When the Heat Is on, These High-Temperature Plastics Perform Under Pressure

Vespel®, Torlon® and, polyimide-based plastics are all part of a class of materials known as high-performance plastics. These plastics are characterized by their excellent mechanical and thermal properties, as well as their resistance to chemical attack.

 

Vespel® is a registered trademark of DuPont, and their material is often used in applications where extremely high temperatures are involved. Torlon® is a registered trademark of Solvay Advanced Polymers; it’s often used in electrical applications due to its excellent dielectric properties.

 

While these polymers each perform well under pressure and high temperatures, they have slight differences that set them apart. It’s important to know these distinctions when planning out the material selection for a performance plastic. In this informational brief, we’re covering all the nuances between Vespel® and Torlon® down to the molecular level.

 

Features and Capabilities

Both Vespel® (PI) and Torlon® (PAI) are considered high-performance thermoplastics and share similar capabilities. However, there are slight differences in chemical makeup at a molecular level.

For instance, Polyimides are performance polymers containing imide group (-CO-N-OC-) in their repeating units. The polymer chains are either an open chain or closed chain. On the other hand, Polyamides all consist of amide (-CONH-) linkages in their polymer backbone. The amide group is classified as a polar group, which allows polyamides to build hydrogen bonds between chains. By doing this, they improve the interchain attraction.

These slight differences in the chemical makeup enhance various properties of Polyamide-imide over Polyimide and vice versa. The following chart displays the strengths and weaknesses of these two materials.

 

Strengths Weaknesses
 

Vespel® (PI)

·         Thermal stability

·         Excellent chemical resistance

·         Dielectric strength

·         Mechanical toughness

·         Superior temperature adaptability

·         Excellent tensile and compressive strength

·         Transparency in many microwave applications

·         Radiation resistance

·         Superior bearing and wear properties

·         High manufacturing cost

·         High-temperature requirement in the processing stage

·         Specified operating processes such as annealing operations at specified temperatures

·         Sensitive to alkali and acid attacks

 

Torlon® (PAI)

·         Excellent Chemical Resistance

·         Excellent Stress Resistance

·         Excellent Thermal Resistance

·         Excellent Wear Resistance

·         High Stiffness

·         High Strength

·         Higher moisture absorption rate than other performance plastics

·         High manufacturing cost

·         Narrow processing window when temperatures exceed 600°F

·         Melt viscosity that is highly sensitive to temperature and shear rate

·         Thermal cure for 20 or more days at 500 F to optimize properties after melt processing

 

 

 

Applications of Vespel® and Torlon®

Vespel® and Torlon® both maintain stability and functionality under high temperatures and pressures. For this reason, they are often found in applications with harsh, demanding environments, including:

  • energy
  • automotive
  • aerospace
  • and military & defense

 

Does one material perform better than another in certain cases? Let’s take a look.

 

Vespel®: An all-around performer

Polyimides like Vespel® are often used in electrical insulation, aerospace components, and high-temperature bearings. Unlike most plastics, Vespel® Resin does not produce significant outgassing (even at high temperatures). This makes it useful for lightweight heat shields and crucible support. It also performs well in vacuum applications and extremely low cryogenic temperatures. Although there are polymers that surpass individual properties of this polyimide, the combination of these factors is Vespel’s® primary advantage.

 

Torlon®: Bring on the heat

On the other hand, Torlon® is a polyamide-imide with even better mechanical and thermal properties than Vespel®. It is often used in pump housings, valves, and chemical-resistant seals. PAI comes in several grades, including TORLON® 4203 (electrical and high strength), TORLON® 4301 (general purpose wear), TORLON® 4XG (glass-reinforced), and TORLON® 4XCF (carbon-reinforced).

 

Takeaway: Both Vespel® and Torlon® are widely used in industries that require reliable performance under extreme conditions. It’s important to consider the environment, especially for Torlon®, as it has a higher moisture absorption than other performance plastics.

 

Vespel® polyimide Torlon® polyamide-imide
·         Aerospace Applications

·         Semiconductor Technology

·         Transportation Technology

·         Bearing Cages

·         High-Temperature Electrical Connectors

·         Structural Parts

·         Valve Seats

·         Wear Rings

 

 

 

CNC Machining Vespel® vs Torlon®

Let’s talk about processing and machining. While Vespel® and Torlon® can be injection molded, extruded, or CNC machined, we’re going to focus on the protocols for subtractive CNC machining.

