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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.

Plastics not always better than metals: New study reveals why polymer coronary artery stents failed

By Anne Trafton, MIT

Many patients with heart disease have a metal stent implanted to keep their coronary artery open and prevent blood clotting that can lead to heart attacks. One drawback to these stents is that long-term use can eventually damage the artery.

Several years ago, in hopes of overcoming that issue, a new type of stent made from biodegradable polymers was introduced. Stent designers hoped that these devices would eventually be absorbed by the blood vessel walls, removing the risk of long-term implantation. At first, these stents appeared to be working well in patients, but after a few years these patients experienced more heart attacks than patients with metal stents, and the polymer stents were taken off the market.

Researchers hope that their work will lead to a new approach to designing and evaluating polymer stents and other types of degradable medical devices. [Image: Pei-Jiang Wang]

 

 

MIT researchers in the Institute for Medical Engineering and Science and the Department of Materials Science and Engineering have now discovered why these stents failed. Their study also reveals why the problems were not uncovered during the development process: The evaluation procedures, which were based on those used for metal stents, were not well-suited to evaluating polymer stents.

"People have been evaluating polymer materials as if they were metals, but metals and polymers don't behave the same way," says Elazer Edelman, the Thomas D. and Virginia W. Cabot Professor of Health Sciences and Technology at MIT. "People were looking at the wrong metrics, they were looking at the wrong timescales, and they didn't have the right tools."

The researchers hope that their work will lead to a new approach to designing and evaluating polymer stents and other types of degradable medical devices.

"When we use polymers to make these devices, we need to start thinking about how the fabrication techniques will affect the microstructure, and how the microstructure will affect the device performance," says lead author Pei-Jiang Wang, a Boston University graduate student who is doing his PhD thesis with Edelman.

Edelman is the senior author of the paper, which appears in the Proceedings of the National Academy of Sciences the week of Feb. 26. Other authors include MIT research scientist Nicola Ferralis, MIT professor of materials science and engineering Jeffrey Grossman, and National University of Ireland Galway professor of engineering Claire Conway.

Microstructural flaws
The degradable stents are made from a polymer called poly-l-lactic acid (pLLA), which is also used in dissolvable sutures. Preclinical testing (studies done in the lab and with animal models) did not reveal any cause for concern. In human patients, the stents appeared stable for the first year, but then problems began to arise. After three years, over 10 percent of patients had experienced a heart attack, including fatal heart attacks, or had to go through another medical intervention. That is double the rate seen in patients with metal stents.

After the stents were taken off the market, the team decided to try to figure out if there were any warning signs that could have been detected earlier. To do this, they used Raman spectroscopy to analyze the microstructure of the stents. This technique, which uses light to measure energy shifts in molecular vibrations, offers detailed information about the chemical composition of a material. Ferralis and Grossman modified and optimized the technique for studying stents.

The researchers found that at the microscopic level, polymer stents have a heterogeneous structure that eventually leads to structural collapse. While the outer layers of the stent have a smooth crystalline structure made of highly aligned polymers, the inner core tends to have a less ordered structure. When the stent is inflated, these regions are disrupted, potentially causing early loss of integrity in parts of the structure.

"Because the nonuniform degradation will cause certain locations to degrade faster, it will promote large deformations, potentially causing flow disruption," Wang says.

When the stents become deformed, they can block blood flow, leading to clotting and potentially heart attacks. The researchers believe that the information they gained in this study could help stent designers come up with alternative approaches to fabricating stents, allowing them to possibly eliminate some of the structural irregularities.

A silent problem
Another reason that these problems weren't detected earlier, according to the researchers, is that many preclinical tests were conducted for only about six months. During this time, the polymer devices were beginning to degrade at the microscopic level, but these flaws couldn't be detected with the tools scientists were using to analyze them. Visible deformations did not appear until much later.

"In this period of time, they don't visibly erode. The problem is silent," Edelman says. "But by the end of three years, there's a huge problem."

The researchers believe that their new method for analyzing the device's microstructure could help scientists better evaluate new stents as well as other types of degradable polymer devices.

"This method provides a tool that allows you to look at a metric that very early on tells you something about what will happen much later," Edelman says. "If you know about potential issues in advance, you can have a better idea of where to look in animal models and clinical models for safety issues."

The research was funded by Boston Scientific Corporation and the National Institutes of Health.

Published March 2018

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