This video shows real images of a microscopic gear and actuator in a MEMS (microelectromechanical system) device. A tiny actuator moves back and forth in a ratcheting motion that drives the rotation of a microscopic ring gear. To track the actuator's motion, researchers attached fluorescent particles to the actuator. Using the light-emitting particles, researchers were able to track displacements as small as billionths of a meter, and rotations as tiny as several millionths of a radian at a rate of 1,000 times per second.
Video credit: Jennifer Lauren Lee/NIST. Music credit: Kevin MacLeod. Music licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/). Source: http://incompetech.com/music/royalty-free/index.html?isrc=USUAN1200003.
Microscopic machines can fail in the blink of an eye
Researchers at the NIST have developed a method for quickly tracking MEMS as they work and, just as importantly, as they stop working.
How long can tiny gears and other microscopic moving parts last before they wear out? What are the warning signs that these components are about to fail, which can happen in just a few tenths of a second? Striving to provide clear answers to these questions, researchers at the National Institute of Standards and Technology (NIST) have developed a method for quickly tracking microelectromechanical systems (MEMS) as they work and, just as importantly, as they stop working.
By using this method for microscopic failure analysis, researchers and manufacturers could improve the reliability of the MEMS components that they are developing, ranging from miniature robots and drones to tiny forceps for eye surgery and sensors to detect trace amounts of toxic chemicals.
Throughout the past decade, researchers at the National Institute of Standards and Technology (NIST) have measured the motion and interactions between MEMS components. In their newest work, the scientists succeeded in making these measurements a hundred times faster, on the scale of thousandths, rather than tenths, of a second.
This video shows real images of a microscopic gear and actuator in a MEMS (microelectromechanical system) device. A tiny actuator moves back and forth in a ratcheting motion that drives the rotation of a microscopic ring gear. To track the actuator's motion, researchers attached fluorescent particles to the actuator. Using the light-emitting particles, researchers were able to track displacements as small as billionths of a meter, and rotations as tiny as several millionths of a radian at a rate of 1,000 times per second. Video credit: Jennifer Lauren Lee/NIST. Music credit: Kevin MacLeod. Music licensed under a Creative Commons Attribution license (https://creativecommons.org/licenses/by/4.0/). Source: http://incompetech.com/music/royalty-free/index.html?isrc=USUAN1200003.
The faster time scale enabled the researchers to resolve fine details of the transient and erratic motions that may occur before and during the failure of MEMS. The faster measurements also allowed repetitive testing – necessary for assessing the durability of the miniature mechanical systems – to be conducted more quickly. The NIST researchers, including Samuel Stavis and Craig Copeland, described their work in the Journal of Microelectromechanical Systems.
As in their previous work, the team labeled the MEMS components with fluorescent particles to track their motion. Using optical microscopes and sensitive cameras to view and image the light-emitting particles, the researchers tracked displacements as small as a few billionths of a meter and rotations as tiny as several millionths of a radian. One microradian is the angle corresponding to an arc of about 10m along the circumference of the earth.
A faster imaging system and larger fluorescent particles, which emit more light, provided the scientists with the tools to perform their particle-tracking measurements a hundred times more rapidly than before.
“If you cannot measure how the components of a MEMS move at the relevant length and time scales, then it is difficult to understand how they work and how to improve them,” Copeland says.
In their test system, Stavis, Copeland, and their colleagues tested part of a microelectromechanical motor. The test part snapped back and forth, rotating a gear through a ratchet mechanism. Although this system is one of the more reliable MEMS that transfer motion through parts in sliding contact, it nonetheless can exhibit such problems as erratic performance and untimely failure.
The team found that the jostling of contacting parts in the system, whether contact between the parts occurred at only one point or shifted between several points, and wear of the contacting surfaces, could all play a key role in the durability of MEMS.
“Our tracking method is broadly applicable to study the motion of microsystems, and we continue to advance it,” Stavis notes.
