Plastic Machining - AIP Precision Machining

THE ADVANTAGES OF PEEK IN ORTHOPEDIC AND SPINAL FUSION

March 7, 2023

Why PEEK Plastic Material Biocompatibility Is the Standard in Orthopedic Surgery

Medical-grade Polyetheretherketone (PEEK) is a radiolucent high-performance polymer alternative to metallic biomaterials. It comes in different versions ranging from unfilled grades with varying molecular weight, to those with image-contrast and carbon fiber-reinforcement grades for demanding medical treatments inside the body or in the operating room. Carbon-reinforced PEEK is similar in strength to cortical bone, making it an attractive biomaterial for spinal fusion surgery, and reduce stress shielding.

In orthopedics, PEEK has been used for intervertebral cages, posterior & anterior instrumentation, and standard lumbar fusion. Additionally, clinical studies of PEEK for cervical fusion have revealed its advantages over titanium or cadaver bone.

As this material continues to gain traction in the orthopedic industry, it has shown superior qualities over stainless steel and titanium for biocompatibility, radiolucency, and durability.

A Brief History of PEEK in Orthopedic Surgery

Since the 1980s, Polyaryletherketones (PEEK) have been utilized as biomaterials in trauma, orthopedic, and spinal implants. Due to its relative inertness, radiolucency and chemical resistance, PEEK has had the greatest clinical impact in spine implant design.

Laboratory studies during the 1990s confirmed that PEEK implants had the needed combination of wear, strength, creep, and fatigue resistance to replace the metallic biomaterials in spinal implants. An intervertebral fusion cage was the first piece of spinal instrumentation that had been made with PEEK rather than metal. It was implanted in 1999 and made with PEEK-OPTIMA™ from Invibio Biomaterial Solutions.

The Future of PEEK Beyond Spinal Implants

Since then, PEEK has only expanded as a performance biomaterial for instrumented spine surgery. In the United States, spine fusion is one of the leading surgeries for patients who suffer from chronic neck and back pain that does not respond to preliminary treatments.

According to Orthopedic Design & Technology, around 215,000 Americans underwent spine fusion procedures in 1997. By 2007 that number had increased to 402,000. PEEK is now an established biomaterial that will only continue to expand.

The Biocompatibility and Biostability of PEEK

PEEK displays excellent biocompatibility and biostability as a performance medical-grade material. To differentiate, let’s briefly discuss biocompatibility versus biostability.

Biocompatibility – The biological requirements of a biomaterial or biomaterials used in a medical device. When it comes into contact with human tissue and fluids, it’s compatible with the environment and will not incur adverse effects.

Biostability – The ability of a material to maintain its physical and chemical integrity after implantation into living tissue. The FDA mandates that any medical material that comes into direct or indirect contact with human tissue and fluids must maintain mechanical and molecular integrity.

Anything touching or interacting with human tissue and bone must be both biocompatible and biostable for a patient. This is one area where metals fail compared to PEEK. Metals like titanium are a standard material for spinal fusion, yet clinical studies continue to reveal the advantages of PEEK.

Benefits of PEEK for Spinal Fusion

PEEK has a growing advocacy in the field of orthopedics for cervical fusion as well as spinal fusion. Published literature supports the material’s advantages and highlights these key benefits for patients with spinal and cervical fusion surgery:

• Improved spinal alignment and geometry
• Reduced hospital stays and decreased blood loss
• Decreased complication rates
• Good/excellent functional outcomes and improved patient satisfaction
• Excellent fusion rates

Biomaterial Comparison: PEEK Versus Metals

When it comes to standards of medical biomaterials, PEEK tends to outshine metals such as stainless steel and even titanium alloy.

Stainless Steel

Stainless steel has the advantage of being inexpensive, durable, and easily alloyed. However, as medical practices have advanced, stainless steel is often replaced by titanium and PEEK implants for spinal fusions.

First, stainless steel has low biocompatibility and is more likely to leech artifacts due to corrosion once implanted. This is a danger to patient safety and increases the need for surgeries overtime. PEEK, on the other hand, closely resembles cortical bone tissue and is flexible enough to graft onto tissue.

Additionally, metals like stainless steel visually obscure the healing site under fluoroscopy, making it more difficult for doctors to see whether the spine is healing correctly when doing checkups via X-rays or MRIs. Conversely, PEEK is a radiolucent material that offers ease, comfort, and a clear view to monitor stability and healing.

Titanium Alloy

Titanium alloy is an accepted standard biomaterial for spinal and cervical fusion surgeries. Compared to PEEK, it has a similar rate of fusion for cervical and lumbar spine fusions.

One potential complication of spinal fusion is the subsidence of disc height in the post-operative period. Recent studies to assess subsidence in titanium and PEEK cages showed a notably increased rate of subsidence in titanium versus PEEK in patient follow-ups.

This is a serious concern for surgeons looking to improve the rate of patient recovery and lessen repeat spinal fusion surgery. In this regard, PEEK is a superior performance material for safer and better spinal fusion practices.

