This is the first part in a two-part blog post series answering the questions you asked during the webinar Selecting a Thermal Gel or Thermal Gap Pad now, available on-demand.

The objective of thermal management programs in electronics packaging is the efficient removal of heat from the semiconductor junction to the ambient environment. While selecting a material for your application can be daunting, two of the most popular thermal interface materials you should consider are thermal gap filler pads and dispensed thermal gels.

In our recent webinar Selecting a Thermal Gel or Thermal Gap Pad, available on-demand, our team of thermal material engineers answered your top 14 most interesting and thought-provoking questions, starting with #14 below. 

14. What is the difference between thermal resistance and thermal impedance?

Thermal resistance is a measure of how a material of a specific thickness resists the flow of heat. Thermal impedance is a more comprehensive value as it is the sum of the material thermal resistance as well as the contact resistance. 

Because real surfaces are never truly flat or smooth, the contact plane between a surface and a material can also produce a resistance to the flow of heat. Surface irregularities on a micro-scale and surface warp on a macro scale create contact points and microscopic air-filled voids. Air voids resist the flow of heat and force more of the heat to flow through the contact points. 

This constriction resistance is referred to as surface contact resistance and can be a factor at all contacting surfaces.

13. What does PEN stand for when referring to your PEN film carriers for thermal gap pads?

PEN stands for polyethylenenaphthalate and is a common carrier used to improve the durability of thermal gap pads. This carrier permits the gap pad to see a shearing motion and offers a clear, cost-effective dielectric film with fair thermal performance. 

12. Do THERM-A-GAP GELs cure?

One of the most important properties of thermal dispensable GELs is that there is no cure required, as they are supplied in a fully cured state from Parker Chomerics. THERM-A-GAP GEL materials do not change properties once dispensed and do not require any processing after being dispensed. 

Used within the limits of recommended operating conditions, GELs will not be become brittle, will not harden, will not flow, and will not soften over time. 

11. What are the re-workability requirements for thermal GELs and gap pads?

THERM-A-GAP gap filler pads have a very easy work process. They can be easily peeled off and replaced with identical gap pads. Using a clean cloth with a solvent such as an isopropyl alcohol (IPA) will clean the surface and help reduce contact resistance as well as adhesion of the pads. The rework process for thermal GELs is similar. 

Using a rag with a bit of IPA or similar solvent, simply wipe the previous gel away. Re-dispense the necessary amount of gel back onto the board or component and the process is complete. GELs should be re-dispensed every time the enclosure is opened. 

Gap filler pads are more durable but should be replaced if the enclosure is opened after being in a compressed state for an extended period. 

10. Do THERM-A-GAP GELs or gap filler pads experience long term creep?

THERM-A-GAP GELs and thermal gap filler pads go through extensive reliability testing (based on automotive standards) to ensure long term product survivability. GELs are formulated to resist sagging or flowing out of applications, especially in properly compressed situations. 

THERM-A-GAP thermal gap filler pads, even in vertical applications, should not move out of applications if proper compression is maintained. Gap pads will experience a compression set and should be replaced after extended periods of time in a compressed state. 

9. How do you calculate the quantity of gel to be dispensed?

Our applications engineers would be happy to help support calculations on gel volume, but the general principle is that you are looking for 80-90% of the total compressed volume. Multiplying the surface area of the component by the nominal compressed height will yield a volume that should be multiplied by 80-90% to get a starting point for gel volume. It is important to consider the expected gap height variation as well. 

8. What are some current standards or specifications for THERM-A-GAP GELs and putties?

We meet ROHS standards with all our thermal materials and meet ASTM standards with regards to the thermal and electrical properties. Reliability testing is conducted on our GELs and putties with tests based on automotive standards such as GMW 3172. 

7. Does Parker Chomerics have internal manufacturing capabilities for cutting gap pads?

Parker Chomerics can cut thermal gap filler pads to nearly any shape or size. We have a variety of cutting techniques that can be used for complex geometries and higher volume repeatability. Select your material we’ll get started on your quote right away.

Stay tuned for part II as we dive into more of your questions. Be sure to watch the webinar on-demand below!

this blog was contributed by Ben Nudelman, market sales engineer, Parker Chomerics Division.

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The Difference Between Thermal Conductivity and Thermal Impedance

This is the second part in a two-part blog post series answering the questions you asked during the webinar Selecting a Thermal Gel or Thermal Gap Pad now, available on-demand. Missed part 1? View it here now.

The objective of thermal management programs in electronics packaging is the efficient removal of heat from the semiconductor junction to the ambient environment. While selecting a material for your application can be daunting, two of the most popular thermal interface materials you should consider are thermal gap filler pads and dispensed thermal gels.

You asked us a variety of interesting and thought provoking questions during the webinar, which our team of thermal material engineers have answered below.

6. What is the recommended surface roughness for THERM-A-GAP thermally conductive gels?

A surface roughness of N8 (3.2 micro-meters or 125 micro-inches) or rougher is recommended for use with thermal gels

5.  Are all your thermal interface materials electrically insulating?

All Parker Chomerics thermal interface materials are meant to be thermally conductive and electrically insulating. This is accomplished by using ceramic particles in a silicone binder system. 

4. What incremental thickness are thermal gap pads offered in?

Thermal gap filler pads are available in standard thicknesses from 0.010” to 0.200”. They are traditionally available in increments of 0.010” or 0.005” but we are able to create gap pads to meet any nominal thickness

Are the thermal gel materials non-Newtonion, where viscosity is a function of shear rate?

Yes, our thermal gels and dispensable putties are Non-newtonian. Please see the blog post about viscosity and flow rate of these materials:

Are there any plans to develop silicone-free formulations?

Silicone is far and away the most common binder material, as it offers a greater operating temperature range than non-silicone options. However, Parker Chomerics does have a non-silicone option for thermal gels. GEL 25NS is a 2.5 W/m-K thermal gel with the NS in its name designating its binder package as being non-silicone.. 

What are the shelf lives for gels and pads? 

Thermal gap pads have an indefinite shelf life with the exception of those that come on an aluminum carrier with PSA. These gap pads have an 18-month shelf life from date of shipment. Thermal gels have a shelf life of 18 months from date of manufacture. 

Will dispensing equipment wear due to abrasive filler particles in Gels? 

To achieve high thermal conductivity, THERM-A-GAP GEL materials are highly filled with ceramic particles. Due to this high loading, the thermal compounds have higher viscosity and may be abrasive to dispense equipment. Material selection should be defined prior to selecting equipment to optimize the material performance and long-term equipment maintenance. The proper equipment choice will be a function of geometry, throughput requirements, material type, and package.

To successfully dispense GELs with minimal impact to physical properties, simple ram/piston pump systems with adequate force capability have proven most reliable. Reciprocating pumps, gear pumps, or other complex pumping designs impart excessive stress on the material. Pump systems that have a high degree of mechanical interaction with the material may increase maintenance needs due to the high concentrations of thermally conductive and abrasive fillers. 

