The Technical Hub
O-Ring Calculator
This interactive calculator assists engineers with selection of O-ring and hardware dimensions, and to form the basis of an O-ring installation.
Chemical Compatibility Checker
This interactive guide will help you choose a seal material based on existing compatibility test results of known chemicals and elastomers.
Interactive Engineering Calculators
Click here for volume, mass and compression set values for O-rings and rotary seal and hydraulic cylinder calculations.
Unit Converter
Our interactive conversion tools allow engineers to switch between units of measurement when preparing engineering calculations.
Engineering Tables
Our reference tables provide cross reference information for surface finish, metal hardness and polymer hardness measurement units.
Silicone O-rings for De Soutter EcoPulse™ lavage systemDe Soutter Medical Ltd specialises in the development, production and worldwide distribution of high performance orthopaedic tools for surgical procedures, offering their customers a comprehensive range of technically innovative and high quality products.
The application
De Soutter Medical recently launched their new EcoPulse™ lavage system for use in orthopaedic surgery. The company approached us to manufacture two different sized Silicone O-rings for the ECO Pulse upgraded design. The EcoPulse™ connects onto the front of a reusable De Soutter handpiece, and allows surgeons to lavage the surgical site using saline water. It can simultaneously be connected to a suction device to remove waste from the surgical site. The EcoPulse™ is supplied as a single use sterile packed product. It has a range of nozzles available for specific surgical procedures. The new EcoPulse™ has a pared back functional design to eliminate superfluous plastic. Additionally, instead of using disposable batteries (and the associated single use wiring and motors), it connects onto a reusable power tool that is already being used to perform the surgical procedure. This eliminates a large amount of clinical and WEEE waste (more information HERE). Furthermore, compared to other products in the market, reduces clinical waste by up to 60%.
Our sealing solution
The seal application is located within the disposable pump/irrigation attachments to ensure that no saline water leaked, and there is no loss of suction during use. This is a relatively straightforward application in terms of mechanical sealing. However, due to the nature of the product there are critical demands on the material and during the manufacturing process. Our engineers specified a USP Class VI translucent silicone; suitable for medical devices due to its biocompatibility features and resistance to bacterial growth. The (bespoke and dedicated) moulding tool was coated in titanium nitride. Therefore the use of release agents during the manufacture process of the silicone O-rings is not necessary. This is to mitigate the risk of any cross contamination with the O-rings. Additionally this is important when producing seals used within devices where there is any risk of patient fluids crossover. Cleanroom manufacturing and the silicone O-rings are double bagged packaging in order to avoid any cross contamination. These parts are manufactured and packaged at our ISO13485 approved manufacturing site to achieve these requirements.
Customer satisfaction
We work in conjunction with our valued customer De Soutter Medical. We assist with design support and technical recommendations on the development and manufacture of sealing products for use within their medical devices. For more on our full range of O-rings see this page: HERE Read more about our Life Sciences & Medical expertise: HERE
Why use Push-in-Place gaskets?Where a seal groove follows an irregular path or profile, a common sealing solution is to design a custom Push-In-Place (PIP) gasket that has the same profile as the centre line of the groove, simply drops into place and is retained by the features of its own design.
Gasket sealing overview
There are many ways to seal the static join between two components. This could be to keep fluids inside a cavity or to keep fluids or contaminants out of a device or assembly. The options can vary from simple O-rings, moulded elastomer gaskets and flat sheet style materials, to liquid gaskets (or RTV’s). As with all sealing applications, the optimal sealing solution is designed by first reviewing the application conditions. These include temperature, pressure, fluid exposure etc; and other variables such as life requirement, equipment serviceability and seal compression set should all be considered. Arguably though, compared to other sealing applications, when designing face, cover or flange sealing solutions it is imperative to consider the packaging requirements and assembly issues of gasket sealing options. The need to avoid or seal around bolt holes (or other retaining/clamping devices), together with optimizing hardware wall sections or depths can play a very important part in choosing the most suitable gasket sealing technique.
What are Push-in-Place gaskets?
With the right combination of application conditions, an o-ring style approach to sealing may be the most appropriate. O-rings tend to require relatively shallow grooves compared to their cross section in one half of the assembly, and in cases where the groove is round in plan view – they can be a good solution. However, in cases where the groove follows a more irregular path or profile (frequently referred to as a “racetrack”) the O-ring can sometimes pop out in places – often where the two housing parts are being brought together. A common solution is to design a custom moulding that has the same profile as the centre line of the racetrack groove and simply drops into place. A similar approach is used when the application or hardware constraints steer the design towards a gasket that has a greater cross section depth compared to the width; this would typically be designed so the centre line of the gasket matches the centre line of the groove plan profile – again so that it drops easily into place. An inherent problem with gaskets that can drop into place is that often, they easily drop out of place too. If the component needs to be inverted, or has the potential for rough handling during assembly then the gasket may become partially or fully dislodged from the groove, which results in a badly sealed interface. The best solution to this issue is to incorporate retention pips or bumps in the gasket design, a solution known as Push-In-Place (PIP) gaskets. These require a distinct force to put them into the groove, and as a result require more than just gravity to get them out of the groove.
