Hot-fire tests show 3D-printed rocket parts rival traditionally manufactured parts | Kurzweil AI

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NASA engineers at the Marshall Space Flight Center in Huntsville, Ala., have put rocket engine parts to the test and compared their performance to parts made the old-fashioned way with welds and multiple parts during planned subscale acoustic tests for the Space Launch System (SLS) heavy-lift rocket.

In little more than a month, Marshall engineers built two subscale injectors with a specialized 3-D printing machine and completed 11 mainstage hot-fire tests, accumulating 46 seconds of total firing time at temperatures nearing 6,000 degrees Fahrenheit while burning liquid oxygen and gaseous hydrogen.

“We saw no difference in performance of the 3-D printed injectors compared to the traditionally manufactured injectors,” said Sandra Elam Greene, the propulsion engineer who oversaw the tests and inspected the components afterward. “Two separate 3-D printed injectors operated beautifully during all hot-fire tests.”

Post-test inspections showed the injectors remained in such excellent condition and performed so well the team will continue to put them directly in the line of fire.

“The additive manufacturing process has the potential to reduce the time and cost associated with making complex parts by an order of magnitude,” said Chris Singer, director of the Marshall Center’s Engineering Directorate.

Traditional subscale rocket injectors for early SLS acoustic tests took six months to fabricate, had four parts, five welds and detailed machining and cost more than $10,000 each. Marshall materials engineers built the same injector in one piece by sintering Inconel steel powder with a state-of-the-art 3-D printer. After minimal machining and inspection with computer scanning, it took just three weeks for the part to reach the test stand and cost less than $5,000 to manufacture.

Since additive manufacturing machines have has become more affordable, varied, and sophisticated, this materials process now offers many possibilities for making every phase of NASA missions more affordable.

The SLS injector test series complements a series of liquid oxygen and gaseous hydrogen rocket assembly firings at NASA’s Glenn Research Center in Cleveland, which hot-fire tested an additively manufactured, select laser melted injector developed through collaboration of industry and government agencies.

A J-2X engine exhaust port cover made at the Marshall Center became the first 3-D printed part tested during a full-scale engine hot-fire test at NASA’s Stennis Center.

Marshall materials engineers are currently making a baffle critical for pogo vibration mitigation; it will be tested at Marshall and Stennis and is a potential candidate for the first SLS mission in 2017. Marshall engineers are finishing up ground tests with Made in Space, a Moffett Field, California company working with NASA to develop and test a 3-D printer that will build tools on the International Space Station next year. NASA’s Johnson Space Center in Houston is even exploring printing food in space.

“At NASA, we recognize ground-based and in-space additive manufacturing offer the potential for new mission opportunities, whether printing rocket parts, tools or entire spacecraft,” Singer said. “Additive manufacturing will improve affordability from design and development to flight and operations, enabling every aspect of sustainable long-term human space exploration.”

NASA is a leading partner in the National Network for Manufacturing Innovation and the Advanced Manufacturing Initiative, which explores using additive manufacturing and other advanced materials processes to reduce the cost of spaceflight.



Microreactor speeds nanotech particle production by 500 times | Oregon State University

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CORVALLIS, Ore. – Engineers at Oregon State University have discovered a new method to speed the production rate of nanoparticles by 500 times, an advance that could play an important role in making nanotechnology products more commercially practical.

The approach uses an arrayed microchannel reactor and a “laminated architecture” in which many sheets, each with thousands of microchannels in them, are stacked in parallel to provide a high volume of production and excellent control of the processes involved.

Applications could be possible in improved sensors, medical imaging, electronics, and even solar energy or biomedical uses when the same strategy is applied to abundant materials such as copper, zinc or tin.

A patent has been applied for, university officials say. The work, just published in the journal Nanotechnology, was done in the research group of Brian Paul, a professor in the OSU School of Mechanical, Industrial and Manufacturing Engineering.