Paper: C.R. Copeland, C.D. McGray, J. Geist and S.M. Stavis. Particle Tracking of Microelectromechanical System Performance and Reliability. Journal of Microelectromechanical Systems, Published online October 25, 2018. DOI: 10.1109/JMEMS.2018.2874771
Forecasts for the medical device industry shown continued growth in 2019 but is also changing, reflecting the increasing demand for new, innovative devices and services (such as wearables, at-home monitoring, health data/analytics); pricing pressures from health insurers/hospitals; and changing regulations in the U.S. and abroad.
As these changes in the market continue to unfold, medical device manufacturers are watching their processes and profits closely in order to stay competitive.
Situated amongst tall pines in the picturesque area between Minneapolis and St. Cloud, Minnesota, one wouldn’t suspect Big Lake to be a hotbed of medical device manufacturing creativity and world-renowned excellence. But it is, and recently its capacity has nearly doubled in size and scope.
Expansion
LISI MEDICAL Big Lake’s 55,000ft2 expansion, almost doubles the size of the building from 66,000ft2 to 121,000ft2. The culture of the parent company, LISI, is evident in its green policies.
“This expansion features a lot of large windows for natural light, something not normally seen in a machine shop building,” Production Manager Francisco Orench notes, “We are also using the Absolent system to cut down on mist.”
Orench joined the Big Lake facility on April 1, 2011 – he has been through three ownership changes, “But I believe that LISI has bought Big Lake for the long-term.” LISI has already made a large commitment to the company, investing millions of dollars in expansion and improvement.
“Initially it de-cluttered this part of the facility,” Orench says, “We had 46,000ft2 of production, and it was filled to about a 99% capacity.”
Michael Truenow, journeyperson machinist at LISI MEDICAL Big Lake is checking a setup on one of the company’s Hydromat machines.
Construction was conceived with an environmental goal of zero net ground addition/extraction. Crews extracted 3 million square yards of dirt, but none left the site, and none was brought in.
After the April 2017 ground breaking LISI MEDICAL Big Lake was able to quickly take partial occupancy in December, and they started moving machines into position.
Hydromat row
As additional capacity was required for some specialty components, the lineup of Hydromat and Icon Technologies machines had expanded, leaving LISI MEDICAL Big Lake with a floor space problem. Now, in a prominent place on the new floor, Orench has moved machines and created his Hydromat Row, a lineup of all his Hydromat transfer and Icon mill/turn machines.
When Orench joined the Big Lake facility, he saw Hydromat and Icon machining in action for the first time and became enamored with the production possibilities. At that time, they were in the process of buying their second Hydromat advanced technology (AT) pallet transfer machine, and later they would purchase a third. The AT 10-115 features 10 machining positions and a 10-position pallet-transfer design. This arrangement provides strength and flexibility in a turnkey machining system.
The machines from Icon Technologies, a Division of Hydromat Inc. located in St. Louis, Missouri, are multiple-station, offering the rigidity to handle all components and all material types within its work envelope. The creation of Icon Technologies 2008, and the subsequent development of the Icon 6-150 was a perfect fit for LISI MEDICAL’s needs. Described by Hydromat as a mill/turn productivity center, it is a 4-machining position design with horizontal and vertical spindles at each station, and a tool changer for each spindle. The table uses a 6-position pallet transfer design with a load/unload station and another station for gaging or inverting the part for 6-sided machining. The Icon 8-150 is a 6-machining position, 8-pallet version for additonal capacity. The Icon machines specialize in precision metal cutting, LISI MEDICAL now has a number of 6-150s and 8-150s running production.
The Icon 6-150s and 8-150s in production at LISI MEDICAL have the precision machining capability for various workpieces and many styles of medical components.
“Including the robots within the Icon Technologies machines, we have more than 30 robots in this facility,” Orench says. He has some robots that unload multiple Swiss machines, removing parts and running them through the secondary processes.
Christopher Weihrauch, machinist (left), Tim Corrigan, project manager (center), and Joseph DeRock, senior development engineer discuss a part changeover on the Icon 8-150 production for later that day.
