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Engineering challenge: Which 3D-printed parts will fade?

How does prolonged exposure to intense UV light impact 3D-printed plastics? Will they fade? This is what Xometry's Director of Application Engineering, Greg Paulsen, set to find out. In this video, Paulsen performs comprehensive tests on samples manufactured using various additive processes, including FDM, SLS, SLA, PolyJet, DLS, and LSPc, to determine their UV resistance. Very informative. Some results may surprise you.
View the video.

Copper filament for 3D printing

Virtual Foundry, the company that brought us 3D-printable lunar regolith simulant, says its popular Copper Filamet™ (not a typo) is "back in stock and ready for your next project." This material is compatible with any open-architecture FDM/FFF 3D printer. After sintering, final parts are 100% pure copper. Also available as pellets. The company says this is one of the easiest materials to print and sinter. New Porcelain Filamet™ available too.
Learn more and get all the specs.

Copper foam -- so many advantages

Copper foam from Goodfellow combines the outstanding thermal conductivity of copper with the structural benefits of a metal foam. These features are of particular interest to design engineers working in the fields of medical products and devices, defense systems and manned flight, power generation, and the manufacture of semiconductor devices. This product has a true skeletal structure with no voids, inclusions, or entrapments. A perennial favorite of Designfax readers.
Learn more.

When glass or plastic can't cut it: Transparent ceramics solve critical design challenges

Complex designs are still possible when grinding and polishing Fused Silica or Sapphire. Ceramic properties such as wear, abrasion resistance, and strength of these optical materials can be a designer's dream solution when high temperatures or severe environments rule out standard optical glass or plastic. INSACO is a machine shop specializing in ultra-hard and extreme materials.
→ Contact Jackson Evans, Sales Engineer at INSACO jpe@insaco.com.
→ Learn more about INSACO materials and capabilities.

New aero and defense PEKK-based FDM polymers from Stratasys

Stratasys has partnered with top aerospace and defense companies to develop two newly qualified materials for 3D printing. Antero 800NA is a PEKK-based FDM polymer with excellent physical and mechanical properties for demanding applications. Antero 840CN03 is a high-performance PEKK-based FDM polymer with electrostatic dissipative (ESD) properties. These new advanced industrial solution materials were rigorously qualified in collaboration with Northrop Grumman, Boeing, Blue Origin, Raytheon, Naval Air Systems Command, the National Institute for Aviation Research, United States Air Force, BAE, and Stratasys Direct Manufacturing.
Learn more.

EOS expands its Nickel superalloys for 3D printing

EOS, a leading supplier of manufacturing solutions for industrial 3D printing, has added two new metal additive manufacturing materials: EOS NickelAlloy IN738 and EOS NickelAlloy K500, both delivering excellent performance, part properties, and value to a variety of industries that leverage EOS Laser Powder Bed Fusion (LBPF) 3D-printing technology. The IN738 superalloy is aimed at high-strength, high-stress energy and turbomachinery applications, while the K500 superalloy is a cost-effective, corrosion-resistant option for chemical, maritime, and space industries.
Learn more.

CNC machining: How to avoid high costs on thin walls

Parts that are light and strong are crucial to nearly every industry. To achieve better performance without risking part failure, parts must maintain a specific wall-height-to-thickness ratio and wall-height-to-length ratio. Additionally, some geometries and supports can support thin walls to achieve a lighter component weight. Dive deeper into the cost drivers behind CNC-machined thin walls in this Xometry design-for-manufacturing article.
Read the full article.

Eco-friendly thermoplastic: Light, rigid, strong, damping

Polyplastics has launched PLASTRON^® LFT (Long Fiber-Reinforced Thermoplastic) RA627P, an eco-friendly composite of polypropylene (PP) resin and long cellulose fiber that delivers low density, high specific rigidity, high impact strength, and excellent damping for a range of applications including audio components and housings of industrial components. LFT exhibits 10% lower density than 30% short glass fiber-reinforced PP resin, roughly the same flexural modulus, and a specific rigidity that is higher.
Learn more.

Sound-dampening foam with an eco edge

BASF has introduced Basotect^® EcoBalanced melamine foam, a material that helps to reduce the product carbon footprint (PCF) of many sound-absorption applications in the transportation, building, and construction industries. This easy, drop-in solution has an up to 50% lower PCF than the respective BASF standard grades but demonstrates the same material performance. Applications include engine covers, wall and ceiling sound absorbers, HVAC parts, and air cleaners.
Learn more.

Fastest large-format SLA 3D printer in the world

Built on Formlabs' next-generation Low Force Display print engine, the new Form 4L SLA 3D printer delivers unmatched reliability with a 99% print success rate compared to other SLA 3D printers. These benefits, combined with a build volume nearly 5x the size of Form 4, allow Form 4L users to solve big problems and print smaller parts at high volume. Large-scale prints finished in under six hours.
Learn more.

Keypad teardown and design insights with Autodesk and Xometry

Take a deep dive into the second revision of the macro keypad developed for Autodesk University's Factory Experience 2024 in this exclusive, on-demand webinar hosted by Xometry's Greg Paulsen and Autodesk Fusion's Jonathan Odom. This presentation features a live teardown of the keypad, showcasing how the design team addressed challenges and elevated the product. No registration required.
Watch this Xometry webinar at your convenience.

Tube cutting and bending design guide: Xometry

Xometry's no-cost tube design guide offers design tips and tricks for laser-cut tube parts, including: minimums, tolerances, and sizes. The guide also covers important rules for mandrel tube bending, such as tolerancing, distance between bends, bend center line radius, types of bends to avoid, and more. Incredibly handy. If you need parts, Xometry can help with that too. It's easy to get a quote.
Learn more.

SPEE3D develops ultra-corrosion-resistant alloy
-- a game-changer for maritime additive manufacturing

Australian manufacturer SPEE3D has developed two grades of an ultra-corrosion-resistant Nickel Aluminum Bronze alloy that are compatible with its Cold Spray Additive Manufacturing technology. The powder material is a game-changer for maritime OEMs and the U.S. Navy, as it will help with supply chain delays and keep critical maritime systems operational.
Read the full article.

New polymer bearings are PFAS- and PTFE-free

igus has developed a new polymer bearing material called iglide JPF that is free of both per- and polyfluoroalkyl substances (PFAS) and polytetrafluoroethylene (PTFE). This innovation marks an important step in the company's efforts to create sustainable alternatives to conventional plain bearings. JPF is a dry-running, wear-resistant polymer that offers comparable friction and wear performance to iglide J. It delivers high wear resistance and durability.
Learn more.

New high-speed PSLA 270 printer from 3D Systems

The all-new PSLA 270 projector-based polymer 3D-printing platform and associated new materials from 3D Systems enable faster production times for a wide range of applications. This machine's high throughput and accuracy make it ideal for industries like healthcare, aerospace, automotive, and manufacturing, where precise and durable components are critical. Complementary Wash and Cure systems streamline post-processing and ensure high-quality finished parts.
Learn more including materials and build sizes.

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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