Advancing Orthopedic Innovation With Medical-grade PEEK

The fields of orthopedics and spinal fusion continue to research new methods for best practices in the industry. Over the last three decades, medical-grade PEEK has established itself as the performance biomaterial of choice for surgeons and OEMs. Medical device design demands the highest level of sanitation, biocompatibility, and precision in one of the most extreme environments, the human body.

As a material that closely resembles cortical bone, PEEK has an established advantage over other metals such as titanium that have shown degradation and leeching over time. As OEMs search to expand the horizon of orthopedic medicine, PEEK polymer machinists like AIP stand at the ready to provide unrivaled expertise on design, function, and quick prototyping.

Talk to a team member from AIP about your next medical grade PEEK project.

Follow AIP Precision Machining on Linkedin

THE ADVANTAGES OF TORLON®: THERMAL & ELECTRICAL PROPERTIES IN AEROSPACE APPLICATIONS

February 6, 2023

Torlon® Takes the Heat in Mission-Critical Aerospace Components

Few businesses on the planet share the same level of scrutiny towards their components as those in the aerospace industry. The material properties of Torlon® are what make the high-performance thermoplastic a top material pick in the industry.

To pass the benchmark, aerospace components must be:

– Impervious to corrosive and oxidizing chemicals
– Able to function in both cold and hot environments
– Lightweight to reduce overall vehicle weight and increase payload
– Strong enough to withstand constant friction, impact, wear, temperature extremes, and high pressures

Few polymer materials can check all those boxes, but Torlon® is among them. For decades aerospace OEMs have relied on Torlon® to solve unique challenges in the aerospace and defense sector. One of its most outstanding properties is the ability to maintain mechanical stability at extreme temperatures. For this reason, it’s often used for bushings, fasteners, and screws in Boeing 787s and even F-16 fuel and air connectors.

Properties of Torlon®

Besides incredible thermal stability and resistance rivaling aluminum, copper, and steel, Torlon® is well known for its strength under pressure and chemical resistance. Torlon’s benefits include the following:

– Wear resistance in dry and lubricated environments
– Maintains strength and stiffness up to 500°F (260°C)
– Low-temperature toughness and impact strength
– Chemical resistance, including acids and most organics
– Low creep and wear under load
– Excellent compressive strength and extremely low CLTE
– Low flammability and smoke generation

→ Discover our precision plastics

High-Temperature Wear Resistance

Torlon® falls within the family of imidized performance polymers. Celazole® (PBI), VESPEL® (PI), and Torlon® (PAI) all perform at elevated temperatures up to and above 500°F (260°C). These grades of thermoplastics have resistance to chemicals, steam, and wear. Torlon® PAI is often accepted as a metal replacement in aerospace applications where temperatures range from cryogenic to extreme heat, and the application requires thermal/electrical insulation and weight reduction.

Torlon® Solves Tough Aerospace Challenges

Torlon® has been a critical material for many years with industries relying on its innate qualities to solve complicated challenges. How can Torlon® do the same for the aerospace industry? Consider the following:

1. Boeing thermal isolators – Increasing fuel efficiency by reducing aircraft weight is a constant goal for the aviation industry. In the case of the Boeing 787, Torlon® was able to help make that goal attainable. The engineers at Boeing theorized they could reduce the overall weight of the aircraft by feeding hydraulic lines through the fuel tanks rather than around them. For this to work, the hydraulic lines needed insulation that could handle being exposed and heated by harsh environments. Torlon® 4203 PAI was a perfect choice because it does not conduct heat nor electricity, which would have caused problems, as temperatures range from -40°F (-40°C) up 350 F (177°C).

2. Boeing bushings for blocker doors – Blocker doors allow the aircraft to slow down by creating a reverse thrust. The doors must be precise, and that task falls to the bushings in the hinge assembly. They must maintain a low friction and wear rate while surviving temperatures ranging from -40° to 500°F (260°C), and all without lubrication. Torlon® 4301 PAI provides all these needed properties.

3. Worldwide Aviation fastening screws – Aerospace OEMs need screws made from a material that can provide a capacity for heavy load-bearing while being optimized for production. In the case of radar systems, the screws also need to be made out of a material that won’t interfere with detection capabilities. For that reason alone, metal screws are out, as they’ll interfere with the radar’s ability to function. Torlon® 4203, on the other hand, is both RFI and EMI transparent, it doesn’t corrode, and it has a fantastic strength-to-weight ratio.

4. F-16 fuel and air connectors – With auxiliary tanks, the F-16 can take on the role of a strategic bomber, as its range is extended by a full 50%. At first, the fuel connectors were made from stainless steel but required additional insulation against lightning strikes, rendering metal connectors infeasible. Finding an alternative material proved difficult due to other variables; it needed to be resistant to temperatures up to 400°F (205°C), be chemically resistant to jet fuel, and handle constant vibrations. Torlon® 4203 was the answer, as it reached all those requirements while also handling pressures beyond 650 psi. This choice improved both the part performance and manufacturing costs.

In all of these real-world examples, Torlon® demonstrates its superiority in strength and thermal stability. The fact that it’s successfully used in critical applications is proof of the material’s reliability.

