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Exoskeleton with Lightweight Plastic Components Finds Applications in Medicine, Manufacturing, and Agriculture.

Applications in which businesses use engineered plastics continue to emerge, including some industries that might seem startling. Construction, electronics, packaging, office equipment, transportation, and home products--everything from microwaves to toothbrushes--contain some measure of plastics.

A new device that supports manufacturing workers is among the latest technological advancements that speak to the power of plastics. The device, called the Airframe[TM], is made by San Diego-based Levitate Technologies and includes engineered plastic components made by igus, a German company which is also represented by a facility in East Providence, Rl. The exoskeleton, Levitate claims, improves quality and precision, boosts productivity, and helps reduce worker fatigue.

The Airframe is designed similarly to a backpack and can be adjusted to almost any body size with a frame and straps. The exoskeleton supports the upper extremities of professionals and skilled trade workers who are exposed to repetitive arm motions and/or stationary arm elevation.

'The benefits of this device have been incredible," says Terry Butler, former director of environmental health and safety at the Vermeer Corp., a manufacturer of industrial and agricultural equipment in Iowa. 'The team members that have used this tool are more than happy to use it and have seen more prolonged work activities without feeling fatigued by the end of their shift."

Designed with Doctors in Mind

The product was introduced by engineer Mark Doyle in 2013, and he worked with design company Pathway LLC to enhance the exoskeleton's manufacturability. It is produced by D&K Engineering Inc. Initially, Doyle designed the device for surgeons who suffered from fatigue and pain after long procedures.

When Doyle designed the Airframe, there were no models that allowed a surgeon to move freely while operating. Only stationary delivery systems were in use at the time. Surgeons who used the wearable frame found it had a positive effect, and a study from an internal review board at the hospital where surgeons wore the exoskeleton confirmed its value. The study found fatigue in surgeons who wore the exoskeleton decreased by 50 percent in operations after 12 minutes, and the pain rate decreased by about 25 percent.

"When we were designing the exoskeleton, we thought it would work for photographers, and in the general consumer market," says Joseph Zawaideh, the vice president of marketing and business development for Levitate. "But we weren't sure. We thought surgeons would be a good starting point."

While the Airframe proved successful for surgeons, manufacturing facilities learned of the product. One major auto manufacturer quickly found the benefits for its employees and Levitate switched its marketing focus and ramped up production.

"We became laser-focused on manufacturing and our business plan switched," Zawaideh says. "We changed our focus."

Finding a Home in Manufacturing

The Airframe is now being used in manufacturing plants in aerospace and airplane assembly, heavy machinery, ship building, agriculture, paper, and chemical industries. The U.S. Navy has also used the device for maintenance work.

Automotive assembly facilities have also used the device. The Airframe has been used extensively at a BMW Manufacturing facility in Spartanburg, S.C., where its X-series SUVs are assembled.

'They embraced the Airframe quickly and even mentioned that they do not want to go back to not using it," Zawaideh says. "Users said that they appreciated that the Airframe was very low profile, lightweight, and did not restrict motion."

Tests were conducted over a five-day period at a manufacturing facility in which welders and painters wore the Airframe. In both cases, productivity and quality spiked.

In dynamitic tasks in which painters wore the Airframe, the amount they were able to paint before their muscles became fatigued increased 53 percent. Quality improved as well, as the exoskeleton helped subjects maintain a steady hand while performing tasks. Tests in static tasks in evaluating welders saw an 86 percent increase in productivity and an increase in quality. Welders were able to complete successful welds over a much longer period while wearing the Airframe, according to statistics provided by Levitate.

"The automotive industry has been one of the early adopters of this technology," Zawaideh says. "It's also a good fit for aerospace, engine manufacturing, airplane building and in heavy machinery. When we thought about the product, we found it can reach all these different verticals. There are six million non-supervisory production jobs in the United States, so there is a massive opportunity."

Improving the Health of Workers

Besides increased productivity and efficiency, the Airframe might also help workers stay healthy. A safety and ergonomic risk assessment at one auto manufacturer found that the Airframe reduced physical work stress by 20 percent.

Levitate also reported the findings of a study it conducted that measured the impact of wearing the Airframe during a series of physical activities that mimic common industrial tasks. During the study, objective measures of shoulder and neck muscle exertion and force were collected via electromyography (EMG) sensors placed on the muscles. Measures of dexterity were collected during tests, and subjective comfort and effectiveness data was collected.

The results indicated a statistically significant reduction in the muscle exertion required to perform the physical tasks, a slight increase in manual dexterity, and a preference regarding the comfort of the device. The device lessens shoulder muscle fatigue and, by supporting the upper arm and offloading weight to the hips, reduces spinal compression forces on the lower back.