Why use Push-in-Place gaskets?
There are other less effective solutions for tricky groove sealing, such as the use of a sticky grease, or the use of an adhesive. These can bring compatibility and health and safety issues to consider. Additionally, it carries the risk that any contaminant could keep the gasket off the surface that it is supposed to be sealing against. Therefore, the integrity of the seal can be severely compromised as a result. Neither of these approaches can be recommended, and instead the use of retention pips is a safe and secure way of ensuring the gasket remains in the groove. To determine the optimum number, size and position of the retention bumps, Finite Element Analysis (FEA) is used. This ensures they provide sufficient squeeze to prevent the gasket being easily dislodged. Additionally, it is important there’s no overfilling the groove space with seal material or interfering with the seal compression footprint against the hardware faces. The bumps can be strategically positioned to control any distortion of the gasket under pressure or temperature conditions. For example, low temperature conditions can shrink the gasket and tighten the radius it adopts around a bend in the racetrack profile. This can reduce the seal compression locally and potentially create a leak path.
Correct positioning
By positioning retention bumps at either end of the bend, the thermal contraction can be controlled to minimize the risk of leakage. Effective retention ensures that if the part needs to be inverted (which could be the preferred assembly method for practical reasons) or is subject to rough handling – the gasket remains correctly located in the groove. For large gaskets this is normally the most effective solution. On smaller gaskets (particularly those located well inside the periphery of the assembly), there is a significant risk of a dislodged gasket being totally undetected unless using a PIP gasket design. It’s possible to include tell-tale signs on a gasket design. For example, if a part of the elastomer gasket protrudes sideways through a gap in the housing wall, the presence of the gasket can be checked. This would be either with the human eye or an automated vision system. However, this does not ensure correct seating all around the gasket length, and cannot be used for internal gasket locations. In these cases a missing or badly fitted gasket would only be discovered during post-build testing, or even worse with a machine failure at a customer.
Further considerations
If included at the design stage, the small additional tooling and material costs associated with a PIP gasket are negligible compared to the costs of an impossible assembly scenario, strip and re-build costs on the assembly line, or the consequential costs associated with failure of an assembly once delivered to a customer. More information on PIPs and gaskets can be found HERE
Perfluoroelastomers in valvesIs it time to re-visit using perfluoroelastomer seals in your valves? First developed by DuPont™ in the late 1960s, perfluoroelastomers (or FFKMs), are now widely known and understood in a variety of markets. But for those that may be less familiar with these high performance materials, here is a quick recap...
What are perfluoroelastomers (FFKMs)?
They are essentially highly or fully fluorinated compounds with a fluorine content above 75%, and they offer outstanding chemical resistance. Generally better than all other elastomer types, FFKMs are often referred to as having the resistance of PTFE but in elastomer form. The term “universal” chemical resistance is commonly used; although it’s not strictly true as we will learn shortly. Unlike PTFE, the molecular make-up of FFKM includes crosslinks (or spring-like elements). This is contrast to just a backbone of carbon-carbon atoms surrounded by protective fluorine atoms. These crosslinks are what give the FFKMs their crucial elastic behaviour (in other words returning quickly to their original shape after being deformed). But the crosslinks are also a drawback as they can be a weak point for a chemical attack. Different crosslinking systems can be used when developing FFKMs and the choice will determine the high and low-temperature capabilities. Compounds developed for extreme high-temperatures (up to around 325oC) generally have a less broad chemical resistance. This is in comparison to the lower temperature grades (up to 225oC). Similarly, FFKMs developed to have excellent resistance to specific fluids (such as amines or high-temperature steam) can have limitations of low-temperature capability or compression set. As a result, there is no universal material that covers all application criteria bases.
