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.

 

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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.

 

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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.

 

 

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A Universal Standard of Safety and Quality

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

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 asses: 

  • 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.

 

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Keeping it clean with precision polypropylene medical devices

 

Polypropylene (PP) is a versatile, low-cost thermoplastic often used for medical devices where sustainability and multiple steam-sterilizations are necessary. Along with its resistance to moisture and steam, polypropylene offers durability and strength, even after several uses. These qualities are what make it an excellent lifesaving material in medical settings.

 

For the last 38 years, AIP has been machining precision plastics for the medical and life sciences. From thermoplastics reducing the need for brain surgeries to working closely with OEMs producing today’s leading medical devices and prosthetics, we have seen firsthand the scientific leaps taken with precision plastics. In this technical brief, we discuss the advantages of medical grade polypropylene.

 

 

The Advantages of Medical Grade Polypropylene

 

In the last decade, thermoplastics like polypropylene have gained traction in medical device development. Not only are they more sanitary than reusable metal devices, which can rust or retain bacteria, plastics provide a durable, lightweight solution in an industry where material selection is critical to lifesaving procedures.

 

Features

Polypropylene is a cost-effective medical-grade plastic material and is used where steam-sterilized medical devices are necessary. In addition to resistance to steam sterilization, mechanical performance properties of polypropylene include durability for the number of cycles it can be reused. Its recyclability also makes it an attractive medical-grade plastic.

 

  • Good resistance to cleaning and disinfectants
  • Suitable for repeated sterilization with hot steam
  • High dimensional stability
  • Good machinability
  • Laser marking possible

 

Applications

Polypropylene’s greatest strength is its versatility. Depending on the medical grade, it can be used for disposable syringes or finger-joint prostheses. Additionally, with a lower density than other products, polypropylene can help manufacturers save money by producing lighter weight products. Other applications include the following:

 

  • Pipettes
  • Syringes
  • Cuvette
  • Luers
  • Diagnostic devices
  • Medical device components
  • Labware

 

Meeting market demands

As the medical market continues to evolve, precision plastics, such as polypropylene and PEEK are revolutionizing the medical and life sciences industry. Precision plastics continue to show superior qualities and functionality over traditional materials, including metal, ceramic, and glass. These medical grade polymers can vary, but many share characteristics and properties, as well as meet industry regulatory standards.

 

What to look for in a machine shop for your precision plastic medical device

 

What do you look for in a precision plastics machining shop? The medical device industry has strict standards of material manufacturing as well as the regulatory bodies that enforce them, such as the FDA. As you seek out a machining shop, make sure to ask your machinist questions about the types of materials they machine, what regulatory standards they follow and meet, and take a look at their track record working with healthcare OEMs.

 

Plastics Only

It’s a good idea to pick a shop that machines only plastics. Some shops machine metal and plastic or other materials, and the consequences of mixing materials or machining fluids can damage your end product. Plastics only machine shops have the right equipment, an array of thermoplastics and composites, and use the appropriate techniques to ensure the quality of a performance medical product.

 

Regulatory standards

Medical device manufacturing follows strict ISO and FDA standards of cleanliness and environmental conditions. Seek a machine shop that not only meets these standards, but also has the right people, processes, and equipment approved by regulations. Medical devices leave no space for a margin of error—“measure twice, cut once” is a rule of thumb to live by when choosing a precision plastics manufacturer.

 

Industry experience

The most important factor to take into account overall is experience. Your supplier should be familiar with the types of polymers and composites you need machined, and should additionally know the best machining process for your application.

 

You want to find a manufacturer that can display a portfolio of projects that meet the complex needs of the medical industry. As an example, if your precision device is coming into contact with bodily fluids and tissue, then they must be biocompatible per ISO 10993.

 

A manufacturer must be familiar with the processes and regulations that accompany machining precision medical components. With 38+ years of experience, AIP is well acquainted with precision machining for the medical industry and guarantees careful material selection and processing for your medical applications.

 

Contact our team for a consultation on your precision medical grade polypropylene device or ask about our other medical grade thermoplastics. Let our team go to work for you!

 

Supportive Information

 

Polypropylene Machining Guide

 

Looking for more medical grade thermoplastics?
Here’s 8 to consider for your next precision machined medical device.

 

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A discussion with the plastics pros at AIP on how to choose the right plastic for your medical application

 

When it comes to selecting a polymer for a medical application, there are a myriad of factors that play into deciding which grade of polymer is the best candidate. Of course, the number one concern in medical device design is safety of human life.

