Torlon - AIP Precision Machining

Plastics in Aerospace: The Secret to Fuel-Efficient Aircraft in 2020

February 4, 2020

How Aluminum Got Dethroned by Thermoplastics in Aerospace

Cup holders. Magazines. Suit cases. Aircraft engines. Here’s a riddle, what do these items all have in common? If you’re an aircraft operator, the answer is obvious: they all add weight, making them a drain on your fuel costs.

If weight is one of the main operating costs of an aircraft, then it’s no surprise that airlines want to lose a few pounds. Over the last 36 years, AIP has witnessed firsthand the incredible weight savings that can be gained from using lightweight polymers and composites for aerospace applications.

How Airlines “Slim Down” Operating Costs

How much can an ounce cost you? Plenty. In the case of United Airlines, removing a single ounce from its in-flight magazine has translated to saving $290,000 a year. Yes, a single ounce can hit an airline with up to six digits in costs.

If thinner paper can have such an impact on your bottom line, then you can imagine the significant cost savings that can come from manufacturing lighter aerospace components. What’s the most lightweight solution for aircraft operators today? We have one word for you: plastics.

What Makes Plastics the Secret to Aircraft Fuel-Efficiency

Aluminum was popular during the “Golden Age of Aviation” because of its strength and durability as well as its lightness when compared to other metals like steel. As a result, many aircraft components have traditionally been metal, from aircraft interiors, to landing gear, aircraft engines and structural components.

Now consider the fact that polymer and composite materials can be up to ten times lighter than metal. It’s no wonder that as more thermoplastic materials come on the market and new manufacturing opportunities arise, metal replacement has been seen as one of the best opportunities to reduce airline weight.

How big is the impact of switching from aluminum to plastic parts like PEEK and ULTEM in aerospace applications? Operators can earn weight savings of up to 60%. This translates to lower lifetime fuel costs, reduced emissions and extended flight range for operators.

“Weighing” the Option of Plastics in Aerospace

Weight alone is a massive reason to consider thermoplastics for aerospace, but weight isn’t the only factor at play in material selection.

After all, wood is lighter than metal, but there’s a reason we don’t build spruce airframes like the first plane from the Wright brothers: it wouldn’t be safe today to fly a wooden plane! Aerospace components need to be able to survive in corrosive, harsh environments as well as provide resistance to high temperatures.

In other words, it’s crucial that your mission-critical components aren’t just lightweight, but also high-performing.

At AIP, we carefully apply our decades of material expertise to select the right material for your application’s needs. Remember that your aerospace plastics manufacturer should understand the unique demands of your industry and your application, and have experience machining the material you require.

Want to learn more about how AIP reduces costs for aircraft operators?

Read how machined polymer components can take a load off aircraft interiors in our aerospace case study.

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Mission Critical Components: The Advantages of Plastics Over Metals

February 3, 2020

When design engineers need a custom-machined component for a project, many consider metals first for their strength and durability. However, this is not the case anymore; metals are moving over as polymers and composites become a more sensible alternative for precision-machined, high-strength durable parts. This is true across many industries, but especially in the aerospace and defense sectors. In this article, we will explore the benefits of opting for a plastic material for mission-critical aerospace and defense parts.

Overall Benefits

Machined polymer and composite components are the most cost-effective solution compared to metal.

First, machined plastic parts are lighter and, therefore, provide immense advantages over metals by offering lower lifetime freight costs for equipment that is regularly transported or handled over the product’s lifetime. Furthermore, polymers allow lower power motors for moving parts due to lower frictional properties of polymer wear components compared to metals. The low frictional properties preserve the integrity of the part as well, which translates to less maintenance-related downtime. What does this mean for operators? Equipment remains online longer doing what it’s supposed to do – produce profit and functionality. Not only are plastics lighter, but they’re also less expensive than many raw metal materials used for parts. Plastics can be produced in faster cycles than metals, which helps keep manufacturing costs down as well.

