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What's a SLIC Pin^®? Pin and cotter all in one!

The SLIC Pin (Self-Locking Implanted Cotter Pin) from Pivot Point is a pin and cotter all in one. This one-piece locking clevis pin is cost saving, fast, and secure. It functions as a quick locking pin wherever you need a fast-lock function. It features a spring-loaded plunger that functions as an easy insertion ramp. This revolutionary fastening pin is very popular and used successfully in a wide range of applications.
Learn more.

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.
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Full-color 3D-printing Design Guide from Xometry

With Xometry's PolyJet 3D-printing service, you can order full-color 3D prints easily. Their no-cost design guide will help you learn about different aspects of 3D printing colorful parts, how to create and add color to your models, and best practices to keep in mind when printing in full color. Learn how to take full advantage of the 600,000 unique colors available in this flexible additive process.
Get the Xometry guide.

Tech Tip: How to create high-quality STL files for 3D prints

Have you ever 3D printed a part that had flat spots or faceted surfaces where smooth curves were supposed to be? You are not alone, and it's not your 3D printer's fault. According to Markforged, the culprit is likely a lack of resolution in the STL file used to create the part.
Read this detailed and informative Markforged blog.

Test your knowledge: High-temp adhesives

Put your knowledge to the test by trying to answer these key questions on how to choose the right high-temperature-resistant adhesive. The technical experts from Master Bond cover critical information necessary for the selection process, including questions on glass transition temperature and service temperature range. Some of the answers may surprise even the savviest of engineers.
Take the quiz.

Engineer's Toolbox: How to pin a shaft and hub assembly properly

One of the primary benefits of using a coiled spring pin to affix a hub or gear to a shaft is the coiled pin's ability to prevent hole damage. Another is the coiled pin absorbs wider hole tolerances than any other press-fit pin. This translates to lower total manufacturing costs of the assembly. However, there are a few design guidelines that must be adhered to in order to achieve the maximum strength of the pinned system and prevent damage to the assembly.
Read this very informative SPIROL article.

What's new in Creo Parametric 11.0?

Creo Parametric 11.0 is packed with productivity-enhancing updates, and sometimes the smallest changes make the biggest impact in your daily workflows. Mark Potrzebowski, Technical Training Engineer, Rand 3D, runs through the newest functionality -- from improved surface modeling tools to smarter file management and model tree navigation. Videos provide extra instruction.
Read the full article.

What's so special about wave springs?

Don't settle for ordinary springs. Opt for Rotor Clip wave springs. A wave spring is a type of flat wire compression spring characterized by its unique waveform-like structure. Unlike traditional coil springs, wave springs offer an innovative solution to complex engineering challenges, producing forces from bending, not torsion. Their standout feature lies in their ability to compress and expand efficiently while occupying up to 50% less axial space than traditional compression springs. Experience the difference Rotor Clip wave springs can make in your applications today!
View the video.

New Standard Parts Handbook from JW Winco

JW Winco's printed Standard Parts Handbook is a comprehensive 2,184-page reference that supports designers and engineers with the largest selection of standard parts categorized into three main groups: operating, clamping, and machine parts. More than 75,000 standard parts can be found in this valuable resource, including toggle clamps, shaft collars, concealed multiple-joint hinges, and hygienically designed components.
Get your Standard Parts Handbook today.

Looking to save space in your designs?

Watch Smalley's quick explainer video to see how engineer Frank improved his product designs by switching from traditional coil springs to compact, efficient wave springs. Tasked with making his products smaller while keeping costs down, Frank found wave springs were the perfect solution.
View the video.

Top die casting design tips

You can improve the design and cost of your die cast parts with these top tips from Xometry's Joel Schadegg. Topics include: Fillets and Radii, Wall Thicknesses, Ribs and Metal Savers, Holes and Windows, Parting Lines, and more. Follow these recommendations so you have the highest chance of success with your project.
Read the full Xometry article.

What's the latest from 3D Systems? Innovations for different industries, processes

3D Systems unveiled several new solutions at the RAPID+TCT 2025 show in April designed to change the way industries innovate. From new 3D printers and materials for high-mix, low-volume applications to marked improvements in how investment casting can be done, learn what is the state of the art from the original inventors of 3D printing.
Read the full article.

Clever! Indexing plungers with chamfered pins

JW Winco has developed a new type of indexing plunger -- GN 824 -- that can independently latch into edges and grooves. This is made possible by a chamfered plunger pin. When the chamfered pin encounters a raised latching geometry, it retracts and then springs back out again once it reaches the latching point. This new indexing plunger can be ordered with axial thread for fastening and a black plastic knob for operating the indexing plunger. In a clever design, the plunger pin can be adjusted by 360 degrees to ensure that it encounters the mating surface perpendicularly. This hardware is well suited for transport frames, mechanisms, or covers that need to be locked in place quickly and securely, especially without the need for manual intervention.
Learn more.

Drones relay RFID signals for inventory control

A new system developed by MIT researchers enables small, safe aerial drones to read RFID tags in large warehouses at a distance of several meters.