 

For this reason, trends in medical device design are moving toward miniaturization and portability. Additionally, sterilization and cleanliness continue to lead design considerations globally, requiring devices to withstand a range of chemicals and sterilization techniques.

 

As a precision plastics machining company, AIP has over 35+ years of experience working with medical OEMs to develop parts for critical medical devices. In this issue of our monthly blog, we will discuss what makes a polymer medical grade and how to choose the right polymer for a medical device application.

 

What are medical grade plastics?

 

Let’s begin with what a medical grade plastic is. Medical-grade plastics refer to plastics used to make medical products, products for in vitro diagnostics and primary packaging for pharmaceuticals.

 

Most importantly, plastics used in the medical field are coming in contact with human tissue, fluids, chemicals, drugs and many more substances. There are literally thousands of medical applications from packaging to spinal implants. Based on this information, your supplier should be familiar with the types of polymers and composites you need machined. They should additionally know the best machining process for your application. That’s why design conception is crucial as the first step.

 

1. Design requirements and constraints

 

First and foremost, what is the function of the polymer for the device?

 

Your machine shop should be asking you in depth questions about your medical application. Questions to consider include:

 

  • Should the material be biocompatible?
  • Is the product for single use?
  • Will the component undergo sterilization? If so, which method?
  • Does color and aesthetics matter in the machining process?
  • Is UV resistance needed?
  • What tolerances must be met for temperature, wear, impact, etc?

 

The following material selection flow-chart displays the overall process of developing a medical grade plastic part or device:

 

Market Needs Infographic

 

2. Industry Standards

 

What industry standards and regulations control the production of the material?

 

At AIP, our plastics are processed with strict hygienic procedures to ensure the highest level of sanitation. Make sure that your machining company is compliant and/or registered with the appropriate regulatory organizations. Some common medical certifications include the following:

 

  • ISO 10993
  • ISO 13485:2016
  • FDA Registered

 

3. Biocompatibility

 

How long does the component need to be in contact with the human body or tissue?

 

There are three categories of contact duration if a component is subject to body tissue or fluid:

 

  • Short-term contact (Less than 24 hours)
  • Medium term contact (Between 1-30 days)
  • Long-term or Permanent contact (Greater than 30 days)

 

4. Sterilization/Cleanliness

 

Will the device need to be resistant to chemicals or undergo multiple sterilizations?

 

Whether it’s a feeding tube, a drug delivery device or a surgical implant, the polymer material must be able to withstand chemical degradation and multiple sterilizations.

 

The most common sterilization methods include:

 

  • Radiation (gamma/e-beam)
  • Chemical (ETO)
  • Autoclave (steam)

 

Chemicals to consider for contact with the device could be:

  • Intravenous medications
  • Blood/Fluids/human tissue
  • Hospital cleaners – bleach, isopropyl alcohol, peroxides

 

5. Polymer Characteristics

 

What mechanical properties does the polymer need to fulfill?

 

Selecting a plastic material is based on a number of traditional material requirements such as strength, stiffness or impact resistance. Engineered thermoplastics like PC, PEEK, PPSU, POM, show excellent mechanical properties at low and high temperatures. These properties are required for a variety of climate conditions, including during transportation, where the influence of temperature on drop impact may result in different outcomes for device integrity.

 

Your machinist should be able to give you details about all the plastics in their portfolio such as:

 

  • High wear resistance
  • Tensile strength
  • Temperature resistance
  • Corrosion resistance
  • Durability
  • Dimensional stability

 

6. Aesthetics

 

Does the end product need to be a certain color or have certain qualities?

 

For instance, if it is a prosthetic for a foot, the polymer needs to be machined a certain shade to match skin tone.

 

7. Other Material Selection Factors

 

Anything else?

 

Other factors to consider and discuss with your machinist include additives for increasing the performance of the polymer, manufacturing process as well as the cost. Take into account the following:

 

  • Radiopacity
  • Conductive
  • Lubrication
  • Manufacturing feasibility
  • What manufacturing processes are you using and why?
  • Technical performance
  • Can we make this product with the material, and can we make it well?
  • Economics
  • If we can make it, can we make it for a reasonable cost?

 

At AIP, we are unrivaled experts in medical grade plastic machining.
Talk to our team about how to bring your project from concept to completion.

 

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Which thermoplastics are best suited for your machined medical application?

