3D Printing in a Nutshell

Here's a introduction to 3D Printing in a nutshell. Lets watch a 3D Printer in action: 

This video by 16x9, covers almost all of the things you need to know about 3D printing. The most interesting thing about 3D printing is that there is no end to what you can print. We are printing tissues, food items, metal pieces and even guns. 

What lies ahead? There are currently research going on to print electronics, various types of metals, and ability to print multiple materials in the same item, instead of printing them separately and then assembling them.

The Science Behind 3D Printing

The science behind 3D printers is really old. It has been in existence since 1984, but recently with the innovation in field of IT technology and material science, it has become cheaper, easily accessible and cost effective. Most of the 3D printers work on a bottom's up approach and deposit a layer of plastic, then another layer on top and keep on doing that till they get the finished product. This is how 3D printing of plastic parts is done and requires a hot head to melt plastic and deposit it, like the ink heads of the old inkjet printers. 

Another technique is printing resin, it uses LED's to print them. So, its more easy to maintain, gives you a lot more print and the product are almost as strong as those of the plastic printing. Lets see a video by FormLabs, one of the innovators in field of using resin for printing: 

But when it comes to printing metal you need to deal with really high temperatures, and instead of pouring in molten metal or a shooting a jet of liquid metal, its preferred to melt a layer of powdered metal, so that they are bonded. This is known as sintering, and is usually done by high energy laser. But still this method doesn't gives you the same amount of strength as a cast structure would have provided. 

So, if you can find out a way to 3D print metals with the strength that of a cast structure or control the microstructural properties of the product, maybe print in different part with different alloy composition - you will be on your way to become a billionaire. I hope this has provided you all with a basic insight about 3D printing and the enormous potential it has. 

Follow us for more news of Material Science and 3D Printing.

New Segment on 3D Printers

Hey Everyone,
After a long break, we are break and this time with a special segment on 3D Printers. 3D Printers is one of the hottest topics in innovation today. No other technology is developing at a greater pace and affecting so many lives as 3D Printing. It has truly brought innovation to your desktops.
In the segment we will be following all the updates on this front from Kickstarter campaigns to releases from big corporations like HP (it claims to have made the first multi-material 3D Printer) and all the promising research work in this field.
For those of you who do not know about 3D Printers - it's a rapid Prototyping technique which allows you to print any shape or design from a CAD file into reality. Most of the current 3D printers print only in plastic or Resin. They deposit layer of plastic from a nozzle similar to the inkjet printers. Then a new layer is deposited on the previous one. In this manner, layer by layer the whole structure takes form.
Here are a few examples of what you can make with a 3D Printer:

Need a gear, just print it. Need a assembly of gears, just print it and it will work. 

Yes, you can even print apparels from a 3D printers

Art work? Now, only your imagination and CAD abilities are the limit

Don't forget to follow us, for the latest news in the field of Material Science Research and 3D printers. 

Cool Hot Electronic Devices using Electropolymerization

Scientists at Georgia Institute of Technology,  have successfully increased the thermal conductivity of Polymers by 20 times. They have used Electropolymerization to produce aligned array of nano-fibers. The thermal interface material can operate at temperatures as high as 200 degrees Celsius.

The material has been fabricated on  heat sinks and heat spreaders and adheres well to devices, potentially avoiding reliability challenges that are caused by differential expansion in other conducting materials. The new material can be used to conduct heat away from LEDs, servers, automobiles and certain mobile devices.

“Thermal management schemes can get more complicated as devices get smaller,” said Baratunde Cola, an assistant professor in the George W. Woodruff School of Mechanical Engineering at the Georgia Institute of Technology. “A material like this, which could also offer higher reliability, could be attractive for addressing thermal management issues. This material could ultimately allow us to design electronic systems in different ways.”

Research scientist Virendra Singh, from the George W. Woodruff School of Mechanical Engineering at Georgia Tech, holds a test sample used to measure thermal conductance and thermal cycle reliability in a new polymer material developed to remove heat from electronic devices. (Georgia Tech Photo: Candler Hobbs)

The research, which was supported by the National Science Foundation, was reported March 30 in the advance online publication of the journal Nature Nanotechnology. The project involved researchers from the Georgia Institute of Technology, University of Texas at Austin, and the Raytheon Company. Virendra Singh, a research scientist in the Woodruff School, and Thomas Bougher, a Ph.D. student in the Woodruff School, are the paper’s co-first authors.