 

 

By Larry Hardesty, MIT

Radio frequency ID tags were supposed to revolutionize supply chain management. The dirt-cheap, battery-free tags, which receive power wirelessly from scanners and then broadcast identifying numbers, enable warehouse managers to log inventory much more efficiently than they could by reading box numbers and recording them manually.

But the scale of modern retail operations makes even radio frequency ID (RFID) scanning inefficient. Walmart, for instance, reported that in 2013 it lost $3 billion in revenue because of mismatches between its inventory records and its stock. Even with RFID technology, it can take a single large retail store three months to perform a complete inventory review, which means that mismatches often go undiscovered until exposed by a customer request.

MIT researchers have now developed a system that enables small, safe aerial drones to read RFID tags from tens of meters away while identifying the tags' locations with an average error of about 19 cm. The researchers envision that the system could be used in large warehouses for both continuous monitoring, to prevent inventory mismatches, and location of individual items, so that employees can rapidly and reliably meet customer requests.

The central challenge in designing the system was that, with the current state of autonomous navigation, the only drones safe enough to fly within close range of humans are small, lightweight drones with plastic rotors, which wouldn't cause injuries in the event of a collision. But those drones are too small to carry RFID readers with a range of more than a few centimeters.

The researchers met this challenge by using the drones to relay signals emitted by a standard RFID reader. This not only solves the safety problem but also means that drones could be deployed in conjunction with existing RFID inventory systems, without the need for new tags, readers, or reader software.

"Between 2003 and 2011, the U.S. Army lost track of $5.8 billion of supplies among its warehouses," says Fadel Adib, the Sony Corporation Career Development Assistant Professor of Media Arts and Sciences, whose group at the MIT Media Lab developed the new system. "In 2016, the U.S. National Retail Federation reported that shrinkage -- loss of items in retail stores -- averaged around $45.2 billion annually. By enabling drones to find and localize items and equipment, this research will provide a fundamental technological advancement for solving these problems."

VIDEO: RFly: Drones that find missing objects using battery-free RFIDs.

The MIT researchers describe their system, dubbed RFly, in a paper they presented at the end of August at the annual conference of the Association for Computing Machinery's Special Interest Group on Data Communications. Adib is the senior author on the paper, and he's joined by Yunfei Ma, a postdoc in the Media Lab, and Nicholas Selby, an MIT graduate student in mechanical engineering.

Phase shift
Relaying RFID signals and using them to determine tags' locations poses some thorny signal-processing problems. One is that, because the RFID tag is powered wirelessly by the reader, the reader and the tag transmit simultaneously at the same frequency. A relay system adds another pair of simultaneous transmissions: two between the relay and the tag and two between the relay and the reader. That's four simultaneous transmissions at the same frequency, all interfering with each other.

This problem is compounded by the requirement that the system determine the location of the RFID tag. The location-detection -- or "localization" -- system uses a variation on a device called an antenna array. If several antennas are clustered together, a signal broadcast toward them at an angle will reach each antenna at a slightly different time. That means that the signals detected by the antennas will be slightly out of phase: The troughs and crests of their electromagnetic waves won't coincide perfectly. From those phase differences, software can deduce the angle of transmission and thus the location of the transmitter.

The drone is too small to carry an array of antennas, but it is continuously moving, so readings it takes at different times are also taken at different locations, simulating the multiple antenna elements of an array.

Ordinarily, to combat interference, the drone would digitally decode the transmission it receives from the tag and re-encode it for transmission to the reader. But in this case, the delays imposed by the decoding-encoding process would change the signals' relative phases, making it impossible to accurately gauge location.

All radio systems encode information by modulating a base transmission frequency, usually by shifting it slightly up and down. But because an RFID tag has no independent power source, its modulations are detectably smaller than those of the reader. So the MIT researchers devised an analog filter that would subtract the base transmission frequency from the signals that reach the reader and then separate the low-frequency and high-frequency components. The low-frequency component -- the signal from the tag -- is then added back onto the base frequency.

Frame of reference
At this point, however, another problem still remains. Because the drone is moving, the phase shift of the signals that reach the reader result from not only the drone's position relative to the RFID tag but also its position relative to the reader. On the basis of the received signal alone, the reader has no way to tell how much each of those two factors contributed to the total phase shift.

So the MIT researchers also equip each of their drones with its own RFID tag. A drone alternates between relaying the reader's signal to a tagged item and simply letting its own tag reflect the signal back, so that the reader can estimate the drone's contribution to the total phase shift and remove it.

In experiments in the Media Lab that involved tagged objects, many of which were intentionally hidden to approximate the condition of merchandise heaped in piles on warehouse shelves, the system was able to localize the tags with 19-cm accuracy while extending the range of the reader tenfold in all directions, or one hundredfold cumulatively. The researchers are currently conducting a second set of experiments in the warehouse of a major Massachusetts retailer.

"Relays have been used in communications for a long time, even to bring networks to rural areas," says Swarun Kumar, an assistant professor of electrical and computer engineering at Carnegie Mellon University. "What changes here is that one of the ends is battery-free, and they want to location-track the battery-free device, which requires phase-consistent measurements. These together make the problem quite challenging. That's what I think is the conceptual novelty in this work. I anticipate that there might be a lot more applications than the inventory tracking problem -- which in and of itself is quite important."

Published October 2017

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