The use of LSR is growing in both traditional rubber applications and those where traditional rubber materials had not previously been used.

Liquid silicone rubber (LSR) injection molding has been around for years. Its use has significantly expanded recently, especially in medical devices and wearable technology. LSR cures faster and offers properties not obtainable with traditional rubber materials, especially heat-resistance, extreme low-temperature flexibility, chemical resistance, biological inertness, and an intrinsic capacity for reducing friction. The material’s expanded use has resulted in the development of new LSR process equipment, especially technology that optimizes LSR injection molding machines to provide the greatest value and ease of use.

The basic raw material for silicone rubber is sand, or silicon dioxide. The material is processed into pure silicon. It is then reacted with methyl chloride, after which a range of processing steps create a variety of silicone types, including liquid.

LSR is a two-component reactive chemical with a thick, almost paste-like consistency, which has been compared to peanut butter. The two components are usually shipped in separate containers. Some medical-grade silicones are shipped in small disposable plastic cartridges. The two components are mixed in a 1:1 ratio to produce a reaction. Accelerated by heat, the two liquids then change to a rubber.

LSR injection molding is an inherently clean production process, because the component chemicals are sealed within a closed system. No ambient air contacts the parts until they are removed from the mold, eliminating issues with dust and moisture. This also improves part quality, because contaminants can diminish the cured rubber’s physical properties.

Use of LSR is growing in both traditional rubber applications and those where traditional rubber materials had not previously been used. Key examples include medical devices, wearables, automotive, industrial, and even home goods (see sidebar).

Medical devices – LSR cures completely and quickly. This is especially critical when medical devices are placed in a patient’s body, because it means the device will not leach chemicals and cause potential adverse reactions. By contrast, latex, a material long used in the medical industry, does not fully cure during production, and can lead to adverse patient reactions.

Due to LSR’s chemical makeup, it does not degrade until heated to very high temperatures – much higher than most other polymers could tolerate. So LSR can handle sterilization processes, contributing to its effectiveness for medical and baby care uses.

A final (and critical) advantage is the ability to use LSRs to manufacture drug-eluting devices (DEDs). For example, hormones used in the NuvaRing contraceptive product are injected as an additive in the LSR dosing process. LSR DEDs can also be placed in pacemaker heart catheter leads, enabling the leads to introduce anti-inflammatory medication directly into heart tissue for improved results.

Wearable technology – Wearable fitness trackers, such as FitBit and Jawbone, are largely responsible for the expansion of the flexible wearables category. With its ability to handle both high and low temperatures, ultraviolet (UV), and ozone without degrading, LSR is a better fit than traditional materials for wearable technology used under constant sun exposure. Unlike other rubber, products manufactured with LSR are unlikely to cause adverse skin reactions when worn by users, even for extended periods of time.

To achieve LSR’s benefits, injection molding machines must be optimized for value and ease of use.

While LSR equipment is similar in many ways to that used in the plastics industry, manufacturing LSR tools in the same manner as a plastic tool can lead to production failures. It is essential to use tool makers with a history of making LSR tooling. Also critical is working with an injection molding machine company that can assist with processing challenges, since successful LSR manufacturing requires that all components work properly together.

The Graco F4-5 and F4-55 systems take the ability to meter material flow to an almost microscopic level. Its helical gear uses multiple gear teeth to measure flow in very small increments. The increased number of measurements offers more assurance the machine remains on-ratio. https://goo.gl/sQFHKz

The most common pain points in LSR manufacturing are managing waste and controlling color changes and additives. Excess material is wasted because it is difficult to reclaim due to air bubbles, loss of certification, and a lack of lot tracking. Color changes can pose production down time, because extensive cleaning processes between colors can take as long as 4 to 6 hours. In addition, control of color or additives is a concern, especially controlling functional additives in the medical device industry.

Waste and increased additive control can be addressed through closed-loop control system technology. For example, Graco Fluid Automation F4 series systems use a dosing valve and a high-resolution flow meter to provide a closed-loop control for third- and fourth-stream additives, such as color and medications. The system monitors and adjusts to ensure the additive is being dispensed in the appropriate amount. If there is an out-of-tolerance condition, the system stops production.

