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Human impacts

Ctrl+P: 3D printing applications for oceanography

Original Research Article

 Mohammed, J.S. (2016). Applications of 3D printing technologies in oceanography. Methods in Oceanography 17, 97–117. Doi: 10.1016/j.mio.2016.08.001

From printing jewelry to jet engines, shirts to shoes, pianos to prosthetic limbs, 3D printing has revolutionized the world of design and manufacturing. With speedy advancements made in the field since its inception by Charles Hull in 1984, even ocean sciences are now privy to a diverse range of valuable 3D printing tools. But before we dive into deep waters, let us revisit: what exactly is 3D printing?

3D printing (aka additive manufacturing) is the process of making a three-dimensional object by depositing successive layers of desired material(s) using design information stored within a digital file (Fig 1). Sounds easy, right? Well, it is, and it is not. Building the digital file (called a computer-aided design or CAD file) is the toughest part, and it requires proficiency in computer design and troubleshooting. On the other hand, benefits of 3D printing include lowering costs of production and a whirlwind of new manufacturing capabilities. For some of its fascinating applications, let us venture back to the oceans…

Fig 1. Schematic diagram of how 3D printing works. (Source: T. Rowe Price)

Can someone please print those coral reefs?

The continuing loss of coral reef diversity over the last several decades has illustrated the growing fragility of underwater ecosystems. Numerous researchers are attempting to mitigate this loss by successfully printing reef structures, which are then submerged into areas that have a scarcity of corals. So how is this restoration done? Firstly, an imaging technique called computer tomography is used to scan actual coral reef specimens, extracted from oceans, using x-rays to generate a computer model of their 3D surface. Next, a small physical plaster model of this coral specimen is 3D printed (Fig 2). Using various innovative techniques, researchers can then interact with this prop, studying how their plaster model compares to the real corals. Once the features are decided upon, life-size coral replicas are 3D printed using a process called powder bed fusion with sandstone and/or ceramics typically used to make these corals. The process involves placing a first layer of powdered sandstone, and fusing subsequent layers using electron beams.

Fig 2. (Left) An example of a computer rendered design used to create a 3D printed sandstone coral replica (right). Source: SOI 2012

Although certainly not a true substitute for real coral reefs (since they are structurally similar but functionally inanimate) this application could be a game changer for ecosystems dependent on the coral structure itself. Introducing 3D printed reefs could recreate protective passageways and spaces for marine predators and prey. Coral replicas can also potentially act as support for live, developing corals to grow on. The process of generating these artificial reefs itself is no easy feat; many of these replica- reefs weigh up to 2.5 tons, and can take up to 2 weeks of printing time! Since this technology is at a nascent stage of development, there remain many unanswered questions: can 3D printed reefs mitigate coral bleaching caused by storms? How sustainable will these structures be? What kinds of corals will be attracted to these model reefs? Only time will tell.

Mimicking Mother Nature

 Apart from being used as a possible ecological savior, 3D printing is also advantageous for understanding how naturally ocurring 3D structures work. Biomimetics (aka biomimicry or bionics) is the field of studying and using principles and concepts from nature to make highly efficient products for improving human life. One of the most famous examples of biomimetics is the invention of Velcro. In the 1940s, Swiss engineer George de Mastral was inspired by the adhesive property of the fruit of the rough cocklebur (Xanthium strumarium), recreating the cocklebur-like hook-and-fastener technique into the now nylon-based household item.

Recent studies have explored various biomimetic properties of marine organisms in an effort to design highly efficient micro underwater vehicles (MUVs). These micro vehicles could perform various functions that larger underwater vehicles would be unable to perform. These include sensing marine

Fig 3. External skeleton of a boxfish (carapace) contains many fused and rigid scales.

microorganisms, exploration of shipwrecks, in-pipe inspections, and aiding in formation of underwater sensor networks. To this end, one type of fish species has been studied with particular interest. Boxfish have a (you guessed it!) rigid box-like body shape called carapace, and numerous oscillating fins, which allow them to cruise and maneuver with great ease and stability.

Being able to use these properties would mean that MUVs would have steadier hydrodynamics and greater flexibility in movement. The question is: how can humans make use of this locomotion property? Remarkably, commercially available 3D models of boxfish (made of epoxy resin: think coating, adhesives, fiberglass reinforcements) have already been used to generate agile robotic fish designs using yet another 3D printing technique called stereolithography. The process is built around the principle of using a UV laser to dry light-sensitive liquid resin into hardened plastic. Potential ecological applications, which could provide significant benefits for environmental health, include making autonomous micro robots that cleanup oil spills and sense hazardous water acidity levels.

Apart from technology, 3D printing can also be used as an educational module for oceanographic researchers, especially to study shapes and structures of marine creatures. For example, by investigating 3D printed square-shaped seahorse tails, researchers have learnt that square-shape tails are less likely to be damaged (deformed or fractured) given a physical stressor, and have higher grasping properties than cylindrical ones. This could inspire advancements in biomedicine, robotics and the defense industry. Additionally, 3D printed models of differently shaped seashells have been used to conduct various mechanics and physical load assessments. Analyses have revealed insights about the evolution and growth of complex shell shapes in nature.

A cautionary tale

 Real life applications of 3D printing technologies to unveil and utilize the extraordinary amount of information within oceans are becoming apparent, from possible restoration of local marine environments using sandstone and ceramics to mimicking Nature’s complexity to improve machinery. However, most materials used in oceanography-based 3D products are plastic-based, such as polyethylene, polypropylene and polystyrene. Studies on the ecological impact of littering such synthetic materials have shown decreased reproductive capabilities of oysters, as well as increased toxicity to zebrafish embryos. So before hitting Ctrl+P, the detrimental impacts of 3D printing need to be carefully and continually assessed and taken into consideration.

Reference:

1. https://individual.troweprice.com/staticFiles/Retail/Shared/PDFs/3D_Printing_Infographic_FINAL.pdf

2. SOI, 2012. Worlds First 3D Printed Reef. http://www.sustainableoceans.com.au/images/stories/Media_releases/SOI_Worlds_FIRST_3D_printed_reef_MEDIA_RELEASE_2012.pdf.

3. Farina, S.C., and Summers, A.P. (2015). Biomechanics: Boxed up and ready to go. Nature 517, 274–275.

 

 

Prabarna Ganguly

I’m a fourth year PhD candidate in the Department of Psychology at Northeastern University. My research focuses on the impact of early life stress in the form of maternal separation on neurological and behavioral abnormalities that appear later in life. Being a biologist at heart, marine sciences have always fascinated me. Check out my twitter @prabarna for more science-related fun!

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