Sealing and Shielding Blog

High performance QSFP-DD optical modules must use thermal interface materials to help dissipate heat efficiently and effectively to ensure the optimum operating performance, reliability and dependability of the high-speed transceiver.

The introduction of QSFP-DD, or Quad Small Form Factor Pluggable Double Density optical modules, have now doubled of the number of high-speed electrical interfaces that the module supports compared with a standard QSFP28 module.

Greater density, greater heat

QSFP-DD modules are the newest standard in high speed pluggable connectors, as they are the smallest form factor 400 G/s transceivers, offering the highest bandwidth density while leveraging the backward compatibility to lower-speed QSFP pluggable modules and cables. Highly integrated and advanced PAM-4 DSP chips, externally modulated laser (EML) diodes, and GaAs laser diodes enable the 400 G/s performance, yet these ICs come with significant thermal issues.

Power loads of up to 25W require significant considerations for heat dissipation, including the application of thermal interface materials.

The goal of a system thermal design is to remove the heat from the module case to ensure that the internal components in the module stay within operating temperature ranges to ensure optimal performance and reliability.

The role of thermal interface materials (TIMs)
Thermal interface materials such as thermally conductive gap filler pads, thermal greases, and dispensed thermal gels improve heat dissipation by filling minute air gaps and voids and by being dispensed or in contact with heat generating chipsets. Maximizing the contact area of the heatsink to the module lowers the thermal resistance and improves the system’s ability to cool the module.  Types of TIMs available

High power thermal gels, such as Parker Chomerics THERM-A-GAP GEL 75, with 7.5 W/m-K thermal conductivity, as well as high performance single component thermal greases such as THERM-A-GAP GEL 8010 3 W/m-K, are typically robotically dispensed for high volume applications such as optical modules.

Robotically dispensing thermal interface material can dramatically reduce costs, save valuable time, and greatly improve the overall performance of the QSFP-DD module. Thermal gap filler pads can be die cut into exact shapes to help dissipate heat from any heat generating component. Thermal gap filler pads provide a soft and effective method of heat dissipation as well as helping to reduce vibration stress for shock dampening. 

Need help deciding on a thermal interface material? Our recent blog Thermal Gels or Gap Filler Pads? Top 6 Things You Should Know can help!

A TIM for every design; yes, even yours

Whatever your design is, be it a stacked card cage, or belly-to-belly, the thermal interface between the optical cable connector module and the heatsink attached to the outer case/cage is important to your design.

With speeds of 400 G/s being introduced now and 800 G/s on the near horizon, you must also consider the thermal heat dissipation needs of not only the module itself, but the interface connection on the PCB, as well as at the rack unit or cabinet level. 

Cabinets featuring 40U to 46U racks require immense thermal heat dispersion featuring both active and passive cooling technologies. Higher data transfer speeds, low latency, and constant availability require more computing power, which in turn means higher power densities per rack.

No matter what your thermal interface material need, Parker Chomerics can help, download our Thermal Interface Materials for Electronics Cooling Guide now!

 

 

 

 

 

This blog post was contributed by Jarrod Cohen, marketing communications for Parker Chomerics

 

 

 

 

 

 

 

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We receive many requests regarding seal retention but why is it so important? There are 3 main reasons: ease of component assembly, serviceability, and transit issues. For example, seal retention is important when you have complex groove paths where your groove wanders around bolts or ports. It is also valuable in improving operator ergonomics by reducing installation strain or fatigue in high volume applications.  Additionally, seal retention improves serviceability by eliminating the need for liquid sealants which can be difficult to clean. Last but not least, seal retention resolves transit issues by ensuring seals are retained from workstation to workstation or if components are assembled in different locations.

Parker offers an array of Press-in-Place (PIP) Seals to accommodate these application challenges. Additionally, each particular profile provides performance properties to address issues like larger tolerance stock, low seal load, and complex groove paths to name just a few. 

Press-In-Place Benefits

Parker’s Press-In-Place (PIP) seals are custom designed to fit into complex groove patterns without having to be stretched. These custom seals are designed to withstand a wide variety of environments, fluids, pressures and temperatures.

In comparable seal heights, a standard PIP groove is 60 percent narrower than traditional grooves. Seal retention is achieved by sidewall interference, requiring no adhesives. The PIP design also maintains high pressure differentials, provides lower seal load, optimizes material use and is easy to install.

Compared to dispensed Form-In-Place (FIP) seals, PIP seals have several advantages. For example, during maintenance, PIP seals can be easily and quickly changed out, where FIP removal often damages the groove. FIP seals also require a considerable investment in machines and fixtures while PIP seals deliver higher performance and robustness without expensive tooling or fixture costs. 