The valve that dispenses or controls the amount of material dispensed needs to be constructed of wear-resistant components to endure the maximum number of cycles. The most successful valves use a progressive cavity (ie. displacement type option) and are geometrically simple.

Be sure to watch the webinar on-demand below! Have questions or feedback? Reach out to us, we'd love to hear from you.

This blog was contributed by Ben Nudelman, market sales engineer, Parker Chomerics Division.

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How to Identify Quality Thermal Gap Fillers in Four Steps

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The Difference Between Thermal Conductivity and Thermal Impedance

As well as pharmaceutical production based on complex organic molecules, manufacturing of advanced biologic drugs and vaccines must ensure that in-process contamination risks are mitigated as effectively as possible. Tailored polymer-based single-use fluid management solutions offer a range of significant safety and efficiency benefits over conventional glass- or steel-based multi-use systems specifically to biopharma manufacturers.
 

In addition to safety aspects, biopharma manufacturers are particularly challenged to achieve cost efficiencies in a wider variety of laboratory settings and production scenarios, i.e. from very small to medium to larger scales, depending on the type of vaccine or drug and scope of therapeutic application. Another key challenge is the prevention of costly losses of these complex and typically high-value products due to in-process leakage or contamination. Last but not least, vaccine manufacturers may have to quickly and efficiently ramp up their production volumes in response to suddenly emerging increases in demand. Conversely, processes must allow for equally easy down-scaling when demand drops.  

The utilization of customized, fully scalable polymer-based single-use fluid management systems yields major safety, cost efficiency, and flexibility/scalability benefits and thus are highly suitable for meeting all of the above challenges.   

Drawing on many years of experience in the field of polymer materials and clean room production as well as extensive knowledge of biopharmaceutical processes and validation procedures, Parker Prädifa assists in identifying and maximizing the potential applications of single-use systems in laboratory and production environments.   

The available solutions range from standardized TriClamp sanitary gaskets to highly customized solutions. They are based on a cost-effective open architecture and manufactured from approved TPE and LSR materials using state-of-the-art proprietary overmolding technology.

The support by a specialized team of industry experts starts with product design and culminates in a final, fully scalable, and ready-to-use solution ensuring that all regulatory and safety requirements are met. Every single-use solution is precisely tailored to the existing, validated production framework and provides significant overall system cost reduction potential.

Manufacturing, assembly, and packaging processes in certified cleanrooms are a basic prerequisite for serving pharmaceutical and biopharmaceutical customers. In Europe, Parker Prädifa operates two cleanroom production facilities: one in Sadska (Czech Republic) certified according to ISO 14464 Class 7 and one in Pleidelsheim (Germany) certified according to ISO 14464 Class 8.

Additional information:

• Industry Page: www.parker.com/praedifa-biopharma
• Brochure: Single-Use Systems - Tubing Manifolds and Container Systems
• Product Catalog: Single Use Systems
• Webinar: Risk Mitigation in Biopharma through Single-Use Fluid Management Systems 
  
   

Posted by Dr. Heinz-Christian Rost, market unit manager life sciences, Engineered Materials Group Europe, Prädifa Technology Division

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The advent of new and advanced technology has revolutionized the space industry, ushering in a new era of innovation and change brought by private space companies. 

Parker Chomerics was recently honored by one customer for its engineering accomplishments in the development and application of its EMI shielding and thermal interface materials for challenging applications in private aerospace.

Private space flight companies have increased over the last few decades as more and more government-run agencies are now depending on these private companies to provide technology and engineering support for future space missions. 

Getting more companies involved in space missions will “lower the cost and lower the risk” of doing business in outer space, said former NASA chief financial officer Jeff DeWit.

Many companies who have extensive resources and those who have been in the aerospace market for decades are now looking to these relative startups for their new, innovative approach to space technology development. 

“Our technology portfolio and material science know-how gives Parker Chomerics a unique advantage,” says aerospace & defense market specialist Sierra Eiden. “We’ve been working hand-in-hand with the established aerospace and defense players for decades, and this experience allows us to bring our knowledge and expertise to the private space startups as well.”

Parker Chomerics has helped to address the emerging EMI shielding and thermal interface material needs of the private aerospace industry, while simultaneously aligning with large scale manufacturing protocols and design. 

In one private aerospace application, the customer chose the one-part Parker Chomerics THERM-A-GAPTM GEL 37 dispensable thermal gel because of its unique combination of both a high thermal conductivity, at 3.7 W/m-K, and 30 g/min flow rate, coupled with its consistent and repeatable dispensing compared to leading products in the market today. 

This design for repeatable dispensing helps to “minimize batch-to-batch flow rate variations which increases efficiency and reduces downtime during the manufacturing process,” says Parker Chomerics thermal product line manager Callie King. "And it's particularly suited for spaceflight due to its lower specific gravity compared to other thermal interface materials."

THERM-A-GAP GEL 37 also has passed 1,000 hours of gap stability testing and more than 1,000 hours of thermal cycling testing without any material cracking or degradation in thermal conductivity.

Parker Chomerics regularly tests outgassing of its materials to the industry standard test ASTM E595, developed by NASA to screen low outgassing materials for use in space. THERM-A-GAP GEL 37 registers 0.18% TML and 0.07% CVCM, meeting these low outgassing standards.

The team of application engineers at Parker Chomerics is ready to assist and help with design and technical questions for your space applications. Contact us now to get started.

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

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What can be done if a bore requires radial sealing but lack of a lead-in chamfer prevents the installation of a seal? A situation like this occurs for instance when an existing bore should be closed with a cover and space around the bore is too small for a classic flange seal. A seal would not survive an attempt to install it in a bore without a lead-in chamfer. Part of the seal would be sheared off at the edge of the bore even if the edge was chamfered or rounded.

The Roll2Seal® concept solves this problem. Instead of destructively squeezing the seal at the critical edge it is simply made to roll across it. This is achieved by providing the cover with a geometry which, together with the edge of the bore, forces the seal to rotate. Subsequently, the triangular cross-section of the seal makes it possible for the seal to roll off at the dangerous edge of the bore with a minimum seal height and thus without risk of seal damage.
 

Roll2Seal®

• Innovative geometry
• No lead-in chamfer
• No deburring
• No lubrication
• Immune to unbroken edges of the bore
• Metal or plastic cover
• Available in pre-assembled condition
• Easy installation
• Suitable for repeated and overhead installation
• Space- and cost-saving

• where bores already exist for subsequent installation of additional component assemblies but require effective temporary or permanent sealing (e.g. for test runs or shipping),
• where lubrication during the assembly process is not possible,
• where non-pressurized systems require reliable sealing without screw connections.

Additional information:

• Website 
• Webinar
• Brochure
• Video
  
   

Posted by Samuel Brenner, application engineer, Engineered Materials Group Europe, Prädifa Technology Division

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The growing connected vehicle and electric car markets are currently driving up demand for IP-rated (Ingress Protection rating) and EMI protection. Even standard road vehicle electronics need to be increasingly protected environmentally and electrically.

Vehicle functionality is being taken over by sophisticated electronics and these systems need protection against EMI and environmental elements such as dust, dirt, and water to operate efficiently.

