Monday, June 22, 2015

Solving the Last Great 3-D Printing Challenge: Printing in Color

Nobody mentions the big problem with 3-D printing: how to do it in color. Now they won’t have to, thanks to a new technique.
3-D printing is driving a huge revolution in the world of design and technology. In the process, it is changing the way we think about the design, prototyping, and manufacturing of just about everything.
But anyone who has played with a 3-D printer will be aware of one significant problem. This 800-pound gorilla is the issue of color. 3-D prints can be magnificent copies of more or less any shape. But in terms of color, they are mere shadows of the originals.
Today, that looks set to change thanks to the work of Alan Brunton and pals at the Fraunhofer Institute for Computer Graphics Research in Germany, who have worked out how to produce accurate colors in a 3-D print for the first time. Their work promises to take 3-D printing to an entirely new level.
The new approach takes advantage of a relatively new way to make 3-D prints. In general, these objects are made one layer at a time by fusing powder or laying down extruded plastic. Neither approach gives anything but rudimentary control over an object’s color.
What’s needed instead is a way of creating objects in the same way as 2-D printers make images, pixel by pixel. In other words, this requires 3-D prints to be laid down, not in layers, but voxel by voxel.
In the last year or so, exactly this technology has come to market. It works using a number of inkjets that lay down an object, droplet by droplet. These droplets are instantly cured by UV light to form a solid.
That immediately allows the possibility of much more accurate control of color, since each droplet can be thought of as a voxel. This is the approach that Brunton and pals have taken, but it is easier said than done for a number of reasons.
The first is the sheer volume of data and number crunching involved in creating a virtual color 3-D object, even before the printing begins. The droplets from inkjets are tiny—there are some 18 million of them in a solid cubic centimeter. So any decent-sized object must be made up of tens of billions of voxels and the impact that each one has on the final color has to be calculated.
The second is that the droplets are translucent because UV light must be able to pass through to cure them. This has a significant impact on their visual appearance since light ends up passing through several layers of voxels, being scattered along the way.
That means droplet color has to be carefully controlled to a depth of several voxels throughout the object. And this dramatically increases the complexity of the algorithms needed to calculate their required colors.
The final challenge comes from the nature of 3-D printing. In 2-D printing, it is possible to combine up to three different inks at any point on an image. In a 3-D print, each droplet must be a single material and that places important constraints on what is possible colorwise.
Nevertheless, Brunto and co have made significant advances by bringing to bear the many decades of research that has been done on color management for 2-D printing and for color imaging in general.
Their approach is to combine two techniques. The first is the 3-D equivalent of a 2-D printing technique called half-toning. This is where continuous shade and color is replaced by an arrangement of dots of different sizes and spacing. The second is a way of calculating the color of a surface given the way light has been scattered for several layers of voxels below.
And the results look impressive. In the pictures above, three apples and the thumb are real. The rest are 3-D prints but it is no easy task to tell them apart.
And Brunton and co say the results should get better in the near future as materials scientists develop less translucent printing materials and as printers become even higher resolution. In both these respects, the team’s algorithms are future proof. Less translucent inks should be easier to handle and the higher resolution should be manageable too.
The ability to combine translucent and opaque inks should even make it possible to reproduce the surface appearance of many biological materials that are also semi-translucent, such as skin.
That’s fascinating work. It will usher in a new generation of printing application. And it will make the current generation of printers look thoroughly old-fashioned in just a few years. (