A variety of grades
Previously the number of perfluoroelastomer grades was less prolific than other elastomer types such as FKM, EPDM, and NBR. However more than 50 years of technical developments have created a range of FFKM grades for specific and challenging applications. These are particularly in chemical process, oil and gas, semiconductor, and aerospace industries. Additionly, options with a hardness range of 65 to 90 durometer, and versions that meet international standards or specifications for food, medical, CPI, and oil & gas applications means the portfolio of FFKM-based compounds available to engineers is now substantial. In addition to technical developments, manufacturers and compounders have also been addressing the only real drawback of FFKM materials; the cost. They are difficult and time-consuming base polymers to manufacture. With a relatively low volume production base and sometimes lengthy processing times, FFKM seals carry a high financial premium over FKM seals. Even several times greater than FKM itself has over NBR. In recent years, there’s been more focus on making general-purpose grade FFKMs with broader temperature and chemical resistance capabilities more financially attainable. The initial procurement costs remain high compared to less capable elastomer bases. The overall cost of ownership may now be more appealing than it was twenty or even ten years ago. The ability of FFKM seals to survive for much longer in applications where exposure to a variety of fluids (perhaps wider than originally specified) is possible. This considerably reduces unplanned costs associated with maintenance and downtime.
Focus on dry coatings
The cost of unscheduled maintenance and repair in pump and valve equipment can be high in any industry, but exceptionally so in petrochemical, oil & gas, and semiconductor. When these costs are fully considered in the overall lifetime of a product, the initial price of seals in a valve is considered relatively minor, but it can still be a barrier in the material selection process. With both technical and commercial developments in recent times FFKM materials now compare more favourably against other materials for static, or low-duty dynamic applications in valves. In applications where persistent and sporadic issues keep coming back to cause problems, they are now a more financially attainable choice of material to avoid re-work, overhaul, downtime, customer dissatisfaction, and ultimately, more costs. Read more about FFKM as a suitable sealing material HERE
Seals for Life Sciences & Medical ApplicationsWhen designing and manufacturing sealing solutions for applications within critical devices and equipment, the strictest demands in product integrity and the highest specifications of hygiene and cleanliness must be met. Characteristics of Life Sciences & Medical sealing The Life Sciences & Medical industry is one of the most demanding and stringently regulated. There are a variety of areas of product development and manufacture where seals for Life Sciences & Medical Applications are required.
Diagnostics
Because of technology changes, there are now many ways of supporting patients with accurate results for the safe management of health conditions. This includes at home and within a clinical setting. It’s vital that diagnostic devices and systems are developed with the accuracy and speed of response to enable targeted analysis and therapy.
Patient management and care
Repeatable and reliable control of the equipment used in patient management and care is paramount. Applications include seals for ventilators, anaesthesia pumps, respiratory therapy and monitoring equipment. Minimally invasive surgery equipment and metered dose aerosols (such as inhalers) also need Life Sciences & Medical seals. Optimised working friction and wear life are demands on seals. The critical feature’s function & tolerance control are also pressures on the seal, coupled with management of gas, liquids, or solid media at accurate rates.
Biotech and pharmaceutical processing
There's continued development of complex and expensive drugs and research control media. Therefore, demand for high performance interactive components within the biotechnology process industry is crucial. Typical applications include seals for analytical equipment, pumps, valves & actuators, monitoring & control equipment. In addition to storage equipment & transportation vessels. We support engineers on recommending Ultra High Purity (UHP) materials for application working extremes correspondingly with sensitive chemical media, and seal design recommendations for dead space and entrapment elimination within these applications.
Ultra High Purity (UHP) materials
Silicone based rubbers are a common choice of elastomer materials for seals used within medical devices. This is because of their biocompatibility features and resistance to bacterial growth. Commonly they’re platinum cured for injection moulded liquid silicone rubbers (LSR’s) and platinum and peroxide cured for compression moulded heat cured silicones (HCR’s). There’s a diverse range of silicone rubbers currently available in varying shore hardness’s that are already approved, making them a go to choice if the specification allows. An application could need a seal material to have better mechanical properties or more temperature versatility or media compatibility. Therefore EPDM and FKM rubbers are also a good choice. Many of our materials are fully compliant and therefore have the required industry approvals, read more HERE
Cleanroom Manufacturing
Life Science and Medical sealing products are produced in a cleanroom environment. Especially this is essential for manufacturing and packaging of products. Equally, external particulates such as dust, dirt, airborne microbes, and aerosol particles should not come into contact or contaminate the surface/the area. A cleanroom is created by removing air, circulating through a filtering system and distributing (the filtered) back into the cleanroom. This is achieved at varying levels of cleanliness depending on what is specified for each individual manufacturing environment, or the finished product requirements. Different cleanliness levels are classified by the concentration of airborne particles within a measured space. We provide a complete cleanroom production process. This includes material blank production through to inspection and packaging using controlled materials within state-of-the-art cleanrooms. Read more about our Life Sciences & Medical industry expertise HERE
3D printing for seals3D printing has developed significantly and now performs a crucial role in many applications. 3D printed products vary from fully functional to purely aesthetic applications; with the most common application being for manufacturing. Here we discuss how our engineers use 3D printing to demonstrate a seal concept.
