Printing with Plastic

(Source: Ralph Yeung)

By Ralph Yeung

From applications that alert people that you’re running late to Bluetooth activated coffee machines, one trend in technology is increasingly clear: people want customizable technologies that fill very particular niches in their needs and wants. There’s one problem: specificity is hard to mass produce, and custom craftwork is never cheap. The price tag of such uniqueness easily becomes overwhelming for any developer or consumer.

Which is why people have decided to print them instead.

In the past year or two, the technology behind 3D printing has really come into the spotlight. The idea is simple: digital blueprints are made via a computer program, the digital prints are sent to a printer, and immediately layer upon layer of polymeric material is printed out until a full, 3D object is created, exactly to specifications. There are few boundaries to what we can print and there is no shortage of ideas, either.

“’Thingiverse’, a repository of digital designs, has over 30,000 [blueprints of] “things” and is expanding rapidly,” Joshua Pearce, a Queen’s mechanical engineering professor, said. The “things” on the website range from garden fences and gears to model toys and even cat costumes (complete with missiles of course). Users are free to download the blueprints and create the objects via their 3D printer.

Last year, Pearce pioneered a competition at Queen’s that challenges students to use his 3D printing prototyping machine to create engineering solutions to pressing human development needs.

“When we first started the contest it had mostly toys and things for your printers. Now there is everything from scientific equipment and tools, to art and useful household items,” he said.  Since then, many successful open source designs have spawned from the competition.

“Every time someone posts another open design, the value of a 3D printer goes up,” Pearce said.

It’s become such an inspiring technology that the United States’ President Obama recently decided to invest in the development of 3D printing technology. He listed it as one of the critical innovations that will most likely have widespread impacts on production and the economy.


One might imagine printing off machine parts and gadgets, but this technology has heart-warming tales in biomedical applications as well.  At the time she was born, Emma Lavelle was diagnosed with arthrogryposis, a condition that shortens certain joints. The condition left her unable to properly use her arms, that is until researchers at Alfred du Pont Hospital for Children in Delaware decided to help. They wanted to downsize an existing metal exoskeleton prototype they had developed for adults with similar conditions. Unfortunately, at just two-years-old Lavelle required something much smaller and lighter than the exoskeleton they already had. On top of this, her childhood rapid growth would guarantee that a new exoskeleton would be needed every few months.

“That’s when we thought, we have this … 3D printing machine and we could print it out for her,” Dr. Tariq Rahman, part of the team that built Lavelle’s skeleton, said in a video documenting Lavelle’s case. According to Whitney Sample, the engineer who worked with Dr. Rahman in the design of the exoskeleton, the plastic material used to make Emma’s prosthetic is the same material used to make Lego blocks. The result was a newly designed, custom-fit, lighter exoskeleton that could be worn by Lavelle, allowing her to move around with a prosthetic that aids her arm movements.

Best of all are the implications for maintenance of the exoskeleton: if a piece breaks (as may be common with an active toddler), a replacement may be easily printed and sent to the family.

“This is one of those industries that matches perfectly with 3D printing, because we need custom everything,” Sample said in the video. The video concludes with a heart-felt testimony of Lavelle’s “magic arms” and a hug between mother and daughter that may have otherwise never occurred.

And this is just one example of 3D printing’s major biomedical applications. Here at Queen’s University, Professor Pearce had a personal experience with 3D printing’s biomedical applications involving his family.

“My wife recently hurt her ankle and needed an ankle board.  I looked online and the good ones were selling for over $100. That seemed silly so I spent a few minutes [designing] and printed out one,” Pearce said. “[It] is parametric so if anyone else ever needs one, they can change to fit their needs and print [one off] easily.”

For anyone interested, a 3D printer retails at about $20,000 to $30,000 and each cartridge of polymeric material is about $250. Additionally, you may need to account for the cost of energy to run the printer — large objects may take up to 36 hours to print.


Both Emma’s and Dr. Pearce’s experiences closely mirror research happening at the Human Mobility Research Center (HMRC) at Kingston General Hospital. At the HMRC, multi-faceted research groups develop a multitude of prototypes for prosthetics and rehabilitation devices. In a field that continuously manufactures unique hardware prototypes, the value of 3D printing is immediately obvious. “Any time we want to see something [in reality during] the design process, we can just print one,” Dr. Tim Bryant, who specializes in engineering artificial joints, said.

To give an example, Dr. Rudan and Dr. Kunz of HMRC have published a scholarly article on a novel guidance device for hip surgery that is totally customized to each patient. A computed tomography (CT) scan of a patient’s hip joint is used to create the blueprint of the surgical device, which will fit perfectly around the patient’s hip bone during surgery. At the top of the device is a component that has a drill hole precisely calculated to be the optimal entry point for a prosthetic device to be implanted into the patient’s hip. This precision in rod insertion directly translates into better results for the patient. The idea behind a tailored, locally made surgical device sounds expensive, but one of these devices could be printed off for $150-$200, which pales in contrast to if one of these had to be custom-made from solid metal.

Outside of medicine, 3D printing has many other applications. There are groups that are thinking bigger, both metaphorically and physically. For example, Dr. Behrokh Khoshnevis’s group at the University of Southern California have presented their prototype 3D printer that can build a house in 20 hours, using a variety of materials.

Pearce emphasized that 3D printing is not a technology restricted to researchers and creating proof-of-concept designs. “3D printers are already used in high-end manufacturing and are standard for rapid prototyping. I think in the next five years they will be common in schools and libraries and perhaps soon after that it will be an item that is not out of place in people’s homes,” he said.

If a 3D printer becomes as ubiquitous as the computer, one can imagine just how many open source blueprints there will be, if the current reservoir isn’t impressive enough already.  Pearce reflected on his now free, publically available ankle board design. “In this way, we all become wealthier. This is the real secret of the open source hardware movement,” Pearce said. Of course, this would then have drastic ethical impacts: what can we print, and what can’t we print at home?

There are some who are already vocalizing about the dangers of access to technology like this. Some believe that it will make weapons more accessible. Others, like NASA, believe in the technology’s ability to achieve great progress for building research facilities in less hospitable places like the moon and are investing heavily into the technology.

In the end, all this author can think of, in terms of ethical and practical implications, is one infamous quote from an anti-piracy advertisement from
long ago:

“You wouldn’t steal a car…”

No, I wouldn’t.

But I might just print one.




One response to “Printing with Plastic

  1. Actually open-source 3D printers like the RepRap have radically reduced costs — you can build one yourself for less than $1000.

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