Parker offers a variety of PIP standardized profile options. These include:

• Molded Diamond—molded to the shape of the groove path using retention beads intermittently along the seal to keep it secure. This PIP seal can save space up to 60 percent versus traditional seals and allows a much smaller bend radius. The diamond seal can combine multiple parts into one and enables fast assembly. Applications include high volume automotive and low volume military programs.
• Hexapod—excellent for retention and lower pressure applications. It is also extruded and spliced which makes it a great choice for large enclosures. Applications include EV battery and heavy-duty engines.
• Keyhole—also extruded and spliced with reduces deflection and number of fasteners thanks to its low load. This PIP seal is also great for environmental sealing (little or no pressure) and larger tolerances, and is easy to install. Applications include plastic housings and stamped covers.
• Jigsaw—extruded and supplied in long lengths with no splicing required. The Jigsaw seal can be cut to size and requires no adhesive but does require a groove overlap. Applications may include multiple port sizes where just one part number can be used for the whole assembly, and in field installations where a pre-sliced or continuous part may be impossible to install.
• O-Ring—this seal is a good solution for retention and comes in three types: standard & custom sizes; extruded with spliced rings and cord stock; and custom molded plan view. Each type has its own benefits and limitations including cost effectiveness, bend radius, customized cross-sections and more.
• EZ-Lok—an axial seal designed for retention in dovetail grooves. the EZ-Lok seal is designed specifically to simplify and error-proof the installation process. In addition, this PIP seal minimizes seal wear on groove corners and removes the parting line from the sealing surface. It is currently used in the semiconductor market and is recommended when seal installation and performance are critical. 
• Hollow O-Ring—extruded, spliced and low load which allows for a reduction in fasteners or clamps. They are easily customizable and are slightly oversized compared to the groove. However, they will not overfill the groove like a standard O-Ring. Like other hollow profiles, the Hollow O-Ring is not suitable for high pressure applications.
• Bulb—come in standard and custom profiles and are highly compliant to variation, i.e., your components to flex, run out, etc. If you have a groove that is already machined or spec’d in and you need a seal to fit, a custom bulb seal may be your best option.

Other retention options include: Friction Fit Hollow O; Friction Fit Hollow Profile; PSA on Profile; Dart Profile in Custom Groove; Dart Profile in FF Groove; Hollow Profile Mechanically Fastened; PSA on Hollow D; and Hollow Profile Pressed into Metal Track.

A full summary of our PIP options with performance properties and our recommendations are provided in our Press-In-Place (PIP) Sealing webinar below. For help in determining the right solution for your application, please contact our O-Ring & Engineered Seals design team at OESmailbox@parker.com or 1-859-335-5101.

 

 

   

 

 

 

 

This blog was contributed by Samantha J. Sexton, marketing communications manager, Parker O-Ring & Engineered Seals Division.

 

Press-in-Place Seals for Axial Sealing Applications

Press-in-Place Seals Solve Problems for Automotive Applications

Innovative Solutions Improving Seal Retention

Challenges abound for oil and gas companies during drilling and well completion operations. Drilling mud and frac fluids are some of the harshest and most destructive media to be sealed. It takes tough, rugged sealing components to last long run-time hours and continuously move high volumes of abrasive frac fluid that cause wear and tear on parts. And thermoplastic polyurethanes are raising the bar for performance expectations and proving out as preferred sealing materials.

Polyurethane has been an industry standard for dynamic sealing in hydraulic applications for more than 30 years. But polyurethane materials are not all formulated from the same hard- and soft-segment chemistry. The specific diisocyanate and chain extenders used in the synthesis of a polyurethane affect its physical and mechanical properties. When looking to achieve the best performance with mud and frac pumps, Parker’s Resilon® polyurethane is recommended. Our proprietary PPDI (p-phenylene diisocyanate) TPU formulation is specifically suited for injection molding of both large and small articles while retaining superior high-temperature performance.

The characteristics common to Resilon formulations make this PPDI class of material a leading choice for high pressure, dynamic sealing applications. These characteristics include exceptional:

• Wear resistance
• Thermal stability
• Hydrolytic stability
• High bond strength
• Compression set resistance
• Resiliency

 

Where to Use Resilon

 

Resilon polyurethane can be used with high effectiveness in many areas on mud and fracking pumps. The advantages are evident in each area.

Pony Rod Seals.  Eliminate hydraulic fluid leakage and simplify installation by replacing standard two-piece seals with the single-piece design made from Resilon 4300. With its high contact force sealing lip design, coupled with compression-set resistant Resilon seal material, this patent-protected pony rod seal design retains lubricating oil in the power end, eliminating necessity of shut down to replenish lost hydraulic fluid. When maintenance and change over is called for, pony rod seal installation is much simpler. The integrated, single component oil seal/rod wiper can be secured via press fit so there’s no need for snap rings or retaining plates. 