What is 3D printing?
3D printing is typically the more common name used for additive manufacturing. This process involves the construction of a three dimensional shape that is designed and generated from a computer aided design program (or CAD). The most typical process used for 3D printing is FFF (Fused Filament Fabrication) or FDM (Fused Deposition Modelling). The FDM process uses a continuous filament of a thermoplastic material that is then deposited onto the 3D print bed, creating layer by layer and gradually building up the structure of the 3D model. This is the process we commonly use to create our design and development range of 3D printed models and seal prototypes.
What material is suitable for 3D printing?
The materials used for 3D printing must of course be compatible with the process – these include a range of thermoplastic grades. Typical suitable material grades include; Polylactic acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Thermoplastic Polyurethane (TPU), Nylon and Polypropylene (PP). The most common grade we use for 3D printing is PLA – for its great strength and stability. We’ve also adapted our design process to use more TPU based material grades, as it loosely demonstrates the same properties as elastomer grades and is better for using in prototype programmes where mechanical fit in groove is tested.
Why use 3D printing for seals?
3D printing can be used for a variety of designs and seal types; from O-rings, gaskets and lip seals – to grommets, multi shot mouldings and large seal assemblies. There are many benefits of using 3D printing during the initial design stages of a project. The rapid turnaround means that a simple seal design can be produced in around 15 minutes, and even more complicated parts can be manufactured in the same day. We can even print the application housings and it’s the perfect way to demonstrate to an engineer what they can expect from a seal part in terms of shape and fit for hardware without the lead time and cost of cutting a prototype tool for moulded parts. One example of this is by quick turnaround of gasket designs typically to suit automotive applications or similar critical markets. Our engineers can design the concept and then 3D print a rapid prototype of a gasket to suit a 3D printed gauge groove. This further demonstrates to the customer that the seal has been fit checked for installation and builds further confidence in the design recommendation. Our engineers combine the 3D print with FEA simulation reports to offer a fully engineered sealing solution. Learn more about our design and simulation service HERE
E1244-70 seals in Life Sciences & Medical applicationsPacked with multiple benefits, and recommended for pharmaceutical manufacturing, biopharmaceutical processing and disposable medical devices, E1244-70 is an internally lubricated compound, eliminating the need for an external lubricant.
What is E1244-70?
E1244-70 is a 70 durometer internally lubricated, black EPDM (Ethylene Propylene Diene Monomer Rubber) material. E1244-70 possesses an internal lubricant, which reduces installation force and dynamic friction. Additionally, E1244-70 is compatible with all water-soluble chemistries and has excellent resistance to repeated conditions. For example steam, gamma, ozone and ethylene oxide sterilization. Here we take a closer look at the use of E1244-70 seals in Life Sciences & Medical applications. Adding external lubricants can be problematic; the risk of leaking into flow paths and migrating into areas where they are not needed. Additionally, even ‘clean’ lubricants like USP silicone, which can trap dirt and dust, can compromise patient health. Removing the need for an external lubricant by using E1244-70 is clean and safe with no risk of leakage.
Benefits, application and use
E1244-70 has a temperature range of -54°C to 121°C (-65 to 250°F). Consequently, E1244-70 has a low compression set, and is suitable for both dynamic and static seal applications. Because this material does not need an additional lubricant, it prevents issues associated with non-lubricated seals. For example, mismanagement by not using a lubricant when needed, can lead to friction and heat build-up, resulting in erosion and potential leakage and failure of the application. Fully compliant with USP Class VI biocompatibility and USP cytotoxicity standards for life sciences applications. The internal lubricant derives from the fatty acid family, significantly reducing patient reactions. This means it is safe for medical devices and pharmaceutical applications. In summary, it is suitable for: Dynamic applications & difficult installations
• Surgical instruments
• Pharmaceutical manufacturing
• Biopharmaceutical processing
• Disposable medical devices
• Repeated device sterilization Our Life Sciences & Medical expertise
We have clean room manufacturing facilities which are Class 7 (10,000) manufacturing and Class 5 (100) inspection, cleaning, and packaging. Our application engineers utilise the latest in 2D/3D CAD and FEA simulation software to design and replicate seal performance before finalising each individual seal design, incorporating significant feature and critical function elements for integration with customer mating parts. We offer material development and testing, and a component endurance testing service. Learn more about how we support our customers in the Life Science and Medical Industries HERE
Tools
O-Ring Calculator
This interactive calculator assists engineers with selection of O-ring and hardware dimensions, and to form the basis of an O-ring installation.
