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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.
Learn more.

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).
Learn more.

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.
Read the full article.

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.
Learn more.

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.

Tough gel stretches to 21 times its length, recoils, and heals itself

A team of experts in mechanics, materials science, and tissue engineering at Harvard have created an extremely stretchy and tough gel that may pave the way to replacing damaged cartilage in human joints, among other uses.

Called a hydrogel, because its main ingredient is water, the new material is a hybrid of two weak gels that combine to create something much stronger. Not only can this new gel stretch to 21 times its original length, but it is also exceptionally tough, self-healing, and biocompatible -- a valuable collection of attributes that opens up new opportunities in medicine and tissue engineering.

The material, its properties, and a simple method of synthesis are described in the September 6 issue of Nature.

The researchers pinned both ends of the new gel in clamps and stretched it to 21 times its initial length before it broke. [Photo courtesy of Jeong-Yun Sun.]

 

 

"Conventional hydrogels are very weak and brittle -- imagine a spoon breaking through jelly," explains lead author Jeong-Yun Sun, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS). "But because they are water-based and biocompatible, people would like to use them for some very challenging applications like artificial cartilage or spinal disks. For a gel to work in those settings, it has to be able to stretch and expand under compression and tension without breaking."

Sun and his coauthors were led by three faculty members: Zhigang Suo, Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials at SEAS and a Kavli Scholar at the Kavli Institute for Bionano Science and Technology at Harvard; Joost J. Vlassak, Gordon McKay Professor of Materials Engineering and an Area Dean at SEAS; and David J. Mooney, Robert P. Pinkas Family Professor of Bioengineering at SEAS and a Core Faculty Member at the Wyss Institute for Biologically Inspired Engineering at Harvard.

To create the tough new hydrogel, they combined two common polymers. The primary component is polyacrylamide, known for its use in soft contact lenses and as the electrophoresis gel that separates DNA fragments in biology labs; the second component is alginate, a seaweed extract that is frequently used to thicken food.

Separately, these gels are both quite weak -- alginate, for instance, can stretch to only 1.2 times its length before it breaks. Combined in an 8:1 ratio, however, the two polymers form a complex network of crosslinked chains that reinforce one another. The chemical structure of this network allows the molecules to pull apart very slightly over a large area instead of allowing the gel to crack.

The alginate portion of the gel consists of polymer chains that form weak ionic bonds with one another, capturing calcium ions (added to the water) in the process. When the gel is stretched, some of these bonds between chains break -- or "unzip," as the researchers put it -- releasing the calcium. As a result, the gel expands slightly, but the polymer chains themselves remain intact. Meanwhile, the polyacrylamide chains form a grid-like structure that bonds covalently (very tightly) with the alginate chains.

Therefore, if the gel acquires a tiny crack as it stretches, the polyacrylamide grid helps to spread the pulling force over a large area, tugging on the alginate's ionic bonds and unzipping them here and there. The research team showed that even with a huge crack, a critically large hole, the hybrid gel can still stretch to 17 times its initial length.

The researchers used a razor blade to cut a 2-cm notch across the gel. In the image above (left), the gel has been stretched very slightly so that the notch is visible. This damaged gel was still able to stretch to 17 times its initial length without breaking. [Photo courtesy of Jeong-Yun Sun.]

 

 

 

 

Importantly, the new hydrogel is capable of maintaining its elasticity and toughness over multiple stretches. Provided the gel has some time to relax between stretches, the ionic bonds between the alginate and the calcium can "re-zip," and the researchers have shown that this process can be accelerated by raising the ambient temperature.

Video caption: The short video above shows a metal ball dropping onto a very thin sheet of hydrogel without rupturing it.

The researchers' combined expertise in mechanics, materials science, and bioengineering enabled the group to apply two concepts from mechanics -- crack bridging and energy dissipation -- to a new problem.

"The unusually high stretchability and toughness of this gel, along with recovery, are exciting," says Suo. "Now that we've demonstrated that this is possible, we can use it as a model system for studying the mechanics of hydrogels further, and explore various applications."

"It's very promising," Suo adds.

Beyond artificial cartilage, the researchers suggest that the new hydrogel could be used in soft robotics, optics, artificial muscle, as a tough protective covering for wounds, or "any other place where we need hydrogels of high stretchability and high toughness."

Published October 2012

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