 

 

"Our sales team members receive inquiries from well completion operators who are frustrated when they are interrupted and have to shut down to replenish gallons of hydraulic fluid lost from leaking seals. These operators and their service technicians who are in the field doing the change-overs make it known they 'want the the tan colored pony rod seal,' referring to Parker's recognizable tan-colored Resilon 4300 formulation. Some operators are so pleased with the performance of the Parker pony rod seal they are demanding that the mud pump manufacturers install it as a condition to deploy their pumps on the job site."

Dana Severson, oil and gas market sales manager for Parker's Engineered Materials Group

 

Suction and Discharge Cover Seals. Our HGP Profile suction and discharge cover seals provide four times the reliable service life compared to traditional elastomer D-rings. Owing to its combination of unique geometry and Resilon 4300 polyurethane material, the HGP Profile resists wear due to the abrasive fluid proppant, high pressure and vibrating motion generated by high frequency pulsating pressurization. The tough, rugged material improves sealing reliability and minimizes degradation of fluid end mating hardware.

Fluid End Valve Seats. Valves take a beating from repeated cycling in highly abrasive drilling fluids and aggressive fracking fluids. But valves made with our unique geometry and Resilon polyurethane have shown to extend valve life by over 50 percent. Resilon valves reduce material failure caused by hysteresis and the optimized geometry increases service life and reliability of the valve seal. These can be formulated in both bonded and snap-in configurations.

Mud Pistons. Our design expertise in piston sealing applications has resulted in piston cups that outlast the competition, reducing costly downtime and eliminating leaks. Resilon polyurethane piston seals are long wearing and outperform traditional urethanes in hot water. Enhanced resilience/rebound characteristics allow the sealing lips of the mud piston to conform to the seal interface – maintaining consistent critical sealing lip contact under rapid cycling conditions, plus reduce frictional heating. In addition, Resilon formulations are compatible with oil and water-base drilling muds. 

Well Service Packings. For positive displacement pumps, the materials used in our well service and vee-ring packings have exceptional compressive force resistance to manage side loading yet remain pliable enough for sealing. The material range includes Resilon polyurethanes to aramid fabric reinforced HNBR/FKM. Resilon is compatible with a wide range of hydraulic fracturing fluids.

 

Resilon® Material Formulations Help Overcome Oil & Gas Completion Challenges

 

With well conditions becoming increasingly challenging and taking a toll on equipment and expendables, you require sealing products that will enable you to achieve greater production efficiencies, improve performance and reduce down time. Whether you service frac pumps, run completion operations, or build frac pump equipment, Parker’s proprietary Resilon materials can improve your bottom line by:

• Reducing frequency of component replacement (MTTM)
• Reducing cost for maintenance since less maintenance and fewer replacement parts are needed
• Providing better compatibility in water application
• Ensuring rugged, resilient sealing force

Learn more about Resilon® and watch Parker’s video on temperature/pressure challenges and sealing requirements for Oil & Gas.

 

This blog post was contributed to by Shannon Johnson, marketing communications for Parker Engineered Polymer Systems Division.

 

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If I had to estimate the number of times someone asked for a seal meeting AMS7287, the answer is very few.  On the other hand, the number of times someone has asked for a seal material meeting Mil-R-83485, AMS-R-83485, MS83485 or AS83485 it would be too many to count. The lack of inquiries surrounding AMS7287 is surprising, given the document has been active since 2012. Therefore, if you are reading this blog and are familiar with the AMS-R-83485 specification, but do not know much about the AMS7287 specification you are not alone!  This blog is intended to explain the differences and help you understand one specification with respect to the other.

But first, let me provide the title and status of each document as of April 2021:

 

table { font-family: arial, sans-serif; border-collapse: collapse; width: 100%; } td, th { border: 1px solid #6f6754; text-align: left; padding: 8px; } tr:nth-child(even) { background-color: #fdd880; } Number Title Status & Rationale Part Drawing & Numbering System Mil-R-83485 Rubber, Fluorocarbon Elastomer, Improved Performance at Low Temperature/td> Cancelled, S/S by AMS-R-83485 Mil-R-83485/1 M83485/1-xxx AMS-R-83485 Rubber, Fluorocarbon Elastomer, Improved Performance at Low Temperature Cancelled May 2014, S/S by AMS7287 (Ty I O-rings) AMS3384 (Ty 2 Molded parts) Mil-R-83485/1 M83485/1-xxx AMS7287 Fluorocarbon Elastomer (FKM) High Temperature / HTS Oil Resistant / Fuel Resistant Low Compression Set / 70 to 80 Hardness, Low Temperature Tg -22F (-30C) For Seals in Oil / Fuel / Specific Hydraulic Systems Active; Issued 2012-08 AS83485A M83485/1-xxx

 

Mil-R-83485 & AMS-R-83485 revisions

Looking at both Mil-R-83485 and AMS-R-83485, the document was largely unchanged in both requirements and intent.  Qualification requirements included limits for:

Basic physical properties

TR-10 (Temperature Retraction) of -20°F

Compression set for 70 hours @ 75°F

Compression set for 22 hours @ 392°F

Dry Heat age of 70 hours in 528F air for a change in physical properties and weight.