Amorphous polymer materials are poor thermal conductors because their disordered state limits the transfer of heat-conducting phonons. That transfer can be improved by creating aligned crystalline structures in the polymers, but those structures – formed through a fiber drawing processes – can leave the material brittle and easily fractured as devices expand and contract during heating and cooling cycles.

The new interface material is produced from a conjugated polymer, polythiophene, in which aligned polymer chains in nanofibers facilitate the transfer of phonons – but without the brittleness associated with crystalline structures, Cola explained. Formation of the nanofibers produces an amorphous material with thermal conductivity of up to 4.4 watts per meter Kelvin at room temperature.

The material has been tested up to 200 degrees Celsius, a temperature that could make it useful for applications in vehicles. Solder materials have been used for thermal interfaces between chips and heat sinks, but may not be reliable when operated close to their reflow temperatures.

“Polymers aren’t typically thought of for these applications because they normally degrade at such a low temperature,” Cola explained. “But these conjugated polymers are already used in solar cells and electronic devices, and can also work as thermal materials. We are taking advantage of the fact that they have a higher thermal stability because the bonding is stronger than in typical polymers.”

The structures are grown in a multi-step process that begins with an alumina template containing tiny pores covered by an electrolyte containing monomer precursors. When an electrical potential is applied to the template, electrodes at the base of each pore attract the monomers and begin forming hollow nanofibers. The amount of current applied and the growth time control the length of the fibers and the thickness of their walls, while the pore size controls the diameter. Fiber diameters range from 18 to 300 nanometers, depending on the pore template.

After formation of the monomer chains, the nanofibers are cross-linked with an electropolymerization process, and the template removed. The resulting structure can be attached to electronic devices through the application of a liquid such as water or a solvent, which spreads the fibers and creates adhesion through capillary action and van der Waals forces.

“With the electrochemical polymerization processing approach that we took, we were able to align the chains of the polymer, and the template appears to prevent the chains from folding into crystals so the material remained amorphous,” Cola explained. “Even though our material is amorphous from a crystalline standpoint, the polymer chains are highly aligned – about 40 percent in some of our samples.”

Though the technique still requires further development and is not fully understood theoretically, Cola believes it could be scaled up for manufacturing and commercialization. The new material could allow reliable thermal interfaces as thin as three microns – compared to as much as 50 to 75 microns with conventional materials.

“There are some challenges with our solution, but the process is inherently scalable in a fashion similar to electroplating,” he said. “This material is well known for its other applications, but ours is a different use.”

Engineers have been searching for an improved thermal interface material that could help remove heat from electronic devices. The problem of removing heat has worsened as devices have gotten both smaller and more powerful.

Rather than pursue materials because of their high thermal conductivity, Cola and his collaborators investigated materials that could provide higher levels of contact in the interface. That’s because in some of the best thermal interface materials, less than one percent of the material was actually making contact.

“I stopped thinking so much about the thermal conductivity of the materials and started thinking about what kinds of materials make really good contact in an interface,” Cola said. He decided to pursue polythiophene materials after reading a paper describing a “gecko foot” application in which the material provided an estimated 80 percent contact.

Samples of the material have been tested to 200 degrees Celsius through 80 thermal cycles without any detectable difference in performance. While further work will be necessary to understand the mechanism, Cola believes the robustness results from adhesion of the polymer rather than a bonding.

“We can have contact without a permanent bond being formed,” he said. “It’s not permanent, so it has a built-in stress accommodation. It slides along and lets the stress from thermal cycling relax out.”

In addition to those already mentioned, co-authors of the paper included Professor Kenneth Sandhage, Research Scientist Ye Cai, Assistant Professor Asegun Henry and graduate assistant Wei Lv of Georgia Tech; Prof. Li Shi, Annie Weathers, Kedong Bi, Micheal T. Pettes and Sally McMenamin in the Department of Mechanical Engineering at the University of Texas at Austin; and Daniel P. Resler, Todd Gattuso and David Altman of the Raytheon Company.