Controlling the flow of the two primary material components in a closed-loop system allows the machine to react to changes in the material viscosity and the presence of air bubbles. Operators can vary the ratio to ensure the correct amount of material is used.

Closed-loop-control of two-component LSR dispense ratio is achieved by monitoring the material flow using high-resolution, helical gear-style flow meters. The helical gear uses multiple gear teeth to measure the flow in small increments. Flow meter data is fed back to the controller, which operates the valve to alter the flow of material to the flow meter, forming the closed loop.

The increased number of measurements provides more assurance that the machine is running on-ratio, and significantly reduces waste and rework caused by off-ratio dispensing.

The system offers a calibration routine that can be performed by the end user as necessary for a particular process, which also has a significant impact on product quality. The sample is collected and weighed, and resulting data is entered into the display module, calculating the current actual dispense ratio and calibrating the control system.

Other controls monitor processes to reliably manage the LSR system for its entire life cycle. The Graco Control Architecture (GCA), for example, provides longer life cycles than standard PLC products, and has a faster response time than other control architecture types.

In a state of rapid expansion, LSR continues to offer new and improved materials to replace older technologies with longer-lasting, more effective solutions. Improvements to LSR physical properties for individual applications mean LSR will likely continue replacing traditional rubber materials in existing industries and possibly others. With the advanced dispense and production technology currently on the market, manufacturing of LSR products can be managed to minimize problems and take full advantage of this material’s wide-ranging potential.

About the author: Mike Pelletier, business development manager at Graco Inc., can be reached at mpelletier@graco.com or 248.635.8817.

Liquid silicone rubber (LSR) injection molding is increasingly being used in markets that previously had not embraced the technology.

Automotive – LSR use in windshield wiper blades helps them remain flexible throughout the product’s life, extending a windshield wiper blade’s life while traditional rubber materials continue to cure due to UV exposure and heat, gradually making the windshield wipers ineffective.

Used in LED headlights, reflectors and lenses are made from special LSR grades designed for clarity and longevity. The reflectors are manufactured with additives that allow the LSR product to reflect back nearly 100% of light, amplifying the LED brightness. So, low-energy, long-lived LED bulbs can be as bright and effective as higher-energy, shorter-lived light sources. LED lenses are made with optical grade silicone, offering glass-like clarity and headlights made with LSR reflectors and lenses also make them suitable for traffic signals, streetlights.

Industrial applications– In the electronics industry, LSR is being used for millions of parts, including connector seals, grommets, and strain relief devices. Offering resistance to extreme temperatures, UV, and ozone, LSR also acts as an insulator or conductor, dependent upon material additives. On its own, silicone is a highly effective insulator, but can also serve as a conductor when manufactured with such fillers as carbon black.

LSR-based connector seals are often manufactured with an additive of red iron oxide to increase the product’s temperature resistance to 500°F. As new additives are created and physical properties of LSR products improve, the use of LSR for seal and gasket material will likely grow.

Uncertainty has become a defining characteristic of healthcare manufacturing.

Uncertainty has become a defining characteristic of healthcare manufacturing.

Driving factors include the long back-and-forth in Washington regarding U.S. healthcare policy and emerging technologies such as artificial intelligence and virtual reality. The consensus among our clients is less concern with the rules, or what they could become, and more of a desire to have them established without imminent risk of change.

If the Affordable Care Act (ACA) is repealed – after the healthcare industry has spent years adjusting to it – this uncertainty will put many healthcare operations on hold. Additionally, while new technologies are promising and ever- advancing, many are not yet proven, further contributing to doubt regarding what to put faith – and money – into.

How can medical device manufacturers adapt and prepare themselves when they don’t know what the future holds?

Medical device manufacturers can cope with uncertainty by evaluating operations strategies and leveraging finance options to improve cash flow.

