Sealing and Shielding

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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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 the 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 were 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 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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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 is 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 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
• 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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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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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.

Related content:

How to Identify Quality Thermal Gap Fillers in Four Steps

Need Better Flow Rate Control? Look to THERM-A-GAP GEL 37

The Difference Between Thermal Conductivity and Thermal Impedance