A patent application has been filed on the material. Cola has formed a startup company, Carbice Nanotechnologies, to commercialize thermal interface technologies. It is a member of Georgia Tech’s VentureLab program.

This research was supported by the National Science Foundation (NSF) through award CBET-113071, a seed grant from the Georgia Tech Center for Organic Photonics and Electronics and an NSF-IGERT graduate fellowship. Any conclusions or opinions are those of the authors and do not necessarily represent the official views of the NSF.

CITATION: Virendra Singh, et al., “High thermal conductivity of chain-oriented amorphous polythiophene,” (Nature Nanotechnology, 2014). http://www.dx.doi.org/10.1038/nnano.2014.44

MIT Develops Self Healing Metal

By a happy mistake, researchers at MIT have developed a metal that heals itself  under certain conditions putting a cracked piece of metal under tension. Thus instead of tearing it apart, the applied force caused the edges to come close and fuse together.

The surprising finding could lead to self-healing materials that repair incipient damage before it has a chance to spread. The results were published in the journal Physical Review Letters in a paper by graduate student Guoqiang Xu and professor of materials science and engineering Michael Demkowicz.

Watch The Vedio Here

Most metals are made of tiny crystalline grains whose sizes and orientations can affect strength and other characteristics. But under certain conditions, Demkowicz and Xu found, stress “causes the microstructure to change: It can make grain boundaries migrate. This grain boundary migration is the key to healing the crack,” Demkowicz says.

The very idea that crystal grain boundaries could migrate within a solid metal has been extensively studied within the last decade, Demkowicz says. Self-healing, however, occurs only across a certain kind of boundary, he explains — one that extends partway into a grain, but not all the way through it. This creates a type of defect is known as a “disclination.”

Disclinations were first noticed a century ago, but had been considered “just a curiosity,” Demkowicz says. When he and Xu found the crack-healing behavior, he says, “it took us a while to convince ourselves that what we’re seeing are actually disclinations.”

These defects have intense stress fields, which “can be so strong, they actually reverse what an applied load would do,” Demkowicz says: In other words, when the two sides of a cracked material are pulled apart, instead of cracking further, it can heal. “The stress from the disclinations is leading to this unexpected behavior,” he says.

Having discovered this mechanism, the researchers plan to study how to design metal alloys so cracks would close and heal under loads typical of particular applications. Techniques for controlling the microstructure of alloys already exist, Demkowicz says, so it’s just a matter of figuring out how to achieve a desired result.

“That’s a field we’re just opening up,” he says. “How do you design a microstructure to self-heal? This is very new.” 

The technique might also apply to other kinds of failure mechanisms that affect metals, such as plastic flow instability — akin to stretching a piece of taffy until it breaks. Engineering metals’ microstructure to generate disclinations could slow the progression of this type of failure, Demkowicz says.

Such failures can be “life-limiting situations for a lot of materials,” Demkowicz says, including materials used in aircraft, oil wells, and other critical industrial applications. Metal fatigue, for example — which can result from an accumulation of nanoscale cracks over time — “is probably the most common failure mode” for structural metals in general, he says.

“If you can figure out how to prevent those nanocracks, or heal them once they form, or prevent them from propagating,” Demkowicz says, “this would be the kind of thing you would use to improve the lifetime or safety of a component.”

William Gerberich, a professor of chemical engineering and materials science at the University of Minnesota who was not involved in this research, says that the significance of disclinations in materials was initially reassessed a few years ago. Xu and Demkowicz, he says, “have taken this one step further and suggested that wedge dislocations, in conjunction with stress-driven grain boundary migration, could actually heal cracks. This is indeed provocative [and] may be a plausible and exciting pursuit.”

The work was funded by the BP-MIT Materials and Corrosion Center

Scientists find formula to improve ‘PLASTIC’ Semiconductors

Understanding how the molecular structure of polymers influences their electrical characteristics could hasten the advent of flexible electronics

Anyone who’s stuffed a smartphone in their back pocket would appreciate the convenience of electronic devices that could bend. Flexible electronics could spawn new products: clothing wired to cool or heat, reading tablets that could fold like newspaper, and so on.