At AIP, we can machine and deliver parts in as little as 10 business days.

Explore AIP’s Machining Capabilities

Plastics are more resistant to chemicals than their metal counterparts.

Without extensive and costly secondary finishes and coatings, metals are easily attacked by many common chemicals. Corrosion due to moisture or even dissimilar metals in close contact is also a major concern with metal components. Polymer and composite materials such as PEEK, Kynar, Teflon, and Polyethylene are impervious to some of the harshest chemicals. This allows for the manufacture and use of precision fluid handling components in the chemical and processing industries. These parts would otherwise dissolve if they were manufactured from metal materials. Some polymer materials available for machining can withstand temperatures over 700°F (370°C).

Plastic parts do not require post-treatment finishing efforts, unlike metal.

Polymer and composites are both thermally and electrically insulating. Metallic components require special secondary processing and coating in order to achieve any sort of insulating properties. These secondary processes add cost to metallic components without offering the level of insulation offered by polymer materials. Plastic and composite components are also naturally corrosion resistant and experience no galvanic effects in a dissimilar metal scenario that require sheathing. Additionally, plastic materials are compounded with color before machining, eliminating the need for post-treatment finishing efforts such as painting.

Benefits to the Aerospace & Defense Sector

Polymers bring many advantages to the aerospace and defense industry, particularly in the form of weight-saving capabilities. Let’s take a closer look at the benefits of precision machined mission-critical components.

Lightweight: Polymer and composite materials are up to ten times lighter than typical metals. A reduction in the weight of parts can have a huge impact on an aerospace company’s bottom line. For every pound of weight reduced on a plane, the airline can realize up to $15k per year in fuel cost reduction.

Corrosion-Resistant: Plastic materials handle far better than metals in chemically harsh environments. This increases the lifespan of the aircraft and avoids costly repairs brought about by corroding metal components an in-turn reducing MRO downtime provides for more operational time per aircraft per year.

Insulating and Radar Absorbent: Polymers are naturally radar-absorbent as well as thermally and electrically insulating.

Flame & Smoke Resistances: High-performance thermoplastics meet the stringent flame and smoke resistances required for aerospace applications.

Other Benefits for Aerospace and Defense

High Tensile Strength: Several lightweight thermoplastics can match the strength of metals, making them perfect for airplane equipment metal part replacement.

Flexibility & Impact Resistance: Polymers are resistant to impact damage, making them less prone to denting or cracking the way that metals do.

Plastics have a variety of unique attributes which place them above metals in terms of utility, cost-effectiveness and flexibility for precision-machined mission-critical components. To learn more, search specific plastic materials and their applications per industry with our useful material search function.

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Common Thermoplastic Materials in Aerospace & Defense

January 27, 2020

With over three decades of experience machining precision plastic and composite parts for the Aerospace & Defense industry, AIP Precision Machining knows that weight and strength are critical for your flight-ready hardware. That’s why we’ve carefully selected, machined, and tested all our thermoplastic materials to various aerospace industry standards. Our lightweight polymers and composites have stable chemical and corrosion resistance, as well as improved strength to weight ratios when compared to exotic alloys and non-ferrous metals. AIP’s polymer and composite materials maintain their properties even at high temperatures.

Read more on thermoplastic materials commonly used in the Aerospace & Defense industry for every day to mission-critical applications.

ULTEM – PEI

ULTEM has one of the highest dielectric strengths of any thermoplastic material, meaning it works very efficiently as an electrical insulator. Being resistant to both hot water and steam, ULTEM can withstand repeated cycles in a steam autoclave and can operate in high service temperature environments (340F or 170C). ULTEM also has one of the lowest rates of thermal conductivity, allowing parts machined from ULTEM to act as thermal insulators. ULTEM is FDA and NSF approved for both food and medical contact and therefore is an excellent choice for aircraft galley equipment such as ovens, microwaves and hot or cold beverage dispensing systems. UL94 V-O flame rating with very low smoke output makes this material ideal for aircraft interior components.