Chemical Compatibility Checker
This interactive guide will help you choose a seal material based on existing compatibility test results of known chemicals and elastomers.
Interactive Engineering Calculators
Click here for volume, mass and compression set values for O-rings and rotary seal and hydraulic cylinder calculations.
Unit Converter
Our interactive conversion tools allow engineers to switch between units of measurement when preparing engineering calculations.
Engineering Tables
Our reference tables provide cross reference information for surface finish, metal hardness and polymer hardness measurement units.
Articles
Silicone O-rings for De Soutter EcoPulse™ lavage systemDe Soutter Medical Ltd specialises in the development, production and worldwide distribution of high performance orthopaedic tools for surgical procedures, offering their customers a comprehensive range of technically innovative and high quality products.
The application
De Soutter Medical recently launched their new EcoPulse™ lavage system for use in orthopaedic surgery. The company approached us to manufacture two different sized Silicone O-rings for the ECO Pulse upgraded design. The EcoPulse™ connects onto the front of a reusable De Soutter handpiece, and allows surgeons to lavage the surgical site using saline water. It can simultaneously be connected to a suction device to remove waste from the surgical site. The EcoPulse™ is supplied as a single use sterile packed product. It has a range of nozzles available for specific surgical procedures. The new EcoPulse™ has a pared back functional design to eliminate superfluous plastic. Additionally, instead of using disposable batteries (and the associated single use wiring and motors), it connects onto a reusable power tool that is already being used to perform the surgical procedure. This eliminates a large amount of clinical and WEEE waste (more information HERE). Furthermore, compared to other products in the market, reduces clinical waste by up to 60%.
Our sealing solution
The seal application is located within the disposable pump/irrigation attachments to ensure that no saline water leaked, and there is no loss of suction during use. This is a relatively straightforward application in terms of mechanical sealing. However, due to the nature of the product there are critical demands on the material and during the manufacturing process. Our engineers specified a USP Class VI translucent silicone; suitable for medical devices due to its biocompatibility features and resistance to bacterial growth. The (bespoke and dedicated) moulding tool was coated in titanium nitride. Therefore the use of release agents during the manufacture process of the silicone O-rings is not necessary. This is to mitigate the risk of any cross contamination with the O-rings. Additionally this is important when producing seals used within devices where there is any risk of patient fluids crossover. Cleanroom manufacturing and the silicone O-rings are double bagged packaging in order to avoid any cross contamination. These parts are manufactured and packaged at our ISO13485 approved manufacturing site to achieve these requirements.
Customer satisfaction
We work in conjunction with our valued customer De Soutter Medical. We assist with design support and technical recommendations on the development and manufacture of sealing products for use within their medical devices. For more on our full range of O-rings see this page: HERE Read more about our Life Sciences & Medical expertise: HERE
Why use Push-in-Place gaskets?Where a seal groove follows an irregular path or profile, a common sealing solution is to design a custom Push-In-Place (PIP) gasket that has the same profile as the centre line of the groove, simply drops into place and is retained by the features of its own design.
Gasket sealing overview
There are many ways to seal the static join between two components. This could be to keep fluids inside a cavity or to keep fluids or contaminants out of a device or assembly. The options can vary from simple O-rings, moulded elastomer gaskets and flat sheet style materials, to liquid gaskets (or RTV’s). As with all sealing applications, the optimal sealing solution is designed by first reviewing the application conditions. These include temperature, pressure, fluid exposure etc; and other variables such as life requirement, equipment serviceability and seal compression set should all be considered. Arguably though, compared to other sealing applications, when designing face, cover or flange sealing solutions it is imperative to consider the packaging requirements and assembly issues of gasket sealing options. The need to avoid or seal around bolt holes (or other retaining/clamping devices), together with optimizing hardware wall sections or depths can play a very important part in choosing the most suitable gasket sealing technique.
What are Push-in-Place gaskets?
With the right combination of application conditions, an o-ring style approach to sealing may be the most appropriate. O-rings tend to require relatively shallow grooves compared to their cross section in one half of the assembly, and in cases where the groove is round in plan view – they can be a good solution. However, in cases where the groove follows a more irregular path or profile (frequently referred to as a “racetrack”) the O-ring can sometimes pop out in places – often where the two housing parts are being brought together. A common solution is to design a custom moulding that has the same profile as the centre line of the racetrack groove and simply drops into place. A similar approach is used when the application or hardware constraints steer the design towards a gasket that has a greater cross section depth compared to the width; this would typically be designed so the centre line of the gasket matches the centre line of the groove plan profile – again so that it drops easily into place. An inherent problem with gaskets that can drop into place is that often, they easily drop out of place too. If the component needs to be inverted, or has the potential for rough handling during assembly then the gasket may become partially or fully dislodged from the groove, which results in a badly sealed interface. The best solution to this issue is to incorporate retention pips or bumps in the gasket design, a solution known as Push-In-Place (PIP) gaskets. These require a distinct force to put them into the groove, and as a result require more than just gravity to get them out of the groove.