Improved performance
Since joining the LISI Group, LISI MEDICAL Big Lake has embraced their LISI Excellence Achievement Program (LEAP). It’s essentially the Japanese lean system adapted to fit LISI’s specific needs. Also, they employ the single-minute exchange of dies (SMED) program to reduce setup time and increase machine uptime.
“We take it very seriously, we are looking for ways of reducing time,” Orench says. “This creates a better production situation that translates to excellent on-time deliveries and greater customer satisfaction.” They also work under 5S standards and the Workstation Standardization programs. Workstation standards are verified daily. There are 8 standards (Safety, Skills Matrix, 5S, Maintenance, Process Control, Product Control (Quality), Non-conformance Management, and Logistics) for how each workstation should look. “It’s about standardization, sticking to it, and making sure everyone follows it. A place for everything, everything in its place.”
LISI MEDCIAL Big Lake is a 24/7 facility running 4 shifts; two shifts during the normal work week, and two weekend shifts. The weekend a three-day schedule, Friday morning until Monday for a total of 36 hours. The expansion of the facility is also creating new job openings.
Jeremy Deadrick, journeyperson machinist at LISI MEDICAL Big Lake programs an Hydromat AT 10-115.
Shaping new talent
The LISI Apprentice Program helps the company develop young talent to become highly trained, well paid technicians who can start their careers without college debt. The program, which includes tuition reimbursement, brings in local high school students as youth apprentices. Later, they become interns who work 20 to 25 hours a week while attending technical college. They learn the business from the ground up, beginning in the shipping & receiving area, then they move to quality, materials, mills, Swiss, and lasers for a total of 42 months in the program. During this time, they are assigned a mentor, a LISI veteran who they can go to with any question at any time.
“It’s a 5-year program, they get flexible hours and a paid education. We get highly skilled technicians,” Orench says. “Our goal is to graduate two of these apprentices each year.”
Keith Johnson is held up as an exceptional example. He joined the Big Lake facility 26 years ago and now a senior manufacturing engineer who started as a machinist when he was 20 years old. He knows the jobs inside and out. He now deals with the large projects when LISI MEDICAL must bring in new equipment and new technologies.
Tony Brown, quality engineering (left) and Mike Merten, machinist (right) discuss a project that will be run on the Icon 6-150.
Product-focused
Specialties at the Big Lake plant include MIS Advanced Surgical Instruments (scissors, grips, blades, or staplers for example), Spine implants (pedicle screws, rods, connectors, or interbody cages for spine fusion), and Trauma/Extremity implants (plates and screws).
To stay competitive in a marketplace that has ever increasing pricing pressure they look to their workforce for creative thinking, automation to cut overhead, and the use of multi-station machining technologies like the Hydromat Rotary Transfer and Icon Mill/Turn machines to speed production and eliminate secondary operations.
Innomed’s designers, proactively seeking ways to address inherent cleanability challenges with the blind hole employed by existing fastening technology, chose to update the instrument with a canted coil spring.
Photo courtesy of Bal Seal Engineering
Best of 2018: Fixing what isn’t broken
Bal Seal Engineering canted coil spring improves instruments for hip and shoulder surgeries.
When a medical device is profitable, popular, selling well, and meeting all regulatory requirements, it can be tempting to leave well enough alone and focus on new product development instead of improving existing lines through iterative changes.
At Innomed Inc., a Savannah, Georgia-based manufacturer of surgical instruments for orthopedic surgery, founder and president Jim Anderson takes seriously the company’s commitment to continuous improvement. Innomed recently rolled out two revised products to prevent cleanability issues and stay ahead of regulatory guidelines.
Innomed uses ball plungers and ball-and-spring designs with blind holes in its products. Many of those products are designed by orthopedic surgeons to facilitate or expedite specific tasks, and Innomed aspires to foster new and ongoing relationships with surgeons to develop and originate innovative products. Seeking to eliminate – or at least minimize – the inherent potential for contamination in reusable instruments, Innomed began investigating alternative locking mechanisms for two of its best-selling interchangeable instruments – the CupX Acetabular Cup Extraction System and the Kolbel Self-Retaining Glenoid Retractor.