 

With over three decades of experience machining precision plastic and composite parts for the Medical & Life Sciences industry, AIP Precision Machining knows that biocompatible, sterilization-compatible and lightweight materials are critical for medical devices and surgical components. That’s why we’ve carefully selected, machined and tested all our thermoplastic materials to various ISO medical standards and performance considerations.

 

Here are eight examples of thermoplastics we commonly machine for the Medical & Life Sciences industry.

 

Peek Product image

PEEK

PEEK (Polyetheretherketone) has biocompatibility in its medical grades per ISO 10993. In particular, PEEK Optima and Zeniva PEEK are suitable for long term implants and have a uniquely similar modulus to that of human cortical bone. PEEK is radiolucent and also used for dental implants and various medical instruments. 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 is an increasingly popular replacement for metal in the medical industry due to its lightweight nature, mechanical strength, radiolucent properties, creep and fatigue resistance, as well as its ease in processing.

 
ULTEM Product image

ULTEM – PEI

ULTEM PEI (Polyetherimide) is popularly used in medical instrument components, devices and pharmaceutical applications. Medical-grades of PEI are biocompatible per 10993. Not only is ULTEM steam, gamma, EtO and E-beam sterilizable, but it’s also hydrolysis resistant. 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). This makes it especially suitable for reusable medical devices. ULTEM also has one of the lowest rates of thermal conductivity and very high dielectric strength, allowing parts machined from ULTEM to act as thermal insulators. ULTEM however can be consider more brittle than a PEEK or RADEL, therefore it should be avoided for applications experiencing high rates of impact forces.

 
PSU Product image

Polysulfone – PSU

Polysulfone (PSU) maintains a consistent modulus in temperatures ranging from -150°F (-100°C) to 300°F (150°C). PSU also exhibits excellent radiation stability, maintains high resistance to acidic and salt solutions, and is hydrolysis-resistant for continuous use in hot water and steam at temperatures up to 300°F (150°C). It’s capable of experiencing repeated autoclaving, but not as many as PEI, PEEK or PPSU. These qualities make it applicable for analytical instrumentation, medical devices and steam-cleaning equipment. In thin cross sections PSU is nearly clear, providing a window like finish with improved chemical resistance to that of PMMA or PC.

 
RADEL Product image

RADEL – PPSU

RADEL PPSU (Polyphenylsulfone) has been tested for notched izod impact resistance as high as 13 ft.-lbs/in. 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 mean it performs well even under autoclave pressure. In fact, PPSU has virtually unlimited steam autoclave resistance, making it appropriate for machining reusable medical instruments. When thermal considerations are not extreme, RADEL provides for a less expensive alternative to PEEK. RADEL is also available in numerous color options, making a great choice for hip and knee sizing trials.

 
UHWPE Product image

UHMWPE

UHMW-PE (Ultra-High Molecular Weight Polyethylene) is a linear, low-pressure polyethylene resin that has a significantly higher abrasion resistance and impact strength compared to most plastics. Due to its self-lubricating, non-stick surface, it has a low coefficient of friction that makes it desirable in the medical industry. UHMW-PE’s biocompatibility has made it a popular choice for artificial replacement hips, knees, shoulders and other joints as early as the 1960s.

 
TORLON Product image

TORLON – PAI

TORLON PAI (Polyamideimide) is the highest performing thermoplastic built from the TORLON resin. Its compressive strength is double that of PEEK when unfilled, and about 30% higher than ULTEM PEI. In its medical grades, PAI offers high modulus, radiolucency, sterilization-compatibility and high wear resistance, making it ideal for components inside high performance and peristaltic pumps. PAI’s extremely low coefficient of linear thermal expansion and high creep resistance deliver excellent dimensional stability over its entire service range.

 
Teflon Product Image

Teflon – PTFE

Teflon PTFE (Polytetrafluoroethylene) is a fluoropolymer commonly used for tubing in medical device components. PTFE has non-stick qualities, is inert to most chemicals and has the lowest coefficient of friction of any thermoplastic. It also has very good UV resistance, hot water resistance and electrical insulation even at high temperatures.

 
Delrin Product image

Delrin – Acetal Homopolymer

Delrin (Acetal Homopolymer) is ideal for smaller lower performance applications and acceptable for a broad range of general components in the medical industry at temperatures below 250°F (121°C). It has flexible design uses (such as in reusable injection pens), is sterilization-compatible (with limited cycles) and offers options for low friction. Delrin is also tested against relevant parts of ISO 10993 and delivers excellent dimensional stability and natural lubricity.