CELAZOLE – PBI

CELAZOLE provides the highest mechanical properties of any thermoplastic above 400F (204C) and offers a continuous use operating temperature of 750F (399C). CELAZOLE has outstanding high-temperature mechanical properties for use in aircraft engines and other HOT section areas. This impressive lightweight material retains 100% tensile strength after being submerged in hydraulic fluid at 200°F for thirty days.

RYTON – PPS

RYTON’s inherent fire retardancy, thermal stability and corrosion resistance makes it perfectly suited for aerospace applications, while its dimensional stability means even the most intricate parts can be molded from RYTON with very tight tolerances. RYTON is typically used for injection molded parts, however, there is limited availability of extruded rod and plate for machining.

VESPEL or DURATRON – PI

Like RYTON, VESPEL is dimensionally stable and has fantastic temperature resistance. It can operate uninterrupted from cryogenic temperatures to 550°F, with intermittent to 900°F. Thanks to its resistance to high wear and friction, VESPEL performs with excellence and longevity in severe environments—like those used in aerospace applications. VESPEL is a trademarked material of DuPont and can be provided in direct formed blanks or finished parts directly from DuPont. AIP provides precision machined components from DuPont manufactured rod and plate stock. VESPEL is typically used in high temperature and high-speed bearing and wear applications such as stator bushings.

TORLON or DURATRON – PAI

DURATRON PAI’s extremely low coefficient of linear thermal expansion and high creep resistance deliver excellent dimensional stability over its entire service range. DURATRON PAI is an amorphous material with a Tg (glass transition temperature) of 537°F (280°C). DURATRON PAI stock shapes are post-cured using procedures developed jointly by BP Amoco under the TORLON trade name and Quadrant under the DURATRON trade name. A post-curing cycle is sometimes recommended for components fabricated from extruded shapes where optimization of chemical resistance and/or wear performance is required. TOLRON parts are used in structural, wear and electrical aerospace applications.

TECHTRON – PPS

TECHTRON has essentially zero moisture absorption which allows products manufactured from this material to maintain extreme dimensional and density stability. TECHTRON is highly chemical resistant allowing it to operate while submerged in harsh chemicals. It is inherently flame retardant and can be easily machined to close tolerances. It has a broader resistance to chemicals than most high-performing plastics and can work well as an alternative to PEEK at lower temperatures.

RADEL – PPSU

With high heat and high impact performance, RADEL delivers better impact resistance and chemical resistance than other sulfone based polymers, such as PSU and PEI. Its toughness and long-term hydrolytic stability means it performs well even under autoclave pressure. RADEL R5500 meets the stringent aircraft flammability requirements of 14CFR Part 25, allowing the aircraft design engineer to provide lightweight, safe and aesthetically pleasing precision components for various aircraft interior layouts. RADEL can be polished to a mirror finish and is FDA and NSF approved for food and beverage contact.

KEL – F

Kel-F is a winning combination of physical and mechanical properties, non-flammability, chemical resistance, near-zero moisture absorption and of course outstanding electrical properties. This stands out from other thermoplastic fluoropolymers, as only Kel-F has these characteristics in a useful temperature range of -400°F to +400°F. In addition, it has very low outgassing and offers extreme transmissivity for radar and microwave applications. Many aircraft and ground-based random applications use Kel-F.

PEEK

PEEK can be used continuously to 480°F (250°C) and in hot water or steam without permanent loss in physical properties. For hostile environments, PEEK is a high strength alternative to fluoropolymers. PEEK carries a V-O flammability rating and exhibits very low smoke and toxic gas emission when exposed to flame. PEEK is an increasingly popular replacement for metal in the aerospace industry due to its lightweight nature, mechanical strength, creep and fatigue resistance, as well as its ease in processing. Its exceptional physical and thermal characteristics make it a versatile thermoplastic polymer in many aerospace applications. AIP has provided flight control, fuel system, interior, engine and aerodynamic related PEEK components for various aircraft OEM and MRO providers worldwide.

