This is an essay I wrote for a competition. I am in love with this technology. There are some references you could look at. All really cool!
3D Printing: A Revolution
The scientific community
is busier than ever today with new patents coming up like baby mushrooms in a
mushroom farm, with most innovations ending up like bricks in a wall. But of these
myriad inventions, some are especially
attractive and revolutionary. One such invention is 3D printing which has
opened up broad avenues for scientists in various fields of research.
The first kind of
printing began with the Phaistos disc in 1850 BC. Since then printing has gone
through many phases – woodblock printing, Intaglio printing, Lithography,
rotary press , dye-sublimation printing, screen printing, dot-matrix and inkjet
printing, laser printing and finally 3D printing(1). The credit for the first
3D-printed object goes to Chuck Hull, who is now the Chief Technology Officer
of 3DSYSTEMS (2). 3D Printing, also known as additive manufacturing or rapid
prototyping, brings ‘inanimate objects to life’ by realising them in all the three
dimensions and requiring input regarding what we want to get ‘objectised’, in the form of a digital file. Say you want to
‘print’ a pot. The household laser printer will give you a sweet image on a
flat sheet of paper but a 3D printer will give you a pot, the way it really is.
The 3D printer chants
the following without any deviation: Receive, Copy, Slice, Produce, Slice,
Produce, Slice, Produce...finally FORM. The virtual design of the object to be
printed is fed into a printer using CAD i.e. Computer Aided Design. This can be
done in two ways – using a 3D modelling program which allows the creation of a
completely new object or with the help of a 3D scanner that scans an object and
produces its copies (3).
There are different
types of 3D scanners that use lasers, lights or x-rays to generate dense point
clouds or polygon meshes. Laser Triangulation scanners and structured light
scanners consists of a laser source which scans the surface of the object by
emitting laser lines (or laser point) that get reflected off the surface to be
detected by a sensor. The distance between the laser source and sensor is known
accurately, and the system can identify the angle between the line joining the
laser source and a particular point on the object’s surface AND the line
joining the laser source to the sensor. Thus, by performing trigonometric
calculations, the system determines the distance between the laser source and
the given point. This further helps in forming the final 3D image of the object.
The scanners used to form images of
objects kept at a distance greater than a meter from the laser source work on
the simple principle of time-of-flight, speed and distance. Here, instead of
using trigonometric triangulation , the distance between the laser source and the
object is calculated with the help of the time taken to reach the sensor and
the pre-present knowledge of light’s speed(4).
Once the object’s image
is with the printer, it employs a variety of material modelling techniques to
form the object.
To prepare a 3D file for printing, the modelling
software slices up the object’s image into thousands of layers. The printer
then produces these layers one by one. In order to ‘produce’ these layers, the
printer melts or softens particular materials such as photo-reactive resins,
gel, etc. The American Society for Testing and Materials has categorized
additive manufacturing into seven types. These include Vat Photopolymerisation, Material Jetting, Binder
Jetting, Material Extrusion, Powder Bed Fusion, Sheet Lamination and Directed
Energy Deposition (5). These techniques can be broadly classified into
three: Stereolithography(SLA), Fused
Deposition Modelling(FDM) and Selective Laser Sintering(SLS). In the SLA
technology, the object is cut out from a vat ultraviolet curable photopolymer
resin by using ultraviolet rays that differentiate cross-sections of particular
thickness one by one, according to the input received from the 3D modelling
software. FDM works by using a plastic filament which unwinds from a coil and supplying
material to a nozzle through which it flows. This flow can be turned off or on
by a Computer Aided Manufacturing software. The plastic filaments commonly used
are Acrylonitrile Butadiene Styrene and Polylactic Acid. The plastic filament
is melted as it comes out through the nozzle. This then gets solidified on
touching the already-formed surface. In the SLS technology, a laser selectively fuses small particles of
plastic, ceramic or glass powder to form
a 3D structure. Each layer is formed on a powder bed. The powder is reapplied
everytime a new layer is ejected (3).
Additive manufacturing has extensive uses and
permeates all disciplines of science and technology. It has played a pivotal
role in the automotive industry. While earlier additive metal manufacturing was
limited to basic models for testing, experimentation and verification,
contemporary rapid manufacturing is used for making a variety of automotive
parts. Rapid prototyping is now becoming
rapid manufacturing, i.e. industrial applications of this technology have
evolved from making simple models and copies to making the end-products. 3D
printers, now indispensable in the fashion industry, are
used to adorn shirts and pants with
colourful, textured patterns. And
imagine how rapid prototyping will aid the architects! This technology also has
the potential to change the way of education- teachers can use it to
demonstrate complex scientific processes, which are otherwise difficult to
explain. A teacher can explain the toughest
of atomic structures, given her/his 3D printer! There has also been an increase
in the DIY (Do It Yourself) uses of 3D printing. Pete Dilworth made the
3Doodler which allows its owner to draw three dimensional figures in air (6). Need to make the structure of an atom for a
school project? Need to make a sweet gift for your best friend’s birthday? The
3D pen will come to your rescue. And yes
it is possible to own it. As of now the 3D pen costs 50$. The additive
manufacturing technology is becoming cheaper and more accessible every
day. But out of all the wonders it
performs, the most wonderful is undoubtedly its utility in medical sciences.