Fluid Immersion in Fuel, 70 hours at 73°F for a change in physical properties and volume

*Long term Compression set for 166 hours @347°F (with the second set to cool for 18 hours in test fixture)

*Fluid Immersion in Di-ester polyol, 70 hours at 347°F for compression set plus a change in physical properties and volume

(*not carried over to AMS7287)

 

Over the years of “83485” revisions, there were some changes in the exact fluid called out, but the intent did not change.  For example, TT-S-735 Type III was later updated to Fuel B which might appear to be a change, but both are a 70/30 blend of isooctane and toluene.  Similarly, the Stauffer Blend 7700, a di-ester polyol synthetic-based oil, was updated to AMS 3021 (also known as Hatco 7700 and Service Fluid 101) which is basically the Mil-L-7808 oil, also a polyol synthetic-based oil.

 An interesting detail about the specifications has to do with ownership and the subsequent naming convention.  The documents with the ‘Mil’ prefix were owned by Wright Patterson Air Force Base, and when they turned ownership over to SAE, the document number prefix transitioned to “AMS”.  This naming convention also explains why some of the fluids within the specification switched from a brand of di-ester polyol to a reference oil with an AMS prefix.

 

AMS7287 changes 

The change to AMS7287 brought about more than a few changes to nomenclature and standardization of fluids.  The testing criteria which stayed the same are the first six listed above for Mil-R and AMS-R-83485.  The polyol oil immersion from the requirements was carried over, however, there is a difference to the fluid, the testing limits, and the addition of a compression set.  The synthetic oil was updated to AMS3085, which is a reference lubricant for High Thermal Stability (HTS) oils such as Mil-PRF-36699(HTS), Mil-PRF-7808 Grade 4 and AS5780  Class HPC. This change makes sense given the widespread use of AMS-R-83485 seals in HTS oil applications such as gear turbine oils and engine oils.  In addition, the AMS3085 type oil is standard among other SAE-owned specifications, such as AMS7257 and AMS7379.

Further technical changes from AMS-R-83485 to AMS7287 are the addition of the following requirements:

               Glass transition temperature (Tg) of -20°F

               Long Term Compression set for 336 hours @ 392°F

You may notice that the original list of requirements at the beginning includes a 166-hour compression set but at a more modest temperature of 347°F, with a maximum result of 25% on O-rings.  The addition of a 366-hour test at a temperature 45°F higher is significant. Qualified materials must not exceed a compression set of 50%.  This more aggressive condition could easily cause a material that meets the requirements of AMS-R-83485 not to meet the requirements of AMS7287.

Another area of change is with respect to conformance testing. The “83485” specifications require O-rings to undergo acceptance testing on size -214 O-rings molded at the same time as the production batch of O-rings.  The move to AMS7287 requires testing on the actual O-rings unless they are an unsuitable test size. In the case of unsuitably sized O-rings, only then would the -214 O-rings be tested for physical properties and compression set.

The final area of significant change in AMS7287 is the requirement of each manufacturer to have their material approved and listed on the Qualified Producers List (QPL).  This means each manufacturer must also be approved and listed on the Qualified Manufacturer’s List (QML).  QML and QPL status require a robust quality system and rigorous audits by the governing body, which ensure both the material and the necessary manufacturing practices comply with the AMS7287 standard.

Parker’s VM125-75 fluorocarbon meets all the requirements of AMS7287.  For more information on VM125 or the AMS7287 specification, please reach out to one of our Application Engineers, or click here to view test data and our product bulletin.

    
     

Article contributed by Dorothy Kern, applications engineering lead, Parker O-Ring & Engineered Seals Division

 

 

 

 

 

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Parker Chomerics has recently released THERM-A-GAP™ GEL 75, a 7.5 W/m-K thermal conductivity, single-component, dispensable thermal interface material. THERM-A-GAP GEL 75 is the latest from the THERM-A-GAP family of dispensable thermal materials from Parker Chomerics to be released to the market. 

When applied to a heat generating component, THERM-A-GAP GEL 75 provides minimal stress and pressure due to its low compression force. It is form stable in horizontal or vertical applications and allows for lower assembly costs when compared to multiple thermal gap pads in higher volume applications.

