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The Ten Principles of 3D Printing
The underlying rules of 3D printing that help innovators get past key cost, time and complexity barriers.
This article is an excerpt from Hod Lipson and Melba Kurman's new book Fabricated: The New World of 3D Printing.
Predicting the future is a crapshoot. When we were writing this book and interviewing people about 3D printing, we discovered that a few underlying "rules" kept coming up. People from a broad and diverse array of industries and backgrounds and levels of expertise described similar ways that 3D printing helped them get past key cost, time and complexity barriers.
We have summarized what we learned. Here are ten principles of 3D printing we hope will help people and businesses take full advantage of 3D printing technologies.
Principle one: Manufacturing complexity is free. In traditional manufacturing, the more complicated an object's shape, the more it costs to make. On a 3D printer, complexity costs the same as simplicity. Fabricating an ornate and complicated shape does not require more time, skill, or cost than printing a simple block. Free complexity will disrupt traditional pricing models and change how we calculate the cost of manufacturing things.
Principle two: Variety is free. A single 3D printer can make many shapes. Like a human artisan, a 3D printer can fabricate a different shape each time. Traditional manufacturing machines are much less versatile and can only make things in a limited spectrum of shapes. 3D printing removes the over- head costs associated with re-training human machinists or re-tooling factory machines. A single 3D printer needs only a different digital blueprint and a fresh batch of raw material.
Principle three: No assembly required. 3D printing forms interlocked parts. Mass manufacturing is built on the backbone of the assembly line. In modern factories, machines make identical objects that are later assembled by robots or human workers, sometimes continents away. The more parts a product contains, the longer it takes to assemble and the more expensive it becomes to make. By making objects in layers, a 3D printer could print a door and attached interlocking hinges at the same time, no assembly required. Less assembly will shorten supply chains, saving money on labor and transportation; shorter supply chains will be less polluting.
Principle four: Zero lead time. A 3D printer can print on demand when an object is needed. The capacity for on-the-spot manufacturing reduces the need for companies to stockpile physical inventory. New types of business services become possible as 3D printers enable a business to make specialty -- or custom -- objects on demand in response to customer orders. Zero-lead-time manufacturing could minimize the cost of long-distance shipping if printed goods are made when they are needed and near where they are needed.
Principle five: Unlimited design space. Traditional manufacturing technologies and human artisans can make only a finite repertoire of shapes. Our capacity to form shapes is limited by the tools available to us. For example, a traditional wood lathe can make only round objects. A mill can make only parts that can be accessed with a milling tool. A molding machine can make only shapes that can be poured into and then extracted from a mold. A 3D printer removes these barriers, opening up vast new design spaces. A printer can fabricate shapes that until now have been possible only in nature.
Principle six: Zero skill manufacturing. Traditional artisans train as apprentices for years to gain the skills they needed. Mass production and computer-guided manufacturing machines diminish the need for skilled production. However traditional manufacturing machines still demand a skilled expert to adjust and calibrate them. A 3D printer gets most of its guidance from a design file. To make an object of equal complexity, a 3D printer requires less operator skill than does an injection molding machine. Unskilled manufacturing opens up new business models and could offer new modes of production for people in remote environments or extreme circumstances.
Principle seven: Compact, portable manufacturing. Per volume of production space, a 3D printer has more manufacturing capacity than a traditional manufacturing machine. For example, an injection molding machine can only make objects significantly smaller than itself. In contrast, a 3D printer can fabricate objects as large as its print bed. If a 3D printer is arranged so its printing apparatus can move freely, a 3D printer can fabricate objects larger than itself. A high production capacity per square foot makes 3D printers ideal for home use or office use since they offer a small physical footprint.
Principle eight: Less waste by-product. 3D printers that work in metal create less waste by-product than do traditional metal manufacturing techniques. Machining metal is highly wasteful as an estimated 90 percent of the original metal gets ground off and ends up on the factory floor. 3D printing is more wasteless for metal manufacturing. As printing materials improve, "Net shape" manufacturing could be a greener way to make things.
Principle nine: Infinite shades of materials. Combining different raw materials into a single product is difficult using today's manufacturing machines. Since traditional manufacturing machines carve, cut, or mold things into shape, these processes can't easily blend together different raw materials. As multi-material 3D printing develops, we will gain the capacity to blend and mix different raw materials. New previously inaccessible blends of raw material offer us a much larger, mostly unexplored palette of materials with novel properties or useful types of behaviors.
Principle ten: Precise physical replication. A digital music file can be endlessly copied with no loss of audio quality. In the future, 3D printing will extend this digital precision to the world of physical objects. Scanning technology and 3D printing will together introduce high resolution shapeshifting between the physical and digital worlds. We will scan, edit, and duplicate physical objects to create exact replicas or to improve on the original.
Some of these principles already hold true today. Others will come true in the next decade or two (or three). By removing familiar, time-honored manufacturing constraints, 3D printing sets the stage for a cascade of downstream innovation. In the following chapters we explore how 3D printing technologies will change the ways we work, eat, heal, learn, create and play. Let's begin with a visit to the world of manufacturing and design, where 3D printing technologies ease the tyranny of economies of scale.
