May 14, 2024 Volume 20 Issue 18

Mechanical News & Products

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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.
View the video.

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.

New nylon constant torque hinge

Southco has expanded its line of E6 Constant Torque Hinges with a compact, nylon version designed for small applications. The newest addition to the company's E6 50 Constant Torque Position Control Hinge series measures 45 mm with a torque range of 4 to 16 in./lb and is 65% lighter compared to the standard E6 50 Hinge. It provides constant resistance throughout the entire range of motion, enabling users to easily position doors, display screens, and other mounted components and hold them securely at any desired angle.
Learn more.

What injection molding material do I use?

How do you decide what type of plastic to use for your next injection molding project? Xometry can help you narrow your choices. Discover the different strengths and applications for materials that could be ideal for your application by learning about the most common plastic injection molding materials in detail.
Read this detailed Xometry article.

What are carbon composite bellows springs?

The Carbon Composite Bellows Spring (CCBS) from MW Components is a system of carbon fiber elements that combine to work as a high-performance, lightweight, and design-flexible compression spring meant to replace coil springs or metallic Belleville disc springs. A functional spring is made from several individual elements paired and joined to make a stack. The stack spring rate is determined by the number of elements, the base rate of each element, and their series or parallel orientation in the stack. Applications include motorsports, aerospace, and high-performance activities.
Learn more.

Conductive Brush Ring overcomes current leakage in EV powertrains

SKF's new Conductive Brush Ring paves the way to greater reliability and longer life in high-performance electric vehicle powertrain systems. Using pure carbon fiber bristles, it provides a reliable electrical connection between an EV eAxle rotor shaft and its housing. When used in combination with SKF Hybrid ceramic ball bearings, it helps to alleviate parasitic current effects that can lead to premature failure in bearings and other components. Available in different configurations for wet (oil-lubricated) motor designs -- and soon for dry (sealed) applications.
Learn more.

hyperMILL 2024 CAD/CAM software suite

OPEN MIND Technologies has introduced its latest hyperMILL 2024 CAD/CAM software suite, which includes a range of powerful enhancements to its core toolpath capabilities, as well as new functionality for increased NC programming efficiency in applications ranging from 2.5D machining to 5-axis milling. New and enhanced capabilities include: Optimized Deep Hole Drilling, a new algorithm for 3- and 5-axis Rest Machining, an enhanced path layout for the 3D Plane Machining cycle, better error detection, and much more.
Learn more.

One-part epoxy changes from red to clear under UV

Master Bond UV15RCL is a low-viscosity, cationic-type UV-curing system with a special color-changing feature. The red material changes to clear once exposed to UV light, indicating that there is UV light access across the adhesive material. Although this change in color from red to clear does not indicate a full cure, it does confirm that the UV light has reached the polymer. This epoxy is an excellent electrical insulator. UV15RCL adheres well to metals, glass, ceramics, and many plastics, including acrylics and polycarbonates.
Learn more.

SPIROL Press-N-Lok™ Pin for plastic housings

The Press-N-Lok™ Pin was designed to permanently retain two plastic components to each other. As the pin is inserted, the plastic backfills into the area around the two opposing barbs, resulting in maximum retention. Assembly time is quicker, and it requires lower assembly equipment costs compared to screws and adhesives -- just Press-N-Lok™!
Learn more about the new Press-N-Lok™ Pin.

Like Spider-Man: Scientists develop super strong yet reusable adhesive from smart materials

Scientists from Nanyang Technological University, Singapore (NTU Singapore) have developed a smart, reusable adhesive more than 10 times stronger than a gecko's feet adhesion, pointing the way for development of reusable superglue and grippers capable of holding heavy weights across rough and smooth surfaces.

The NTU research team, led by Professor K Jimmy Hsia, found a way to maximize the adhesion of the smart adhesives by using shape-memory polymers, which can stick and detach easily when needed simply by heating them.

Writing last month in the scientific journal National Science Review, the team details their breakthrough in adhesion by designing the shape-memory polymer material in the shape of hair-like fibrils.

This smart adhesive can support extremely heavy weights, opening new possibilities for robotic grippers that allow humans to scale walls effortlessly, or climbing robots that can cling onto ceilings for survey or repair applications.