Those very different products – one is used for hip revision surgery, the other retracts soft tissue during shoulder surgery – were improved with Bal Spring canted coil springs made by Foothill Ranch, California-based Bal Seal Engineering Inc.
Canted coil spring
In 2015, Jim Anderson approached Innomed’s manufacturing partner, Warsaw, Indiana-based Instrumental Machine & Development Inc. (IMD), seeking a solution that could replace the ball plunger in the CupX and the Kolbel without requiring instrument redesign.
Innomed and IMD began investigating alternatives with comparable mechanical holding capability and superior cleanability. While both products have been on the market for years with no complaints about contamination, Innomed was committed to upgrading the instruments so they could be cleaned with no chance of contamination. With the Kolbel, the system would have to accommodate all existing legacy instruments sold throughout the years.
IMD product engineers worked with the engineers at Bal Seal Engineering to consider solutions based on features that could not change, and those that could be slightly modified, as well as the insertion and removal force requirements. The recommendation was a customized version of its canted coil spring. After prototyping, it was an immediate success in both instruments.
The Kolbel with a Bal Seal Engineering- developed retaining spring was introduced to market in December 2016. The updated CupX was introduced in January 2017.
Joe Beard, prototype/engineering manager at IMD says, “Bal Seal Engineering worked with us to develop the correct spring and groove setup we needed. In the end, it yielded great results, and the collaboration allowed us to improve functionality while being proactive about cleanability.”
The CupX Acetabular Cup Extraction System is designed to quickly and precisely removes an acetabular cup in hip surgery with minimal bone loss.The Kolbel Self-Retaining Glenoid Retractor is used to retract soft tissue during shoulder surgery.
Cleanability
The U.S. Food and Drug Administration (FDA) has noted that inadequate reprocessing can result in the retention of biological debris or soil in certain types of reusable medical devices, allowing microbes to survive disinfection or sterilization.
The original CupX and Kolbel instruments met all FDA specifications for material, cleaning, and traceability, yet Innomed and IMD saw opportunities for improvement. The Bal Spring’s ability to withstand repeated cleaning and sterilization processes made it attractive. An independent test report released in 2017 (Cleaning Evaluation R&D Report, test report for Bal Seal Engineering, Nelson Laboratories, May 12, 2017) proved that a sampling of Bal Spring canted coil springs were cleanable and reusable, meeting medical device industry standards as well as FDA regulations.
Conducted under worst-case conditions, testing validated that a device containing a canted coil spring in various groove geometries can be properly cleaned with manual or automated processes, withstanding stringent cleaning methods from manual scrubbing to automated dishwasher systems.
Conclusion
Innomed and IMD are committed to continuous product improvement, meeting or exceeding FDA regulations, and preventing issues before they occur. Because of questions about the cleanliness of the blind hole on the back side of the ball and spring setup in two surgical instruments, the designs were enhanced with Bal Spring canted coil springs, and IMD and Innomed are applying similar design concepts in developing other instruments.
Innomed says it is committed to a quality management system that endeavors “to consistently meet or exceed customer and regulatory requirements and expectations” and “to focus on exceptional customer service, quality products, and continuous improvement.”
With its integration of the Bal Spring canted coil spring in the CupX Acetabular Cup Extraction System and Kolbel Self-Retaining Glenoid Retractor, the company seems intent on fulfilling its promise.
About the author: David Wang is a global market manager for Bal Seal Engineering’s medical device business. An engineer with more than 10 years of design experience, he collaborates with OEMs and tier suppliers to create sealing, connecting, conducting, and EMI shielding solutions that help set new standards for device performance. Wang can be reached at 949.460.2147 or dwang@balseal.com.
Posted by Elizabeth Engler Modic