 

Annealing

As with any performance plastic, annealing preps the material and ensures that it will not crack or craze in the future. AIP Precision Machining has programmed annealing ovens for plastics that heat the material above its recrystallization temperature. By maintaining the heat at that specific point, the structure of the material changes to become finer and more uniform. This process relieves internal stresses in the material. Both Vespel® and Torlon® require specific temperatures and cool-down time after annealing. This is why AIP uses computer-controlled annealing ovens for the best outcome.

 

Machining

Vespel®

Vespel® can be machined using conventional CNC methods. However, there are a few things to keep in mind in order to achieve the best results.

 

First, Vespel® has a relatively low coefficient of thermal expansion (CLTE), meaning it will expand and contract differently than most metals. This can cause tooling and fixtures to loosen over time, so it’s important to check them regularly.

 

Second, Vespel® is a very hard material that can wear down tools quickly. Use sharp cutting tools made of carbide and take light cuts in order to avoid premature tool wear.

 

→ [READ NOW] Machining Vespel: A Plastics Guide

 

Torlon®  

Torlon® is one of the most difficult materials to machine due to its extremely high hardness and wear resistance. In order to machine Torlon® or any polyamide-imide, it is necessary to use a CNC machining center with special tooling and cutting parameters. The cutting tools must be made of extremely hard materials such as carbide or diamond, and the cutting parameters must be carefully optimized to prevent tool wear. With the proper tools and techniques, Torlon® can be machined into parts with very tight tolerances and smooth finishes.

 

→ [READ NOW] Machining Torlon: A Plastics Guide

 

Torlon® or Vespel®? Ask the experts at AIP

Are you looking for a performance material that works continuously under pressure and heat? Not sure if Torlon® or Vespel® is the right material for your project? Our team of engineers and machinists are skilled craftsmen in reviewing your project parameters and design needs. We will ensure that every facet of your project is taken into consideration and work with you to define the best material for your project needs and budget.

 

We pride ourselves on our industry knowledge and partnerships with leading suppliers of top materials: Vespel® SP, Vespel® SCP products, and a variety of Torlon® grades. Contact an AIP engineer today, and we will be happy to help with your unique project.

 

Get a quote on Torlon® and Vespel®

 

 

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Dear friends and family of AIP,

 

As we all work to do our part to combat the COVID-19 outbreak, we want to know how else we can help.

 

At AIP we make precision machined plastic components for multiple industries and end markets. We are currently supplying medical customers in need of components for convalescent plasma treatment. Although still experimental for COVID-19, this treatment has potentially already provided a true lifeline for some of the most critically ill patients. We want to do more! Therefore, if you are in the medical supply chain and in need of machined plastic components to support any medical device, surgical or testing instrument, then please know we are here to serve you promptly. If you are supporting the COVID-19 fight, then you will go to the front of our line.

 

Our facilities in Daytona Beach, Florida, are fully dedicated to plastics machining. We are ISO 13485:2016 and FDA registered. With these high standards of medical safety and compliance, we are prepared and authorized to provide critical parts to medical manufacturers and device companies worldwide.

 

Thankfully we are currently fully operational and have instituted many measures to remain so during and after this crisis. Our team is ready to support your needs.

 

You can contact AIP for a quote or consultation by visiting our website. Feel free to reach out to me personally via email or a call. I am here to provide support and help in any way possible.

 

Best regards,

 

John MacDonald
President
AIP Precision Machining
724 Fentress Blvd.
Daytona Beach, FL 32114
jmacdonald@AIPprecision.com

 

Cell: +1 386.405.7202
Tel: +1 386.274.5335
Fax: +1 386.274.4746
www.AIPprecision.com

 

 

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Key Moments in Aircraft & Aerospace Innovation

 

Aviation technology has come a long way to get to where it is today. Over the course of the last century countless test flights, thousands of blueprints, and endless research from passionate minds have propelled the evolution of aircraft and aerospace technologies. Read on to discover how aviation materials have shifted to create a better, safer, and more efficient flight experience.

 

The Pioneers of Aviation

 

For much of human history, we have been fascinated with taking flight. The ancient Greeks contemplated sprouting wings in myths like Icarus and Daedalus – the boy who flew too close to the sun with wax and feather wings. Leonardo Da Vinci sketched flying machines that were way ahead of Renaissance times. It all came to fruition in 1857 when Félix du Temple de la Croix, a French Naval officer, received a patent for a flying machine. By 1874, he had developed a lightweight steam-powered monoplane which flew short distances under its own power after takeoff from a ski-jump.  Finally, in 1903, the Wright Brothers made the first controlled, powered, and sustained flight near Kitty Hawk, North Carolina. The Wright Flyer featured a lightweight aluminum engine, wood and steel construction, and a fabric wing warping. According to the U.S. Smithsonian Institution, the Wright brothers accomplished the “world’s first successful flights of a powered heavier-than-air flying machine.”