AIP, Unparalleled Results in Aerospace-grade Torlon® Machining

Advancements in aerospace design keep defense technology at the forefront. Material design with precision plastics is a core part of this evolution. High-performance plastics like Torlon® provide lightweight characteristics and mechanical stability even at extreme temperatures above 500°F (260°C). Aerospace contractors look for precision and consistent results in machined precision plastics.

As a global leader in precision performance plastics, AIP understands how one single machined part contributes to the efficacy of an entire aircraft. We have machined complex geometries with .002 mm precision. Our machinists have over 40 years of experience working with defense OEMs. From Torlon to PEEK or Vespel®, our material design vetting process aims to produce a final piece that does more than meet criteria; it accelerates the mission and contributes to your entire bottom line.

Talk to our machinists and engineers today about your aerospace application; we can provide you with a design and part prototype oftentimes within ten business days.

Follow AIP Precision Machining on Linkedin

HOW PEEK ADVANCES BIOCOMPATIBILITY IN MEDICAL TECHNOLOGY

January 7, 2023

PEEK Polymer Biocompatibility in the Operating Room or Inside the Body

Biocompatible precision polymers, such as Polyetheretherketone (PEEK) have revolutionized medical technology practices for over a decade. Medical devices and implants that come direct or indirect contact with human tissue and blood must meet strict guidelines for short and long-term use.

Biocompatibility in spinal and other dental implants, for example, is critical to patient health and bone fusion for long-term functionality. Medical-grade PEEK has the advantage of excellent chemical resistance and stability at high temperatures. This makes it a material choice for medical procedures inside the body or in the operating room.

In our latest PEEK brief, we delve into the advantage of PEEK polymer material biocompatibility.

The Superior Biocompatibility of PEEK for Surgical Instruments & Orthopedic Implants

Medical grade PEEK has gained traction as a leading medical technology for its advanced properties and unique compatibility with human tissue and fluids. It has also become a material choice for implants and instruments over other medical-grade plastics and metals. Additionally, medical OEMs will use PEEK in precision medical devices that require stability in high heat and chemical environments.

Characteristics of Medical-grade PEEK

PEEK fulfills the requirements for biocompatibility under FDA and ISO 10993 guidelines. Not only does it maintain continuous use up to 480°F (250°C), it’s also an attractive precision plastic for components used in the medical field for the following reasons:

• Autoclave Sterilization Stability
• Abrasion Resistance
• Chemical Resistance
• High Ductility
• High Elongation
• Hydrolysis Resistance
• Low Outgassing

Grades of Medical PEEK

There are several medical-grades of PEEK, but here are some common brand names sourced from AIP’s industry partners.

TECATEC® CW50

TECATEC PEEK MT CW50® black plates are based on Victrex® PEEK that is reinforced with 50% vol. carbon fibers. This carbon fiber reinforcement elevates the stiffness and strength to be many times those of plates made from unreinforced PEEK or plates with short fiber reinforcement.

This grade of PEEK has been tested and approved for biocompatibility as per ISO 10993 for blood and tissue contact. It is autoclavable as it shows no significant loss of mechanical properties or degradation, even after many sterilization cycles. TECATEC® PEEK MT CW50 black is also suitable for gamma sterilization and is X-ray transparent. This makes it an ideal material for medical applications in multi-use conditions.

TECAPEEK® MT

Ensinger ‘s TECAPEEK® MT was specially developed to meet the requirements for materials used in medical technology. Applications range from the orthopedic market, with the joint reconstruction and traumatology segments, to surgical instruments, the dental market, and many more.

SustaPEEK MG

Röchling’s SustaPEEK MG (Medical-grade) has excellent chemical resistance, high temperature stability, and excellent resistance to steam sterilization. It is commonly used for metal replacement in surgical implant applications. It is FDA, USP Class VI compliant, & ISO 10993-5 certified.

Ketron PEEK

MCAM’s Ketron® PEEK is a biocompatible polymer that boasts high mechanical properties with a continuous heat resistance of up to 482°F (250°C). Its great dimensional stability, excellent chemical & hydrolysis resistance, as well as its ability to sustain steam cleaning makes it a perfect polymer choice for medical implants, and other medical tool implementations.

Additionally, materials undergo numerous quality tests throughout phases of production, including 100% ultrasonic testing. Lot and batch traceability is available upon request with in-depth certification documents and raw material certificates of analysis.

Your Partner in Advancing Medical Technology

As a premier partner in precision plastic component manufacturing, we understand the demands of the medical industry. Cutting corners is out of the question for AIP’s expertise and craftsmanship. That’s why we are here to provide engineering guidance and finesse throughout the process. From initial design consultation to material selection and prototyping, we make it our priority to machine close tolerances, produce precise geometries, and meet the highest levels of sanitation.

Quality, accuracy, and durability are the norm at AIP. Not only do our customers demand it, we demand it of ourselves. We include quality assurance as an integral part of our process and is addressed at every step of your project, from concept to completion.

Contact an AIP team member for a quote for medical grade PEEK.