Why use Push-in-Place gaskets?
There are other less effective solutions for tricky groove sealing, such as the use of a sticky grease, or the use of an adhesive. These can bring compatibility and health and safety issues to consider. Additionally, it carries the risk that any contaminant could keep the gasket off the surface that it is supposed to be sealing against. Therefore, the integrity of the seal can be severely compromised as a result. Neither of these approaches can be recommended, and instead the use of retention pips is a safe and secure way of ensuring the gasket remains in the groove. To determine the optimum number, size and position of the retention bumps, Finite Element Analysis (FEA) is used. This ensures they provide sufficient squeeze to prevent the gasket being easily dislodged. Additionally, it is important there’s no overfilling the groove space with seal material or interfering with the seal compression footprint against the hardware faces. The bumps can be strategically positioned to control any distortion of the gasket under pressure or temperature conditions. For example, low temperature conditions can shrink the gasket and tighten the radius it adopts around a bend in the racetrack profile. This can reduce the seal compression locally and potentially create a leak path.
Correct positioning
By positioning retention bumps at either end of the bend, the thermal contraction can be controlled to minimize the risk of leakage. Effective retention ensures that if the part needs to be inverted (which could be the preferred assembly method for practical reasons) or is subject to rough handling – the gasket remains correctly located in the groove. For large gaskets this is normally the most effective solution. On smaller gaskets (particularly those located well inside the periphery of the assembly), there is a significant risk of a dislodged gasket being totally undetected unless using a PIP gasket design. It’s possible to include tell-tale signs on a gasket design. For example, if a part of the elastomer gasket protrudes sideways through a gap in the housing wall, the presence of the gasket can be checked. This would be either with the human eye or an automated vision system. However, this does not ensure correct seating all around the gasket length, and cannot be used for internal gasket locations. In these cases a missing or badly fitted gasket would only be discovered during post-build testing, or even worse with a machine failure at a customer.
Further considerations
If included at the design stage, the small additional tooling and material costs associated with a PIP gasket are negligible compared to the costs of an impossible assembly scenario, strip and re-build costs on the assembly line, or the consequential costs associated with failure of an assembly once delivered to a customer. More information on PIPs and gaskets can be found HERE
Perfluoroelastomers in valvesIs it time to re-visit using perfluoroelastomer seals in your valves? First developed by DuPont™ in the late 1960s, perfluoroelastomers (or FFKMs), are now widely known and understood in a variety of markets. But for those that may be less familiar with these high performance materials, here is a quick recap...
What are perfluoroelastomers (FFKMs)?
They are essentially highly or fully fluorinated compounds with a fluorine content above 75%, and they offer outstanding chemical resistance. Generally better than all other elastomer types, FFKMs are often referred to as having the resistance of PTFE but in elastomer form. The term “universal” chemical resistance is commonly used; although it’s not strictly true as we will learn shortly. Unlike PTFE, the molecular make-up of FFKM includes crosslinks (or spring-like elements). This is contrast to just a backbone of carbon-carbon atoms surrounded by protective fluorine atoms. These crosslinks are what give the FFKMs their crucial elastic behaviour (in other words returning quickly to their original shape after being deformed). But the crosslinks are also a drawback as they can be a weak point for a chemical attack. Different crosslinking systems can be used when developing FFKMs and the choice will determine the high and low-temperature capabilities. Compounds developed for extreme high-temperatures (up to around 325oC) generally have a less broad chemical resistance. This is in comparison to the lower temperature grades (up to 225oC). Similarly, FFKMs developed to have excellent resistance to specific fluids (such as amines or high-temperature steam) can have limitations of low-temperature capability or compression set. As a result, there is no universal material that covers all application criteria bases.