This trend is also seen in the defense industry and today more than 20% of vehicle designers (commercial and military) who approach Parker Chomerics, need a solution for both EMI and environmental protection. 

The IP code, or Ingress Protection rating, is an international standard EN/IEC 60529 which is used to define the level of sealing effectiveness of an electrical enclosure or mechanical casing against intrusion from environmental elements. In addition, international standard ISO 20653 is used for IP degrees of protection specifically for road vehicles. Parker Chomerics offers a range of EMI shielding gaskets and seals that are being used to meet this growing IP rated environmental exposure demand.

Some of the most common IP ratings required by vehicle manufacturers include IP65, IP66, IP67 and IP69.

The IP rating can be identified by the letters IP, followed by two numbers such as 65 (IP65). The first number refers to the amount of projection the enclosure has against a specific solid element, in this case ‘6’, indicates full protection against dust.  The enclosure is dust tight. The second number defines the level of protection against liquids -  see below.

• IP65 – The enclosure is dust tight and protected against jets of water. Parker Chomerics CHO-SEAL® Co-Extruded gasket profiles LD55 and LH10, when used as elastomer gaskets in a groove, are an ideal solution. 

• IP66– The enclosure is dust tight and protected against strong jets of water. 

• IP67– The enclosure is dust tight and provides protection against temporary immersion for up to 30 minutes at depths between 15cm and 1 meter. Again, a CHO-SEAL® Co-Extruded gasket in a groove creates an effective all-round solution to this meet this requirement.

• IP68– Is not applicable in vehicle applications as it relates to protection against continuous immersion.

• IP69– The enclosure is dust tight and is protected against both high-pressure and high-temperature jets of water.

• IP69K– Provides the same protection as IP69 but with additional resistance to wash-down and steam-cleaning procedures. This rating is most often seen in specific road vehicle applications.

As outlined above, there is similarity between EN/IEC 60529 and ISO 20653. The EN/IEC 60529 standard was updated to include the IPX9 water ingress test. This test is essentially identical to the IP69K test from ISO 20653. The “K” tests specify special requirements for road vehicles.

The design engineer must consider any EMI shielding and environmental requirements at the conceptual stage of a project in order to protect and extend the lifetime of the electronic system. The customer would benefit from partnering with a reputable EMI shielding technology specialist such as Parker Chomerics, as EMI shielding and sealing materials can be developed and designed specifically for the customer's application.

With such a marked customer-driven trend, it is important to specify the optimum IP rating required for an EMI shielding gasket or seal. However, the rating depends very much on where the EMI shield will be located on the vehicle, and to what elements it will be exposed. For example, typical vehicle applications range from automotive control boxes through to a multitude of requirements in the engine and undercarriage, all which will be particularly demanding from an environmental perspective.

In an application such as a car door, the door itself will deflect most of the water pressure encountered during road use, with the rubber seal being secondary (jets of water will not come into direct contact with the gasket). However, this does not mean the seal is of secondary consideration. Elastomer gaskets with deflection characteristics, along with appropriate mechanical design factors, are recommended to meet IP69 and IP69K requirements.

For applications where a cost-effective solution is required, a well sized – preferably 3mm solid O-section that is galvanically paired with the mating surface, would deliver protection against both EMI and water. Galvanic compatibility is vital in applications where the gasket might be in contact with a component such as an aluminum surface, as conductivity factors come into play and compatibility between metals must be ensured.

Aside from dust and water, there are many other factors to consider when specifying a suitable gasket/seal. For example, road vehicle applications could be exposed to extreme temperatures during the summer and winter months and in some applications, fire retardant and chemical resistant materials are required.

No matter how challenging, there is a solution for every application requiring EMI and environmental protection and by working closely with a specialist such as Parker Chomerics, customers can benefit from testing services that are application specific and in line with the customer requirements. 

Other Parker Chomerics solutions widely used in road vehicle applications are CHO-FORM® Form-In-Place EMI Gaskets and THERM-A-GAPTM Thermal Interface Materials.

This blog was contributed by Melanie French, marketing communications manager, Parker Chomerics Europe.

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Honeycomb air vent panels are used to help cool electronics with air flow and while maintaining electromagnetic interference (EM) shielding. Recently, our team of experts held a webinar on EMI shielding air vent panels, now available on-demand. This blog post will highlight some topics discussed on the webinar.

The thickness of the air vent panel also has an impact on both the air flow and the shielding effectiveness. If the cell size were kept the same, the lower the thickness of the vent panel, the greater the allowable air flow. 

The decreased air flow is caused by the surface friction of the air flowing through the honeycomb cells. However, reducing the vent thickness will also reduce the attenuation capabilities of the honeycomb. Again, the key is to try and find the middle ground between good air-flow (less pressure drop) and shielding effectiveness.

Aluminum honeycomb is made from thin ribbons of bent aluminum that are adhered together using a non-conductive adhesive. The points at which the ribbons come together are known as nodes and can cause EMI shielding leakage. With single layer honeycomb vents, there is actual directional EMI shielding. This is known as the polarization principle. 

It’s also important to note that this is only the case with aluminum honeycomb vents because with brass and steel vent construction, the nodes are welded together and therefore are inherently conductive. 

One way to reduce the directionality of attenuation in vent panels is by using what Parker Chomerics calls an OMNI CELL construction. This means that a second layer of aluminum honeycomb is stacked on top of the first at a 90-degree angle.

The directionality is offset by the second layer and the new panel should have nearly equal attenuation in both directions. One small drawback is that the two layers will reduce air flow across the new vent panel.

OMNl-CELL can be a great option in many cases, but for applications where an OMNI-CELL construction will not work because of space or high attenuation needs, you can achieve the same effect by plating the honeycomb. The plating of aluminum honeycomb will bridge the non-conductive node, and eliminate the directional effect of the honeycomb.

It’s also a much more thorough coverage, which results in better shielding. Platings will protect the vents from corrosion and standard wear and tear. Electroless nickel is one of the most common plating option, as is a chromate conversion coating.

And lastly, EMI vents can be coated with aesthetic paints to match any enclosure design. This includes CARC paints and common military color patterns. 

Want to learn more about specific applications and get more detail? Watch our on-demand webinar EMI Shielding Honeycomb Air Vent Panels: Application and Design 101 now!

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

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Fluids play a critical role in sustaining life. Keeping animals and humans hydrated and helping plants grow are obvious ways. Less obvious ways include moving cargo around the world and keeping equipment operating (hydraulic oils, coolants, engine oils, etc.). All these applications require seals of some sort ranging from public water systems to hydraulic pumps. What happens when these fluids become aggressive? People typically think of acids as being an aggressive media, but for many fluoroelastomers, bases are more aggressive presenting severe challenges. Using material science and technology, Parker has created a new class of Base Resistant (fluoro) Elastomer (BRE) compounds. 

