 3D printing is also known as additive manufacturing, underlying the difference within traditional production processes (as turning or milling), which usually subtracts material from a stock item.
How does it work?
The process starts from a file, a three-dimensional model drawn with Computer Aided Drafting (CAD) software. This becomes the input of another software, a Computer-Aided Manufacturing (CAM) software, which shapes matters according to the file, progressively splitting out horizontal lines from the matter. These lines have variable heights (from 10 to 100 microns); the smaller the height, the more accurate the outcome of the printing will be.
There are many technologies for 3D printing. For those interested in the technicalities, the technologies are summarised below, others who are less interested can skip to the next section.
Stereolithography Apparatus (SLA)
This is an addictive technique which employs a laser to cross-link photopolymer resin into a three-dimensional solid. The process is shown in the diagram below.
Pros:
- Precision: the final product will have the highest quality and highest level of detail
- Good functional surface quality
- Resin could be recycled and reused for building the next object
Cons:
- Fragility: objects could be easily broken under pressure
- Expensive machines
- Long printing time: not suitable for industrial production
- Supporting structures are needed
Selective Laser Sintering (SLS)
This is another additive technique that uses a laser which shapes solid material from powdered nylon. The process is described in the diagram below.
Pros:
- Final products are very resistant-
- High quality
- No need for support structures
Cons:
- Large equipment which is unsuitable for domestic usage or office environments
- Powder can’t be reused
- Grainy surface on finished parts: post-processing needed
- Equipment and materials are expensive, with post-processing and a power recycling stations needed
Fused Filament Fabrication (FFF)
This technology employs a continuous filament of plastic material which is heated and deposited in the horizontal plane where it shapes, one layer at a time, with vertical movement. The process is more easily understood by looking at a diagram, like the one below.
Pros:
- Clean process not requiring any harsh chemical
- Small dimensions
- Easy to operate
- Low cost
- All the previously listed features make it suitable for domestic uses too
Cons:
- Low quality: layer lines often visible
- Since it must operate on a horizontal plane, the angle between the layers must be smaller than 45 degrees
- For the reason above, support structures may be needed
What’s the best technology?
There’s no definitive answer. The best 3D-printing technology depends on the company and what it needs to address through additive manufacturing.
As previously shown, each of the technologies presents its strengths and weakness. The following graph is an aid for visualising them — the technology best suited for an organisation’s needs should be chosen.
Why industries should care
3-D printing directly fits into additive manufacturing, which could drastically change the way some industries operate. Here are some examples:
- Mass customisation: 3D-printing could merge tailor-made and mass production, allowing industries to personalise any quantity of goods
- Time to market and Rapid Prototyping: no more time wasted customising the supply chain, with any idea easily and quickly implemented without changes to the underlying manufactories machinery
- New forms and new design: objects can be designed to be lighter, employing less raw materials as they won’t need any more internal structures, but they will be directly modelled with forms previously unthinkable
- New models of distribution: instead of outlets and shops, some companies could sell files that users could buy, download and finally print
Why people should care
This last point is particularly relevant to everybody’s lives. Like video and music streaming services replaced corner and video rental shops, in the future people will be able to pay for one file and print it at the corner shop downstairs or maybe, in a few years, at home.
Similarly, anyone with the right software and skills will be able to design her/his goods which will be 100% personalised at no extra cost! Forget about the conformism of ready-to-assemble furniture: 3D-printing will hopefully boost people’s creativity and shape the world we live in!
References
Jerez-Mesa, Ramon & Travieso-Rodriguez, J.A. & Corbella, X. & Busqué, Raquel & Gómez-Gras, Giovanni. (2016). Finite element analysis of the thermal behaviour of a RepRap 3D printer liquefier. Mechatronics. 36. 10.1016/j.mechatronics.2016.04.007 [online]. Available at: https://www.researchgate.net/figure/Schematic-representation-of-a-Fused-Filament-Fabrication-process_fig1_301761967
Kim, Guk & Lee, Sangwook & Kim, Haekang & Yang, Dong & Kim, Young-Hak & Kyung, Yoon & Kim, Choung-Soo & Choi, Se & Kim, Bum Joon & Ha, Hojin & Kwon, Sun & Kim, Namkug (2016). Three-Dimensional Printing: Basic Principles and Applications in Medicine and Radiology. Korean Journal of Radiology. 17. 182. 10.3348/kjr.2016.17.2.182 [online]. Available at: https://www.researchgate.net/figure/Basic-principle-of-stereolithography-apparatus-method_fig3_297605485
SPI LASERS LIMITED (2020), Direct Metal Laser Sintering & Selective Laser Melting. [online]. Available at: https://www.researchgate.net/figure/Basic-principle-of-stereolithography-apparatus-method_fig3_297605485
Temporelli Massimo, Colorni Francesco, Bernardo Gamucci (2017). 4 punto 0. Milano: Ulrico Hoepli.