3x faster flow rate, highest thermal conductivity 

THERM-A-GAP GEL 75 represents the highest thermal conductivity dispensable available from Parker Chomerics. With a flow rate of 30 grams per second, it is nearly 3x faster than the next closest performing material in the THERM-A-GAP family. 

The gel-like consistency enables superior performance and long-term thermal stability and is designed to be dispensed in applications requiring low compressive forces and minimal thermal resistance for maximal thermal performance.  

Superior, reliable performance in the field 

Parker Chomerics has conducted a detailed examination of the thermal reliability of this high-performance gap filler after being subjected to long-term environmental aging under dry heat, heat and humidity conditions, and temperature cycling from -40°C to 125°C. 

The thermal performance of THERM-A-GAP GEL 75 was examined, and the findings were reported in the THERM-A-GAP GEL 75 Reliability Report TR1104. After being subjected to multiple environmental stress tests, the thermal impedance of the aged samples did not experience a significant increase after any of the treatments studied.  

After a 1,000-hour dwell at 125°C, 1,000 hours at 85°C/85% relative humidity, and 1,000 temperature cycles from -40°C to 125°C, there was no statistically significant increase in impedance according to one-way ANOVA with the Tukey method for multiple comparisons.  

NASA outgassing results 

The National Aeronautics and Space Administration (NASA) criteria for low-volatility materials limits the total mass loss (TML) to 1.0% and collected volatile condensable material (CVCM) to 0.10%. Outgassing results for GEL 75 are 0.18% TML and 0.05% CVCM. Independent laboratory results indicate THERM-A-GAP GEL 75 passes the NASA outgassing criteria for low-volatility material. 

Based on these results, THERM-A-GAP GEL 75 demonstrates the ability to withstand long-term aging without a reduction in thermal performance. THERM-A-GAP GEL 75 is best suited for high volume, automated production, specifically found in telecommunication applications, base stations, power supplies, and memory and power modules.

Learn more about THERM-A-GAP GEL 75 and receive a free product sample.

 

 

 

This blog post was contributed by Jarrod Cohen, marketing communications for Parker Chomerics. 

 

 

 

 

 

 

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In the Oil & Gas industry, the need for elastomers to seal higher pressures for sustained periods of time with minimal damage is abounding. Applications such as drilling tools, completions equipment, blow out preventers, and subsea pressure control systems now routinely require or exceed 15,000 psi with both liquid and gas media for functional testing and qualification. Parker meets this challenge, providing a best-in-class extrusion and rapid gas decompression resistant hydrogenated nitrile (HNBR) compound called KB292.

  Background

One of the most common failure modes for seals utilized in high pressure applications is known as extrusion or nibbling.  This failure method emerges when the seal material is forced into a clearance gap that is present between the mating substrates and gradually can be cut, nicked, or chewed away.  Typical applications which can see this transpire include dynamic reciprocating cylinders and/or vessels where pressure fluctuations cause clearance gap to open and close trapping the seal between mating surfaces.  The higher the pressure or the larger the clearance gap that is present, the more likely extrusion or nibbling is to occur.  Once a mass of the material is removed from the seal geometry it is inevitable that a leak will eventually form which normally results in failure of the system.  Section 10 of the Parker O-Ring Handbook highlights extrusion and nibbling as well as includes several suggestions for prevention.

 

 

 

 

 

 

 

 

 

Another failure mode which can be seen for high pressure gaseous applications is known as Rapid Gas Decompression (RGD), also referred to as Explosive Decompression (ED). This damage arises after a period of service under high pressure gas, when pressure is reduced too rapidly, the gas trapped within the internal structure of the seal expands rapidly, causing small ruptures or fissures to develop. There are many Oil and Gas industry standard tests which have been developed to determine whether compounds are RGD resistant. Parker routinely tests and acquires certificates for these standards which can be supplied upon request for end user documentation.  Our Oil & Gas Reference Guide outlines our numerous materials, temperature ranges, recommended uses, and a list of approved certifications by material. 
 

        New Technology

To combat seal damage and the typical failures in high pressure applications, Parker has developed material KB292. This hydrogenated nitrile (HNBR) based material has been formulated with physical properties which allow it to withstand exposure to the highest-pressure environments with extreme extrusion resistance. With hardness of 95 +/- 5 Shore A points, KB292 is one of the hardest elastomers in the Parker OES material offering. The extreme extrusion resistance is also identified with a modulus value of 2500psi at 50% elongation as well as excellent abrasion and tear resistance. The material offers good compression set and chemical resistance that is expected from all Parker HNBR’s used in the O&G industry. Additionally, Parker's KB292 has been tested to and passes the requirements of ISO 23936-2 RGD which shows excellent resistance to explosive decompression for high pressure gas applications.  