Follow AIP Precision Machining on Linkedin

FOUR KEY POLYMERS ENABLING SUCCESS IN THE ROCKET INDUSTRY

December 19, 2022

Mission Critical Polymers for Performance Rocketry

Every part of a rocket’s design is critical. If one piece fails or the performance of that piece doesn’t match the demands of the environment, then the whole rocket fails. Organizations like NASA, Boeing, Blue Origin and SpaceX approach rocket part design and selection with careful consideration.

Polymers have a unique position in the Aerospace and Defense market as they present features and capabilities that can stand the test of harsh environments and continuous use. High heat, dielectric strength, moisture resistance, insulative properties and impact strength all come into play in building the parts that make a performance rocket launch skyward.

In this insightful blog, we discuss four key aerospace polymers enabling success in the rocket industry.

VESPEL® by DuPont

Polyimide (PI) is an extreme-performance thermoplastic branded by DuPont Co. as VESPEL®. The material’s prime characteristics include outstanding creep resistance, high impact strength, and low wear at high PV. VESPEL® components allow for continuous operation temperatures of 500°F (260°C) with short-term excursion capabilities of 900°F (482°C). It is a well-known performance thermoplastic for aircraft parts, such as thrust washers, valve seats, seals and wear components.

VESPEL® is available in many grades to meet specific design requirements. The current available grades include SP-1 (Unfilled), SP-21 (15% Graphite), SP-22 (40% Graphite), SP-211 (15% Graphite and 10% PTFE) and SP-3 (15% Molybdenum Disulfide).

TORLON®

When it comes to high heat and stress, TORLON® can take it. Polyamide Imide (PAI) is an amorphous thermoplastic with the highest performing, melt-processability. It maintains strength and stiffness up to 500°F (260°C), has excellent wear resistance, and endures harsh thermal, chemical and stress conditions. With its continuous use under high heat and stress, this material is often used in the following aerospace applications: bearing cages, high temperature electrical connectors, structural parts, valve seats, seals and wear components.

There are several TORLON® grades available for PAI, including TORLON® 4203 (electrical and high strength), TORLON® 4301 (general purpose wear), TORLON® 4XG (glass-reinforced) and TORLON® 4XCF (carbon-reinforced).

KEL-F®

KEL-F, or PCTFE (polychlorotrifluoroethylene), is a type of fluoropolymer that has a wide range of applications in the aerospace industry. It is prized for its high strength and durability, as well as its resistance to chemicals, heat, and wear. What makes KEL-F® stand out is its temperature range from -400°F to +400°F. KEL-F® In aerospace applications, KEL-F® is often used in fuel lines, hydraulic systems, and gaskets. Thanks to its unique properties, KEL-F® is an essential material for many aerospace applications.

At AIP, we machine various grades and brand name PCTFE. Branded names include the following: KEL-F® and NEOFLON®.

PTFE

PTFE, or Polytetrafluoroethylene, is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications in aerospace due to its low coefficient of friction, high temperatures and chemical resistance, and non-stick properties. PTFE was first used in the aerospace industry in the 1940s and has since been used in a variety of aerospace applications such as fuel lines, hydraulic systems, and gaskets.

At AIP, we machine various grades and brand name PTFE. Branded names include the following: FLUOROSINT® 207, FLUOROSINT® 500, DYNEON®, SEMITRON® ESD 500HR, SEMITRON® PTFE, TEFLON®.

Polymers take flight as a new standard of aircraft excellence

As aerospace rocketry and aircraft continue to evolve with advanced technologies and sophisticated capabilities, material selection is crucial. Every piece that goes into a rocket is carefully thought and crafted for the highest level of performance. Torlon®, Vespel®, KEL-F® and PTFE are all thermoplastics enabling success in mission critical Aerospace and Defense rocketry.

Supporting Materials

Aerospace Market Materials

Aerospace & Defense Machining

Follow AIP Precision Machining on Linkedin

TORLON® PAI, tough as metal but at half the weight

December 5, 2022

The top 3 reasons to consider Torlon® over metal for your advanced engineering application

PolyamideImide (PAI) is a leading thermoplastic engineering plastic that offers extraordinary toughness and strength, even at temperatures up to 275°C (525°F). One of the leading PAI grades on the market is Solvay’s Torlon®. Developed for demanding aerospace and defense applications, Torlon® has also found broad use in automotive, energy, medical and other industries. Its superb performance makes it an excellent replacement for metals in many weight-sensitive applications. With its high strength-to-weight ratio, Torlon® PAI can help reduce component weight and lower manufacturing costs.

In this informational guide, we discuss the top three properties that make Torlon® a leading material pick for mission critical applications.

Top 3 Properties of TORLON® PAI

There is no doubt, this thermoplastic works well under pressure. PAI competes with metals like titanium and steel when it comes to high strength and wear resistance. These properties coupled with good mechanical stability over a broad range of temperatures put Torlon at the top of the material selection list. Let’s take a closer look.

High strength and wear resistance

Wear-resistant grades of Torlon® PAI offer custom combinations of mechanical and tribological properties. For this reason, PAI is often a metal replacement due to its capability to function under a wide range of temperatures, high pressure and velocities (PV). This is the case even when lubrication is marginal or non-existent. PAI can be formulated into specialized grades to suit even the harshest of environments.

