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How ball spline coatings enhance performance and extend component life

According to Thomson, "Precision ball splines have gained popularity as an ideal choice for applications that require low-friction linear and rotary motion. These components, which utilize a single splined shaft, enable complex movements in multiple directions." But how do you keep these ball splines performing at their peak for longer? Coatings can do the trick, and Thomson has three of them: black oxide, hard chrome plating, and nickel plating. Learn more about these coatings and which one makes the most sense for your precision ball spline solution.
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Key factors for ball screw applications

Learn the six key factors that should be considered when specifying ball screw assemblies in motion control applications. PCB Linear gathered a panel of experts in the field of linear motion to concentrate on this important topic -- particularly when it comes to the company's new miniature ball screw product line. Learn about precision and accuracy, orientation, speed and acceleration, duty cycle, linear motion travel, and load capacity. Podcast available too.
Read the PCB Linear blog.

3D printer uses pellet extrusion system instead of filament

The latest addition to 3D Systems' industry-leading portfolio of EXT Titan Pellet systems is the EXT 800 Titan Pellet. With a build volume of 800 x 600 x 800 mm, this thermoplastics 3D printer harnesses the speed, reliability, and efficiency of the company's large-format pellet systems in a more compact unit with lower upfront investment. Use this machine to fabricate more modestly sized functional prototypes, tooling, fixtures, sand casting patterns, thermoforming molds, and end-use parts. Markedly faster than competing FFF and FDM printers, and up to 10X reduced material costs compared to filaments.
Learn more.

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.

World's first current-carrying fastening technology

PEM^® eConnect™ current-carrying pins from Penn-Engineering provide superior electrical connections in applications that demand high performance from internal components, such as automotive electronics. This first-to-market tech provides repeatable, consistent electrical joints and superior installation unmatched by traditional fastening methods. Features include quick and secure automated installation, no hot spots or poor conductivity, and captivation options that include self-clinching and broaching styles.
Learn more about eConnect pins.

New flat quarter-turn clamping fastener

IMAO Fixtureworks has expanded its One-Touch Fastener lineup to include a new quarter-turn clamping fastener that features an innovative flat design and is ideal for clamping in limited spaces. The QCFC flat quarter-turn fastener features a recessed body that protrudes only 2 mm from the mounted surface, a knob that rests flush inside the body, visible ON and OFF markings for safety, and an audible click when fully turned to clamped or unclamped position.
Learn more.

Bellows and disc couplings with higher torque capacity

Ruland Manufacturing now offers bellows and double disc couplings with bore sizes up to 1-3/4 in. or 45 mm for use in systems with torque up to 1,400 in.-lb (158 Nm). High-torque applications in precision semiconductor, solar, conveyor, and factory automation applications often use these shaft sizes. Ruland disc and bellows couplings accommodate all forms of misalignment, are zero-backlash, and have a balanced design for reduced vibration at speeds up to 10,000 rpm.
Learn more.

Simplify your designs with slewing ring bearings

According to Kaydon Bearings, "A slewing ring bearing has rolling elements designed to create a reactive moment within the bearing's dimensions envelope to oppose applied (overturning) moment load," so you can use one bearing instead of two, reducing the height requirements, and even improve performance. Slewing ring bearings can also simplify a drive system by utilizing gear teeth on the inner or outer race. Learn all about slewing ring bearings in this informative article.
Read the Kaydon whitepaper.

Jet valve for ultra-small dispensing

DELO's DELO-DOT PN5 LV pneumatic jet valve is designed for micro-dispensing low-viscosity adhesives and other media in miniaturized applications. Thanks to its compact design, it also requires very little space to install in production systems. Interchangeable nozzles with different diameters and a flexible, adjustable plunger stroke ensure precise and reliable applications at different droplet sizes. Volumes of as low as 1 nl can be achieved, which corresponds to droplet diameters of 250 µm or less.
Learn more.

Stainless steel constant-torque flush-mount hinge

Southco has introduced a flush-mount version of its popular and durable E6 constant-torque hinge. Its low-profile, corrosion-resistant package makes it an ideal solution for maximizing security, longevity, and aesthetics. It offers high torque for demanding applications while maintaining its low profile. Lots of uses.
Learn more.

Claw vacuum pump for industrial applications

Vacuum expert Leybold has added a new model to its proven CLAWVAC dry claw vacuum pump series: the CLAWVAC CP B. This innovative, rough vacuum pump, designed for robust processes including food processing, material handling, and environmental industries, is powerful, energy efficient, and easy to clean. The intuitive handling of this unit is mainly due to its functional design, which features a pair of claws that rotate in the cylinder with no contact or wear. Its separate gearbox prevents oil contamination. The design ensures short downtimes and long service intervals: 20,000 hr between oil changes and up to 48,000 hr between general overhauls.
Learn more.

DualVee linear guides and tracks used in warehousing

See how Bishop-Wisecarver's DualVee^® motion tech can add huge benefits to warehousing operations. This video highlights two applications: a manual storage and retrieval system and an automated storage and retrieval system of long aerospace-grade carbon fiber in sub-zero temps. Patented DualVee guides and tracks keep operations running smoothly.
View the video.

Build-to-order knobs and hand hardware

Rogan Corp.'s innovative use of two-shot plastic injection and insert molding has been providing customers with high-quality plastic clamping knobs, levers, and control knobs for almost 90 years. Rogan offers concurrent engineering, product design, and assistance in material selection to ensure customer satisfaction for standard or customized parts, with a focus on cost optimization and on-time delivery. Custom colors, markings, decorative inlays, or engineered materials to meet special requirements, such as adding extra strength or utilizing flame-retardant material, are all offered.
Learn more.

Slewing ring bearing made of wood and plastic

The PRT-02-30-WPC slewing ring bearing is another step forward by igus toward integrating renewable raw materials into industrial production. Made of 50% wood and 50% high-performance plastics, the cost-effective and lubrication-free slewing ring bearing balances strength and durability with a proven low CO2 footprint. The materials incorporate solid lubricants, making the new slewing ring bearing smooth running and maintenance-free.
Learn more.

Flex Locators for quick fixture changeover

Flex Locators from Fixtureworks are designed for quick changeover of small and large fixtures, automation components, and more. They are ideal for applications that require frequent disassembly, providing excellent repeatability for locating and clamping in a single operation. Manual and pneumatic versions are available. Just turn the handle, knob, or screw!
View the video.

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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