 

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Strict Hygienic Procedures for Precision Machining

 

It’s no secret that cleanliness and sterilization are crucial for applications in the medical industry. Any manufacturer you hire for machining your plastic component should be aware of this, and taking actions to prevent any contamination from taking place.

 

Here are three ways you can ensure that your medical application is being precision machined by a manufacturer committed to following strict hygienic procedures.

 

1) Check Industry Standards

 

Ensuring sterilization starts with picking the right manufacturing company, and you’ll want to be sure they take the matter of contamination seriously. To start, check their commitment to quality management and industry standards.

 

All product manufacturing companies must follow industry standards like International Organization for Standardization (ISO) and Food and Drug Administration (FDA). Before you work with a manufacturing company for your medical application, look at their certifications.

 

For example, ISO 13485 specifies requirements for a quality management system where a company demonstrates it can provide medical devices and related services to consistently meet customer and regulatory requirements. ISO 9001 focuses on meeting customer expectations and continually delivering satisfaction, plus reflects constant improvement from the company.

 

If the manufacturer you are interested in using does not have any of the above standards, then you may want to ask them why.

 

Here at AIP Precision Machining, we have been successfully audited by some of the most stringent OEMs in the orthopedic and medical device industries, and are ISO 13485:2016., ISO 9001:2015 , and FDA registered.

 

2) Plastic Machining isn’t Metal MachiningMetal vs Plastic Machining

 

Be wary of any manufacturer who machines both plastics and metals in the same facility. The tiniest sliver of metal embedded in a plastic part can have widespread ramifications, such as an unexpected electrical problem in the medical device.

Additionally, it’s common for metal machining companies to use oil-based cutting fluids. Any equipment that machines metal, then, can contaminate your plastic parts with those fluids. Many plastic materials are especially sensitive to those petroleum-based liquids, and they can degrade when in contact with them; others are hydroscopic and will absorb the oils.

 

It should be noted that plastic parts manufactured using equipment that machines metal parts will not meet FDA-approval, or the other industry standards mentioned above. The safest way to avoid this is to hire a plastics expert, not a metal machining company.

 

AIP takes the matter of sterilization seriously, and ensures the highest level of sanitation down to the sub-molecular level for its products. By designing, stress relieving and machining only plastics, AIP significantly reduces the threat of metallic cross contamination and therefore allows for the highest hygienic products possible.

 

3) Look for Experience

 

The most important factor to take into account overall is experience. Your supplier should be familiar with the types of polymers and composites you need machined, and should additionally know the best machining process for your application.

 

For the medical industry, you want to know that your manufacturer is experienced with the complex needs of your applications. For example, if your components are going to come into contact with body tissue or fluids, then they must be biocompatible per ISO 10993.

 

Which is to say: If you’re machining implants, your plastics will require different needs than if you’re machining reusable surgical instruments. Both require, however, careful attention to detail. A surgical instrument must be designed with sterilization compatibility for regular cycles in mind, while an implant requires biocompatibility to be safe for use.

 

Be sure that your manufacturer is familiar with the processes that come with your application, and check that they’ve done it before.

With 35+ years of experience, AIP is well acquainted with precision machining for the medical industry and guarantees careful material selection and processing for your medical applications.

 

The #1 Best Way to Avoid Contamination?

Overall, the best thing you can do to avoid contamination is to hire a plastic manufacturer with the experience and the credentials to complete your project to the highest standards of quality possible. Keeping the above three factors in mind will help you do just that.

 

To ask about AIP Precision Machining’s capabilities for precision machining medical applications, please contact us.

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Thermoplastics in Medical ApplicationsWhen it comes to choosing a thermoplastic material for your medical applications, product durability, agency approval, biocompatibility and cleanliness aren’t just desirable—they’re essential. Beyond even that, though, a host of other factors must be considered when determining which high-performance plastic or composite material to use for an implant, orthopedic surgical guides, body fluid contact components, spinal devices, or surgical instruments. Medical product applications are becoming more and more advanced due to critical performance and alignment requirements as well as the need for radiolucency to support minimally invasive procedures. Therefore, the choice of plastic material specified for a given application as well as a manufacturer with battle-hardened experience is the critical first step in your decision process.

 

AIP has well over three decades of expertise with thermoplastic materials, and understands how plastics react when machined. We are one of a very select few companies able to hold incredibly tight tolerances in plastic parts. AIP has been successfully audited by some of the most stringent OEMs in the orthopedic and medical device industries, and are ISO 13485:2016, ISO 9001:2015 and FDA registered.