High temperature resistance and functionality

When it comes to heat, PAI outperforms many advanced engineering resins, exhibiting great durability at 200 C (400 F). This makes it a leading choice for mission critical components used in repetitive-use, load-bearing operations. Carbon-fiber and glass-filled grades of PAI add stiffness, strength, low creep, and enhanced thermal expansion properties.

Chemical resistance

In critical industries like automotive and aerospace, chemical exposure is common for engineering materials. Performance materials like PAI are unaffected by aliphatic and aromatic hydrocarbons, chlorinated and fluorinated hydrocarbons, and most acids at moderate temperatures. However, this polymer does not respond well to saturated steam, strong bases, and some high-temperature acid systems. This is why it’s important to ensure proper post-cure for PAI parts. Torlon®, like PEEK, does not perform well in moist environments and will absorb water, but the rate is slow and parts can be restored to original dimension and properties by drying.

Industry Applications of Torlon® PAI

Aerospace and defense

Components for aerospace and defense have to maintain functionality under extreme temperatures, withstand high pressures, and resist corrosion and friction. Torlon® PAI is one of the leading thermoplastics on the market that meets these requirements, while also saving aircraft on weight reduction.

Automotive

Thermoplastics like Torlon® PAI have gained popularity as a metal replacement, especially in the automotive industry. PAI has the strength, impact resistance, and high temperature tolerance at a fraction of the weight of metal. It is used for transmission components where there are high levels of heat, pressure and friction.

Oil and gas

Due to its chemical resistance and continuous use under pressure and intense temperatures, PAI is a natural pick for unpredictable, harsh environments like those in the oil and gas industry. Where metal easily corrodes in these environments, PAI is the right material pick for applications like seals, back-up seal rings, bearings and bushings.

Electric / Electrical

Applications of PAI in the electric / electrical sector include insulators and electrical connectors. PAI has excellent dielectric strength, outstanding impact strength, and electrical insulation. These properties make it an ideal material pick for high-performance connectors, relays and switches.

Semiconductors

The semiconductor industry demands high-temperature processing and continuous stability. PAI offers both and more. It keeps components dimensionally stable at variable temperatures, provides pure surfaces, and has a strong resistance to chemicals like acids and solvents. In the semiconductor industry, common applications for PAI include wafer handling, bearing surfaces, IC test equipment sockets and handlers.

Grades of TORLON® PAI machined at AIP

At AIP, we partner with leading polymer suppliers like Solvay to provide the best grades of thermoplastic PAI on the market. We source and machine several grades of Torlon® from general purpose to metal replacements for advanced engineering applications.

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. PAI has the highest strength and stiffness of any thermoplastic up to 275°C (525°F). Torlon® 4203 can be used for a variety of applications but due to its excellent electrical properties, it is commonly machined for electronic equipment, connectors, spline liners, thrust washers, valve seals, bearings and temperature test sockets.

Torlon® 4301

Torlon® 4301 is a general purpose, wear-resistant grade of PAI containing PTFE and graphite. It offers high compressive and flexural strength with a low coefficient of friction along with good mechanical properties. Where high temperature and strength are a necessity, Torlon® 4301 is a good material choice. Common applications include thrust washers, bearings, and wear rings.

Torlon® 4XG

As a 30% glass-reinforced extruded grade of PAI, Torlon® 4XG is well suited to higher load structural or electronic applications. For applications that require a high degree of dimensional stability, 4XG offers high-performance. Several uses of 4XG include burn-in sockets, gears, valve plates, impellers, rotors, terminal strips and insulators.

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 thermoplastics. This durable PAI grade is a common metal replacement for mission-critical aerospace components, in addition to impellers, shrouds and pistons.

Follow AIP Precision Machining on Linkedin

Why RADEL® Is the Material Pick for Aircraft Interiors

November 21, 2022

Precision PPSU Takes Flight in Mission-Critical Aerospace Applications

Safety and engineering finesse come together in every aircraft on the market. It’s not just about ensuring a good flight experience for consumers; it’s the law. The Federal Aviation Administration (FAA) has regulations in place that dictate the material choices for commercial aircraft. For instance, fireproof materials are an essential part of aircraft interiors.

In the late 1980s, FAA statistics showed that about 40% of survivors from impact-related aircraft crashes died from post-crash fire and smoke exposure. At the time, most aircraft interiors were made of combustible plastics. In 1987 the FAA mandated the use of fire-resistant plastics in all passenger planes.

Performance plastics like Solvay’s RADEL®, polyphenylsulfone (PPSU), offer not only high impact resistance but also high heat resistance. RADEL® is a key material in mission-critical performance within the cabin of an aircraft. In this article, we discuss the advantages of RADEL® for aerospace applications.

Demands of Aircraft Interiors – Beyond Comfort

Passengers might think about leg space and seat comfort, but there is a lot of thought put into the safety of cabin space. Fireproofing an aircraft is a crucial part of construction and engineering. Yet, engineers also look for a material that meets the industry’s lightweight and durability requisites.