KYNAR – PVDF

Another example of thermoplastic materials used in aerospace and defense is KYNAR, or PVDF. This polymer has impressive chemical resistance at ambient and elevated temperatures, as well as good thermomechanical and tensile strength. KYNAR is extremely durable due to its weather-ability and toughness even in the most severe environments. In addition to being flame-resistant, KYNAR is easy to machine, too. You can typically find KYNAR components in pipe fitting and various fuel or other fluid-related precision manifolds or connectors.

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The Untold Story of Re-Useable Plastics

November 19, 2019

Learn about the re-useable capabilities of precision plastics

In the world of recycling, plastic tends to have a bad reputation or it gets whispered like a dirty word. Indeed, according to the UN Environment Programm, one million plastic drinking bottles are purchased every minute. This is certainly a disturbing statistic, and we are tasked with addressing the consequences of this waste. However, it is important to distinguish the type of plastics causing severe pollution. Plastic bottles and plastic bags are single-use, disposable plastics. These are the ones that are clogging up the environment.

What people don’t discuss often is plastics that are re-usable and recyclable. At AIP, the plastics that we precision machine are high grade, quality polymers made for durability and continuous use in the following industries: Aerospace and Defense; Medical and Life Sciences; Power and Energy; Specialized Industrial. That means they are evergreen materials that will not only last, but could be repurposed for a different application altogether. Read on to find out about some of the high-performance polymers we work with, what they are used for and how they can be recycled.

Everyday Sustainable Precision Plastics
Polymer	Properties	AIP’s Machined Applications
PPS	Broadest chemical resistance; zero moisture absorption; dimensional stability; ultra-low wear factors and structural strength *available in several grades	Case Study: High-quality PPS wheel bushings for a theme park water ride. Reduced ride downtime Saved on maintenance and inventory costs Lower energy cost Efficient design Low-wear
TORLON	Highest performing, melt-processible plastic; maintains strength and stiffness up to 500 F; chemical, thermal and stress resistance *available in several grades	Ideal for critical mechanical and structural components for severe levels of temperature and stress Jet Engine Components High Temperature Electrical Connectors Automotive Transmission components Wear Rings in Oil Recovery Valve Seats
PEEK	Biocompatible; abrasion and chemical resistant; low moisture absorption; very low smoke and toxic gas emission *available in several grades	Case Study: PEEK Dynamic Telescopic Craniotomy (skull plate for brain traumas Reduced ride downtime Saved on maintenance and inventory costs Lower energy cost Efficient design Low-wear
RADEL	Impact resistance; hydrolytic stability; excellent toughness; chemical resistance; heat deflection temperature of 405 F (207 C)	Medical Tubing Case Study: Aircraft Interiors Hot Water Fittings Dental Instruments Sterilization Tray Lids
ULTEM	Excellent heat and flame resistance; high rigidity and strength; low thermal conductivity; highest dielectric strength *available in several grades	Used as structural components in several industries High-voltage circuit-breaker housings High-temperature bobbins, coils, fuse blocks and wire coatings Jet-engine components Aircraft interior and electrical hardware parts Microwave applications Replaces glass in medical lamps

Thermoplastics – The Green Plastic

There are two types of polymers – thermoplastics and thermosets. The plastics that we work with primarily at AIP are thermoplastics. So, what’s a thermoplastic and how is it re-usable or recyclable?

It’s all about how the polymer reacts to chemicals and temperature. Thermoplastics soften when heated and become more fluid, which makes them a very flexible polymer. For this reason, these plastics can be remolded and recycled without losing their mechanical properties or dimensional stability. Let’s go in depth on some of the common thermoplastics we use for evergreen applications.

The AIP case study focusing on the use of PPS for the log flume ride bushing component is an excellent example of a thermoplastic built and machined for continuous use. The bushing made from PPS could be used over and over again without wear. Furthermore, it could be immersed in water and other chemicals without losing dimensionality or durability.