 

Here are just a few initial, yet critical considerations that take place when we determine the thermoplastic to best suit your particular medical or life science application.

 

Biocompatibility

 

If your components are going to come into contact with body tissue or fluids, then those components must be biocompatible per ISO 10993; if the manufacturer you are working with is not familiar with this standard and cannot provide you with this certification for the material, then move on to a manufacturer with medical industry knowledge. This is especially true if the polymers will undergo long-term contact with body tissues and fluid, such as when used as an implant. Polymers can undergo degradation due to biochemical and mechanical factors in the body, which results in ionic attack and formation of hydroxyl ions and dissolved oxygen. In turn, this can lead to tissue irritation, inflammation, and other reactions with body-like corrosion, wear and potential death. Due to this, very few polymers are available as medical grade for medical application, with an even smaller amount considered a candidate for implants.

 

AIP Precision Machining includes machined PEEK implants among its many capabilities for custom medical applications precisely due to PEEK’s biocompatibility. PEEK is also inert to body fluids, making it exceptional for bone surgery as well as areas of traumatology and orthopaedics. Another valuable trait of PEEK is that this material has a very similar modulus to that of human bone. The similar modulus to bone reduces the potential for stress shielding. Stress shielding is common with metallic implants whereby the metal implant and bone do not become one nor work in unison to form a single construct. By using Invibio’s PEEK Optima or Solvay’s Zeniva PEEK as an implant material, the bone and PEEK will grow into a single construct mimicking the bone’s natural tendency to repair the fracture or fusion.

 

Sterilization Compatibility

 

Plastics react differently to various sterilization methods, and if a product is not a single-use device and involves body tissue and fluid contact, then it may regularly undergo sterilization. The usual sterilization methods are radiation (gamma/e-beam), chemical (ETO), or autoclave (steam). ETO is rarely a concern, but radiation and autoclaving both require resistance from plastics. Several radiation resistant thermoplastics are:

 

 

When it comes to autoclaving, the best polymers for resistance are PPSU and PEEK, with both capable of handling exposure to thousands of cycles.

 

AIP takes the matter of sterilization seriously and ensures the highest level of sanitation down to the sub-molecular level for its products. By designing, stress relieving and machining only plastics, AIP significantly reduces the threat of metallic cross-contamination and therefore allows for the highest hygienic products possible.

 

Chemical Resistance

 

A polymer can be exposed to plenty of disinfection chemicals in a hospital. That exposure can deteriorate plastics, and negatively affect part performance. Polymer chains can be affected by isopropyl alcohol, bleaches, and peroxides. Semi-crystalline polymers like PP, PE, PTFE and PEEK can be expected to have better chemical resistance than amorphous polymers like ABS and PC. However, it’s important to check the performance to be certain of resistances, as exceptions can take place.

 

With decades of experience working with thermoplastics, AIP guarantees extreme chemical resistance in its material selection for your medical applications.

 

Electrical & Thermal Properties

 

Dielectric strength and thermal resistance are necessary for medical devices enclosed in areas that require high heat resistance. Thermoplastics such as PC (Polycarbonate), PC blends, PPS (polyphenylene sulfide), PEI and PS (polystyrene) blends have electrical properties that perform well, some even at elevated temperatures.

 

AIP’s material library includes thermoplastics that exhibit extreme thermal performance, and we are familiar with machining them in applications for medical life & sciences.

 

Mechanical Properties

 

Properties such as tensile and compressive strength, wear resistance, impact strength, and bending stiffness also must be considered when choosing your thermoplastic. Engineered thermoplastics such as PC, PEEK, PPSU, POM, PEI and reinforced grades of these same materials (glass, aramid and carbon fillers) perform very well in this respect, making them ideal for a variety of climate conditions, such as during transportation.

 

AIP provides thermoplastics that show extreme wear resistance, x-ray visibility or invisibility and high structural performance.

 

These are just a few of the many considerations that take place when choosing the right plastic for your medical applications. AIP offers you our full material consultancy from concept to completion, so that together, we find the right thermoplastic for your projects.

 

 

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Join Us at MD&M East!

We can’t wait for the biggest Medtech event on the East coast: MD&M East! We’ll be there, ready to talk about implantable devices, medical material components and more. Visit us at our Booth #2370 to learn about our unmatched precision in plastics manufacturing.

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