The beginning of useful fluoroelastomer polymers (FKM) was introduced in the early 1960’s. Since that time, FKM materials have come a long way and improved in many areas ranging from fluid resistance to low and high temperature performance. In 1975, Asahi Glass Ltd. introduced a new polymer under the name of Aflas®. The composition of this polymer gives it a slightly improved high temperature range, but also imparts the polymer with a wider range of fluid compatibility. One area that Aflas® excels in is high pH (basic) fluids. Traditional FKM polymers will become stiff and embrittled with long term exposure to basic fluids. While Aflas® has benefits in basic fluids, it also has some significant downsides. The two main downsides are it’s low temperature performance and swell in some hydrocarbons. One measure of low temperature performance is a materials glass transition temperature (abbreviated as Tg). The Tg is the temperature at which materials transition from being soft and pliable to being rigid and glassy. The Tg of many Aflas® materials is -3°C, whereas some FKMs can reach below -40°C. 
 

Parker’s new BRE compounds offer the best of both worlds. Designed specifically for the oil and gas market but applicable to any market space, these materials exhibit improved base resistance over traditional FKMs while possessing improved low temperature and hydrocarbon performance over Aflas®. 

These new compounds are named VP309-80 and VP316-90 . They are 80 and 90 Shore A durometer respectively. Both are designed to be all-encompassing material options and possess a balance of properties between traditional FKM and Aflas®. As shown in the spider chart at the right, Parker’s BREs are formulated to fill a broader design space when compared to ASTM D1418 Type 1 FKMs and Aflas®. Even when compared to more chemically resistant FKM types, Parker’s BRE compounds show improvements in high pH fluid resistance. 

Utilizing Parker’s experience in molding and extrusion technologies, these new compounds can be processed into a wide variety of products ranging from small O-rings to thick cross section downhole packing elements. Combining the BRE compounds with Parker LORD’s adhesive options result in a material that can be molded to a variety of substrates and resist aggressive media in harsh conditions. Both VP309-80 and VP316-90 are ISO 23936-2:2011 Rapid Gas Decompression (RGD) tested and approved. VP316-90 has also been tested in H2S according to NACE TM0187.

While these materials were specifically developed for the oil and gas market segment, they can find uses in a variety of other markets such as aggressive gear lubes for pumps and aggressive fluids utilized in automotive and chemical processing industry (CPI) applications. 

For more information on these materials, download our the Parker OES 7004 brochure or visit the Parker O-Ring & Engineered Seals Division website to chat with our applications engineers.

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

Ryan Gruell, materials engineer III, Parker Hannifin O-Ring & Engineered Seals Division

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The popularity of electric and zero-emissions vehicles is growing substantially, although their share of the overall automobile market remains relatively small. 

Automobile manufacturers are spending tens of billions of dollars to develop better electric car battery technology that will help shift the market to all electric vehicles.  

Experts agree, however, that the key to increasing the competitiveness of zero-emissions vehicles is identifying new materials and designs that drive down battery costs and weight, extend driving range, and improving time spent at public fast-charging stations. 

Learn how Parker is helping evolve to sustainability trends, read our Transportation Trends White Paper.

Creating a cost parity with internal combustion engines is critical to gaining greater acceptance of electric vehicles. Most of this area’s focus has been on reducing the structure and complexity of the battery, as well as increasing the use of automation in the manufacture of batteries to reduce labor costs and increase productivity. 

Much work also has been done in identifying more cost-effective materials. Innovations such as low-cobalt and cobalt-free battery chemistries represent a major step forward since cobalt is the most expensive material in many of today’s batteries. On the horizon are long-life nickel-manganese-cobalt batteries with cathodes that consist of 50% nickel and only 20% cobalt. Besides the obvious cost advantages, this type of battery is largely recyclable. 
 
Another way to bring down overall cost is to extend battery service life, limiting the number of times they need to be replaced.  Advances are being made in the use of chemical additives and nano-engineered materials that make existing lithium-ion batteries tougher and more resistant to bruising from stress caused by rapid charging. 

Creative approaches to the packaging of battery cells are also being explored. Something known as a cell-to-pack eliminates the bundling of cells, effectively reducing both weight and cost of the battery. 

Battery life anxiety is another key challenge that the market must overcome if electric vehicles are truly to become our future. That means we need to increase battery life and/or build a better infrastructure that includes more charging stations so consumers have the confidence of knowing they can safely drive without running out of power.  

The market is quickly adapting to these challenges with many people now having charging stations at their homes. Super chargers are also becoming the norm and continue to evolve with the goal of being able to fully charge a vehicle in as little as 10-15 minutes.  

Most electric car batteries on the road today are lithium-ion. Drawbacks to this technology include a short life and tendency to overheat which have prompted interest in alternatives that provide better fire resistance, quicker charges and longer life spans.  

Some experts see solid-state and lithium-silicon technologies as game changers. The addition of silicon significantly enhances energy density, prompting manufacturers to add more and more silicon to achieve silicon-dominant anodes. By encasing the silicon in the anode with graphene, an exotic form of carbon sheets that is only one atom thick, further cost reductions can be realized, along with a significant increase in driving range. Chemical additives and coatings are also being explored to reduce the internal stress on the battery, allowing it to store more energy for longer periods of time.  

Longer term, these silicon-based anodes will likely give way to solid-state batteries.  Their advantage is the elimination of liquid elements found in traditional lithium-ion batteries and their ability to increase energy density using “dry” conductive materials that are less likely to catch fire. 

Cobalt-free lithium-iron-phosphate batteries are attractive because of their higher charge rates and long lives. To make them more energy dense, engineers are looking at ways to switch from the standard cylindrical cells to prism-shaped cells. The advantage is that prisms are more space-efficient, allowing more batteries to fit within a given space. 

To learn about new battery sealing technologies from Parker, check out our webinar presented by Will Shurtliff, global sales manager electric vehicles, and Bhawani Tripathy, division engineering manager, O-Rings and Engineered Seals Division

Supercapacitors represent yet another important development. These charged metal plates can boost a device’s charging capacity by pumping electrons into and out of a circuit at blindingly fast speeds.  

Still, other research is looking at new binders that hold the lithium-ion battery components together to get a lot more energy per pound of battery. New research is focused on creating binders that stabilize the silicon particles, effectively extending battery life, increasing charging speed and improving thermostability.   

There is also research into possible improvements in the separators which, to date, have been vulnerable to heat shrinkage that seriously reduces a battery’s life span and creates safety concerns. By coating the separators with ceramic particles, for example, the battery can better handle temperature increases while keeping the separators intact and preventing the anode and cathode from touching each other. 

The future of electric cars rests with the market’s ability to produce the next big battery breakthrough. A lot of progress has been made in the identification of possible changes and alternatives. Getting some of these new technologies market-ready may still take a few more years. But with so many companies focused on the result of creating a financially viable, long-running, quick-charging battery, it is only a matter of time before electric vehicles dominate the road. 

And to catch up on how Parker is helping evolve to sustainability trends, read our Transportation Trends White Paper.

This article was contributed by Will Shurtliff, global sales manager – vehicle electrification, Parker Engineered Materials Group  

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As the automotive industry moves toward more automated, connected vehicles, engineers are challenged to identify technologies that can process and transfer large volumes of data in real-time without adding significantly to the price of the vehicle. 

