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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.
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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.
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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!
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New way to make wet suits better: 'Artificial blubber' protects divers in frigid water

By David Chandler, MIT

When Navy SEALs carry out dives in Arctic waters, or when rescue teams are diving under ice-covered rivers or ponds, the survival time even in the best wetsuits is very limited -- as little as tens of minutes, and the experience can be extremely painful at best. Finding ways of extending that survival time without hampering mobility has been a priority for the U.S. Navy and research divers, as a pair of MIT engineering professors learned during a recent program that took them to a variety of naval facilities.

That visit led to a two-year collaboration that has now yielded a dramatic result: a simple treatment that can improve the survival time for a conventional wetsuit by a factor of three, the scientists say.

The findings, which could be applied immediately, were reported recently in the journal RSC Advances, in a paper by Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering; Jacopo Buongiorno, the TEPCO Professor and associate head of the Department of Nuclear Science and Engineering; and five others at MIT and George Mason University.

The process they discovered works by simply placing the standard neoprene wetsuit inside a pressure tank autoclave no bigger than a beer keg, filled with a heavy inert gas, for about a day. The treatment then lasts for about 20 hours, far longer than anyone would spend on a dive, explains Buongiorno, who is an avid wetsuit user himself. The process could also be done in advance, with the wetsuit placed in a sealed bag to be opened just before use, he says.

From left, graduate student Anton Cottrill, Professor Jacopo Buongiorno, and Professor Michael Strano try out their neoprene wetsuits at a pool at MIT's athletic center. Cottrill is holding the pressure tank used to treat the wetsuits with xenon or krypton. [Photo: Susan Young]

 

 

 

 

Though Buongiorno and Strano are both on the MIT faculty, they had never met until they were both part of the Defense Science Study Group for the Department of Defense. "We got to visit a lot of bases and met with all kinds of military people up to four-star generals," says Buongiorno, whose specialty in nuclear engineering has to do with heat transfer, especially through water. They learned about the military's particular needs and were asked to design a technological project to address one of those needs. After meeting with a group of Navy SEALs, the elite special-operations diving corps, they decided the need for longer-lasting protection in icy waters was one that they could take on.

They looked at the different strategies that various animals use to survive in these frigid waters and found three types: air pockets trapped in fur or feathers, as with otters and penguins; internally generated heat, as with some animals and fish (including great white sharks, which, surprisingly, are warm-blooded); or a layer of insulating material that greatly slows heat loss from the body, as with seals' and whales' blubber.

In the end, after simulations and lab tests, they ended up with a combination of two of these -- a blubber-like insulating material that also makes use of trapped pockets of gas, although in this case the gas is not air but a heavy inert gas, namely xenon or krypton.

The material that has become standard for wetsuits is neoprene, an inexpensive material that is a mix of synthetic rubber materials processed into a kind of foam, producing a closed-cell structure similar to styrofoam. Trapped within that structure, occupying more than two-thirds of the volume and accounting for half of the heat that gets transferred through it, are pockets of air.

Strano and Buongiorno found that if the trapped air is replaced with xenon or krypton, the material's insulating properties increase dramatically. The result, they say, is a material with the lowest heat transfer of any wetsuit ever made. "We set a world record for the world's lowest thermal conductivity garment," Strano says -- conductivity almost as low as air itself. "It's like wearing a coat of air."

They found this could improve survivability in water colder than 10 deg C, raising it from less than one hour to two or three hours.

The result could be a boon not just to those in the most extreme environments, but to anyone who uses wetsuits in cold waters, including swimmers, athletes, and surfers, as well as professional divers of all kinds.

Holes in a wetsuit reveal the thickness of the neoprene material. The new MIT-developed treatment could provide the same amount of insulation with just half the thickness, the researchers say. [Photo: Susan Young]

 

 

 

 

"As part of this project, I interviewed dozens of wetsuit users, including a professional underwater photographer, divers working at the New England Aquarium, a Navy SEAL friend of mine, and random surfers I approached on a San Diego beach," says co-author and former MIT postdoc Jeffrey Moran PhD '17, who is now an assistant professor at George Mason University. "The feedback was essentially unanimous -- there is an urgent need for warmer wetsuits, both in and out of the Arctic. People's eyes lit up when I told them about our results."

Currently, the only viable cold-water alternatives to wetsuits are dry suits, which have a layer of air between the suit and the skin that must be maintained using a hose and a pump, or a warm-water suit, which similarly requires a hose and pump connection. In either case, a failure of the pump or a cut or tear in the suit can result is a quick loss of insulation that can be life threatening within minutes.

But the xenon- or krypton-infused neoprene requires no such support system and has no way of quickly losing its insulating properties, and so does not carry that risk. "We can take anyone's neoprene wetsuit and pressurize it with xenon or krypton for high-performance operations," Strano says. MIT graduate student Anton Cottrill, a co-author of the paper, adds, "The gas actually infuses more quickly during treatment than it discharges during its use in an aquatic environment."

Another possibility, they say, is to produce a wetsuit with the same insulating properties as present ones, but with a small fraction of the thickness, allowing more comfort and freedom of movement that might be appealing to athletes. "Almost everyone I interviewed also said they wanted a wetsuit that was easier to move around in and to put on and take off," says Moran. "The results of this project suggest that we could make wetsuits that provide the same thermal insulation as traditional ones, but are about half as thick."

One next step in their research is to look at ways of making a long-term, stable version of a xenon-infused neoprene, perhaps by bonding a protective layer over it, they say. In the meantime, the team is also looking for opportunities to treat the neoprene garments of interested users so that they can collect performance data.

"Their approach to the problem is a remarkable feat of materials science and also very clever engineering," says John Dabiri, a professor of civil and environmental engineering and of mechanical engineering at Stanford University, who was not involved in this work. "They've managed to achieve something close to an ideal air-like thermal barrier, and they've accomplished this using materials that are more compatible with end-uses like scuba diving than previous concepts. The overall performance characteristics could be a game-changer for a variety of applications."

And Charles Amsler, a professor of biology at the University of Alabama at Birmingham, who has made almost 950 research dives in Antartica but was not connected with this research, says, "It could be very beneficial in cases where flexibility, lack of bulkiness, swimming speed, or reduced drag with diver propulsion vehicles are at a premium, or where environmental hazards make the chance of dive suit puncture high. Normally, diver thermal protection in very cold water is by use of dry suits rather than wetsuits. But wetsuits typically allow much more diver flexibility."

Amsler adds, "One concern with drysuits is that ... should the suit be badly punctured, a diver loses much or all of that insulation. ... In a deep or long-duration dive where staged decompression would be required to prevent decompression illness ("the bends"), wearing one of these thermally enhanced wetsuits would significantly reduce the chance that a diver with a punctured suit would have to make the choice between potentially fatal hypothermia and potentially debilitating or fatal decompression illness."

Published July 2018

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