Many animal care organisations have protested
against live animal trials and experimentation. Invariably, in all biological
research laboratories, rodents are used for this purpose. But now, with the
evolution of rapid prototyping in the form of bio-printing, animal tissue and
organ models can be reproduced according to requirements by specialised 3D
printers. For example working mini-brains can now be produced for drug
testing, to test neural tissue transplants, or to experiment with how stem
cells work. Brain cells do not perform any cogitation , rather they produce
electric signals and form their own neural connections. This brain is
relatively easier to ‘make’ and can act as an effective test cushion in
neurological research (7, 8). The
process involves extraction of a small sample tissue from a rodent. The desired
cells are isolated and concentrated by centrifugation techniques, followed by
seeding cell culture in agarose moulds using
the refined sample (8). “The materials are easy to get and the
mini-brains are relatively simple to make”, said the researchers. They talked
about the effectiveness of 3D printers in this case and highlighted the
presence of an expanding market for a technology which was once a rarity. "We
could allow all kinds of labs to do this research."(8) And guess what is
the cost of all this. The mini-brain stands at an incredulous price of 0.25$.
But 3D printing offers more surprises.
3D printing can make model tissue and organs- the one thing that is now
obvious. But can it make REAL organs? The mere thought of it is probably crazy.
Is it possible? No comments. But is there a possibility? Yes, indeed.
There were 154,324 patients waiting for a transplantable organ in the
United States(2009). Among them, only 27,996 patients received organ
transplantation . 8,863 patients died while they were still on the waiting
list. Therefore, 25 people died everyday when they were waiting for a suitable
organ donor (9). This number increases each year as more and more patients get
added to the waiting list for organ replacement surgeries, which are also very
expensive (7). Imagine what would happen if we could build ORGANS! Critics are
of the opinion that artificial organ reproduction is not very feasible and its applications in
medicine are a little far-fetched. A basic tenet of R&D is that new
technology should be useful enough to justify the precious dollars being
fuelled into research. This is because thick tissues must consist vasculature.
Many biological approaches, such as VEGF (Vascular Endothelial Growth Factor),
have fallen short of their promises. So scientists are now shifting their
attention to developing engineering approaches that rebuild microvasculature (7).
Layer-by-layer building techniques which
recreate cellular scaffolds have offered some promise in producing complex 3D
structures (10). With an appropriate bioink, such as HMVEC (Human microvascular
endothelial cells), human microvasculature can be recreated quite accurately (11).
A bio-printing technique most commonly in use today is thermal inkjet printing.
The bioink used in thermal inkjet
printing is water based and hence allows adjustable production, safe aqueous
environment for cells to be compatible with living systems and less printerhead
clogging. Taken together, bioprinting based on thermal inkjet printing
technology demonstrated feasibility of printing living systems and the benign
effects that it does have on the printed cells can in fact be used for more tempting
applications, such as gene transfection and drug delivery. A particular
application of bio-printing has been noted. It is that a user-friendly printer
can be used in clinics to reconstruct damaged tissues by immediately scanning
them and the healthy ones, then providing required fillers (11). Bio-printing has the potential to completely
change the scenario of medical treatment. One can only imagine how amazingly
bio-printing can help hundred thousands of patients who need organ transplants.
The organ donor shortage can be resolved and humans can be benefitted without
compromising anyone’s health.
3D printing involves interlinked applications of mechanics, computer
science, material studies and biology, and also has a significant impact in
these areas. It stems from STEM and stems STEM research and innovation. It is
going through some dramatic positive changes which include affordability and
accessibility. It can bring about a new industrial revolution- 3D printed
goods, deeper and more effective research and much required lifeline for critically
ill patient . If this technology
actually fulfils all these exciting possibilities, its 3 cheers to 3D printing.
References
1. Tom Walker, ‘ The
History of Print From Phaistos to 3D’ (2015).
2.‘Chuck Hull: The Father of 3D
printing who shaped technology’, The Guardian (2014)
4.‘3D
Scanners’ (available at www.rapidform.com/3d-scanners/)
5. Committee F42 on Additive
Manufacturing Technologies, (available
at www.astm.org/COMMITTEE/F42.htm)(2009)
7. X Cui, Department of
Molecular and Experimental Medicine, The Scripps Research Institute, USA; Department
of Metallurgical & Materials Engineering, University of Texas at El Paso,
USA. Thermal Inkjet Printing in Tissue Engineering
and Regenerative Medicine (2012).
8.
Molly Boutin, Yu-Ting Dingle, Hoffman-Kim. ‘Tissue
Engineering: Part C’.
9. OPTN & SRTR Annual Data
Report 2010, Health Resources and Services Administration, U.S. Department of
Health and Human Services.
10. Catros
S, Guillemot F, Nandakumar A, Ziane S, Moroni L, Habibovic P, et al. ‘
Layer-by-layer tissue microfabrication supports cell proliferation in vitro and
in vivo’, Tissue Eng Part C Methods (2011).
11. Cui X, Boland T. Human microvasculature
fabrication using thermal inkjet printing technology. Biomaterials.