For example, Level-5 autonomous driving (meaning the vehicle is capable of safely performing all driving functions on its own) requires a combination of: 

• radar  
• Lidar 
• video camera technology; and, 
• high-performance, on-board computer systems to perform highly complex functions. 

Accommodating all the necessary cameras, sensors and electronic control units (ECUs) that enhance connectivity and ensure autonomous vehicle safety has proven to be problematic due to the resulting electromagnetic interference (EMI) and excess heat being generated by the growing complement of electronic devices, including advanced driver assistance systems (ADAS).  

Parker is aggressively responding to both challenges with innovative shields and thermal management technologies that contain the electromagnetic noise and transfer heat away from critical components. 

To learn more about Parker solutions for ADAS, autonomous and connected vehicles, read our Transportation Trends White Paper.

EMI pollution not only interferes with communications, but it deteriorates the durability and proper function of electronic equipment. This has opened the door to numerous technology advances in the form of EMI shielding.  

EMI shielding uses materials to act as barriers to reflect and/or absorb electromagnetic radiation. Although metals are great for the task and have been used extensively to date, a major drawback is added weight. Other concerns include costs and vulnerability to corrosion. 

In 2018, Parker Chomerics introduced its innovative CHOFORM 5575 silver-aluminum filled form-in-place EMI gasket, which is a moisture cure silicone system that provides reliable EMI protection for packaged electronic assemblies. Robust enough to provide corrosion resistance and able to endure high-temperature applications, it is ideal when isolation and complex cross-section patterns are required, which is often the case with ADAS modules and telecommunications boxes. 

In recent years, the market has witnessed the emergence of more flexible polymer components that are lightweight and corrosion-resistant and offer superior electrical, dielectric, thermal, mechanical, and magnetic properties, which are highly useful for suppressing electromagnetic noise. Even newer are flexible polymer composites comprised of metals and various forms of carbon nanofillers, such as:  

• carbon black  
• carbon nanotubes  
• graphite  
• graphene, and 
• graphene oxide  

Among these options, graphene has thus far shown the most promise and is a focus of Parker’s ongoing R&D efforts. 

Challenges abound regarding thermal management, which includes thermal connectivity and the cooling of electrical components. Not only are engineers working to manage heat from the large array of electric components required to make today’s cars more connected and autonomous, but they are doing so in confined spaces of the vehicle where temperatures are often elevated. With components under the hood reaching ambient temperatures as high as 221°F (105°C), there is an added burden on thermal management solutions. 

Equally challenging is controlling noise associated with a cooling system, such as the case with any type of fan. Today’s discriminating automobile purchaser expects a quiet driving environment uncompromised by the whirring of fan blades. That means solutions must be identified that generate little to no noise and possess high thermal conductivity and low interface resistance with a low-pressure bond.  

While there are many possible Thermal Interface Materials to choose from, the most pursued today in the automotive sector are dispensable thermally conductive gap fillers (gels), which are also commonly referred to as Gap Filler Liquids (GFLs). Proponents of thermally conductive gels tout the products’ softness and low viscosity that make them highly effective in managing heat and easy to use. 

Other engineers prefer thermal gap filler pads because of their high level of flexibility and enormous mechanical resistance. 

Parker continues to test new chemistries and advanced polymers that offer greater thermal conductivity. Parker Chomerics THERM-A-GAP™ GELs are examples of Parker’s success in developing products that are meeting growing demands for thermal management. The cross-linked gel structure provides superior long-term thermal stability and reliable performance without needing to be cured. Parker is currently the only company to provide a single component, fully cured conductive gap filler. 

On the horizon are new thermal absorbent materials with unique properties that can also absorb some of the EMI noise. 

Beyond the search for alternative materials, work also is being done with novel active heat sink designs, which are sealed miniature loops with liquid metal alloys, such as Galinstan. Connecting a heat source to heat sink has proven to be a highly efficient means for thermal cooling of electronic components while simultaneously having an electrically insulating effect. 

Other types of active cooling approaches also are gaining interest, including spray and jet impingement. With these designs, the vehicle’s AC loop is modified by adding a pump and integrating a spray chamber. One problem in the early designs, however, continues to be the added weight of the loop. 

In another test, two-phase cooling of the underside of automotive power inverters was investigated.  The study involved two pressure-atomized nozzles that sprayed antifreeze coolant at 190.4°F (88°C) on the bottom thick-film resistors. Early results are encouraging since this method resulted in cooler temperatures than those obtained using a commercially available heat sink. 

Still, other work is being done to modify the aerodynamics of a vehicle in recognition of the impact of convective cooling on thermal management. 

Cost remains a key obstacle. Parker’s contribution to the cost equation has been to simplify product designs as a means for lowering total costs. 

Driving many of Parker’s advancements in the automotive sector are adaptations of technologies currently used for military applications. Lidar is an example of a technology once used exclusively by the military that is proving valuable for automobiles. Lidar is a method of measuring distances by illuminating the target with laser light and measuring the reflection with a sensor. Its advantage over traditional cameras is in its ability to function well even at night or on cloudy days. 

The military uses lidar to map out the terrain of the battlefield and to know the exact position of the enemy and its capacity. Lidar is a critical technology for the advancement of driverless military vehicles. The superior resolution produced by lidar is a result of its use of light pulses that have about 100,000 times smaller wavelengths than the radio waves used by radar. The speed and sensitivity of the lidar components, combined with the massive amount of data that is being processed, require specific material properties that optimize the accuracy, reliability, and durability of the lidar assembly. This is where Parker comes in, providing the specialized EMI shielding and thermal conductivity necessary to support the advanced lidar technology. 

Industry experts agree that it is a matter of when, not if fully connected, autonomous vehicles will become a reality. Some of the remaining challenges relative to EMI and thermal management have proven a bit more difficult than originally envisioned, but progress is being made in both areas to bring us closer to a new driving reality. 

To learn more about Parker solutions for ADAS, autonomous and connected vehicles, read our Transportation Trends White Paper.

This article was contributed by Daniel Chang, Global Automotive Market Sales Manager, Parker Chomerics Division. 

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Clean energy consultancy Gladstein, Neandross and Associates, in its recent report on sustainable fleets¹, predicts another decade of diesel-powered heavy trucks leading long-haul. Diesel efficiency and emissions reductions are important areas of research as broader trends toward sustainable fleet adoption accelerate. 

One new technology to the diesel market is cylinder deactivation (CDA). This technology has been commercially applied to the automotive sector as “Displacement on Demand” to improve fuel economy in V-8 engines. In the diesel market, CDA not only helps with fuel economy, but it also helps to increase exhaust temperatures and reduce engine-out nitrogen oxides (NOx).  