Work-related musculoskeletal disorders (WMSD) are a huge problem for many businesses. More than 650,000 cases of WMSD cases are reported each year. WMSD disorders represent 33 percent of every dollar spent on workers compensation. "From 1961 to 2011, disability claims from heart disease and stroke decreased from about 30 percent to 8 percent," Zawaideh says. "Disability claims from musculoskeletal disorders jumped from 10 to 33 percent. There's a critical need for assisting workers. The average age of workers is 47."

Work-related musculoskeletal disorders are responsible for $50 billion in lost productivity annually in the United States, and account for nearly 70 million physician office visits each year, according to the Centers for Disease Control and Prevention.

Nearly 45 percent of workers in certain professions experience shoulder pain. Pain and injuries result in missed days, decreased productivity, and escalating healthcare costs for business--and lower profits. More businesses are using ergonomics researchers to closely examine personal lift assist devices like the Airframe as a potential solution.

Targeting the Core

The Airframe transfers the weight of the arms from the shoulders, neck, and upper back to the core through pads that rest on the outside of the hips, thus relieving muscle and joint strain. The device transfers upper extremity load.

The unit is flexible and scalable to individuals of any size, slips on and off easily, and moves seamlessly with the wearer without limiting dexterity or intruding upon the workspace, Levitate claims. The mechanical support system progressively activates as the arm is raised and gradually releases as the arm is lowered to provide the right level of support at each point in the movement. The Airframe lowers exertion levels up to 80 percent, according to company estimates.

'The difference between the Airframe and other exoskeletons now on the market is that it's very lightweight, and extremely comfortable," Doyle says. "It's very comfortable and makes motion very natural. We worked hard to make it feel smooth and natural when being worn and activated."

The Right to Light

Doyle said the primary challenge in designing the Airframe was keeping the unit light. "The goal was light weight and maintenance free," Doyle says. "I always favored parts that are self-lubricating. They're also corrosion-resistant and easy to install, which made them ideal for this application."

"Asking human beings to wear a metallic frame and do their jobs is not an easy task," Zawaideh says. "We needed something that was lightweight, low profile, and could adjust to all the different mechanisms and synchronization. It required attention to detail on every screw and every bolt. Our mindset was if you don't need it, don't add it."

The key to the Airframe's light weight are the engineered plastic bearings. The bearings are self-lubricating and resist dirt and dust. The Airframe includes 32 plastic bushings manufactured by igus.

'There are a lot of exoskeletons on the market," Zawaideh says. "This is the lightest one out there. It's light enough that workers can wear it all day."

The Strength of Bearings

The iglide[R] G300 bearing is used in the Airframe. The bushing is used frequently in agricultural machines, automotive, construction, sports and leisure, machine building, and mechatronics.

The iglide G300 has a PV value of 12,000, a tensile strength of 30,460 at 68[degrees], and a density of 1.46 g/c[m.sup.3]. Typical applications include medium to high loads, medium sliding speeds, and medium temperatures. "It's a general-purpose bearing and has a good mix of wear, low friction, and reasonable cost," Doyle says. "It's a good all-around performer."

Doyle also needed to adjust some bushings as he developed the exoskeleton. "I have experience with the igus bushings, so I was not surprised they performed well," he says. "I was surprised our device was able to generate heat. The conditions the bushings were subjected to were different than what we expected, and we found out what was causing failure. But it only appeared in live testing. We have not seen failure in the field."

To stand up to higher temperatures, Doyle chose the iglide T500 and Z bushings for parts of the exoskeleton. The T500 bushing is temperature resistant to 482[degrees] and has a tensile strength of 24,660 at 68[degrees] F. The bushing has very low moisture absorption and universal resistance to chemicals. The Z bushing is used in applications that require high dynamic loads and wear resistance. The bearings are suitable to temperatures up to 482[degrees] and have compressive strength of 9,425 psi. The Z series also offers a 348,1000 modulus of elasticity.

Doyle also selected the iglide[R] M250 bushing for the exoskeleton for qualities that are important to the manufacturing sector. The bushing can also absorb dirt and dampens vibration. Lightweight materials are also an important feature. The M250 bushing is the lightest of all igus components in the unit, weighing just 1.14/g/c[m.sup.3].

Lightweighting, a topic typically discussed in the automotive sector, is just as relevant to a device workers are expected to wear for long shifts.

As worker safety and productivity continues to be top of mind across multiple industries, exoskeletons like those developed by Levitate could become a standard feature on the factory floor.

By Thomas Renner

Catalyst Marketing Communications

ABOUT THE AUTHOR

Thomas Renner is an award-winning journalist who has written extensively on products in manufacturing, construction, and other trade industries.
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Title Annotation:TECHNICAL ARTICLE
Author:Renner, Thomas
Publication:Plastics Engineering
Date:Mar 1, 2018
Words:1791
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