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Weird stuff: Moon dust simulant for 3D printing

Crafted from a lunar regolith simulant, Basalt Moon Dust Filamet™ (not a typo) available from The Virtual Foundry closely mirrors the makeup of lunar regolith found in mare regions of the Moon. It enables users with standard fused filament fabrication (FFF) 3D printers to print with unparalleled realism. Try out your ideas before you go for that big space contract, or help your kid get an A on that special science project.
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Make nylon 3D-printed prototypes and parts in the office

The new SLS 300 from 3D Systems is an affordable, turnkey, closed-loop 3D-printing system designed to operate in a smaller-footprint environment. SLS 300 makes selective laser sintering available to a broader range of customers with a high-reliability, affordable solution to produce end-use parts. Users can produce tough, durable parts from a range of production-grade nylon materials. Amazing fill, finishing, and clean-up systems.
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Will it erode? 3D-printing materials comparison from Xometry

Which 3D-printed plastics are the toughest? In this "Will it ..." video, Greg Paulsen, Xometry's Director of Application Engineering, 3D printed Benchies (3D test models) using different materials (such as polycarbonate, PLA, polypropylene, ULTEM, and Nylon 11 and 12) and processes (such as FDM, SLS, MJF, SLA, LSPc, Polyjet, and DLS) and then ran several abrasion tests on them. Watch to find out which 3D-printed plastic is truly the toughest of them all!
View Part 1.
View Part 2.

Graphene Handbook: Learn all about this wonder material

Metalgrass LTD has published the 11th edition of its "Graphene Handbook," a comprehensive resource on graphene technology, the industry, and the market for this wonder material made of single layers of atoms of pure carbon. The book includes development history, production methods, current research, an intro to metrology and standardization, and even an investment guide. Under 100 bucks for digital edition. Hard copy available too.
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Who knew? How colorants affect plastic

In plastic injection molding, one aspect of polymer characteristics that doesn't always get the consideration it deserves is the addition of colorant. Believe it or not, there is a whole scientific body of knowledge about the ways in which adding color to plastic can affect its behavioral properties. This short article by Denny Scher of ICO Mold takes a high-level look at some of the different, and surprising, ways colorants can affect plastics.
Read the full article.

Retaining magnets from JW Winco: Universal and clever

JW Winco has expanded its magnet line to support more applications with new materials, shapes, systems, and even raw magnets. Learn about their latest offerings, including retaining magnets designed for corrosive environments (GN 50.8), encapsulated magnets designed for sensitive or painted surfaces (GN 51.8), handle magnets (GN 53.3), and powerful magnets designed to handle challenging environs (GN 52.6).
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3D print tool steel with the ease of a plastic

The Virtual Foundry, a pioneer in advanced 3D-printing materials, is excited to announce the launch of their latest innovation: M300 Tool Steel Filamet™ (not a typo). This material answers the demand for FFF 3D-printable Tool Steel, delivering unparalleled strength and versatility. What sets this material apart is its seamless compatibility with various 3D printers, including Creality, Bambu Lab, Ultimaker, and more. The filament prints effortlessly, resembling the ease of working with PLA (plastic).
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Great Resources: Sheet metal design guide

If you're looking for a basic guide to sheet metal design, this one from Xometry will serve your needs well. Follow the design requirements and tolerances in this guide to ensure parts fall closer to design intent. This is the type of information you'll sock away and then refer to again and again.
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Particle foam perfectly distributed thanks to simulation with Ultrasim

BASF's Ultrasim simulation solution now includes Infinergy, an expanded thermoplastic polyurethane (E-TPU) that is used in a wide range of applications to make components with particle foam -- from bicycle tires to the soles on shoes. Identify and solve problems related to pneumatic filling when distributing particle foams in molds, even taking gravity and mold closing into consideration. Avoid those pesky air pockets.
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Premium polymer DLP printer is half the price of its predecessor

Desktop Metal has just launched the ETEC Pro XL -- a premium polymer digital light processing (DLP) printer that enters the market at less than half the price as its predecessor. DLP is regarded by many as a superior polymer 3D-printing technology for speed, surface finish, and accuracy. Ideal for automotive and machine parts, aerospace components, housings, connectors, jigs and fixtures, short-run molds, and more.
Read the full article.

CNC machining case study: One-of-a-kind computer chassis

Learn how Josh Sniffen, the YouTuber behind the popular PC-building channel "Not From Concentrate," trusted Xometry to provide a wide range of manufacturing options, personalized Design for Manufacturing (DFM) feedback, and order management support for his latest creation: the HEXO ATX computer chassis. All in all, Sniffen procured parts using Xometry's CNC machining service, selective laser sintering 3D-printing service, and sheet metal cutting and fabrication services. A neat insider look at the process.
Read this Xometry case study.