Read our Transportation Trends White Paper to learn more about how Parker is helping heavy truck and bus manufacturers evolve to sustainability trends,

CDA would be used when the diesel engine runs below its normal operating temperatures, such as in a cold start or when the engine is under light loads (i.e., idling or cruising at highway speeds). In these conditions, the system deactivates some of the cylinders to increase the load on the remaining cylinders. When this occurs, more fuel per injection is required and this produces more heat in the engine block. This, in turn, raises the exhaust gas temperature to an appropriate operating level to activate the diesel particulate filter (DPF) burn off cycle. Successful development and commercialization of CDA technology would help the industry meet 2024 emissions standards. 

Another major advancement has been in the development of ducted fuel injectors. Developed by Sandia National Laboratory’s Combustion Research Facility, the ducted fuel injectors offer many benefits. They clean emissions like soot (another potent climate change chemical second only to carbon dioxide) from vehicle fuel, and they represent an inexpensive transition by working well with conventional diesel fuels. They can easily be retrofitted into existing engines, require no after-treatment systems, and have the potential to lengthen oil change intervals. 

The ducts are small tubes that are mounted to the underside of the cylinder head near the injector nozzle. Researchers continue to search for appropriate high-temperature alloys for those tubes without substantially increasing costs. 

A desire to improve energy efficiency and cut greenhouse gas emissions has led to considerable interest and research in various waste heat recovery techniques. Topping the list of options are thermoelectricity and Rankine Cycle. Rankine Cycle offers the greatest potential due to its higher cycle efficiency. 

Rankine Cycle is not a new concept. It has been widely employed in large-scale power plants for years. But it has yet to be fully implemented for heavy-duty trucks and buses.  

The cycle works by recovering wasted heat from the engine through an intermediate heat transfer loop that is filled with a working fluid. The fluid captures some of the energy from the waste heat source. The fluid is often water, but with organic Rankine cycles, a higher molecular mass fluid with a lower boiling point is used to reduce the amount of heat needed for energy recovery.  

Despite its tremendous potential, some challenges remain, such as limitations of heat available in the heat source, heat rejection constraints, backpressures during the recovery process, and safety and environmental impacts of the chosen working fluid.  

The beauty of this form is that its heat source--exhaust waste heat--exists on all current engines on the market. 

Today there is a large array of aerodynamic aids available for heavy-duty trucks and trailers, all designed to increase efficiency by reducing drag and fuel consumption by as much as 12%. 

Some of the more popular options include front and underbody deflectors, side skirts, rear diffusers and boat tails. Companies have experimented with the specific design and rigidity of such aids to further enhance aerodynamic performance. While all of these can provide some benefit, the key is to identify the right combination of aids that provides enough fuel savings to offset the added costs. 

Low-rolling resistance tires also improve truck aerodynamic performance by reducing resistance caused by the tires rolling on the highway’s surface, often through tread depth and design. To date, however, while more fuel-efficient truck tires have garnered interest because of their ability to minimize energy and boost fuel economy, their lower life cycles cause concerns for bottom line-oriented owners and operators.  

Another trend in commercial trucking is the replacement of dual tires with super single tires. The advantage of reducing the number of tires on a large rig is minimized friction and resistance. However, safety concerns arising from what happens when a tire blows are keeping most fleets from making the switch. 

Electric (battery or fuel cell) is not the only alternative energy source being explored, as companies continue to research the potential of various renewable fuels, like renewable natural gas (RNG), biodiesel and renewable diesel (RD) which are efficient as fuel sources while producing inherently lower greenhouse gas emissions. 

California leads the way in renewable energy research with herds of dairy cows already powering fleets, homes and factories throughout the state. An especially promising development is the recycling of dairy cow waste to produce methane--an option that creates a negative carbon footprint. Known as biomethane, it is an attractive tool for battling climate change.  

Beyond dairy waste, RNG can come from other sources of manure, landfills, as well as wastewater. The advantage is that it can be easily exchanged with natural gas drilled out of the ground, minimizing the need to overhaul natural gas engine designs.  

Biodiesel (B) and renewable (R) diesel, both of which can be made from similar feedstocks, recycled cooking oil (i.e., oil used to make French fries), oil from algae, soybeans, and other oilseed crops, are also attractive alternatives for existing diesel engines. Not only are they carbon neutral, but, like RNG, their use does not necessitate a diesel engine modification. However, biodiesel blends above 20 percent (B20) will require use of higher performance fluorocarbon sealing compounds. Learn more in our Seal Materials for Biodiesel blog.

One of the concerns for renewable diesel is the choice of which feedstock is used. Palm oil feedstock, for example, has been linked to significant land use impacts, including deforestation, which results from allocating land to grow and farm the palm oil. 

Yet another alternative fuel is ethanol. One company recently completed tests showing that its system matched the torque and power of a commercial diesel engine using ethanol instead of diesel fuel, delivering over 500 hp and 1850 ft lb. of torque without additional aftertreatment. 

There are several points of concern for fleets that operate Class 4 through Class 8 vehicles with multiple power sources, i.e., some diesel, some natural gas, some electric, etc. Among other things, they will face “right to repair” and maintenance challenges as technicians must be sufficiently trained in the repair of multiple power-source vehicles. For example, mechanics working with electric systems need to be well-versed on sensors and how to properly ground them to avoid serious injuries. In addition, a wide variety of parts may need to be inventoried to maintain an array of engine types.  

Another point of concern is the training of first responders—not only the emergency responders, but also tow/salvage operators. Diesel, natural gas, and electric engines require different approaches to putting out fires in a roadway vehicle crash or in a facility where electric vehicles are charged.  

When considering options for lessening environmental impact, total cost of ownership still plays a role in ultimately determining which technologies will be adopted and to what extent. The ability to make these innovations affordable, safe, reliable, and sustainable is the key to the future of a sustainable transportation model. 

To learn more about how Parker is helping heavy truck and bus manufacturers evolve to sustainability trends, read our Transportation Trends White Paper.

This article was contributed by Christopher Overmyer, Senior Field Application Engineer, Parker Engineered Materials Group 

¹ Cision PR Newwire - State of Sustainable Fleets Report Released, Finds Sustainable Vehicle Technologies and Fuels Are Growing Across All Sectors

State of Sustainable Fleets Report by Gladstein Neandross & Associates

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In 1933, Kenworth Motor Truck Co. became the first American truck manufacturer to introduce the Cummins 4 cylinder, 100 hp, HA4 model diesel engine as standard equipment. By 1938 the first two-stroke diesel powered bus was introduced. In 1940, Cummins was the first diesel engine manufacturer to offer a 100,000-mile warranty. By the 1950s, diesel engines had virtually replaced gasoline engines in commercial trucks. Since 1997, engineers of diesel engine manufacturers have risen to the challenges of meeting new and more stringent limits for particulate matter (PM) and nitrogen oxides (NOx) and increasing the fuel efficiency of the engine. 

As the heavy truck and bus market continues to evolve, engineers need to meet new challenges by identifying and adopting innovative technologies. 

Download our Transportation Trends white paper and learn how Parker is helping heavy truck and bus manufacturers respond to sustainability trends.

Consider the trend of commercial vehicle electrification. Driven largely by concerns over emissions and environmental impact, the vehicle electrification market has grown substantially. And enhanced vehicle battery technologies are the key to driving truck and bus electrification. 