 

 

Just 12 years later, the first all-metal airplane (Junkers J1), built by Hugo Junkers (1859-1935), took flight in 1915. Previously, aircraft experts believed that airplanes can only fly with light materials such as wood, struts, tension wires, and canvas. Junkers thought differently and believed that heavier materials like metal were necessary to transport passengers and goods.

 

The Golden Age

 

The Roaring 20’s ushered in airplane racing competitions, which led aircraft designers to focus on performance. Innovators, such as Howard Hughes, found that monoplanes (aircraft with one pair of wings) were more aerodynamic in comparison to biplanes, and that frames made with aluminum alloys were capable of withstanding extraordinary pressures and stresses. Due to its lightweight properties, aluminum also made its way into the internal fittings of the aircraft decreasing the weight and allowing for a more fuel-efficient design.

 

In 1925, Henry Ford acquired the Stout Metal Airplane Company, utilizing the all-metal design principles proposed by Hugo Junkers, Ford developed the Ford Trimotor, nicknamed the “Tin Goose.” The “Tin Goose” propelled the race to design safe and reliable engines for airline travel. A few years later, Henry Ford’s Trimotor NC8407 became the first airplane flown by Eastern Air Transport, a leading domestic airline in the 1930s flying routes from New York to Florida. This positioned metal as the primary material for domestic aircraft, and eventually military applications with the onset of WWII.

 

 

Plastic’s Mettle: Wartime Materials Take Flight

 

By the 1930’s, the use of wood became obsolete and all-metal aircrafts were produced for their durability. Imperial Airways, known today as British Airways, made headway in the air travel industry with advertisements of luxury and adventure to cross borders. However, those borders were sealed off with the breakout of WWII. In 1939, Imperial Airways, a private commercial airline, was ordered to operate from a military standpoint at Bristol Airport.  Across the Atlantic, engineers focused their efforts on building aircraft meant specifically for military strategy – strength, durability, agility, and weaponry.  The Boeing P-26 “Peashooter” entered service with the United States Army Air Corps as the first all-metal and low-wing monoplane fighter aircraft. Known for its speed and maneuverability, the small but feisty P-26 formed the core of pursuit squadrons throughout the United States.

 

 

In times of war, there are often significant advancements in material usage, weaponry, and machinery. World War II was no different. Plastics entered the scene during World War II, starting with the replacement of metal parts for rubber parts in U.S. aircraft after Japan limited metal trade with the United States. Following that, plastics of higher grades began to replace electrical insulators and mechanical components such as gears, pulleys, and fasteners. Aircraft manufacturers began to replace aluminum parts with plastics as they were lighter and thus more fuel efficient than aluminum.

 

The Race for Space

 

Lighter and more fuel efficient were the key words following World War II as nations turned their attention to the skies and beyond. The space program in the 1960’s brought together illustrious minds to solve the seemingly impossible feat of being the first country to put mankind on the moon, thus, the great race for space began. Aircraft were now going beyond the sky and NASA scientists knew they were dealing with new territory in aero innovation. They needed a material that could break the Earth’s atmosphere and carry a hefty amount of fuel, while protecting the spacecraft’s crew from extreme temperatures. NASA scientists turned to plastics, specifically Kevlar and nylon. Layers of nylon and other insulators were wrapped under the body of the spacecraft to protect the crew from the extreme temperatures of space. Both of these plastics are still staples in the aerospace industry – keeping the Hubble telescope and many other satellites scanning humanity’s charted and uncharted expanse.

 

 

Plastics of the Future

 

Plastics continue to lead the future of materials in aerospace and aviation industries for their durability, precision, and ingenuity. For example, in 2009, the 787-8 Dreamliner made its first maiden flight, becoming the first aircraft to have wings and fuselage made from carbon-fiber plastics. Besides being lightweight, plastics offered increased safety with their resistance to high impact, and their proven ability to withstand chemically harsh environments. This proved plastics an invaluable material when compared to alternative material choices like glass or metal.

 

 

Starting in the 1970s, plastics began to play a more crucial part in the defense and military industry, especially in stealth aircraft. The U.S. Air Force saw the potential of plastics when they learned that plastics could absorb radar waves. The added benefit of reduced radar signature makes plastics ideal for creating stealthy aircraft. Plastics continue to contribute to innovation in the defense industry, especially with stealth fabrics and other composite materials which can virtually create invisibility to radars in the near future.