For more information about the KB292 compound, reference Parker’s OES 7003 technical bulletin or chat live with an applications engineer by visiting our website.  

 

 

Nathaniel Sowder, business development engineer, Parker Hannifin O-Ring & Engineered Seals Division

 

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Robotic surgery systems or robot-assisted surgery, offer immense patient benefits -- from shorter recovery time, to better surgeon visualization, which leads to a more precise, effective and successful surgery. Robot systems are used for various surgical procedures, including urologic, gynecologic, cardiothoracic, general, and head and neck surgeries. Manufacturers and designers of these surgical systems are now focusing on robot specialization instead of all-encompassing surgical systems.

This means there will be more specialized systems developed to perform specific surgeries, and the breadth of those procedures is expanding too. General surgery uses are increasing the fastest, followed by gynecology and urology uses. In 2017, there were 877,000 robotic surgeries performed in the US alone. That number is expected to rise exponentially in the years to come.

Any medical device that employs onboard electronics can be impacted by EMI

Robotic surgery system manufacturers and engineers consider EMI shielding when designing their systems. EMI shielding prevents equipment failure and keeps manufacturers compliant with federal regulations. Understanding EMI and taking steps to prevent it is paramount, as the resultant issues could cause robots to behave unexpectedly, such as requiring frequent restarts, showing a limited radio frequency range, moving unintentionally or affecting other nearby robots.

Remember, EMI is when electromagnetic emissions from a device or natural source interfere with another device or system. EMI might occur if the following three factors are present — the source of EMI, a coupling path and a receptor.

The coupling path from the source to the receptor can be either an electric current, magnetic field or an electromagnetic field. The EMI source can be a natural source, such as lightning. It can also come from devices such as radios, computers, wireless networks, cell phones or any electric device designed to transmit signals.

Robotic surgery systems are computer controlled, and therefore sensitive electronic components must be shielded from electromagnetic interference (EMI) and generated heat must be effectively dissipated from various integrated circuits (ICs). On top of these stringent requirements, components must be able to withstand high heat sterilization, and resist damage caused by harsh chemical cleaning agents in the hospital environment.

Discover the top four EMI shielding and thermal interface material applications for robotic surgery systems

1. Electronics generate heat. Thermal interface materials are used to dissipate heat away from the heat generating component onto a heatsink. This task is completed by using a thermal interface material (TIM). Popular TIMs include thermal gap pads and thermal dispensable compounds. Parker Chomerics manufactures thermally conductive gap filler pads which offer excellent thermal properties and the highest conformability at low clamping forces. There are a variety of thermal performances available from 1-6.5 W/m-K thermal conductivity.
    
2. Electrically conductive elastomers are reliable over the life of the equipment, and the same gasket is both an EMI shield and an environmental seal. Electrically conductive elastomer are available in many different conductive filler and binder options, in virtually any size or shape you can design.
    
3. Electrically conductive plastics provide "immunity" for sensitive components from incoming electromagnetic interference (EMI) and/or prevent excessive emissions of EMI to other susceptible equipment. Available in a variety of available options.
    
4. Electrically conductive paints and coatings are available in a variety of options, designed for high levels of EMI shielding on plastic or composite substrates.

With proven solutions in EMI shielding and critical thermal management, Parker Chomerics gives you a wealth of integrated, multi technology systems and components that meet or exceed your specifications and expectations.

 

 

 

 

 

 

 

 

 

 

 

 

 

This blog post was contributed by Jarrod Cohen, marketing communications for Parker Chomerics.

 

 

 

Related Articles:

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2. Form-In-Place Gaskets: What They Are and What They Are Not

3. New Thermal Gel Benefits Consumer and Automotive Applications

Have you been frustrated with going through multiple design iterations when rubber components are failing due to high stresses or your device has been leaking due to insufficient compression? Have you lost months and months of precious time having to recut tools and make design changes?

 

FEA takes out the guesswork

Finite element analysis (FEA) is an effective tool used in design iterations. It allows for different design ideas, options, and alterations to be quickly, effectively, and precisely compared. 

Using FEA can improve both the speed and quality of product design as well as reduce the overall cost. Rubber parts, such as silicone diaphragms, septums, seals, valves, tubing, and balloons are critical components in today’s medical devices that can benefit from the use of FEA. It can be an excellent design tool to improve the functional performance of these devices. FEA for rubber products is actually far more complex than for metal or plastic products. It requires sophisticated nonlinear FEA software  - such as MSC Marc - as well as a good understanding of the material behavior, material modeling, and testing requirements.

Rubber is highly stretchable, flexible, and durable. This blend of elastic properties differentiates rubber from other materials and makes it one of the best choices for many components in medical devices. However, it’s important to note that rubber materials are not 100 percent elastic because they can develop compression sets and force decay, causing eventual performance degradation and shorter useful life.