PEEK and ULTEM are both common polymers we machine at AIP. With PEEK’s high chemical resistance and biocompatibility, it is ideal for surgical applications such as the Dynamic Telescopic Craniotomy Case Study. This polymer can withstand the internal temperatures and fluids of the body for extended use.

ULTEM is known for its strength and rigidity in extreme environments and temperatures. This polymer is often used for re-useable medical instruments, since it reacts well to autoclave sterilizations. Additionally, it’s flammability rating and dimensional stability make it ideal as a weight-saving aerospace component.

As the plastics industry continues to innovate, the next generation of research will turn towards more sustainable and environmentally conscious materials. Thermoplastics are one of the pioneers of this industry – leading plastics into the future as a material that can be reused and recycled.

Unrivaled Expertise. Unparalleled Results

Helicopter landing on ship With 36+ years of experience in the industry, our dedicated craftsmen and ties to leading plastic manufacturers allow us to provide you with unrivaled knowledge and consulting in material selection, sizing, manufacturing techniques and beyond to best meet your project needs.

AIP offers a unique combination of CNC machining, raw material distribution, and consultancy as a reliable source for engineering information for materials such as PEEK, TORLON, ULTEM and more.

We are AS 9100D compliant; certified and registered with ISO 13485 and ISO 9001 and standards in our commitment to machining quality custom plastic components for specialized industrial sectors. Quality assurance is included as an integral part of our process and is addressed at every step of your project, from concept to completion. Unrivaled Expertise. Unparalleled Results.

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Advantages of Polymer Components over Metallic Materials for Machined Parts

March 25, 2019

This post was originally published in August 2017 and updated in March 2019.

When in need of a custom-machined component for a project, choosing a metallic material may be the instinctive consideration to the design engineer. This article is intended to provide educational insight as to a more sensible alternative for precision-machined, high-strength, durable parts: machined polymers and composites. Let’s explore the benefits of opting for a plastic material versus the more traditional metal materials for precision parts.

Benefits Across the Board

Machined polymer and composite components are the most cost-effective solution when compared to metal.

Machined plastic parts are lighter and therefore provide immense advantages over metals by offering lower lifetime freight costs for equipment that is regularly transported or handled over the product’s lifetime. In bearing and wear applications, polymers provide extensive advantages over metals by allowing for lower power motors for moving parts due to lower frictional properties of polymer wear components compared to metals. The low frictional properties provide for less wear as well. The lower wear rates allow for less maintenance-related downtime. Now your equipment can be online longer producing you more profit. Not only are plastics lighter, but they’re also less expensive than many raw metal materials used for parts. Plastics are produced in faster cycles than metals which helps keep manufacturing costs down as well.

Plastics are more resistant to chemicals than their metal counterparts.

Without extensive and costly secondary finishes and coatings, metals are easily attacked by many common chemicals. Corrosion due to moisture or even dissimilar metals in close contact is also a major concern with metal components. Polymer and composite materials such as PEEK, Kynar, Teflon, and Polyethylene are impervious to some of the harshest chemicals. This allows for the manufacture and use of precision fluid handling components in the chemical and processing industries which would otherwise dissolve if manufactured from metallic materials. Some polymer materials available for machining can withstand temperatures over 700°F (370°C).

Plastic parts do not require post-treatment finishing efforts, unlike metal.

Polymer and composites are both thermally and electrically insulating. Metallic components require special secondary processing and coating in order to achieve any sort of insulating properties. These secondary processes add cost to metallic components without offering the level of insulation offered by polymer materials. Plastic and composite components are also naturally corrosion resistant and experience no galvanic effects in a dissimilar metal scenario that require sheathing. Unlike metals, plastic materials are compounded with color before machining, eliminating the need for post-treatment finishing efforts such as painting.

Let’s Break It Down by Industry

The benefits and features of plastic materials over metals discussed above span across multiple industries, showcasing the utility and versatility that plastic brings to the table.