“A number of new and important types of nanoparticles have been developed with microtechnology approaches, which often use very small microfluidic devices,” said Chih-hung Chang, a professor in the OSU School of Chemical, Biological and Environmental Engineering, and principal investigator on the study.

“It had been thought that commercial production might be as simple as just grouping hundreds of these small devices together,” Chang said. “But with all the supporting equipment you need, things like pumps and temperature controls, it really wasn’t that easy. Scaling things up to commercial volumes can be quite challenging.”

The new approach created by a research team of five engineers at OSU used a microreactor with the new architecture that produced “undecagold nanoclusters” hundreds of times faster than conventional “batch synthesis” processes that might have been used.

“In part because it’s faster and more efficient, this process is also more environmentally sensitive, using fewer solvents and less energy,” Chang said. “This could be very significant in helping to commercialize nanotech products, where you need high volumes, high quality and low costs.”

This research, Chang said, created nanoparticles based on gold, but the same concept should be applicable to other materials as well. By lowering the cost of production, even the gold nanoclusters may find applications, he said, because the cost of the gold needed to make them is actually just a tiny fraction of the overall cost of the finished product.

Nanoparticles are extraordinarily tiny groups of atoms and compounds that, because of their extremely small size and large surface areas, can have unusual characteristics that make them valuable for many industrial, electronic, medical or energy applications.


Self-contained chemical synthesis | Chemistry World

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Scientists in the UK have used reactors made on a 3D printer to complete a three stage organic synthesis. The reagents, catalyst and purification step for the synthesis are completely integrated into the chambers of the sealed reactor. When the reactor is rotated, gravity pulls reactants through the different chambers to complete the synthesis.

Initially, Leroy Cronin, who lead the work at the University of Glasgow, had envisaged a ‘Rubik’s cube for synthesis’, where different manipulations of the reactor would produce different products. ‘The code, like opening a safe, would be in the rotation,’ he explains. ‘I thought it was genius. My group told me I was stupid.’ The team convinced Cronin to start with an easier L-shaped three step reactor, but he still plans to create the Rubik’s cube in the future.

A three-step organic reaction sequence was performed in the L-shaped reactor. The sequence began with a Diels–Alder cyclisation followed by formation of an imine and then hydrogenation of the imine to the corresponding secondary amine.

The team’s next challenge is to use 3D printing to trap reactive intermediates within the device. Research into this is already underway. The scientists suggest that sensors could also be included to monitor the reactions. ‘Closed loop synthesis–sensor–synthesis would be a revolution,’ says Cronin.

Filipe Vilela from Max Planck Institute of Colloids and Interfaces, Potsdam, Germany, an organic synthsis expert, says that apart from having an incorporated catalyst and purification step, which leads to a stand-alone reactor for a multi-step synthesis and purification, this technology stands out for its inexpensive nature and will soon rival other multi-step reactors like micro and millifluidic devices.

‘The 3D platform allows for the reproduction of a reactive system in any laboratory that has a 3D printer,’ says Vilela. ‘Given the open-source nature of this technology, a scientist can download the 3D printing files made available by the authors and load the 3D printer with the materials originally used to reproduce the system.’ He envisages that in the future, with this technology, experimental protocols will have the simple sentence “3D printing verified” to validate a particular reaction and/or system.


Industrial nitroglycerin made fast and safe | Chemistry World

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A microreactor (Credit: Micronit)Since the invention of nitroglycerin in the mid nineteenth century, people have been trying to find safer ways to manufacture the highly unstable liquid explosive. Now, researchers at the Fraunhofer Institute for Chemical Technology (ICT) in Pfintzal, Germany, have come up with what might be the safest approach yet – using microreactors to produce nitroglycerin continuously rather than in batches. This is not only safer but also quicker, facilitating a tenfold increase in production rate.

Nitrogylcerin is made by adding glycerol, a simple hydrocarbon with three hydroxyl groups, to a mixture of sulfuric acid and nitric acid. The reaction is extremely exothermic, but if the temperature gets too high – somewhere above 30°C for example – ‘runaway’ can occur, increasing dramatically the risk of explosion.