Which parts should be 3D printed? AI combs through CAD files to find out

One of the biggest challenges in transitioning to additive manufacturing (AM) is the ability to identify which parts are best suited for the process quickly and easily. Learn how Danfoss, Stanley Engineered Fastening, and even the U.S. military have utilized advanced additive manufacturing software to automate the process, reducing material waste and energy costs, improving part reliability, decreasing lead times, as well as now having the ability to identify part consolidation opportunities through intelligent AM decision-making.
Read the full article.

9 key design tips for injection molding

Keep costs down and quality up all while optimizing your injection molded designs with these helpful tips from Xometry. Learn how to build better injection molded parts and products -- using draft angles, ribs and gussets, radii, fillets, and more -- and set expectations for the injection molding process. Good info here.
View the video.

Metal additive manufacturing: Rocket turbopump design

Mixing undergraduate curiosity and real-world engagement, two students from Colorado University Boulder Aerospace Engineering Sciences program, Zachary Lesan and Patrick Watson, started an independent effort on turbopump design and manufacture that is a lesson in determination and industry collaboration. With lots of supplies and advice from industry heavy hitters including Velo3D, CFturbo, SpaceX, and many more, their project has reinforced significant points being made about next-generation rocketry.
Read the full article.

Transparent ceramics for extreme optics

Sapphire is an inherently transparent ceramic material that is resistant to extremes of temperature and environment. Sapphire can be processed to unique and precise shape/form by diamond grinding and polishing to allow full transparency. INSACO is a global leader in this capability -- and working with ultra-hard materials in general.
Learn more.

MIT researchers make surfaces that are easier to cool under extreme heat

By Nancy W. Stauffer, MITEI

When an earthquake and tsunami struck Japan's Fukushima nuclear power plant in 2011, knocking out emergency power supplies, crews sprayed seawater on the reactors to cool them -- to no avail.

One possible reason: Droplets can't land on surfaces that hot. Instead, they instantly begin to evaporate, forming a thin layer of vapor and then bouncing along it -- just as they would in a hot cooking pan.

Now, MIT researchers have come up with a way to cool hot surfaces more effectively by keeping droplets from bouncing. Their solution: Decorate the surface with tiny structures and then coat it with particles about 100 times smaller. Using that approach, they produced textured surfaces that could be heated to temperatures at least 100 deg C higher than smooth ones before droplets bounced. The findings are reported this week in the journal Applied Physics Letters.

"Our new understanding of the physics involved can help people design textured surfaces for enhanced cooling in many types of systems, improving both safety and performance," says Kripa Varanasi, the Doherty Associate Professor of Ocean Utilization in MIT's Department of Mechanical Engineering and the lead author of the study.

The goal for Varanasi and his co-authors, recent MIT PhD recipient Hyuk-Min Kwon and former MIT postdoc J.C. Bird, was to find a way to increase the temperature at which water droplets start bouncing. Past research indicated that rough materials would add more surface area to hold onto the droplets, making it harder for them to bounce. But the research team discovered that not just any rough surface will do.

Through systematic studies using well-defined surfaces, they found that installing microscale silicon posts on a silicon surface raised the temperature at which droplets transitioned from landing to bouncing. But it worked best when the posts were relatively diffuse. As the posts got closer together, the transition temperature gradually dropped until it was no higher than that of a smooth surface.

"That result was surprising," says Bird, who is now an assistant professor of mechanical engineering at Boston University. "Common knowledge suggests that the closely spaced posts would provide greater surface area, so would hold onto the droplets to a higher temperature."

By analyzing the physics involved, the researchers concluded that closely spaced posts do provide more surface area to anchor the droplets, but they also keep the vapor that forms from flowing. Trapped by adjacent posts, the accumulating vapor layer under a droplet builds up pressure, pushing the droplet off. When the force of the vapor exceeds the attractive force of the surface, the droplet starts to float.

"Bringing the posts closer together increases surface interactions, but it also increases resistance to the vapor leaving," Varanasi says.

To decouple those two effects, the researchers coated the surface featuring spaced-out microscale posts with nanoscale particles. This "micro-nano" surface texture provides both the extensive surface area of the tiny particles and the wide spacing of the posts to let the vapor flow.

Experiments confirmed their approach. When they sprayed water on their micro-nano surfaces at 400 deg C -- the highest temperature their experimental setup could provide -- the droplets quickly wet the surfaces and boiled. Interestingly, under the same conditions, the droplets did not wet the surfaces of samples with either the microscale posts or the nanoscale texture, but did wet the surfaces of samples with both.

In addition to nuclear safety systems, this work has important implications for systems such as steam generators, industrial boilers, fire suppression, and fuel-injected engines, as well as for processes such as spray cooling of hot metal. One application now being considered by Varanasi and his colleagues is electronics cooling. "The heat fluxes in electronics cooling are skyrocketing," Varanasi says. It might be a job for efficient spray cooling -- "if we can figure out how to fit a system into the small space inside electronic devices."

The research was supported by a Young Faculty Award from the Defense Advanced Research Projects Agency, the MIT Energy Initiative, and the MIT-Deshpande Center.

Published November 2013

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