Aerospace & Defense

Lightweight: Polymer and composite materials are up to ten times lighter than typical metals. A reduction in the weight of parts can have a huge impact on an aerospace company’s bottom line. For every pound of weight reduced on a plane, the airline can realize up to $15k per year in fuel cost reduction.

Corrosion-Resistant: Plastic materials handle far better than metals in chemically harsh environments. This increases the lifespan of the aircraft and avoids costly repairs brought about by corroding metal components an in-turn reducing MRO downtime provides for more operational time per aircraft per year.

Insulating and Radar Absorbent: Polymers are naturally radar absorbent as well as thermally and electrically insulating.

Flame & Smoke Resistances: High-performance thermoplastics meet the stringent flame and smoke resistances required for aerospace applications.

Learn More

Medical & Life Sciences

Sterility: In the medical industry, cleanliness is vital when it comes to equipment. Infection is the greatest threat facing hospital patients. Polymer and composite materials are easier to clean and sterilize than metal.

Radiolucency: Radiolucency is the quality of permitting the passage of radiant energy, such as x-rays, while still offering some resistance to it. Surgical instruments and components manufactured from polymer materials allow the surgeon a clear unobstructed view under fluoroscopy. This allows for safer, more precise surgeon outcomes in the OR. Metal instruments impede the surgeon’s view.

Lightweight: Plastic and composite surgical components allow orthopedic OEMs to meet ergonomic weight limits for surgical trays. Each metallic instrument adds weight and strain to the surgical team carrying and using metal instruments.

Reduced Stress-Shielding: Stress shielding occurs when metal implants and bone don’t become one nor work in unison. In medical-grade polymers like PEEK, however, its similar modulus to bone “fuses” with the bone into a single construct.

Learn More

Specialized Industrial

High Tensile Strength: Several lightweight thermoplastics can match the strength of metals, making them perfect for industrial equipment metal part replacement.

Chemical & Corrosion Resistances: Semiconductor equipment and electronics require survival in extreme, high-pressure environments.

Flexibility & Impact Resistance: Polymers are resistant to impact damage, making them less prone to denting or cracking the way that metals do.

Excellent Bearing & Wear Properties: Bearing-grade plastics can withstand repeated friction and wear for your high-load solutions.

Learn More

Power & Energy

Weight, corrosion, and sealing: Plastic materials allow the oil and gas industry to explore deeper depths than ever before by offering tool weight reduction without a loss of strength as well as materials which offer superior sealing attributes.

Superior Insulation: Naturally insulating plastics provide for superior thermal and electrical insulation over metals, which is a must for power generation equipment that deals with electrical currents.

Chemical, Wear & Corrosion Resistances: Plastic components with a strong chemical, wear and corrosion resistances reduce downtime and yield long-lasting performance and reliability.

Extreme Water & Earth Depth Capabilities: These qualities are necessary for high pressure and temperature applications that involve surviving extreme environments.

Learn More

As you can see, plastics have a variety of unique attributes which place them above metals in terms of utility, cost-effectiveness and flexibility for precision-machined components. Search specific plastic materials and their applications per industry with our useful material search function.

Download Our Plastics Over Metals Infographic

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What are the advantages of plastics over metals?

November 16, 2018

AIP explains the advantages of using plastics over metals in our infographic below, with special emphasis on how each industry benefits from using polymers. Read on to learn all about it from the plastics professionals.

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Machining TORLON: A Plastics Guide

May 30, 2018

An Informational Brief on Polymer Machining

AIP Precision Machining has worked with many thermoplastics over the past three decades, including TORLON: a PAI, or polyamide-imide, engineered by Solvay Specialty Polymers.

Due to its reliable performance at severe levels of temperature and stress, TORLON is ideal for critical mechanical and structural components of jet engines, automotive transmissions, oil recovery, off-road vehicles and heavy-duty equipment.