VIDEO:Scientists from NTU Singapore have developed a smart, reusable adhesive more than 10 times stronger than a gecko's feet adhesion. [Credit: NTU Singapore]

"This research is based on a fundamental understanding of the mechanisms of adhesion forces on rough surfaces. It can help us develop very strong, yet easily detachable, adhesives adaptable to rough surfaces," said Professor Hsia, President's Chair in Mechanical Engineering, NTU School of Mechanical & Aerospace Engineering (MAE) and School of Chemistry, Chemical Engineering and Biotechnology. "The technology will be very useful in adhesive grippers and climbing robots and might one day let humans climb walls like a real-life Spider-Man."

It's rubber, it's glue; it remembers its shape and clings on to you
Shape-memory polymers are materials that can hold "memories" of their previous form and return to their original shape after they have been deformed by applying external stimuli such as heat, light, or electrical current. These properties make them ideal to be used as switchable adhesives that can adapt to various surfaces.

In their testing, the researchers used a shape-memory polymer named E44 epoxy, a stiff and glass-like plastic at room temperature. Upon heating, the material turns into a soft rubber-like state that can conform and lock onto microscopic nooks and crevices. As it cools, it becomes glassy, creating extra-strong adhesive bonds due to a shape-locking effect.

When the material is reheated, it reverts to its rubbery state so it can be pulled away and easily detached from the surface it was clinging to.

The researchers found the most effective adhesion came from designing the shape-memory polymer into an array of hair-like fibrils. Each fibril had to be carefully designed -- larger fibrils had weaker adhesion, while the smaller fibrils were hard to fabricate and prone to collapse and degradation. The sweet spot was between 0.5 mm and 3 mm in radius, pushing the limits of adhesion while retaining structural integrity.

In their experiments, the researchers found that one fibril with a 19.6 mm2 cross-section could support loads up to 1.56 kg. Every additional fibril allows for more weight to be supported. A palm-sized array of 37 fibrils weighing about 30 g can hold a weight of 60 kg -- an adult human's weight.

The research paper's first author, NTU Research Fellow Dr. Linghu Changhong, said, "Our smart adhesive exemplifies how shape-memory polymers can maintain and even enhance adhesion as surface roughness increases. This overcomes the 'adhesion paradox,' which scientists have been puzzling over, where there is a decrease in adhesion strength on rough surfaces despite having more surface area for molecules to adhere to. Our tests showed that adhesion strength of the polymer increases along with surface roughness when in a solid state and decreases when in the rubbery state."

Co-corresponding author Professor Gao Huajian, formerly a Distinguished University Professor from NTU's School of MAE and currently the Xinghua University Professor at Tsinghua University, said: "For practical gripping purposes, the adhesive needs to be strong enough to stick onto a surface, yet also easily detach when needed. Switching between the two modes is vital for practical applications. Stronger adhesives can support heavier loading but tend to be harder to detach -- this is what we call a 'switchability conflict.' Our research into shape-memory polymers has resulted in an adhesive that can easily harden to stick onto surfaces, and just as easily soften to detach, all the while being able to bear heavy weights including that of a human being."

Temperature is the main control mechanism
Detaching the shape-memory polymer while it is attached to a surface in a glass state takes less than a minute of heating using a hair dryer to bring temperatures up to 60°C.Conversely, for attachment, it takes about three minutes for the material to cool down thoroughly and lock into place.

The temperature at which the polymer changes states can be controlled by adjusting the ratios of the components used to form the polymer. This allows the polymer to be used in extreme environments, such as hot weather conditions. In their testing, the researchers set the temperature at which the polymer detaches to 60°C, a temperature that falls outside most comfortable real-world conditions. This ability of the material to attach and detach using only heat lets it act as a reusable superglue that does not leave behind sticky residue on walls. It can also be used as soft grippers capable of sticking onto objects with diverse surface textures and reliably holding them for extended periods.

"At this current stage, the heating and cooling times, as well as switching temperature, restrict the number of real-world use cases," said Changhong. "However, our findings show that reducing the wait times to mere seconds is possible, and the switching temperatures can be lowered to near body temperature, dramatically opening up application possibilities."

Source: Nanyang Technological University, Singapore

Published May 2024

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