July 05, 2016 Volume 12 Issue 25

Mechanical News & Products

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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.
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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.
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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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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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New torque inserts provide design flexibility

Reell's TI-330 torque insert completes the gap in torque range between the TI-320 and TI-340 models in the TI-300 series, providing enhanced design flexibility for a wider range of applications. With torque options ranging from 1.0 to 2.5 Nm, the TI-330 features a powdered metal package configuration designed to be press-fit into round holes for quick and easy installation. Mounting profile options include exposed knurled shaft end and a knurled zinc adapter for installation into plastics.
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Superior fastening solution for securing rotating components to a shaft

SDP/SI Shaftloc® fasteners offer distinct advantages over other fastening methods when securing rotating components to a shaft. The key to this compact, efficient design is its asymmetric thread geometry that produces a greater clamping force -- outperforming other fastening methods. Shaftloc is a patented fastening system manufactured by SDP/SI.
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Great design: Handle with integrated lighting/signaling

Signaling and indicator lights, switches, and buttons -- elements that hardly any machine can do without. The new JW Winco cabinet U-handle EN 6284 integrates all these functions into a single, compact element. The new U-handle is designed to enhance the operation of systems and machines. It features an integrated button and a large, colored, backlit area on the back of the handle. These elements can be used individually or in combination, providing a versatile tool for system control and process monitoring that can be seen from across the room.
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SOLIDWORKS: FeatureManager tips for assemblies

Discover tools to make your SOLIDWORKS assembly Feature-Manager design tree display easier to view and use. Learn options to limit the amount of information in each component listing, combine multiple instances of a component into a single listing, and separate fasteners mates into a new folder. Lots more tips on the SOLIDWORKS YouTube channel.
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Top die casting design tips: Xometry

Optimize your die casting project's manufac-turability with these 23 top design tips from Xometry. Ensure your work is cost effective too, so you can hit the ground running and have the highest chance of success. Tips include: fillets and radii, wall thicknesses, ribs and metal savers, holes and windows, parting lines, finishes, and more.
Read the Xometry article.


8 top ways to wreck your coupling-driven system

Engineers at Ruland Manufacturing Co. have compiled the eight best ways to consistently sabotage or damage your coupling-driven system -- and how to avoid these pitfalls in the future. Misunderstanding performance criteria such as misalignment, torque, or rpm can be all it takes to cause a critical and costly failure.
Read the full article.


New washer tech for leak-free automotive sealing

Trelleborg Sealing Solutions has just launched the Rubore® Washer, a unique solution offering virtually leak-free sealing beneath screwheads to safeguard critical systems in vehicles, especially electric ones.
Read the full article.


How Reell electric wrap spring clutches work

Electric wrap spring clutches are ideally suited for critical timing applications requiring consistent, repeatable engagement and disengagement performance. Wrap spring technology used in Reell clutches provides the capability to transmit a large amount of torque in a small size -- package sizes smaller than other clutch technologies such as friction disk, tooth, or magnetic particle. Reell's technology has very positive engagement characteristics and also limits the effects of wear.
Read this informative Reell article.


New 'breathable' rupture disk tech provides overpressure and vacuum relief

To increase equipment safety and reliability, a new rupture disk technology activates at a set burst pressure, but it can also "breathe" to relieve minor pressure fluctuations. The patent-pending, dual-function device from BS&B Safety Systems is ideal for use on low-pressure vessels that are susceptible to ambient temperature changes.
Read the full article.


Engineer's Toolbox: 9 considerations for specifying a slewing ring bearing

In applications that require a bearing to support a structure while it rotates (e.g., cranes, radar, tank turrets), premature bearing failure can put people and equipment at risk. While slewing ring bearings have proven themselves countless times in such applications, designers must consider many factors when specifying them. According to engineers at Kaydon, the bearing's support structure, mounting (including bolt strength, tensioning, and hole patterns), installation, and even storage are all factors in a bearing's success or failure.
Read the full article.


ClampDisk micro fastener is new alternative for automotive and consumer electronics

Designed as a unique alternative in assemblies for the automotive and consumer electronics markets, the ClampDisk Press-on Fastener is a new offering from PennEngineering that delivers a fast, simple way to achieve sheet-to-sheet clamped fastening while replacing the use of standard screws, nuts, and adhesives. The most common challenges that can be eliminated or reduced by using ClampDisk include over installation, cross threading, stripped screw heads, broken screws, and damaged product. This fastener can be removed easily with a sharp-edged tool.
Learn more and see how ClampDisk works.


A metal that behaves like water: Graphene exhibits out-of-this-world characteristics

In a new paper published in Science, researchers at the Harvard and Raytheon BBN Technology have advanced our understanding of graphene's basic properties, observing for the first time electrons in a metal behaving like a fluid. [Credit: Peter Allen/Harvard SEAS]

 

 

 

 

Graphene is going to change the world -- or so we've been told.