AIP has over 35 years of experience machining complex components from TORLON and various other thermoplastic materials. We are providing this Machining TORLON Guide as yet another insightful technical brief about our polymer component manufacturing process, and how it differs from that of metal machining, injection molding, or 3D printing.

Plastic CNC Machining

Before discussing the process of machining TORLON, it’s important to understand exactly what plastic machining is.

CNC (Computer Numerical Control) machining is a process in the manufacturing sector that involves the use of computers to control machine tools. In the case of plastic machining, this involves the precise removal of layers from a plastic sheet, rod, tube or near net molded blank.

The early history of CNC machining is almost as complex as a modern CNC system. The earliest version of computer numerical control (CNC) technology was developed shortly after World War II as a reliable, repeatable way to manufacture more accurate and complex parts for the aircraft industry. Numerical control—the precursor to CNC—was developed by John Parsons as a method of producing integrally stiffened aircraft skins.

Parsons, while working at his father’s Traverse City, Michigan-based Parsons Corp., had previously collaborated on the development of a system for producing helicopter rotor blade templates. Using an IBM 602A multiplier to calculate airfoil coordinates, and inputting this data to a Swiss jig borer, it was possible to produce templates from data on punched cards.

Parsons’ work lead to numerous Air Force research projects at the Massachusetts Institute of Technology (MIT) starting in 1949. Following extensive research and development, an experimental milling machine was constructed at MIT’s Servomechanisms Laboratory.

Due to the many different kinds of polymers and composites, it’s important to have strong technical expertise of polymer materials when machining plastic components; some plastics are brittle, for example, while others cut similarly to metal. The challenge of plastics is their wide range of mechanical and thermal properties which result in varying behavior when machined. Therefore, it’s important to understand the polymer structure and properties of TORLON if you’re machining it.

Thermoplastics vs Thermosets

When it comes to polymers, you have two basic types: thermoplastics and thermosets. It’s crucial to know which one you’re working with due to distinct differences between how these two main polymer categories react to chemicals and temperature.

Thermoplastics soften when heated and become more fluid as additional heat is applied. The curing process is completely reversible as no chemical bonding takes place. This characteristic allows thermoplastics to be remolded and recycled without negatively affecting the material’s physical properties.

They possess the following properties:

• Good Resistance to Creep

• Soluble in Certain Solvents

• Swell in Presence of Certain Solvents

• Allows for Plastic Deformation when Heated

Thermosets plastics contain polymers that cross-link together during the curing process to form an irreversible chemical bond. The cross-linking process eliminates the risk of the product re-melting when heat is applied, making thermosets ideal for high-heat applications such as electronics and appliances.

They possess the following properties:

• High Resistance to Creep

• Cannot Melt

• Insoluble

• Rarely Swell in Presence of Solvents

Phenolic, Bakelite, Vinyl Ester and Epoxy materials would be considered examples of a thermoset, while ULTEM, PEEK, DELRIN and Polycarbonate materials are examples of thermoplastics.

The thermoplastic category of polymers is further categorized into Amorphous and Crystalline polymers per the figure below:

TORLON is considered an amorphous, high-performance thermoplastic. Most amorphous polymers are thermoform capable, translucent and easily bonded with adhesives or solvents.

Various Grades of Machined TORLON

What makes TORLON unique is how it possesses both the incredible performance of thermoset polyimides and the melt-processing advantages of thermoplastics. The compressive strength of (unfilled) TORLON PAI is double that of PEEK and 30% higher than that of ULTEM PEI. In fact, TORLON is considered the highest performing, melt-processible plastic.

High-strength grades of TORLON retain their toughness, high strength and high stiffness up to 275°C. This and its impressive wear resistance allow TORLON to endure in hostile thermal, chemical and stress conditions considered too severe for other thermoplastics. TORLON is also resistant to automotive and aviation fluids, making it a favorite of aerospace and automotive engineers.