Challenges remain, however, before these systems will prove feasible and practical over the long term.  

Lithium-ion batteries have been the primary solution for electric vehicle manufacturers because they have higher energy densities than lead-acid or nickel-metal hybrid batteries. Li-ion batteries also offer attractive features such as low self-discharge and considerable energy storage, or battery capacity. Yet, there are still many barriers for the vehicle electrification market to overcome. Among these barriers are cost, weight and range, safe storage and thermal management. 

A lot of research is being conducted to identify alternative battery chemistries and reduce the use of cobalt. Although cobalt is ideal for rechargeable batteries because of its thermal stability and high energy density, a problem is that it is almost exclusively mined in the Democratic Republic of Congo, an unstable country that has been charged with numerous human rights violations. 

Increased ethics concerns and growing costs have universities, private companies and the U.S. military aggressively researching alternatives to cobalt. 

• The U.S. Army is focusing on a new electrolyte design using silicon particle anodes in conjunction with lower cost transitional fluorides. The solid polymer electrolyte provides greater stability, even at higher temperatures, overcoming previous heat concerns. 
• IBM is researching a cobalt- and nickel-free cathode material and a safe liquid electrolyte with a high flash point. 
• Research at Washington University in St. Louis on potassium-air batteries has shown that the effective selection of the electrolyte in battery chemistries can double their capacity.  
• Engineers at the McKelvey School of Engineering also have developed a borohydride fuel cell that operates at double the voltage of conventional hydrogen fuel cells.  
   

Since it is critical to protect the integrity of a battery from dirt and water, proper sealing is a key design consideration. Electric vehicle battery covers pose unique sealing challenges due to the significant size of the perimeter of the battery, as well as the aggressive performance requirements. Batteries are assigned Ingress Protection (IP) ratings to specify the degree of environmental protection from solids and water that might otherwise enter the enclosure and cause damage. Sealing products from Parker O-ring and Engineered Seals and electronic materials from Parker Lord prevent ingress between battery covers and housings—for both serviceable and non-serviceable batteries.   

View our webinar on Serviceability of EV Battery Packs

Electromagnetic interference is a concern because electric vehicles have multiple battery cells, converters and powered electronics (ADAS, LiDAR and infotainment screens). The signals from one could interfere with those of another. The good news is that special EMI shields now exist to help contain the magnetic signals within the components. 

Among them are seals that are made of electrically conductive elastomers and form-in-place (FIP) conductive gaskets and even plastic pellet materials for housings 

Thermal management tops the list of priority concerns. Parker offers several material innovations in this area that can stand up to excessively high temperatures and are flame-retardant to prevent a catastrophic thermal event, including thermally conductive gap filler pads and thermally conductive structural adhesives  

In addition, there are air ventilation panels that dissipate heat and provide EMI shielding. 

Electric vehicle battery technology is a significant, trending topic in the bus and commercial vehicle market. While lithium-ion is currently the most dominant type of EV battery, engineers are driven by concerns over emissions and environmental impact to find a higher performing alternative. Reduced weight, improved storage, and better thermal management are among the features that engineers are hoping to work into EV batteries.  

To learn more about how Parker is helping heavy truck and bus manufacturers respond to sustainability trends, read our Transportation Trends White Paper.

This article was contributed by Christopher Overmyer, Senior Field Application Engineer, Parker Engineered Materials Group 

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Thermal interface materials are used to eliminate air gaps or voids from adjoining rough or un-even mating surfaces. Because the thermal interface material has a greater thermal conductivity than the air it replaces, the resistance across the joint decreases, and the component junction temperature will be reduced.

Two principal “gap filler” thermal interface materials prevalent on the market today are thermal gels– also known as dispensable gap fillers – and gap filler pads.

So, which one should you select for your application? Here are the top 6 things you need to know:

Both thermal gels and thermal gap filler pads are highly conformable, but the maximum configurability of a gap pad is less than that of a gel due to its solid structure. Dispensable gels provide maximum conformability because they can be dispensed in near infinite shapes and patterns.
 

Gap filler pads have long been the go-to choice for many design engineers, but recent advances in thermal gels, which are highly conformable, pre-cured single-component compounds, can provide superior performance, a greater ease of manufacturing and assembly, and a lower cost in certain high-volume applications; particularly as electronic design applications get smaller, more fragile and more complex.

Looking to learn more about thermal gap pads and dispensable gels? Download our new white paper Thermal Interface Materials: Choosing Between Gels and Gap Filler Pads now!

In this white paper, you’ll learn about the two general types of thermal interface materials – gels (or dispensable gap fillers) and gap filler pads – which are used by design engineers for displacing air voids and ensuring proper heat transfer, as well as:

•    Heat transfer fundamentals refresher
•    Intro to gap filler pads and thermal gels
•    Pads vs. gels – understanding key differences
•    Conclusion and recommendations

This white paper analyzes and draws conclusions about key performance and manufacturability characteristics in both gap pads and new advances in gels. Download it today!
 

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

Selecting a Thermal Gel or Thermal Gap Pad – Your Questions Answered (Part I)

Selecting a Thermal Gel or Thermal Gap Pad – Your Questions Answered (Part II)

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Overcoming Challenges of Fully Autonomous Vehicles

If the words “Fire Seal” bring to your imagination a Sea World show gone terribly wrong, then you probably won’t be interested in this blog. But, for anyone associated with the field of aviation, you’ll recognize a crucial element of aircraft safety. Fire Seals are barriers located within an aircraft nacelle that, in the event of an engine fire, work to keep it contained within the immediate area and deny it the oxygen it needs to propagate. This provides the opportunity to safely shut down the engine or APU.

Few things worry the cautious traveler more than the idea of an aircraft engine fire. After all, it’s not like you can pull over 6 miles above the ground and call Triple-A. But, the reality is that without fire, a flight would be impossible. It is the controlled burn of fuel within the engine that generates the thrust necessary for flight. So, what those burdened with ensuring aircraft safety focus on is the prevention, detection, and suppression of unwanted engine fire. To combat this, aircraft are designed with redundant systems for fire detection which alert the flight crew to engage in appropriate countermeasures. These include cutting off fuel to the compromised engine and activating fire extinguishers. These are examples of active measures for fire control.

Fire seals fall into the category of passive systems. Passive systems are always in place and require no external engagement to function.

Fire seals typically feature a composite structure. A flame-resistant elastomer is layered with a fire-resistant fabric which helps to maintain the structural integrity of the seal for a specific period of time. Typical materials used are silicone, aramid fabrics, ceramic, or other inorganic fabrics. Seals are typically molded for finite lengths (typically < 12 feet long) and can be spliced to meet longer length requirements or irregular geometries. Intricate custom shapes are possible employing salt core molding techniques.

Typical configurations include:

• P-seals

• Bellows

• Diaphragms

• Omega seals

• Gaskets

• Custom shapes

The main specifications governing fire seals are ISO 2685 and AC20-135. These documents define the test methods and acceptance criteria for evaluating seal performance. Seals are evaluated by their ability to survive exposure to a 2000 degree flame for a specified period of time. Components can be classified as either fire-resistant (5 minutes) or fireproof (15 minutes).