 

Nonlinear FEA for rubber products 

Normally, there are three types of nonlinearities encountered: kinematic nonlinearity, material nonlinearity, and boundary nonlinearity. Additionally, rubber products are often subject to large deformations. Whenever material experiences large deformations at least two kinds of nonlinearity - kinematic and material - are involved.

Commonly used nonlinear material models in FEA are elastoplastic models for metals and plastics and hyperelastic models for rubber. in addition, the boundary nonlinearity is usually associated with large deformations.

What are the best test modes to use? One basic engineering rule should apply: always design and perform tests that most closely simulate the actual application conditions that the finished component or device will experience. 

 

Rubbers are almost incompressible

In general, rubber materials are considered nearly incompressible, simply because their volume change is negligible for most applications as a result of that their bulk modulus (105 psi) being several orders larger than their shear modulus (102 psi). The rubber material is actually much more compressible than metal in a confined state (the bulk modulus of typical steel is 107 psi). This understanding is very important to the design considerations of elastomeric products, especially when thermal expansion, limited groove space, or compression of high aspect ratio parts are involved.

 

Simulation accuracy and relativity 

Many factors affect the accuracy and reliability of FEA results,  such as material modeling, geometry simplification, and numerical methods. FEA is mostly used in design iterations for which relative comparison is sufficient in the majority of instances. When analysis results are interpreted in a relative sense, different design ideas, options, or modifications can be compared effectively and accurately, and most importantly, rapidly. Furthermore, some tested cases may already exist and can be used as references.

 

FEA improves product design

FEA is a powerful tool for the development of rubber components for medical devices. The proper use of FEA can minimize physical prototyping and provide for concurrent engineering. It greatly improves both the speed and the quality of product design, as well as provides cost savings.

Parker has more than 20 years of testing experience with FEA. For more information on Parker‘s use of FEA watch our detailed video - Accelerating Your Launch: Reducing Design Iterations with FEA.

Check out all of our Sealing solutions for Life Science applications including featured applications for Diabetes Care, Surgical, Respiratory, Drug Delivery Systems, and more! 

 

 

This post was contributed by Albena Ammann, life science development engineer, Engineered Materials Group, Parker Hannifin.

 

 

 

 

 

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In our recent webinar about electrically conductive sealants and adhesives, our experts covered many topics from electrically conductive filler packages to the physical properties of the materials like adhesive strength, flexibility and working life. Did you miss Introduction to Electrically Conductive Sealants and Adhesives? Watch it now.

The viewer learned the difference between an electrically conductive sealant and an electrically conductive adhesive, why you’d choose one over the other, and the design considerations you need to take now.

During the Q&A portion of the webinar, our experts fielded your excellent questions, so we’ve rounded up our eight top favorites for you below.

1. Are there any major chemical incompatibilities that may cause issues with applying an electrically conductive sealant with a non-conductive sealant on apart simultaneously?
   
   With platinum cured silicone systems, sulfur is one contaminant that's known to kill the cure of these materials. There are other materials that kill the cure of silicone materials such as fatty acids. You must be careful when you're using two different types of polymer systems, each with different types of cure systems on the same part. It is something that you want to make sure that there's no interaction between the two systems.
    
2. Can you describe the difference between flame, corona and plasma treatments?
   
   A flame treatment is the use of actual a gas flame right against the surface of the of the part. Flame treatments, corona treatments and plasma treatments all aim to accomplish the same thing: increase the surface energy of the part and improve adhesion. 
   
   Plasma treatment usually requires a high energy gas in a vacuum type environment. It's more of a batch process, but that's also very effective in increasing the surface energy of plastics. Corona treatment is the application of an electrical arc on the material. These treatments are usually done right before you intend to cure the material into the part. You want to apply the electrically conductive sealants or adhesive right after these surface treatments, because over time, the surface energy will decrease. And the advantage of the gains that you get by using these surface treatments will be reduced.
    
3. Do electrical properties vary with cure temperature?
   
   The higher the cure temperature, the greater both the mechanical and electrical properties are. With these cross-linking systems, you typically get a more dense and tighter cross-link at the higher cure temperatures, and that's what gives you the better mechanical and electrical properties. 
    
4. Is a silver-aluminum filled electrically conductive sealant silver-over-aluminum or aluminum-over-silver?
   
   A silver-plated aluminum particle is on the outside. In many electrically conductive fillers, the outside is either silver or nickel plating over an aluminum particle, a glass sphere, potentially a copper or a graphite particle.
    