Therefore manufacturers continually cool the reaction mixture and – in the traditional batch process – add the glycerol drop-by-drop to the acid to give time for the heat to dissipate and maintain an excess of acid, essential to ensure complete nitration of the all the hydroxyl groups.

‘This is quite old fashioned chemistry,’ says Stefan Löbbecke, deputy director for explosive materials at the Fraunhofer ICT. Switching to a continuous process in a microreactor means working with much smaller quantities – safer for several reasons. It makes it is easier to control the overall temperature and the degree of mixing, which is important to avoid localised temperature variations and dangerous ‘hotspots’. It also makes it easier to control the decomposition products. And in the event of something going very wrong, the resulting explosion would be much smaller.

The microreactor is a hand-sized clear polymer tile with an internal channel that meanders across the plane. The internal channel has two entrances but only one exit – the reactants are brought together at the start and then mixed as they move through the microreactor by turbulence caused by a complex pattern of grooves and ridges on the sides of the channel.
To scale up production, you simply add more microreactors in parallel. A single microreactor might be used to make 10-50kg  of nitroglycerine per day, says Löbbecke. But his group has experimented with production at 2-3 tonnes per week by ‘numbering up’ the microreactors.

That said, this is not an approach for bulk production of nitroglycerin. Low grade product, primarily for the mining and construction industries, can be made cheaply in bulk already. Where this approach is a real advantage, says Löbbecke, is in the manufacture of smaller quantities of nitroglycerin, and other nitric esters, at very high grades for use in the pharmaceutical industry. Nitroglycerin is not only a powerful explosive but also a potent drug (sometimes called glyceryl trinitrate), widely used for treating angina and other heart problems.

The improved safety of the approach reduces costs for the manufacturer, as does the higher rate of production. The microreactor approach is already in use industrially, although Löbbecke declined to say where owing to commercial sensitivities.


Microreactors tame osmium tetroxide | Chemistry World

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Researchers in South Korea and India have made microfluidic reactors that safely harness the synthetically powerful but noxious catalyst osmium tetroxide.

Dong-Pyo Kim at POSTECH in Pohang, South Korea, and colleagues trapped OsO4 in poly(4-vinylpyridine) (P4VP) ‘nanobrushes’ on the inner walls of silicone microreactors. Their reactors catalysed dihydroxylation and oxidative cleavage – steps important in natural product, pharmaceutical and fine chemical synthesis – of 10mmol of various olefins with yields of more than 90%. Only 50µg of OsO4 was needed, making the microreactor catalyst 50 times more efficient than bulk supported systems.

OsO4 powers reactions like the chemistry Nobel prize winning Sharpless asymmetric dihydroxylation, but is toxic and unusually volatile, and therefore produces deadly fumes. ‘Many researchers have tried to stabilise or immobilise it on a polymer or inorganic substrate,’ Kim tells Chemistry World. ‘But leaching and exposure to the environment is inevitable in a bulk reaction system.’

So Kim’s team sought to trap OsO4 in microreactors by moulding two pieces of silicone holding mirror image nano-sized channels using soft lithography. As silicone normally swells in organic solvents they spin-coated the channels with protective polyvinylsilazane (PVSZ) layers, which they then bonded PV4P nanobrushes to. After putting the two halves of silicone together, the researchers infused the microreactor with aqueous OsO4.

Initially, catalytic activity disappeared after just a day. To boost the reactor’s stability, the team reduced OsO4 to a dark blue oxoosmium(VI) complex by feeding tetrahydrofuran through it after catalyst loading. In testing on biomass-based olefins, dihydroxylation reactions exceeded 98% conversion in 10 minutes, and oxidative cleavage reached similar levels in seven minutes. But the reactor’s volume limits it to around 1mmol of product per hour.