Excerpted with permission from the publisher, Wiley, from Fabricated: The New World of 3D Printing by Hod Lipson and Melba Kurman. Copyright © 2013.
Evolution proves to be just about as ingenious as Nikola Tesla
- For the first time, scientists developed 3D scans of shark intestines to learn how they digest what they eat.
- The scans reveal an intestinal structure that looks awfully familiar — it looks like a Tesla valve.
- The structure may allow sharks to better survive long breaks between feasts.
Considering how much sharks are feared by humans, it is a bit of a surprise that scientists don't know much about the predators. For example, until recently, sharks were thought to be solitary creatures searching the seas for food on their own. Now it appears that some sharks are quite social.
Another mystery is how these prehistoric swimming and eating machines digest food. Although scientists have made 2D sketches of captured sharks' digestive systems based on dissections, there is a limit to what can be learned in this way. Professor Adam Summers at University of Washington's Friday Harbor Labs says:
"Intestines are so complex, with so many overlapping layers, that dissection destroys the context and connectivity of the tissue. It would be like trying to understand what was reported in a newspaper by taking scissors to a rolled-up copy. The story just won't hang together."
Summers is co-author of a new study that has produced the first 3D scans of a shark's intestines, which turns out to have a strange, corkscrew structure. What's even more bizarre is that it resembles the amazing one-way valve designed by inventor Nikola Tesla in 1920. The research is published in the journal Proceedings of the Royal Society B.
What a 3D model reveals
Video: Pacific spiny dogfish intestine youtu.be
According to the study's lead author Samantha Leigh, "It's high time that some modern technology was used to look at these really amazing spiral intestines of sharks. We developed a new method to digitally scan these tissues and now can look at the soft tissues in such great detail without having to slice into them."
"CT scanning is one of the only ways to understand the shape of shark intestines in three dimensions," adds Summers. The researchers scanned the intestines of nearly three dozen different shark species.
It is believed that sharks go for extended periods — days or even weeks — between big meals. The scans reveal that food passes slowly through the intestine, affording sharks' digestive system the time to fully extract its nutrient value. The researchers hypothesize that such a slow digestive process may also require less energy.
It could be that this slow digestion is more susceptible to back flow given that the momentum of digested food through the tract must be minimal. Perhaps that is why sharks evolved something so similar to a Tesla valve.
What is Tesla's valve doing there?
Above, a Tesla valve. Below, a shark intestine.Credit: Samantha Leigh / California State University, Domi
Tesla's "valvular conduit," or what the world now calls a "Tesla valve," is a one-way valve with no moving parts. Its brilliance is based in fluid dynamics and only now coming to be fully appreciated. Essentially, a series of teardrop-shaped loops arranged along the length of the valve allow water to flow easily in one direction but not in the other. Modern tests reveal that at low flow rates, water can travel through the valve either way, but at high flow rates, the design kicks in. According to mathematician Leif Ristroph:
"Crucially, this turn-on comes with the generation of turbulent flows in the reverse direction, which 'plug' the pipe with vortices and disrupting currents. Moreover, the turbulence appears at far lower flow rates than have ever previously been observed for pipes of more standard shapes — up to 20 times lower speed than conventional turbulence in a cylindrical pipe or tube. This shows the power it has to control flows, which could be used in many applications."
A deeper dive
Summers suggests the scans are just the beginning. "The vast majority of shark species, and the majority of their physiology, are completely unknown," says Summers, adding that "every single natural history observation, internal visualization, and anatomical investigation shows us things we could not have guessed at."
To this end, the researchers plan to use 3D printing to produce models through which they can observe the behavior of different substances passing through them — after all, sharks typically eat fish, invertebrates, mammals, and seagrass. They also plan to explore with engineers ways in which the shark intestine design could be used industrially, perhaps for the treatment of wastewater or for filtering microplastics.
It could fairly be said, though, that Nikola Tesla was 100 years ahead of them.
The non-contact technique could someday be used to lift much heavier objects — maybe even humans.
- Since the 1980s, researchers have been using sound waves to move matter through a technique called acoustic trapping.
- Acoustic trapping devices move bits of matter by emitting strategically designed sound waves, which interact in such a way that the matter becomes "trapped" in areas of particular velocity and pressure.
- Acoustic and optical trapping devices are already used in various fields, including medicine, nanotechnology, and biological research.
Sound can have powerful effects on matter. After all, sound strikes our world in waves — vibrations of air molecules that bounce off of, get absorbed by, or pass through matter around us. Sound waves from a trained opera singer can shatter a wine glass. From a jet, they can collapse a stone wall. But sound can also be harnessed for delicate interactions with matter.
Since the 1980s, researchers have been using sound to move matter through a phenomenon called acoustic trapping. The method is based on the fact that sound waves produce an acoustic radiation force.