Manufacturers remain under tremendous pressure to maintain current equipment and technology to stay competitive. As manufacturing equipment quickly becomes smarter and more automated, frequent machine updates are needed to keep up with demand and support company growth.

Medical devices are consistently implementing emerging technologies, which in turn require higher-precision equipment to produce. And software systems used for design and operations are becoming obsolete as more efficient alternatives enter the market.

As medical manufacturers weigh the need for new equipment and technology against the cost, the initial prospect can be daunting. However, financing gives an opportunity to keep equipment off their books, preserving capital for items that cannot be financed, such as research and development (R&D).

Medical device manufacturing companies spent an average of 7% of their revenue on R&D last year, higher than almost all other industries.

As capital investments get factored into a company’s bottom line, one way to cope is to alleviate other cost burdens. This is where a well-orchestrated lease or loan strategy comes in.

Companies can lease production equipment and software programs via operating leases, keeping the investments off of company balance sheet, spreading asset costs across several months, and preserving upfront capital for other endeavors.

An operating lease structure allows medical manufacturing companies to defer the decision of whether or not to own the equipment until the end of the lease. When the lease concludes, the company can either purchase the equipment at fair market value, or they can hand it back and upgrade to the latest technology.

This differs from the more common capital lease, which involves higher monthly payments, but ensures ownership at the end of the term.

Capital leases are practical for core manufacturing equipment that isn’t subject to technological obsolescence and has a useful life of at least 7-to-10 years. Operating leases are the better option for equipment that has a shorter lifespan or equipment subject to more rapid technological advances.

There are other financing options that many healthcare manufacturers could be using but are not.

Life cycle asset management (LCAM) is a strategy that combines hard costs (equipment or software cost) with soft costs such as installation, maintenance, and training and merges them all into one consistent monthly payment.

With LCAM, medical manufacturers have no obligation to keep obsolete equipment. The finance provider will handle disposal of the equipment at the end of the term, making way for newer, upgraded equipment or software.

Professionals in healthcare manufacturing should approach financial decisions with extra caution in the current climate of doubt. That said, uncertainty should not hold these companies back from growth and strong profitability.

By analyzing financing options and selecting strategies that preserve cash and ensure that equipment and software are always updated, medical manufacturers can preserve capital, maintain healthy balance sheets, and ultimately navigate the current climate of uncertainty with success.

Innovation is critical to the healthcare industry, and the pursuit of improvements through emerging technologies is the only way to stay competitive.

About the author: Eric Freeman is president of Liberty Commercial Finance and may be reached at efreeman@libertycommercial.com.

The ability to bend without breaking under stress, making it a preferred choice for medical implants, engine parts, and much more.

LLNL materials scientist Joe McKeown looks on as postdoc researcher Thomas Voisin examines a sample of 3D printed stainless steel. Photos by Kate Hunts/LLNL.

Marine grade stainless steel is valued for its performance under corrosive environments and for its high ductility – the ability to bend without breaking under stress – making it a preferred choice for medical implants, oil pipelines, welding, kitchen utensils, chemical equipment, engine parts, and nuclear waste storage. However, conventional techniques for strengthening this class of stainless steels typically comes at the expense of ductility.

Lawrence Livermore National Laboratory (LLNL) researchers, along with collaborators at Ames National Laboratory, Georgia Tech University, and Oregon State University, have achieved a breakthrough in 3D printing one of the most common forms of marine grade stainless steel – a low-carbon type called 316L – that promises an unparalleled combination of high-strength and high-ductility properties for the ubiquitous alloy. The research appears online Oct. 30, 2017, in the journal Nature Materials.

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"In order to make all the components you're trying to print useful, you need to have this material property at least the same as those made by traditional metallurgy," says LLNL materials scientist and lead author Morris Wang. "We were able to 3D print real components in the lab with 316L stainless steel, and the material's performance was actually better than those made with the traditional approach. That's really a big jump. It makes additive manufacturing very attractive and fills a major gap."

Wang says the methodology could open the floodgates to widespread 3D printing of such stainless-steel components.