Reactor performance did not change significantly after 10 hours’ continuous use, or three months’ storage. Reaction mixtures contained just 30–50ppb osmium, around 100 times lower than other reported systems, Kim says. ‘We are now working on scale-up of our reactor system for possible industrial application and further developing microchemical systems for hazardous heterogeneous catalysts,’ he adds.

Paul Watts, who researches microfluidic continuous flow chemistry at Nelson Mandela Metropolitan University in Port Elizabeth, South Africa, notes the increasing interest in such reactors’ safety potential. He says Kim’s team’s reactor ‘provides a very elegant way to use OsO4 within research’. ‘I envisage the methodology being of significant use to other organic chemists,’ he adds.


MicroReactors Eyed For Industrial Use | Chemical and Engineering News

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Chemistry in microreactors has been touted as faster, safer, and cheaper, so it’s not surprising that interest in such systems continues to intensify. Microreactors typically consist of plates containing microstructures that define a very small reaction volume, as well as pumping accessories for continuous operation. Now that microreactors are available off the shelf at modest cost, more and more companies engaged in fine chemicals production are testing the technology.

Recently, Sigma-Aldrich took the plunge. Last February, it installed a standard Cytos Lab System microreactor at its R&D facilities in Buchs, Switzerland. Developed by CPC (Cellular Process Chemistry Systems GmbH, Frankfurt), the system has a list price of about $187,000. Sigma-Aldrich is in good company: Sixteen other pharmaceutical and fine chemicals producers are interested in CPC’s technology, according to Sigma-Aldrich’s Fabian Wahl, manager of R&D for Europe. Wahl’s group is spearheading the firm’s technology evaluation.

The key feature of microchemical systems is the high ratio of surface area to volume. That ratio is 200 for a microreactor with a reaction volume of 1.5 mL, such as that of CPC’s, and only 0.6 for a 1- m3 reactor. Mass transfer, heat transfer, and mixing are vastly more efficient in a microreactor, allowing far more precise reaction control and far better product quality control than can be achieved with conventional reactors, Wahl says.

In addition, an optimized process can be run at any scale without further R&D by simply running in parallel as many reactors as are required. Such a mode of operation is easily executed because microreactor systems typically are modular.

The technology would reduce the cost of scale-up and resources deployed to develop safe and stable processes, Wahl concludes. It is useful and practical for Sigma-Aldrich’s businesses, particularly for developing and making catalog products.

Many of Sigma-Aldrich’s catalog products are produced under usual lab conditions in flasks of up to 20 L. Of the more than 2,000 compounds in this portfolio, about 800 could be produced in microreactors with little or no process modification, Wahl says. For such cases, microreactors would reduce reaction time and cost.

For example, the condensation of 2-trimethylsilylethanol and p-nitrophenyl chloroformate to produce 2-(trimethylsilyl)ethyl 4-nitrophenyl carbonate requires 14 hours to complete in a conventional setup but only 18.4 minutes in a microreactor. Because contact between reagents and products is so brief, the possibility that the desired product will degrade or that by-products will be formed is vastly reduced, Wahl says.

Even more attractive is the opportunity microreactors offer to run problematic chemistries, such as those that are highly exothermic, produce unstable products, or form difficult-to-separate side products. Wahl’s team has explored use of microreactors for two such reactions.

The first is ester hydrolysis to produce an alcohol that readily degrades. Wahl declines to identify the ester or the alcohol. He says only that Sigma-Aldrich could not keep up with the demand for the alcohol because yield deteriorates as the reaction is scaled up: 70% at 5 L, 35% at 20 L, and 10% at 100 L.

Because Sigma-Aldrich’s original process requires an insoluble component, it could not be carried out in a microreactor. “We had to change the chemistry, but we did not know in which way,” Wahl says. With microreactors, they found out quickly.

It took less than a day to run a model reaction under 12 different conditions. A substrate that yields a stable alcohol was used so as not to complicate process development with degradation of the alcohol product of the actual substrate. After the best conditions were identified for the model system, it took only two hours to optimize the reaction of the actual substrate.