 

Aside from plastics becoming increasingly popular for use in the defense and military sector, high grade plastics like PEEK are highly favorable for space travel due to its ability to function in hostile environments, critical in space exploration. Plastics are even being researched for lightweight radiation shielding for the International Space Station and flights to Mars.

 

At AIP, we’re proud to be a continued part of aviation and aerospace advancements and we look forward to engineering solutions for the next frontier. In fact, at the time this article was written, we are AS9100D:2016 certified, which means we meet the high-quality standards of applications in the aerospace industry. In addition, we are also ISO 13485:2016, ISO 9000:2015, FDA audited, and ITAR certified. Above call, we strive to create genuine relationships with our customers to deliver mission critical components with promise. To learn how we can help you, contact us today.

 

Interested to learn more? Read “Plastics in Aerospace: The Secret to Fuel-Efficient Aircraft

 

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AIP Precision Machining is proud to officially be AS9100:2016 certified as part of our dedication to quality in machining for aerospace applications. To share what that means, we’ve put together the following article to explain what AS9100D:2019 certification is and how we achieved it.

 

What is the AS9100D:2016 Standard?

 

AS9100 is a company level certification based on the ISO 9001 quality standard requirements, but with additional requirements based on the needs of the aerospace industry. These satisfy both ISO 9001 quality standards and DOD, NASA and FAA requirements.

 

This certification is based on “Quality Management Systems – Requirements for Aviation, Space and Defense Organizations,” a standard published by the Society of Automotive Engineers (SAE). A third-party certifying body issues AS9100D:2016 certification. Part of this process includes annual or regularly scheduled audits to ensure compliance with the AS9100 standard.

 

AS9100D is meant for any organization that does business in the aerospace sector, including suppliers, contractors and manufacturers, such as AIP. It’s an internationally accepted standard, though different countries use their own numbering conventions.

 

As of this blog, AS9100D:2016 is the most recent version of the AS9100, revising the previous issue, AS9100C.

 

What about this certification helps AIP Precision Machining serve the aerospace market?

 

For the past 36 years, AIP Precision Machining has been supplying mission-critical polymer and composite components to Tier 1 through 3 aerospace OEMs. The latest AS9100D certification was required as a means to help open new “doors” in this marketplace for AIP. We were already the global leader for technical know-how and capability when considering supply options for aerospace like services due to our talented and advanced team. 

 

Similar to a job application, great candidates are many times excluded from opportunities due to lacking minimum accreditations. In our journey to offer our talent and services to new US-based or globally located aerospace OEMs, AS9100 certification allows AIP to showcase our capabilities for this market.

 

“There is no doubt in my mind that AIP is and always had been overly equipped to provide mission-critical precision aerospace components,” said John MacDonald, President of AIP Precision Machining. “It is just that now we have achieved the accreditation to show those who do not know of us that we are capable.”

 

What about AIP Precision Machining allows us to achieve AS9100D:2016 certification?

 

“Anyone who tells you that it is not about the people is wrong,” said MacDonald. “Leadership provided the vision and desire to seek out AS9100D certification, but our awesome team at AIP ran the marathon and got us over the finish line. It is also our team who will maintain and continually enhance those key processes to make us better every day at serving our valued customers.”

 

Want to contact us about aerospace manufacturing?

Get in touch with us online, or see our  AD9100D:2016 certification

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Company News: Retirement

After 40 years in various Quality Control roles—from inspection, regulatory affairs, management, and HSE—Dave Eckroth has retired. Having spent 22 of his 40 years at AIP, his “going-away” party felt like saying goodbye to a family member, not a coworker. We all wish him a safe, happy, healthy and very long retirement.

 

Dave has been instrumental in the regulatory aspects of AIP’s business, such as attaining our ISO certifications and keeping them up-to-date. He consistently raised the company’s Quality Health, Safety and Environment standards. As Dave has often said, “You can’t measure in quality.”

 

In Quality Control, Dave was the final gatekeeper to ensure customers received exactly what they ordered. He balanced efficiency with quality, and designed processes and procedures to avoid mistakes and mitigate risks. If a product needed to shift even a thousandth of an inch during inspection, Dave made sure it did.

 

We celebrated his retirement with a company luncheon. Though Dave could have picked any food, he chose good old-fashioned pizza. Many of us shared how much we’ve enjoyed working with him over the years, including our CEO, John MacDonald. Of Dave’s retirement, he said:

 

“Moments like this make me think that regardless of the many challenges we face, it is quite unique and special to have a dedicated group of people who have stuck together as a team for so many years.”

 

Dave thanked everyone and shared that AIP was the best place he’d ever worked. We sent Dave off with balloons and wish him all the best in retirement, where he plans to remodel his old Chevy truck.

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