A variety of grades
Previously the number of perfluoroelastomer grades was less prolific than other elastomer types such as FKM, EPDM, and NBR. However more than 50 years of technical developments have created a range of FFKM grades for specific and challenging applications. These are particularly in chemical process, oil and gas, semiconductor, and aerospace industries. Additionly, options with a hardness range of 65 to 90 durometer, and versions that meet international standards or specifications for food, medical, CPI, and oil & gas applications means the portfolio of FFKM-based compounds available to engineers is now substantial. In addition to technical developments, manufacturers and compounders have also been addressing the only real drawback of FFKM materials; the cost. They are difficult and time-consuming base polymers to manufacture. With a relatively low volume production base and sometimes lengthy processing times, FFKM seals carry a high financial premium over FKM seals. Even several times greater than FKM itself has over NBR. In recent years, there’s been more focus on making general-purpose grade FFKMs with broader temperature and chemical resistance capabilities more financially attainable. The initial procurement costs remain high compared to less capable elastomer bases. The overall cost of ownership may now be more appealing than it was twenty or even ten years ago. The ability of FFKM seals to survive for much longer in applications where exposure to a variety of fluids (perhaps wider than originally specified) is possible. This considerably reduces unplanned costs associated with maintenance and downtime.
Focus on dry coatings
The cost of unscheduled maintenance and repair in pump and valve equipment can be high in any industry, but exceptionally so in petrochemical, oil & gas, and semiconductor. When these costs are fully considered in the overall lifetime of a product, the initial price of seals in a valve is considered relatively minor, but it can still be a barrier in the material selection process. With both technical and commercial developments in recent times FFKM materials now compare more favourably against other materials for static, or low-duty dynamic applications in valves. In applications where persistent and sporadic issues keep coming back to cause problems, they are now a more financially attainable choice of material to avoid re-work, overhaul, downtime, customer dissatisfaction, and ultimately, more costs. Read more about FFKM as a suitable sealing material HERE
Seals for Life Sciences & Medical ApplicationsWhen designing and manufacturing sealing solutions for applications within critical devices and equipment, the strictest demands in product integrity and the highest specifications of hygiene and cleanliness must be met. Characteristics of Life Sciences & Medical sealing The Life Sciences & Medical industry is one of the most demanding and stringently regulated. There are a variety of areas of product development and manufacture where seals for Life Sciences & Medical Applications are required.
Diagnostics
Because of technology changes, there are now many ways of supporting patients with accurate results for the safe management of health conditions. This includes at home and within a clinical setting. It’s vital that diagnostic devices and systems are developed with the accuracy and speed of response to enable targeted analysis and therapy.
Patient management and care
Repeatable and reliable control of the equipment used in patient management and care is paramount. Applications include seals for ventilators, anaesthesia pumps, respiratory therapy and monitoring equipment. Minimally invasive surgery equipment and metered dose aerosols (such as inhalers) also need Life Sciences & Medical seals. Optimised working friction and wear life are demands on seals. The critical feature’s function & tolerance control are also pressures on the seal, coupled with management of gas, liquids, or solid media at accurate rates.
Biotech and pharmaceutical processing
There's continued development of complex and expensive drugs and research control media. Therefore, demand for high performance interactive components within the biotechnology process industry is crucial. Typical applications include seals for analytical equipment, pumps, valves & actuators, monitoring & control equipment. In addition to storage equipment & transportation vessels. We support engineers on recommending Ultra High Purity (UHP) materials for application working extremes correspondingly with sensitive chemical media, and seal design recommendations for dead space and entrapment elimination within these applications.
Ultra High Purity (UHP) materials
Silicone based rubbers are a common choice of elastomer materials for seals used within medical devices. This is because of their biocompatibility features and resistance to bacterial growth. Commonly they’re platinum cured for injection moulded liquid silicone rubbers (LSR’s) and platinum and peroxide cured for compression moulded heat cured silicones (HCR’s). There’s a diverse range of silicone rubbers currently available in varying shore hardness’s that are already approved, making them a go to choice if the specification allows. An application could need a seal material to have better mechanical properties or more temperature versatility or media compatibility. Therefore EPDM and FKM rubbers are also a good choice. Many of our materials are fully compliant and therefore have the required industry approvals, read more HERE
Cleanroom Manufacturing
Life Science and Medical sealing products are produced in a cleanroom environment. Especially this is essential for manufacturing and packaging of products. Equally, external particulates such as dust, dirt, airborne microbes, and aerosol particles should not come into contact or contaminate the surface/the area. A cleanroom is created by removing air, circulating through a filtering system and distributing (the filtered) back into the cleanroom. This is achieved at varying levels of cleanliness depending on what is specified for each individual manufacturing environment, or the finished product requirements. Different cleanliness levels are classified by the concentration of airborne particles within a measured space. We provide a complete cleanroom production process. This includes material blank production through to inspection and packaging using controlled materials within state-of-the-art cleanrooms. Read more about our Life Sciences & Medical industry expertise HERE
3D printing for seals3D printing has developed significantly and now performs a crucial role in many applications. 3D printed products vary from fully functional to purely aesthetic applications; with the most common application being for manufacturing. Here we discuss how our engineers use 3D printing to demonstrate a seal concept.