The second problematic chemistry tested by Wahl’s team is preparation of methylenecyclopentane from a substrate that Wahl does not wish to disclose. The reaction is highly exothermic, and process control is not good under conventional conditions. Furthermore, up to 30% of the yield consists of the more thermodynamically stable product, 1-methylcyclopentene, which is difficult to separate. For these reasons, production of methylenecyclopentane had been discontinued.

Using the CPC microreactor, Wahl’s team devised a reaction that gives 70% conversion, no by-product, and a throughput of 300 g per hour, Wahl says. A 70% conversion with no by-product is better than a higher conversion with some by-product because separating the product from the precursor is easier than separating it from the by-product, he explains.

Wahl expects microreactor technology also to have a positive impact on Sigma-Aldrich’s custom synthesis business, in which rapid process development is a competitive advantage. His expectation that microreactors would reduce development time by 40% has been met so far. Thus, Sigma-Aldrich is inclined to adopt microreactor technology more widely, he says.

The major drawback is the inability to work with gases and insoluble reagents. A minor one is the fact that the CPC microreactors are fabricated from steel, which is chemically sensitive. CPC is now testing microreactors made with Hastelloy, the chemically resistant material widely used in conventional reactors.

The CPC microreactors are easy to work with, Wahl says. The most common problem is blockage, which often is solved with one call to CPC’s hotline. Changeover from one process to another requires only a five-minute rinse with solvent.

Last month, Wahl visited Massachusetts Institute of Technology for a close look at the microchemical system being developed by Klavs Jensen, a professor of chemical engineering. The MIT system is different from CPC’s in three major ways. First, the reaction volume is in the microliter range, making it possible to carry out a lot of experiments with minuscule amounts of materials. Second, the reactor is made of silicon, which can be oxidized to form glass surfaces familiar to chemists. Because silicon and silicon oxide (glass) surfaces are easy to modify, it is possible to fabricate reactors that are preloaded with catalysts, Wahl says. And third, the structured surfaces of the MIT system are covered with glass, making it possible to observe reactions as they take place.

The MIT system is not yet available commercially. But when it becomes available, Sigma-Aldrich will be considering it for possible adoption into its business operations, Wahl says. Meanwhile, Sigma-Aldrich will be closely following the further development of MIT’s technology, hoping for a chance to test a prototype.


Why 2014 will be a great year for 3D printing | SmartPlanet

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There’s no denying that 2013 has been the year of the desktop 3D printer. They’re now carried by major retailers, like Amazon and Staples; Windows 8.1 has built-in support for 3D printers; and Makerbot, the popular desktop printing company was aquired by Stratasys, a much larger additive manufacturing company. But, while U.S. President Barack Obama called 3D printing the “next revolution” in manufacturing earlier this year, it’s 2014 that could be the year industrial 3D printing takes off.

Why? As Christopher Mims of Quartz reports, important patents for the more advanced selective laser sintering form of 3D printing (which has been around for decades) will expire next February. While these patents have been the highest revenue generating intellectual property of University of Texas for years, their expiration could mean cheaper industrial-grade 3D printers — much like what happened when fused deposition modeling (FDM) patents expired — and wider distribution of laser sintering 3D printers, which isn’t currently happening on a scale that can be true disruptive in the manufacturing world. As Mims reports:

One of Shapeways’ problems is that the company can’t buy enough advanced 3D printers (the laser-sintering kind) to keep up with demand. This is because 3D Systems, the company that makes the models that Shapeways uses, has a 12- to 18-month waitlist for its printers. Cheap laser-sintering 3D printers of the sort made by Formlabs, which sells a desktop laser-sintering 3D printer for $3,300, could finally give people the ability to manufacture (plastic) parts of the same quality as those mass-produced through traditional means.

The bottom line: Starting next year, industrial-grade 3D printing could become cheaper and more accessible, a boon to those hopeful that 3D printing can transform manufacturing.


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