To successfully meet, and exceed, the necessary performance requirements for 316L stainless steel, researchers first had to overcome a major bottleneck limiting the potential for 3D printing high-quality metals, the porosity caused during the laser melting (or fusion) of metal powders that can cause parts to degrade and fracture easily. Researchers addressed this through a density optimization process involving experiments and computer modeling, and by manipulating the materials' underlying microstructure.

(Right) LLNL scientist Morris Wang (left) and postdoc researcher Thomas Voisin played key roles in a collaboration that successfully 3D printed one of the most common forms of marine grade stainless steel that promises to break through the strength-ductility tradeoff barrier.

"This microstructure we developed breaks the traditional strength-ductility tradeoff barrier," Wang notes. "For steel, you want to make it stronger, but you lose ductility essentially; you can't have both. But with 3D printing, we're able to move this boundary beyond the current tradeoff."

Using two different laser powder bed fusion machines, researchers printed thin plates of stainless steel 316L for mechanical testing. The laser melting technique inherently resulted in hierarchical cell-like structures that could be tuned to alter the mechanical properties, researchers said.

"The key was doing all the characterization and looking at the properties we were getting," says LLNL scientist Alex Hamza, who oversaw production of some additively manufactured components. "When you additively manufacture 316L it creates an interesting grain structure, sort of like a stained-glass window. The grains are not very small, but the cellular structures and other defects inside the grains that are commonly seen in welding seem to be controlling the properties. This was the discovery. We didn't set out to make something better than traditional manufacturing; it just worked out that way."

LLNL postdoc researcher Thomas Voisin, a key contributor to the paper, has performed extensive characterizations of 3D printed metals since joining the Lab in 2016. He believes the research could provide new insights on the structure-property relationship of additively manufactured materials.

"Deformation of metals is mainly controlled by how nanoscale defects move and interact in the microstructure," Voisin says. "Interestingly, we found that this cellular structure acts such as a filter, allowing some defects to move freely and thus provide the necessary ductility while blocking some others to provide the strength. Observing these mechanisms and understanding their complexity now allows us to think of new ways to control the mechanical properties of these 3D printed materials."

(Left) Researchers say the ability to 3D print marine grade, low-carbon stainless steel (316L) could have widespread implications for industries.

Wang notes the project benefitted from years of simulation, modeling and experimentation performed at the Lab in 3D printing of metals to understand the link between microstructure and mechanical properties. He called stainless steel a "surrogate material" system that could be used for other types of metals.

The eventual goal, he said, is to use high-performance computing to validate and predict future performance of stainless steel, using models to control the underlying microstructure and discover how to make high-performance steels, including the corrosion-resistance. Researchers will then look at employing a similar strategy with other lighter weight alloys that are more brittle and prone to cracking.

The work took several years and required the contributions of the Ames Lab, which did X-ray diffraction to understand material performance; Georgia Tech, which performed modeling to understand how the material could have high strength and high ductility, and Oregon State, which performed characterization and composition analysis.

Other LLNL contributors included Joe McKeown, Jianchao Ye, Nicholas Calta, Zan Li, Wen Chen, Tien Tran Roehling, Phil Depond and Ibo Matthews.

HSI and Omnivision are delivering turnkey imaging solutions based on HSI's cable technology and OmniVision's image sensors.

Scottsdale, Arizona – High Speed Interconnects LLC (HSI) alongside with OmniVision Technologies Inc. continue to execute their collaboration to solve a myriad of image-capture and transmission challenges across a broad range of endoscope's, catheter, and guide-wire based applications. Expanding their relationship, HSI and Omnivision are delivering turnkey imaging solutions based on HSI's cable technology and OmniVision's OV6946, OV6948 image sensors, wafer-level lens, and back-end image signal processor.

