Your Source for Designing Critical Parts in Core Systems:
The process of selecting the best materials for critical parts in machines we use daily and devices we rely on in aerospace, space, life sciences and industrial manufacturing is multifaceted and requires quite a lot of thought, knowledge and understanding. Because of this, many companies invest in their R&D departments to be their investigators, innovators, problem solvers, and developers and to guide them so they can grow via new product introduction and enabling new technologies and processes.
“I like puzzles and challenging my brain. My work is like a puzzle where I try to find the best way to develop or build,” says Alma Camara, an R&D Group Leader, when asked about her favorite hobby that fittingly connects with her role at Saint-Gobain Seals and where she helps to determine the best products for specific applications.
For Camara, with a Ph.D. in Polymer Technology, Masters in Engineering and Polymer Science and Technology, eight years in R&D, and scientific publications on plastics to her name, working in R&D at Saint-Gobain Seals is a good fit.
“This is an area that complements my skills, capacities, and professional background. I enjoy the dynamics, the creativity in finding solutions and adapting to different circumstances, as well as working with multi-disciplinarian teams,” she says. “As one of the female engineers here, it’s motivating to share my diversity to teach and transmit knowledge to others as well as be part of a special team who can solve issues and find solutions to customer requirements and push the limits of the materials.”
Determining which materials to use involves assessing the application and the environment, says Camara, and for critical parts, it also requires numerous levels of testing and validation that R&D team members explore so they can provide recommendations to business management to make decisions with greater confidence.
The Polymer Material Dilemma: PTFE, PEEK, or Another Option?
With a broad range of high-performance plastics, it may be difficult to determine what solution works best for your application. There are a few polymers that work well but having a partner with a strong R&D presence and technical knowledge that translates into practical application will be very helpful to ensure the precise fit and lifetime confidence that you are searching for.
PTFE (or polytetrafluoroethylene), for instance, is a fluoropolymer known for having the lowest coefficient of friction over almost any other material. The following are several typical properties:
- Excellent dielectric properties and inert to most chemicals
- Resistant to radiation and relatively insensitive to power frequency.
- Working temperature that goes down to -400° F (-240° C) and up to 500° F (280° C) with a melting point of about 621° F (327° C)
The material is used in industrial and life sciences applications in the form of filled PTFE bearings, cup seals, stamped and sliding parts due to its low wear and friction as in Rulon® sliding tapes for seismic base isolation systems, cup seals in portable oxygen concentrators and stamped parts in fuel dispenser pumps. The material is also used in aerospace, space and oil and gas applications in the form of spring-energized seals as in OmniSeal® RACO® face seals for fuel tanks and seat seals for cryogenic trunnion mounted ball valves.
PEEK is another key high-performance plastic often used in bearings, pumps, pistons, thrust washers, and other parts requiring strength. They are used often in automotive applications due to minimal deformation under high pressure and speed conditions. The following are several typical properties:
- Compressive strength of 140 MPa, over 30-40 MPa for PTFE
- High wear resistance with high abrasion resistance and a tensile strength of 90-100 MPa and low levels of deformation
- Outstanding chemical resistance, low moisture absorption, temperature-resistance (retains its physical properties and has a higher melting point than PTFE), and ability to withstand chemical environments
PTFE and PEEK are two options in the high-performance polymer classification; however, you also have other options such as thermoset or thermoplastic polyamide-imides (PAI) or thermoplastic polyimide (PI), which are both part of our Meldin® line. Understanding the properties of each material is the first step to selecting the right sealing or polymer solution. The next step is learning what methodology researchers use to determine how best to address a customer’s specific needs.
Factors that Determine the Materials in Critical Parts
“It starts with a goal and what we want to achieve depending on the final application,” says Camara. “Sometimes PTFE or PEEK or UHMWPE (Ultra-high-molecular-weight polyethylene) will be better for a very specific application. The decision to choose one material over another is a factor of the physical and chemical characteristics of the products being in compliance with customer needs and application conditions.”