Parker's Engineered Materials Group supplies fire seals through our Composite Sealing Systems Division (CSS), headquartered in San Diego, CA. Our seals have been tested by a third-party laboratory and have been proven to meet the requirements of the governing specifications. Testing consists of exposing a production-representative component to a set of application-specific conditions that may include pressurization, airflow, and vibration, all while exposed to a calibrated 2000°F flame. The component must not allow any burn-through during the entire test and should not self-ignite after the burner is removed.

Parker is a major supplier to many major aerospace OEMs. To learn more about how we can help support your production, reliability, and safety goals, contact us.

Learn more by watching our video on all our sealing solutions for aerospace.

Article contributed by Brian Alessio, business development engineer, Engineered Materials Group, Parker Hannifin.

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When designing a gland in which an O-ring or elastomeric seal is the desired sealing component, there are several aspects that need to be considered. A perfectly designed seal with the right material, ideal compression, gland fill and stretch can have inadequate sealing capability if the surface finish of the hardware is neglected. This blog discusses the ideal surface finish requirements for both the application and testing of seals.

Consider these photos of metal surfaces. At first glance, all three may appear to be identical, but looking closely, the main difference is surface finish. Figure 1 illustrates the appearance of surface finish as it will be discussed.

  Figure 1: Left to Right: 500x magnification of 16µin RMS, 32µin RMS, 63µin RMS

Surface finish, as pertinent to seal design, is the measurement of the roughness of the two hardware faces compressing the O-ring or seal. That is why it is sometimes referred to as “surface roughness” as well as surface finish. Maintaining proper surface finish of these two surfaces is essential to obtaining a good seal. Table 1 outlines the basic guidance suggested in the ORD 5700 O-Ring Handbook.

The requirements for sealing gas and vacuum are more restrictive than a liquid due to gas’s ability to find passage through very minute pathways on a hardware surface. Some estimates are that the viscosity of air is 53x to 55x less than that of water, which equates to about 53x more volume of air passing through the hardware indentation than water would. 

For static seals, Parker recommends using a surface roughness value not to exceed 32  µin (32µin RMS) when the seal involves liquid and a maximum of 16µin RMS when the seal involves gas.

If a surface is too rough against a static seal, the O-ring may have difficulty conforming to surface imperfections causing leakage.  Durometer of material can play a role in overcoming surface finish. The softer the material, the more it will fill in the peaks and valleys of the sealing surface, however, this may be at the detriment of other sealing properties, such as contact pressure, compression set resistance, extrusion resistance, or  durability.

For static sealing, consideration of the method used to produce the surface finish can certainly play a role and potentially offer improved sealing margin. Methods such as lathe or some other machining technique that produces tool marks parallel to the groove can be sealed most effectively and in certain situations may seal at roughness values greater than recommended. Other methods, such as end milling or routing, produce tool marks perpendicular to the groove and may be too deep for the O-ring to make full contact which could result in a leak path. In this situation, the recommended roughness values should not be exceeded.

For dynamic seals, the shaft or bore should have a surface finish between 8µin and 16µin RMS. This range of peaks and valleys on the hardware serves the purpose of holding the lubricant against the O-ring and ultimately minimize friction and wear damage. 

Surface finishes above 20µin will cause abrasion on the O-ring surface, and no amount of lube will prevent the O-ring from wearing. Surfaces which are better than 10µin will result in the lubricant being wiped away, which thereby increases friction and accelerates wear over the life of the seal.

Questions come from customers with respect to hardware mismatch, surface porosity, and air or helium testing. Each of these questions often simplify down to the same guidance which has been outlined above. Figure 2 illustrates the mismatch that can be present on a molded housing. While there is not a hard and fast rule for overcoming mismatch, application experience has found success with limiting the step to a maximum of .003”. Like mismatch, surface porosity is another application specific hardware challenge that can be difficult for a seal to overcome. A general rule of thumb is for the maximum porosity size to be less than half of the contact width of the compressed seal in the least material condition. Lastly, a seal designed to contain fluid which is failing an air leak test often has the root cause of leakage due to surface roughness. This comes back to the reality that air and gas are a much more difficult sealing medium than a liquid and a smoother surface finish can often improve this condition. In some instances, mismatch and surface porosity can be overcome with a custom designed seal, but it will not be possible for a custom designed fluid seal to pass a gaseous leak test when the surface finish is the cause of leakage.

If you have additional questions about surface roughness, please visit our website and chat with our support team or reach out to one of our application engineers at OESmailbox@parker.com. 

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

Matt Frye, product design engineer, Parker O-Ring & Engineered Seals Division

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Mitigating the contamination risk in biopharmaceutical manufacturing is essential for two reasons: Obviously, product safety for patients is of paramount importance, but manufacturers must also be protected against substantial financial losses, resulting, for instance, from a necessary destruction of their highly valuable product due to in-process contamination.

For effective and cost-efficient mitigation of contamination risks within the process chain, Parker Prädifa offers an extensive portfolio of “intelligent” and customizable solutions for a wide range of applications in upstream and downstream processes using advanced, proprietary overmolding technology.

• Tailored tube-to-container interfaces (also available as “flex caps” for glass bottles) eliminate the limitations of standard port caps while mitigating the contamination risk at an all-new market level.
   
• Custom-designed overmolding tube-to-tube connections with seamless integration ensure perfect laminar media flow through gateways during filling and emptying processes by avoiding edges, protrusions or dead zones in the flow path.
  
  
• Tamper-proof tube connections require no cable ties and ensure a closed system environment excluding subsequent opening.
   
• Maximum reliability and easy container handling in sampling, manufacturing, storage and (cold chain) transportation processes are ensured by an overmolding portfolio of integrated tube fixations and protection caps including a patented, tamper-evident integrity seal.

Thanks to the open architecture the fully scalable technology spectrum enables the integration of previously validated components such as tubing. This considerably helps reduce overall system costs and offers a closed, tamper-proof system for protection of the product.   

Every single-use solution is precisely adapted to the previously validated production framework and offers substantial overall system cost reduction potential.

Manufacturing, assembly and packaging processes in certified clean rooms are a basic prerequisite for serving pharmaceutical and biopharmaceutical customers. In Europe, Parker Prädifa operates two clean room production facilities: one in Sadska (Czech Republic) certified according to ISO 14464 Class 7 and one in Pleidelsheim (Germany) certified according to ISO 14464 Class 8.

Additional information:

• Industry Page: www.parker.com/praedifa-biopharma
• Brochure: Single-Use Systems - Tubing Manifolds and Container Systems
• Online Product Catalog: Single Use Systems
• Webinar: Risk Mitigation in Biopharma through Single-Use Fluid Management Systems 

Posted by Dr. Heinz-Christian Rost, market unit manager life sciences, Engineered Materials Group Europe, Prädifa Technology Division

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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.

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.

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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.

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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?

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.

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. 

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.

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 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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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.

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.

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.

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