Industry analysts are reporting the demand for minimally invasive medical procedures enabled by endoscope, catheter, or guidewire-based devices is growing rapidly, driven by multiple socioeconomic factors such as increasing healthcare expenses, hospital-acquired infections (HAI), an aging population, and the rise of the middle class in the developing world. Consequently, hospitals are actively investing in endoscopic, catheter, and guidewire technologies. Additionally, growing concerns about cross-contamination and HAIs caused by reusable endoscopes are driving the need for cost-effective, single-use, endoscopes, catheter, and guide-wire based solutions.

Ensuring an endoscope, catheter, or guidewire delivers top quality images requires capturing the images with a best-in-class sensor, then transmitting the signal (and power) via a micro-miniature cable from the distal-tip to proximal-end. HSI's highly-engineered cable must be capable of transmitting images across analog and MIPI interfaces, then be precisely terminated to fine-pitch Omnivision image sensor pad's. Despite of length, the imaging solution must withstand insertion loss, noise, and cross-talk, plus be small enough to fit inside the inner diameter of an endoscope, catheter, or guidewire while sufficiently cost-effective for any single-use medical device application.

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"The engineering expertise of top-tier innovators is essential in meeting the key requirements for high performance, small diameter disposable endoscopes," says Tehzeeb Gunja, senior product marketing and business development manager at OmniVision. "HSI has considerable expertise with its unique extrusion, applied materials, and termination technology platforms to deliver such a wiring subsystem, which couples perfectly with OmniVision's OV6946 and OV6948 image sensors. Together, we believe we can offer high volume, cost-effective solutions that can meet medical device manufacturers' stringent imaging and cabling expectations."

"Leveraging our highly-engineered coaxial cable extrusion and manufacturing capabilities in Portland, Oregon, and a low-cost country assembly operation in Hermosillo, Mexico, enables us to address customer expectations from product development to mass production," says Antonio De La Rosa, founder, CEO, and manager of HSI. "We are delighted to be strategically engaged with OmniVision to deliver cost-effective, high-performance image-capture assembly solutions that allow medical device manufacturers to develop single-use devices for a growing medical market."

Meet Rem Sales’ Swiss CNC engineers and local Tsugami specialists; hear presentations by industry partners Esprit and Edge Technologies Dec. 5-6, 2017.

Windsor, Connecticut – Tsugami/Rem Sales, the exclusive North American importer of Tsugami machine tools, will host the 2nd annual Technology Center Open House in Fullerton, California, Dec. 5-6, 2017, at the Tsugami/Rem Sales office, 1521 E. Orangethorpe Ave., Suite E, Fullerton, California.

The two-day event will consist of presentations by long-time Tsugami/Rem Sales industry partners, Esprit and Edge Technologies. Representatives from Esprit and Edge Technologies will present on Programming Tsugami Swiss and 10 Things Everyone Should Know About Bar Feeding, respectively.

“Edge Technologies has continued to build and maintain a close relationship with Tsugami/Rem Sales that has the workability to overcome almost any obstacle, while focusing on the customers’ best interests. I am grateful to be part of a team that blends the demarcation lines between machine and bar feed and I very much look forward to sharing our insights on the dynamics of Bar feeding as well as the impact that those dynamics have on the machining world at the upcoming open house in Fullerton, California,” explains James Peterson, regional sales manager, Edge Technologies.

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All attendees will have the opportunity to meet with Rem Sales’ Swiss CNC Engineers and local Tsugami specialists. All are encouraged to bring questions, ideas, and drawings of parts for consultation sessions.

“Our annual Fullerton open house is the perfect chance for anyone interested in learning more about the capabilities and power of Tsugami to stop in, look at the machines, and speak with our experts. We pride ourselves in the engineering and customer support behind Rem Sales’ products and partnerships and look forward to welcoming all of the open house attendees,” shares Michael Mugno, vice president, Rem Sales.

Tsugami Machines featured at the open house:

Hours for the Fullerton open house are, Tue. Dec. 5, 10am - 4pm PST and Wed., Dec. 6, 10am – 3pm PST. Lunch will be supplied for all registrants both days.

Please register for the event at www.remsales.com/openhouse or by calling Valentina Ciotto, Tsugami/Rem Sales’ sales coordinator at 860.687.3422.