Performance plastics in aerospace design have played a major role for several decades. Prior to the 1987 FAA mandate for fire-resistant plastics, most cabin interior composites were epoxy-based. These highly-flammable plastics, while providing the aesthetics and durability needed for aircraft interiors, were also highly dangerous in the event of a fire.

Since then, aircraft interior material selection has evolved to meet the standards of aesthetics, durability, AND flame resistance. Flame-resistant polymers for aircraft interiors have physical and chemical properties in terms of their effect on the heat release rate of burning material. Those qualities include: fuel replacement, flame inhibition, intumescence, and heat resistance.

These fire resistance mechanisms, acting simultaneously or collaboratively, are effective at reducing the heat release rate of a new generation of transparent plastics suitable for aircraft cabin interiors.

Properties of RADEL® PPSU for Aerospace

Solvay’s RADEL® PPSU meets all of the stringent requirements of the aerospace sector as well as the FAA regulations on flame retardance. 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. It also performs under repeated chemical and hydrolytic exposure.

Furthermore, RADEL® PPSU meets the aircraft flammability requirements of 14 CFR Part 25, enabling engineers a material choice that is lightweight, safe and, aesthetically pleasing. It comes in a variety of colors to avoid painting and is FDA and NSF-approved for food and beverage contact.

Performance Properties

Excellent toughness and impact strength
Meets OSU 65/65 and FAR 25.853 (a & d)
Color grades eliminate painting
Lower-cost paintable grades
Flame retardant – Inherently UL-94 V0
Exceptional long-term hydrolytic stability

Setting the Standard for Aerospace Precision Plastic Machining

Standards in the Aerospace and Defense sector are rigorous and non-negotiable. Aviation contractors put the greatest pressure on finding manufacturers who exceed the standards of the industry.

At AIP, we make it our priority to set the standard for aerospace precision plastic machining. For over three decades, we have worked with top aviation and defense contractors to deliver cutting-edge plastic components.

We operate an ITAR facility capable of satisfying all customer DOD, NASA, and FAA quality requirements that flow down from our OEM customers. For your next precision machined PPSU project, call on AIP to exceed the standards for mission-critical aerospace applications.

Follow AIP Precision Machining on Linkedin

PEEK Implants in Orbital Reconstruction

November 3, 2022

What Is Orbital Reconstruction?

Orbital trauma (trauma to the facial bone structure) can happen due to injuries, benign and malignant tumors, or infectious diseases. In the case of tumors where bone extraction may be necessary, replacing the bone in the orbital region does not usually cause deformity. However, in cases where significant bony material is lost or extracted, surgeons have typically used bone grafting to restore facial form and normality.

Yet, bone grafting presents its own issues with misalignment. Medical research has turned to materials such as titanium and precision plastics like PEEK. In this insightful brief, we discuss the advantages of PEEK for maxillofacial surgical procedures.

Challenges of Maxillofacial Surgery

There are issues with bone grafting though, namely imperfect alignment and resorption. The slight variability in the three-dimensional (3D) contour of the orbit with flat or slightly curved bone grafts can have a significant aesthetic effect on the outcome.

For a patient who has suffered trauma, coming out of surgery without the aesthetics of their face is emotionally devastating. For surgeons committed to providing the highest level of medical treatment, bone grafting is not always the best option.

In these cases of orbital reconstruction, it’s common for surgeons to use alloplasty, or inert pieces of metal and plastic for reconstruction. Traditional materials for alloplastic have been titanium plates or mesh. However, challenges associated with these materials include proper fixation and revision surgery complications due to soft tissue ingrowth.

Why PEEK Is Changing the Face of This Industry

With advancements in 3D printing and subtractive manufacturing techniques in precision polymers, patient-specific implants (PSIs) have been successfully reported in facial reconstruction. More recently, polyetheretherketone (PEEK) is a polymer with ideal alloplastic properties: nonconductive, biocompatible, and stable in the setting of long-term exposure to bodily fluids, elasticity is similar to native cortical bone, and light material makes it suitable for even large defects. As medical technologies continue to advance, PEEK has become a popular pick for PSIs.

A Case Study in PEEK Implants

One of the setbacks of titanium and metallic implants is that the manufacturing process takes time. In the case of PEEK implants, subtractive manufacturing offers convenient and quick milling precision at 0.4 mm thickness. The design freedom with PEEK is also much easier to produce than with metallic implants.

In addition, PEEK offers excellent imaging properties without artifact blockage, and it is most comparable to cortical bone. Recent research has shown that PEEK is an optimal choice for patients and surgeons with regard to revision surgery as well.

In a PEEK PSI group, diplopia after surgery was absent in 82.1% of patients versus 70.6% of controls with pre-bent titanium. These results showed that PEEK PSI demonstrated higher clinical efficacy in comparison to pre-bent plates in orbital wall reconstruction, especially in restoring the volume and shape of the damaged orbit.

Comparison to Metallic Surgical Materials

The most commonly used surgical material for orbital reconstruction is titanium. Its strength and flexibility set it apart as a material that lends itself well to meld to complex facial structures. However, Polyetheretherketone (PEEK) presents a major benefit as a material pick for its thermostability and comparability to cortical bone. We’ve mapped out a comparison of these common surgical materials below.