What is 3D printing?
3D printing is typically the more common name used for additive manufacturing. This process involves the construction of a three dimensional shape that is designed and generated from a computer aided design program (or CAD). The most typical process used for 3D printing is FFF (Fused Filament Fabrication) or FDM (Fused Deposition Modelling). The FDM process uses a continuous filament of a thermoplastic material that is then deposited onto the 3D print bed, creating layer by layer and gradually building up the structure of the 3D model. This is the process we commonly use to create our design and development range of 3D printed models and seal prototypes.
What material is suitable for 3D printing?
The materials used for 3D printing must of course be compatible with the process – these include a range of thermoplastic grades. Typical suitable material grades include; Polylactic acid (PLA), Acrylonitrile Butadiene Styrene (ABS), Thermoplastic Polyurethane (TPU), Nylon and Polypropylene (PP). The most common grade we use for 3D printing is PLA – for its great strength and stability. We’ve also adapted our design process to use more TPU based material grades, as it loosely demonstrates the same properties as elastomer grades and is better for using in prototype programmes where mechanical fit in groove is tested.
Why use 3D printing for seals?
3D printing can be used for a variety of designs and seal types; from O-rings, gaskets and lip seals – to grommets, multi shot mouldings and large seal assemblies. There are many benefits of using 3D printing during the initial design stages of a project. The rapid turnaround means that a simple seal design can be produced in around 15 minutes, and even more complicated parts can be manufactured in the same day. We can even print the application housings and it’s the perfect way to demonstrate to an engineer what they can expect from a seal part in terms of shape and fit for hardware without the lead time and cost of cutting a prototype tool for moulded parts. One example of this is by quick turnaround of gasket designs typically to suit automotive applications or similar critical markets. Our engineers can design the concept and then 3D print a rapid prototype of a gasket to suit a 3D printed gauge groove. This further demonstrates to the customer that the seal has been fit checked for installation and builds further confidence in the design recommendation. Our engineers combine the 3D print with FEA simulation reports to offer a fully engineered sealing solution. Learn more about our design and simulation service HERE
E1244-70 seals in Life Sciences & Medical applicationsPacked with multiple benefits, and recommended for pharmaceutical manufacturing, biopharmaceutical processing and disposable medical devices, E1244-70 is an internally lubricated compound, eliminating the need for an external lubricant.
What is E1244-70?
E1244-70 is a 70 durometer internally lubricated, black EPDM (Ethylene Propylene Diene Monomer Rubber) material. E1244-70 possesses an internal lubricant, which reduces installation force and dynamic friction. Additionally, E1244-70 is compatible with all water-soluble chemistries and has excellent resistance to repeated conditions. For example steam, gamma, ozone and ethylene oxide sterilization. Here we take a closer look at the use of E1244-70 seals in Life Sciences & Medical applications. Adding external lubricants can be problematic; the risk of leaking into flow paths and migrating into areas where they are not needed. Additionally, even ‘clean’ lubricants like USP silicone, which can trap dirt and dust, can compromise patient health. Removing the need for an external lubricant by using E1244-70 is clean and safe with no risk of leakage.
Benefits, application and use
E1244-70 has a temperature range of -54°C to 121°C (-65 to 250°F). Consequently, E1244-70 has a low compression set, and is suitable for both dynamic and static seal applications. Because this material does not need an additional lubricant, it prevents issues associated with non-lubricated seals. For example, mismanagement by not using a lubricant when needed, can lead to friction and heat build-up, resulting in erosion and potential leakage and failure of the application. Fully compliant with USP Class VI biocompatibility and USP cytotoxicity standards for life sciences applications. The internal lubricant derives from the fatty acid family, significantly reducing patient reactions. This means it is safe for medical devices and pharmaceutical applications. In summary, it is suitable for: Dynamic applications & difficult installations
• Surgical instruments
• Pharmaceutical manufacturing
• Biopharmaceutical processing
• Disposable medical devices
• Repeated device sterilization Our Life Sciences & Medical expertise
We have clean room manufacturing facilities which are Class 7 (10,000) manufacturing and Class 5 (100) inspection, cleaning, and packaging. Our application engineers utilise the latest in 2D/3D CAD and FEA simulation software to design and replicate seal performance before finalising each individual seal design, incorporating significant feature and critical function elements for integration with customer mating parts. We offer material development and testing, and a component endurance testing service. Learn more about how we support our customers in the Life Science and Medical Industries HERE
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Product Range
Our seal products range from simple static O-rings to complex and bespoke seal designs in specialist materials. Whatever your application, we have the seal product for you.