One concern of using TORLON is that its moisture absorption rate is not as low as other high-performance plastics, so special care should be taken when designing components for wet environments.

There’s more than one particular type of TORLON PAI you can machine, and each has slightly different properties for perfecting this material’s use in different applications.

Here are several grades of TORLON PAI we machine regularly at AIP Precision Machining.

TORLON 4203

TORLON 4203 is the unfilled or natural grade of TORLON PAI that outperforms other grades with the best impact resistance and the most elongation. TORLON 4203 PAI can be used for a variety of applications but due to its good electrical properties, it is commonly machined for electronic equipment manufacturing, valve seals, bearings and temperature test sockets.

TORLON 4301

TORLON 4301 is a wear-resistant grade of TORLON PAI containing PTFE and graphite. It has high flexural and compressive strength with a low coefficient of friction, as well as good mechanical properties. Typical applications of 4301 are anything that requires strength at high temperature with wear resistance and low friction. This material is useful for parts such as thrust washers, spline liners, valve seats, bushings, bearings and wear rings.

TORLON 4XG

TORLON 4XG is a 30% glass-reinforced extruded grade of PAI well suited to higher load structural or electronic applications. When you need a high degree of dimensional control, this grade offers the high-performance you need. Various uses of TORLON 4XG include burn-in sockets, gears, valve plates, impellers, rotors, terminal strips and insulators, among others.

TORLON 4XCF

TORLON 4XCF is a 30% carbon-reinforced extruded grade of PAI that has the lowest coefficient of thermal expansion and the most impressive fatigue resistance of all plastic materials. This uncommon grade works well as a replacement for metal applications as well as mission-critical aerospace components, in addition to impellers, shrouds and pistons.

Machining TORLON

Annealing TORLON
TORLON PAI can be received in the form of rods, sheets, tube or film. Stress-relieving before machining through an annealing process is crucial, as it reduces the likelihood that surface cracks and internal stresses will occur from the heat generated. This also helps prevent any warping or distortion of your plastic materials.

TORLON additionally benefits from post-machining annealing to reduce any stress that could contribute to premature failure. Extruded TORLON parts, such as those machined from TORLON 4XCF and TORLON 4XG, benefit from an additional cure after machining to further enhance wear resistance; this is unique to PAI. Proper annealing of Torlon can require more than seven days in special ovens at AIP.

If the machine shop you are working with does not have a computer controlled annealing oven for plastics, then “head for dee hills” as they are obviously not TORLON machining experts.

Machining TORLON

An important consideration to have when machining TORLON PAI is how abrasive it is on tooling. If you’re machining on a short run, carbide tooling can be used, but polycrystalline (PCD) tooling should be considered for lengthier runs, machining for tight tolerance and any time you are working with reinforced grades.

Another thing to keep in mind when machining extruded TORLON shapes is that they have a cured outer skin, which is harder than interior sections. The outer skin offers the best wear and chemical resistance. If wear resistance and chemical resistance needs to be optimized, extruded TORLON should be re-cured.

TORLON PAI will nearly always require the use of coolants due to its stiffness and hardness. Non-aromatic, water-soluble coolants are most suitable for ideal surface finishes and close tolerances. These include pressurized air and spray mists. Coolants have the additional benefit of extending tool life as well.

Many metal shops use petroleum-based coolants, but these types of fluids attack TORLON. Many past experiences have shown parts going to customer without cracks, only to develop cracks over time due to exposure to metal machine shop fluids. Be sure to use a facility like AIP who machines polymers and only polymers.

Preventing Contamination

Contamination is a serious concern when machining polymer components for technically demanding industries such as aerospace and medical. To ensure the highest level of sanitation down to the sub-molecular level, AIP Precision Machining designs, heat-treats and machines only plastics, with any sub-manufactured metalwork processed outside our facility.

TORLON Machining Guide: Supportive Information

Medical Sector Biomaterials Guide

Energy Sector Materials Guide

Aerospace Sector Materials Guide

Amorphous Materials

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