Additive Manufacturing Titanium

3-D manufactured titanium produces surfaces without tools or devices. It also enables options for surface design and intricacies that were previously impossible. In addition, additive manufactured titanium implants are so precise they don’t require reshaping processes.

Advantages
• Wide selection of shapes, structures, and styles
• Precise fitting accuracy
• Exceptionally stability
• Osteoconductive structures are possible
• Complete design freedom for the material and its surface
• Quick operation
• Steam sterilization

Limitations
• Additional material work is required for revision surgeries
• Intraoperative cutting to length is exceptionally difficult

Titanium Mesh

The special microstructure of titanium mesh allows it to be used in three-dimensional deep draw applications. A thermal process helps maintain the closed structure, which means that this material is both stable and intact while still offering excellent biocompatibility with bone apposition potential.

Advantages
• Very good biocompatibility, potential for vascularization
• Good mechanical properties
• Ease of manufacturing and cutting to size
• Bone cell apposition potential
• Relatively low price level
• No other plates required for fixation
• Steam sterilization (autoclavable)

Limitations
• No three-dimensional bone substitute
• Need for tools

Solid Titanium

Solid titanium is a high-strength reconstruction alternative to titanium mesh. Even though it has been widely supplanted by titanium mesh in recent years, it offers several advantages in specific fields of use, such as in relation to the mechanical protective function.

Advantages
• Best mechanical protective function
• High-strength reconstruction alternative
• No plates required for fixation
• Steam sterilization

Limitations
• Increased thermal conductivity
• Post-operative bending is not possible
• Post-operative cutting to size is not possible

PEEK

PEEK is a high-performing thermostable plastic. Its physical properties are similar to the cortical bone’s in humans, making PEEK the most frequently used in orthopedics. PEEK implants can be manufactured to be completely solid or contain holes.

Advantages
• Highly elastic, yet very strong and impact resistant at the same time
• Optimal protective function for patients
• No increase in thermal sensitivity
• Low weight
• Resistant to gamma radiation and magnetic resonance imaging (MRI)
• Low artifact formation in X-rays
• Three-dimensional bone replacement
• Steam sterilization

Limitations
• Only conditional cell apposition potential
• Intraoperative adjustment or cutting to size is only possible with additional effort
• Requires further plates for fixation

Unrivaled Expertise in Medical-grade PEEK Devices

Machining complex medical parts and devices takes more than precision. It takes unrivaled expertise. The medical industry is fast-paced and cutting-edge with technology challenges. Precision plastics like PEEK implants play a key role in meeting the demands of the industry.

PEEK and other precision plastics are highly sought after for their radiolucency, biocompatibility, and sanitation. Time is of the essence in healthcare, especially with traumas like orbital reconstruction. These types of surgery demand a quick turnaround on design and manufacturing to lessen surgical downtime.

At AIP, we make it our priority to set the highest standards of quality and sanitation for our customers in the healthcare industry. Quality assurance is an integral part of our process and we address it at every step of your project from beginning to end.

Follow AIP Precision Machining on Linkedin

CELAZOLE® PBI, THE HIGHEST-PERFORMANCE POLYMER

Celazole® U-Series and Duratron® PBI Take the Heat in Any Extreme Application

Every medical innovation begins with design and manufacturing. Before a small spinal implant goes to the patient, it must meet strict universal industry standards for safety, handling, and product consistency. Afterall, a failure in a medical device can have serious repercussions for not only the health and safety of end users, but also loss of credibility and resources for a manufacturer.

That’s why medical device OEMs demand that machining facilities follow the ISO 13485 standard for medical device manufacturing.

In this informative brief, we take a deeper look at the benefits of this essential certification and how a precision machining facility can get certified.

The Benefits of having an ISO 13485 Certification

PBI has the highest mechanical properties of any polymer over 400°F (204°C). Compared to other performance polymers like Torlon® or PEEK®, it has the highest heat deflection temperature (HDT) at 800°F (427°C), with a continuous service capability of 750°F (399°C) in inert environments, or 650°F (343°C) in the air with short term exposure potential to 1,000°F (538°C).

Wear-Resistant Performance

Celazole® U-60 is an unfilled polymer suitable for injection molding or CNC machining into precision parts. When it comes to wear and abrasion, PBI has the highest compressive strength of all plastics. Its compressive strength is 57 kpsi and, its modulus strength reaches 850 kpsi compared to grades of Torlon® that start at 440 kpsi.

Celazole® can handle high loads at any speed and outperforms wear-grade PAI, PI, and PEEK® under similar conditions. Without additional lubrication, it runs 40-50F cooler than the competition.

PBI Grades

PBI comes in grades that can be extruded or melt processed, but in this brief we are covering grades of PBI that are CNC machined.

Duratron® PBI
Duratron® CU60 PBI is the highest-performance engineering thermoplastic available on the market. It has the highest heat resistance and mechanical property retention over 400°F of any unfilled plastic. It also offers better wear resistance and load-carrying capabilities at extreme temperatures than any other reinforced or unreinforced engineering plastic.