Alas, electronic components such as chips, displays and wires are generally made from metals and inorganic semiconductors -- materials with physical properties that make them fairly stiff and brittle.

In the quest for flexibility many researchers have been experimenting with semiconductors made from plastics or, more accurately polymers, which bend and stretch readily enough.

“But at the molecular level polymers look like a bowl of spaghetti,” says Stanford chemical engineering professor Andrew Spakowitz, adding: “Those non-uniform structures have important implications for the conductive properties of polymeric semiconductors.”

Their theory, published today in the Proceedings of the National Academy of Sciences, deals with the observed tendency of polymeric semiconductors to conduct electricity at differing rates in different parts of the material – a variability that, as the Stanford paper explains, turns out to depend on whether the polymer strands are coiled up like a bowl of spaghetti or run relatively true, even if curved, like lanes on a highway.

In other words, the entangled structure that allows plastics and other polymers to bend also impedes their ability to conduct electricity, whereas the regular structure that makes silicon semiconductors such great electrical switches tends to make it a bad fit for our back pockets.

The Stanford paper in PNAS gives experimental researchers a model that allows them to understand the tradeoff between the flexibility and conductivity of polymeric semiconductors.

Grasping how they created their model requires a basic understanding of polymers. The word “polymer” is derived from the Greek for “many parts” which aptly describes their simple molecular structure, which consists of identical units, called monomers, that string together, end to end, like so many sausages. Humans have long used natural polymers such as silk and wool, while newer industrial processes have adapted this same technique to turn end-to-end chains of hydrocarbon molecules, ultimately derived from petroleum byproducts, into plastics.

But it was only in the late 1970s that a trio of scientists discovered that plastics which, until then were considered non-conductive materials suitable to wrap around wires for insulation could, under certain circumstances, be induced to conduct electricity.

The three scientists, Alan Heeger, Alan MacDiarmid and Hideki Shirakawa, shared the Nobel Prize in Chemistry in 2000 for their co-discovery of polymeric semiconductors. In recent years, with increasing urgency, researchers have been trying to harness the finicky electrical properties of plastics with an eye toward fashioning electronics that will bend without breaking.

The yellow electric charge races through a 'speed-lane' in this stylized view of a polymer semiconductor, but pauses before leaping to the next fast path. Stanford engineers are studying why this occurs with an eye toward building flexible electronics. 

In the process of experimenting with polymeric semiconductors, however, researchers discovered that these flexible materials exhibited “anomalous transport behavior” or, simply put, variability in the speed at which electrons flowed through the system.

One of the fundamental insights of the Stanford paper is that electron flow through polymers is affected by their spaghetti-like structure – a structure that is far less uniform than that of the various forms of silicon and other inorganic semiconductors whose electrical properties are much better understood.

“Prior theories of electrical flow in polymeric semiconductors are largely extrapolated from our understanding of metals and inorganic semiconductors like silicon,” Spakowitz said, adding that he and his collaborators began by taking a molecular-level view of the electron transport issue.

In essence, the variability of electron flow through polymeric semiconductors owes to the way the structure of these molecular chains creates fast paths and congestion points (refer to diagram). In a stylized sense imagine that a polymer chain runs relatively straight before coming to a hairpin turn to form a U-shape. An electric field moves electrons rapidly up to the hairpin, only to stall.

"Terminator Polymer" : Self Healing Polymer

Researchers have created a material that heals itself in just two hours. Called the ‘Terminator’ polymer, this could expand the life-span of plastic parts and other tech.

Read More : http://bit.ly/1aU0Q9E

Liquid-crystalline semiconducting polymers with high charge-carrier mobility

We report on new semiconducting liquid-crystalline thieno[3,2-b ]thiophene polymers, the enhancement in charge-carrier mobility achieved through highly organized morphology from processing in the mesophase, and the effects of exposure to both ambient and low-humidity air on the performance of transistor devices.

Read more at:

http://www.nature.com/nmat/journal/v5/n4/full/nmat1612.html