This involves assessing a list of materials and performing initial benchmarking to determine which perform better for a specific requirement. Once this analysis has been performed, the R&D team performs more extensive research, such as additional application-based testing with more critical/demanding conditions to see up to which limits materials can be pushed to still perform the required function.
A Closer look at Saint-Gobain Seals’ Gate Process
Saint-Gobain Seals uses a gate, or waterfall, process in launching each project. The process, originally implemented by NASA in the 1960s, breaks up development into phases for sequential review before moving to the next gate.
For high impact projects (the majority fall under this category), Saint-Gobain Seals uses five gates. For lower impact projects, it uses three.
The five gates include:
- Preliminary investigation into materials and processes
- Validating the concept
- Development phase
- Pilot validation to experiment with the product before use
- Industrialization and commercialization
Initial meetings assemble people from different departments to establish project goals, determine the project leader, and distribute tasks according to activity and experience of the team (some activities will be more appropriate for marketing, some for R&D, some for production, etc.). Appropriate meetings are set up with the customer as needed for the project. A steering committee is also established to review progress before each gate and determine if specific milestones are met before progressing to the next stage. It will also periodically perform follow up reviews to assess potential constraints and how they might be resolved, as well as look for opportunities to make the steering committee aware of positive findings that could be leveraged in other projects.
In the testing phase, the R&D team ensures the properties of the materials and that they will perform well in the final application. Existing results on performance are plotted for analysis. If the material is being produced for the first time, the R&D team will register the processing conditions so that these can be later used in generating the material at industrial-scale and ensuring it meets customer requirements.
Application and fundamental property testing can include mimicking the application environment, using the part in customer’s equipment, or in some cases, testing it on site to obtain as many properties as possible.
Advances, as well as potential setbacks, strategies and goals are reviewed against progress throughout the project. This information is provided through regular presentations and meetings.
Two current projects that Camara is leading include:
- Leveraging a PTFE-based material in high-temperature applications in aerospace. “It is performing better than other materials intended for such high temperatures,” she says. Along with aerospace applications, Saint-Gobain Seals currently uses Fluoroloy® material in the jacket of their OmniSeal® spring-energized seals for space and oil and gas applications since it is excellent in both cryogenic and high temperature situations.
- Leveraging an ultra-high-molecular-weight polyethylene (UHMWPE) based material in pumps in UHPLC (Ultra-High-Performance Liquid Chromatography) used to separate, identify, and quantify components in mixtures in pharmaceutical and other product development. The goal is to develop a high-pressure resistant seal able to withstand 22K psi up to 2 Mio cycles target. Endurance trials have been conducted at Kontich and Garden Grove sites using actual OEM UHPLC pumps along with external testing that several vendors are doing at their own facilities. In both cases, the pump shaft is in motion to test wear and tear and leakage requirements needed on this equipment.
R&D at Saint-Gobain Seals is more than development and testing; it requires both thinking acuity and hands-on precision to be successful. Each day is definitely different.
On any given day R&D could be performing a variety of tests from analytical, mechanical, physical property testing to application testing to ensure materials and test parts are in accordance with specifications and customer application requirements. In addition, team members prepare and evaluate new material formulations and work with production to make prototype parts and develop new processes. They also prepare presentations from analysis reports to share with other departments, and provide technical support to production and quality departments and other Saint-Gobain sites. In addition to supporting others, R&D team members also “research” for themselves, learning and keeping updated with the most current state-of-the-art materials, processes and technical info in order to develop their work more efficiently and timely.
“We need to prioritize and plan activities of the day, week, month, and the next 3 to 4 months. Sometimes we are following several projects, from R&D to technical support in a single day,” says Camara, “Every day is different; it’s very interesting.”
Do you need help addressing a critical application where R&D can make THE difference? Contact Saint-Gobain Seals today for more information.