Although it is an unreinforced material, Duratron® CU60 PBI is very “clean” in terms of ionic impurity, and it does not outgas (except water vapor). These properties make this material very attractive to semiconductor manufacturers for vacuum chamber applications.

Other properties of Duratron® CU60 PBI include excellent ultrasonic transparency. This makes it a strong choice for delicate parts, like probe tip lenses in ultrasonic measuring equipment.

Duratron® PBI also serves very well as a thermal insulator. Other plastics melt and do not stick to it. For these reasons, it’s an ideal polymer for contact seals and insulator bushings in plastic production and molding equipment.

Celazole® PBI U-Series (U-60)
Celazole® U-Series has superior polymer strength with thermal stability. By itself, PBI can operate at continuous temperatures up to 1,004°F (540°C). As a resin incorporated into plastics, PBI features high heat and chemical resistance and good fatigue resistance, compressive strength, wear resistance, and electrical insulation.

Components made from Celazole® U-Series polymer perform well under conditions too severe for most plastics and outperform other materials like polyamide-imide (PAI) and polyetheretherketone (PEEK®) in many extreme environments.

Celazole® U-60 is an unfilled PBI polymer suitable for compression molding. It is often molded and machined into precision parts for industrial, chemical and petrochemical industries; aerospace, glass making, and liquid crystal display (LCD) panel manufacture.

Follow AIP Precision Machining on Linkedin

Why it’s essential to have ISO 13485 for Manufacturing Medical Devices

September 23, 2022

A Universal Standard of Safety and Quality

That’s why medical device OEMs demand that machining facilities follow the ISO 13485 standard for medical device manufacturing.

In this informative brief, we take a deeper look at the benefits of this essential certification and how a precision machining facility can get certified.

The Benefits of having an ISO 13485 Certification

Global Standard

The ISO 13485 international standard is the world’s most widely used means of measuring the effectiveness of a medical device manufacturer’s quality management system (QMS). While different countries may have different standards for measuring quality and effectiveness, ISO 13485 provides a globally harmonized model of QMS requirements for international markets.

Quality Assurance

When it comes to machining for the Medical, Healthcare, and Life Sciences sector, true culture of quality and consistency in manufacturing techniques are paramount. An ISO 13485 certification ensures that machining processes, product handling, storage, and shipping are all accounted for in a facility’s processes.

Requirement for Business

Most medical device OEMs require compliance with ISO 13485, including all European Union members, Canada, Japan, Australia, and more (165 member countries in total). Therefore, precision manufacturers that want to serve the Medical sector must show proof of and adherence to ISO 13485 guidance.

Works at the Federal & Civil Enterprise Level

The FDA recently proposed aligning current Quality management system regulations with ISO 13485. This means that at the federal and civil enterprise level, ISO 13485 would satisfy standards for quality, consistency, risk management, and in medical device manufacturing.

How to get ISO 13485 certified

The International Standardization Organization establishes and maintains standards, but it is not an enforcement agency. Certification for ISO 13485 is evaluated by third party agencies. The first step is establishing a QMS that is in alignment with the guidance. Then, an independent certification body audits the performance of the QMS against the latest version of the ISO 13485 requirements. The agency must be part of the International Accreditation Forum (IAF) and employ the relevant certification standards established by ISO’s Committee on Conformity Assessment (CASCO). Once an organization passes the ISO 13485 audit, they are issued a certificate that is valid for three years. Manufacturers must undergo a yearly surveillance audit and be recertified every three years.

Here’s what the ISO 13485 certification will assess:

Promotion and awareness of regulatory requirements as a management responsibility.
Controls in the work environment to ensure product safety
Focus on risk management activities and design control activities during product development
Specific requirements for inspection and traceability for implantable devices
Specific requirements for documentation and validation of processes for sterile medical devices
Specific requirements for verification of the effectiveness of corrective and preventive actions
Specific requirements for cleanliness of products

Unrivaled Expertise in Precision Medical Plastics

Performance plastics play a huge role in medical device composition. Whether it’s hip replacement or a PEEK spinal implant, these life-saving technologies require durability, cleanliness, and high temperature and moisture resistance. This is no simple process…it’s precise.

That’s where AIP, global leader in Precision Plastics Machining, provides unrivaled expertise in medical machining practices. For over three decades, we’ve served the medical community providing custom designed thermoplastic components for surgical devices, orthopedic equipment, and performance PEEK implants.

We take quality management seriously because we know that performance is only half the equation for medical device manufacturing. For these reasons, we are an ISO 13485 certified facility and FDA compliant. We have been successfully audited by some of the most stringent OEMs in the orthopedic and medical device industries. Our plastics are processed with strict hygienic procedures to ensure innovative medical advancements continue striding forward. Let our team go to work for you!

Find out more by visiting https://aipprecision.com or call us at +1 386.274.5335.

Learn More

Follow AIP Precision Machining on Linkedin

Vespel® Vs. Torlon®: Which Should You Choose?

September 10, 2022

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®

Follow AIP Precision Machining on Linkedin