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Thursday, June 18, 2015

Nissan, GM Give EV Batteries a Second Life

Automakers have begun harvesting batteries for use in stationary energy storage applications.
The Nissan Leaf went on sale in December 2010, which means that the batteries in the earliest models of the world’s most popular electric vehicle need, or will soon need, to be replaced. Those batteries are not necessarily bound for the recycling bin, though: on Monday Nissan announced the first commercial arrangement to use “second-life batteries,” recovered from EVs, in stationary energy storage systems.
Nissan formed a joint venture with Sumitomo Corp. to develop second-life battery applications not long after the Leaf first appeared. The automaker is working with energy storage supplier Green Charge Networks to redeploy the used batteries in systems for commercial and industrial customers. The announcement from the Japanese automaker came the day before GM unveiled its own battery reuse program: an administration building at GM’s Milford Proving Grounds in Michigan is now equipped with an energy storage system that uses batteries collected from Chevrolet Volts. GM made its announcement Tuesday at the Advanced Automotive Battery Conference in Detroit.
Over time, EV batteries, which often charge and discharge multiple times over the course of a day, lose the ability to propel a vehicle; but they can still function in less demanding, stationary applications. “A battery is like a transmission or an engine: it’s available for remanufacture or reuse,” says Pablo Valencia, GM’s senior manager of battery lifecycle management. “The difference is in the battery application, you can use it on the grid.”
The Volt battery system, not yet on the market for commercial uses, is being deployed to supplement renewable power generation at the Milford facility, making the facility a net zero building, says GM. The company plans to commercialize the system in the future. Nissan and Green Charge are marketing their storage system for companies to manage their utility demand charges, substituting battery power for electricity from the grid at times of peak pricing. Both companies, along with Toyota and other EV makers, foresee a thriving market in retired EV batteries that can supply power to homes and businesses.
Ultimately, automakers seek to fully exploit the energy storage capacity of EVs by incorporating EV batteries not just after their useful transportation life, but while they’re still installed in cars, using vehicle to grid, or V2G, systems. That technology could provide significant benefits—including regulating the frequencies on the grid to smooth the power load and lowering usage during periods of peak demand—to utilities and customers as more vehicles become electrified. One of the stronger advocates of V2G technology is the U.S. Department of Defense, which has invested around $20 million to install 500 V2G-enabled vehicles at bases around the United States.
Such systems require bidirectional capability—the vehicle must be able to send power back to the grid as well as take it from the grid. That’s not yet found on vehicles sold in the states, but in Japan, Nissan and Mitsubishi already sell cars with two-way charging systems. Nissan’s Leaf to Home system can supply an average Japanese home with two days of electricity in case of a power outage.
For the near term, though, it’s mostly former EV batteries that will supply power back onto the grid. By using “pre-owned” batteries, Green Charge and other energy storage suppliers can reduce their costs and, presumably, the prices they charge customers: “Having this type of system available will expand the energy storage market,” says Brad Smith, the director of Nissan’s battery unit in the U.S.
It could also improve the economics of EVs, which still carry a hefty premium compared to internal-combustion models. While the cost of battery packs has fallen rapidly, they still make up as much as one-third of the total price of an EV. Giving the battery a resale value, as it were, could open up the EV market to a wider set of customers. By Richard Martin (

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Thursday, June 11, 2015

Square Announces Apple Pay Reader

Today at the Apple Worldwide Developers Conference, Square announced its most powerful card reader yet: a wireless reader that enables any business with a tablet or smartphone to accept Apple Pay and contactless payments, as well as EMV chip cards. Square is offering 250,000 of these readers free as part of its continued commitment to give local businesses access to the smartest technology through secure and simple hardware. The new reader is also available for pre-order in the U.S. for $49 (with a $49 card processing credit).
"Apple Pay created an easy, fast, and secure payment experience for customers," said Jesse Dorogusker, head of Hardware at Square. "We want to make it easy for every type and size of business to accept Apple Pay with our latest Square Reader, the most powerful and affordable contactless and EMV reader on the market."
Until today, local businesses' only options for accepting contactless payments set them back hundreds of dollars, overwhelmed their countertops with bulky hardware, and required stringent, binding contracts. The new Square Reader comes ready out of the box, connects with Square Stand or wirelessly with a mobile device, and pairs seamlessly with Square's free point-of-sale app. Local sellers -- from brick-and-mortar chains like Blue Bottle Coffee to mobile businesses like Señor Sisig -- can easily use the lightweight, compact, and wireless reader as part of their countertop point of sale, or slip it in their pocket to accept contactless and EMV payments on the go.
Interested sellers can visit to pre-order the new Square Reader. Square will begin shipping the reader in fall 2015.

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