Since its discovery a decade ago, scientists and tech gurus have hailed graphene as the wonder material that could replace silicon in electronics, increase the efficiency of batteries, the durability and conductivity of touch screens, and pave the way for cheap thermal electric energy, among many other things.

It's one atom thick, stronger than steel, harder than diamond, and one of the most conductive materials on Earth.

But, several challenges must be overcome before graphene products are brought to market. Scientists are still trying to understand the basic physics of this unique material. Also, it's very challenging to make -- and even harder to make without impurities.

In a new paper published in Science, researchers at the Harvard and Raytheon BBN Technology have advanced our understanding of graphene's basic properties, observing for the first time electrons in a metal behaving like a fluid.

In order to make this observation, the team improved methods to create ultra-clean graphene and developed a new way to measure its thermal conductivity. This research could lead to novel thermoelectric devices as well as provide a model system to explore exotic phenomena like black holes and high-energy plasmas.

This research was led by Philip Kim, professor of physics and applied physics in the John A. Paulson School of Engineering and Applied Sciences (SEAS).

An electron super highway
In ordinary, three-dimensional metals, electrons hardly interact with each other. But graphene's two-dimensional, honeycomb structure acts like an electron superhighway in which all the particles have to travel in the same lane. The electrons in graphene act like massless relativistic objects, some with positive charge and some with negative charge. They move at incredible speed -- 1/300 the speed of light -- and have been predicted to collide with each other 10 trillion times a second at room temperature. These intense interactions between charged particles have never been observed in an ordinary metal before.

The team created an ultra-clean sample by sandwiching the one-atom thick graphene sheet between tens of layers of an electrically insulating perfect transparent crystal with a similar atomic structure of graphene.

"If you have a material that's one atom thick, it's going to be really affected by its environment," said Jesse Crossno, a graduate student in the Kim Lab and first author of the paper. "If the graphene is on top of something that's rough and disordered, it's going to interfere with how the electrons move. It's really important to create graphene with no interference from its environment."

The technique was developed by Kim and his collaborators at Columbia University before he moved to Harvard in 2014 and now have been perfected in his lab at SEAS.

Next, the team set up a kind of thermal soup of positively charged and negatively charged particles on the surface of the graphene, and observed how those particles flowed as thermal and electric currents.

What they observed flew in the face of everything they knew about metals.

A black hole on a chip
Most of our world -- how water flows (hydrodynamics) or how a curve ball curves -- is described by classical physics. Very small things, like electrons, are described by quantum mechanics, while very large and very fast things, like galaxies, are described by relativistic physics, pioneered by Albert Einstein.

Combining these laws of physics is notoriously difficult, but there are extreme examples where they overlap. High-energy systems like supernovas and black holes can be described by linking classical theories of hydrodynamics with Einstein's theories of relativity.

But it's difficult to run an experiment on a black hole. Enter graphene.

When the strongly interacting particles in graphene were driven by an electric field, they behaved not like individual particles but like a fluid that could be described by hydrodynamics.

"Instead of watching how a single particle was affected by an electric or thermal force, we could see the conserved energy as it flowed across many particles, like a wave through water," said Crossno.

"Physics we discovered by studying black holes and string theory, we're seeing in graphene," said Andrew Lucas, co-author and graduate student with Subir Sachdev, the Herchel Smith Professor of Physics at Harvard. "This is the first model system of relativistic hydrodynamics in a metal."

Moving forward, a small chip of graphene could be used to model the fluid-like behavior of other high-energy systems.

Industrial implications
So we now know that strongly interacting electrons in graphene behave like a liquid -- how does that advance the industrial applications of graphene?

First, in order to observe the hydrodynamic system, the team needed to develop a precise way to measure how well electrons in the system carry heat. It's very difficult to do, said co-PI Dr. Kin Chung Fong, scientist with Raytheon BBN Technology.

Materials conduct heat in two ways: through vibrations in the atomic structure or lattice; and carried by the electrons themselves.

"We needed to find a clever way to ignore the heat transfer from the lattice and focus only on how much heat is carried by the electrons," Fong said.

To do so, the team turned to noise. At finite temperature, the electrons move about randomly: the higher the temperature, the noisier the electrons. By measuring the temperature of the electrons to three decimal points, the team was able to precisely measure the thermal conductivity of the electrons.

"Converting thermal energy into electric currents and vice versa is notoriously hard with ordinary materials," said Lucas. "But in principle, with a clean sample of graphene there may be no limit to how good a device you could make."

Source: Harvard John A. Paulson School of Engineering and Applied Sciences

Published February 2016

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