5. Over time, is there degradation of conductivity due to oxidation of particles?
   
   With silver-plated copper materials, there can be some degradation over time in oxidation, especially in higher temperature applications. Be sure to note the high temperature limit of the material you’re interested in. Some of our silver-plated copper particles have an organic coating or other stabilizing surface treatment which helps to reduce the oxidation over time. While it is true that there are some silver copper particles that may show degradation or oxidation over time, especially at higher temperatures, specifically, there are other silver-copper fillers that that we offer that don't show that same degradation. It's specific to the filler itself.
    
6. How do you spec an electrically conductive fillers for particle size, shape, and surface area?
   
   For particle size, shape and surface area, we use a Microtrac to characterize the particle size distribution, because most of these particles are not one size. There’s usually a particle distribution for different conductor fillers. The shape of the filler particle also has a huge impact on how it's going to perform in an adhesive or in a sealant. Over years and years of testing and analysis of our conductive fillers, we found out that you don't want to design in a spherical particle for any application where you might see a lot of vibration, like a rotorcraft or aerospace type application, because typically when you vibrate conductive particles that are spherical shape, the electrical performance of the shielding will degrade.
    
7. My products are exposed to terrible conditions such as salt fog, jet fuel, low pressures, high temperature swings, mold, vibration and 30-year lifetime. Any suggestions for keeping our RF covers in place?
   
   Combining electrically conductive sealants or adhesives with an electrically conductive coating will help with these requirements as described above. An electrically conductive coating may help in terms of sealing surfaces and providing a longer field life. Additionally, using an electrically conductive elastomer gasket against fuel splash and salt fog may help protect the internal components, as conductive elastomers are designed for both harsh environments and long field life.
    
8. What effect does a high number of thermal cycles have on RF performance of electrically conductive sealants and adhesives? Specifically, I need performance from 1 - 40 GHz and hundreds of cycles from - 55°C to 105°C.
   
   Our materials are run through thermal cycle testing and we test EMI shielding before and after various thermal cycles. It usually has a lot to do with the type of material and the substrate the material will be applied to. Also, how it will perform after thermal cycling will deepened on how closely the coefficient of thermal expansion is between the compound and the substrate that you're applying the compound to. Other things can influence EMI shielding performance following thermal cycling, like particle size and shape and filler loading of the material. It is important test to the specific substrate that you're going to put these materials on in thermal cycling to determine the outcome.

Did you miss this webinar, or maybe want to watch it again? Watch it for free on-demand now.  And so you don’t ever miss another, be sure to sign up for our upcoming webinars.

 

 

 

 

 

 

This blog was contributed by Jarrod Cohen, marketing communications manager, Parker Chomerics.

 

 

 

 

 

 

Related articles:

• 6 Tips When Selecting an Electrically Conductive Adhesive
• EMI Shielding Caulk Delivers Superior Performance in Military Radar Systems
• Surface Preparation for Painting Conductive Coatings

 

 

 

Improvements to a drug delivery system (DDS) can control the consistency and increase the quality of drug delivery. Parker’s self-sealing polyisoprene is designed to improve on existing systems available in the market. Parker’s USP <381> self-sealing polyisoprene elastomers demonstrate exceptional self-sealing capabilities, even with needles as large as 16-gauge. Due to the minimal force required for piercing, our material is ideal for seals and septa used in infusion systems and insulin pumps. Using our USP <381> polyisoprene material may improve septum performance and user safety for doctors, nurses, and patients.

 

The advantages of self-sealing

A needle, as large as 16-gauge, can pierce the polyisoprene septa as many as 20 times with no trace of leaks. Good self-sealing properties ensure that when the needle comes out, the drug stays in. Our self-sealing polyisoprene is non-coring. After piercing, there is no visible fragmentation and therefore no tiny pieces to clog the system or contaminate the fluid. This is important to maintaining the purity of the drug throughout the delivery process and ensuring a safe transfer to the patient.

Parker’s self-sealing polyisoprene meets USP <381> standards for the functional testing of closures intended to be pierced by a needle. It also meets biological testing as defined by USP <88> and USP <87> for in vitro and in vivo testing, respectively. Our self-sealing polyisoprene passed the biological reactivity and systemic injection tests. The material is biocompatible and has shown no harmful reactions or toxic effects.

Using Parker’s self-sealing polyisoprene for seals and septa in insulin pumps and infusion systems provides improved performance, ease of use, and increased safety due to elimination of leaks and reduction of blockages. This pioneering material allows medical staff to have seals and septa that can be pierced multiple times during use with no leaks. The development of this new product is an exciting prospect for the drug delivery market.

Our facilities are located near major cities to enable easy distribution. Contact us for more information on how we can improve reliability with your drug delivery system. 

 

 

This article was contributed by Saman Nanayakkara, Engineering Manager, Parker Hannifin Composite Sealing Systems Division.

 

 

 

 

Related, helpful content for you:

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