"When an acoustic wave interacts with a particle, it exerts both an oscillatory force and a much smaller steady-state 'radiation' force," wrote the American Physical Society. "This latter force is the one used for trapping and manipulation. Radiation forces are generated by the scattering of a traveling sound wave, or by energy gradients within the sound field."
When tiny particles encounter this radiation, they tend to be drawn toward regions of certain pressure and velocity within the sound field. Researchers can exploit this tendency by engineering sound waves that "trap" — or suspend — tiny particles in the air. Devices that do this are often called "acoustic tweezers."
Building a better tweezer
A study recently published in the Japanese Journal of Applied Physics describes how researchers created a new type of acoustic tweezer that was able to lift a small polystyrene ball into the air.
Tweezers of Sound: Acoustic Manipulation off a Reflective Surface youtu.be
It is not the first example of a successful "acoustic tweezer" device, but the new method is likely the first to overcome a common problem in acoustic trapping: sound waves bouncing off reflective surfaces, which disrupts acoustic traps.
To minimize the problems of reflectivity, the team behind the recent study configured ultrasonic transducers such that the sound waves that they produce overlap in a strategic way that is able to lift a small bit of polystyrene from a reflective surface. By changing how the transducers emit sound waves, the team can move the acoustic trap through space, which moves the bit of matter.
Move, but don't touch
So far, the device is only able to move millimeter-sized pieces of matter with varying degrees of success. "When we move a particle, it sometimes scatters away," the team noted. Still, improved acoustic trapping and other no-contact lifting technologies — like optical tweezers, commonly used in medicine — could prove useful in many future applications, including cell separation, nanotechnologies, and biological research.
Could future acoustic-trapping devices lift large and heavy objects, maybe even humans? It seems possible. In 2018, researchers from the University of Bristol managed to acoustically trap particles whose diameters were larger than the sound wavelength, which was a breakthrough because it surpassed "the classical Rayleigh scattering limit that has previously restricted stable acoustic particle trapping," the researchers wrote in their study.
In other words, the technique — which involved suspending matter in tornado-like acoustic traps — showed that it is possible to scale up acoustic trapping.
"Acoustic tractor beams have huge potential in many applications," Bruce Drinkwater, co-author of the 2018 study, said in a statement. "I'm particularly excited by the idea of contactless production lines where delicate objects are assembled without touching them."
Australian parrots have worked out how to open trash bins, and the trick is spreading across Sydney.
Dumpster-diving trash parrots
In a study about these smart birds just published in Science, researchers define animal culture as "population-specific behaviors acquired via social learning from knowledgeable individuals."
Co-lead author of the study Barbara Klump of the Max Planck Institute of Animal Behavior in Konstanz, Germany says, "[C]ompared to humans, there are few known examples of animals learning from each other. Demonstrating that food scavenging behavior is not due to genetics is a challenge."
An opportunity presented itself in a video that co-author Richard Major of the Australian Museum shared with Klump and the other co-authors. In the video, a sulphur-crested cockatoo used its beak to pull up the handle of a closed garbage bin — using its foot as a wedge — and then walked back the lid sufficiently to flip it open, exposing the bin's edible contents.
Major has been studying Cacatua galerita for 20 years and says, "Like many Australian birds, sulphur-crested cockatoos are loud and aggressive." The study describes them as a "large-brained, long-lived, and highly social parrot." Says Major, "They are also incredibly smart, persistent, and have adapted brilliantly to living with humans."(Research regarding some of the ways in which wild animals adapt to the presence of humans has already produced some fascinating results and is ongoing.)
Clever cockie opens bin - 01 youtu.be
The researchers became curious about how widespread this behavior might be and saw a research opportunity. After all, says John Martin, a researcher at Taronga Conservation Society, "Australian garbage bins have a uniform design across the country, and sulphur-crested cockatoos are common across the entire east coast."
Martin continues, "In 2018, we launched an online survey in various areas across Sydney and Australia with questions such as, 'What area are you from, have you seen this behavior before, and if so, when?'"
Word Gets Around
Credit: magspace/Adobe Stock
Although the cockatoos' maneuver was reported in only three suburbs before 2018, by the end of 2019, people in 44 areas reported observing the behavior. Clearly, more and more cockatoos were learning how to successfully dumpster dive.
As further proof, says Klump, "We observed that the birds do not open the garbage bins in the same way, but rather used different opening techniques in different suburbs, suggesting that the behavior is learned by observing others." One individual bird in north Sydney invented its own method, and the scientists saw it grow in popularity throughout the local population.
To track individual birds, the researchers marked 500 cockatoos with small red dots. Subsequent observations revealed that not all cockatoos are bin-openers. Only about 10 percent of them are, and they are mostly males. The other cockatoos apparently restrict their education to a different lesson: hang around with a bin-opener, and you will get supper.
Thanks to the surveys, the researchers consider the entire project to be a valuable citizen-science experiment. "By studying this behavior with the help of local residents, we are uncovering the unique and complex cultures of their neighborhood birds."
The few seconds of nuclear explosion opening shots in Godzilla alone required more than 6.5 times the entire budget of the monster movie they ended up in.