How Aluminum Got Dethroned by Thermoplastics in Aerospace

 

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

 

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

 

How Airlines “Slim Down” Operating Costs

 

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

 

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

 

What Makes Plastics the Secret to Aircraft Fuel-Efficiency

 

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

 

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

 

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

 

“Weighing” the Option of Plastics in Aerospace

 

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

 

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

 

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

 

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

 

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

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

Download our Case Study

 

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

 

Overall Benefits

 

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

 

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

 

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

 

Explore AIP’s Machining Capabilities

 

Plastics are more resistant to chemicals than their metal counterparts.

 

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

 

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

 

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

 

Aerospace and Defense benefits graphic
 

 

Benefits to the Aerospace & Defense Sector

 

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

 

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

 

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

 

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

 

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

 

Aerospace and Defense benefits graphic
 

Other Benefits for Aerospace and Defense

 

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

 

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

 

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

 

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Learn about AIP’s precision machining capabilities for mission-critical components.

 

High-performance precision plastics require high-performance precision CNC machining.  CNC machines, or computer numerically controlled machines, are electro-mechanical devices that use tools at varying axes (usually 3-5) to produce a physical part from a computer design file.

 

Our modern society runs on CNC machined plastic components – from everyday household piping to critical spinal implants.  The breadth of materials, shapes and industries served is endless.

At AIP, we precision machine parts for industries such as the aerospace & defense, medical & life sciences and power & energy.  Each part that is CNC machined comes with design specifications and dimensional tolerances.  Our machinists are capable of crafting parts at .002 mm tolerance, which can make a whole lot of a difference in the performance of a mission-critical part.

 

Let’s back up a moment though.  What are dimensional tolerances? And how do you know if your project should demand a tighter tolerance?  Read on in this month’s blog to find out.

 

Let’s Talk About Tolerance

 

What are machining tolerances?

In CNC machining terms, tolerance, or dimensional accuracy, is the amount of deviation in a specific dimension of a part caused by the manufacturing process.  No machine can perfectly match specified dimensions.  The designer provides these specifications to the machinists based on the form, fit and function of a part.

 

How are tolerances measured?   

CNC machines are precise and measured in thousandths of an inch, referred to as “thou” among machinists.  Any system is usually expressed as “+/-”; this means that a CNC machine with a tolerance of +/- .02 mm can either deviate an extra .02 mm from the standard value or less .02 mm by the standard value.

 

A precision machining tolerance scale
 

Why are tolerances critical?

Tolerances keep the integrity and functionality of the machined part.  If the component is manufactured outside of the defined dimensions, it is unusable, since the crucial features are not fulfilling the intent of the design.

 

How close can a tolerance get?

Tolerance depends on the material that you use and the desired purpose of the design.  In plastics machining, the tolerances can be from +/- 0.10 mm to +/- 0.002 mm.  Tighter tolerances should only be used when it is necessary to meet the design criteria for the part.

 

When .002 mm Matters

 

What is the .002 mm difference?  In many industries, such as the medical industry, it is crucial to machine parts with extreme precision so that they can interact with human tissue or other medical devices.  In fact, when it comes to manufacturing medical applications, subtractive manufacturing (CNC machining) provides tighter tolerances than additive manufacturing (3-D printing).

 

 

Color Pencil compared to precision machining
(AIP PEEK Eye Implant)
 

Tight tolerances like the .002 mm are important because plastics are machined to interact with other parts.  In particular, CNC milled or turned plastics are unique designs for limited quantities, such as custom-made brackets and fasteners, or components for prototyping purposes.

 

One of the most critical considerations when applying tolerances is to take into account fits. This refers to how shafts will fit into bushings or bearings, motors into pilot holes, and so on. Depending on the application, the part may require a clearance fit to allow for thermal expansion, a sliding fit for better positioning, or an interference fit for holding capability.

 

As with anything that is precision machined, tighter tolerances demand time and skill.  Make sure to work with a certified company like AIP that has the infrastructure and expertise to complete your project with unmatched precision and unrivaled experience.

 

Let our team go to work for you

 

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

 

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

 

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

 

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An Informational Brief on Polymer Machining

 

HDPE Product ImageAmong the many polymer materials we machine at AIP, High Density Polyethylene (HDPE) is a common material choice for commercial polymer applications.  HDPE is part of the Polyethylene (PE) family of thermoplastic polymers with variable crystalline structure.

 

First developed in the 1950s by German and Italian scientists Karl Ziegler and Giulio Natta, PE has become one of the most widely produced plastics in the world.  Polyethylene comes in several compounds each with various applications: Low Density Polyethylene (LDPE), High Density Polyethylene (HDPE) and Ultrahigh Molecular Weight Polyethylene (UHMW) are some of the most well-known.

 

For example, you will find LDPE most likely in the grocery store as plastic wrap or grocery bags.  In contrast, HDPE, due to its high density, is much better suited for construction components like a drain pipe.  And UHMW can be machined into high performance applications for medical devices, bulletproof vests and industrial wear components.

 

In this machining guide, we will discuss what goes into machining HDPE and how its considerations differ from other manufacturing options such as metal machining, injection molding, and 3D printing.

 

A Brief History of Plastic CNC Machining

 

How does AIP approach HDPE and its machining process? To start, let’s explore what plastic machining is, specifically CNC machining.

 

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

 

Shortly after World War II, the earliest version of CNC technology was developed as a dependable, repeatable way to manufacture more accurate and complex parts for the aircraft industry.  John Parsons is credited with developing numerical control – a method of producing integrally stiffened aircraft skins.

 

While working at the family-owned, Michigan-based business – Parsons Corp., John collaborated on the development of a system for producing helicopter rotor blade templates.  Using an IBM 602A multiplier to calculate airfoil coordinates, and inputting this data to a Swiss jig borer, it was possible to produce templates from data on punched cards.

 

In 1949 Parson’s templates were applied to Air Force research projects at MIT.  Following extensive research and development, an experimental milling machine was constructed at MIT’s Servomechanisms Laboratory.

 

Machining polymers and composites is a precise science that requires strong technical expertise.  For instance, some plastics are brittle, while others melt at a specific temperature.  These diverse mechanical and thermal properties result in varying behaviors when CNC machined.  Thus, it is imperative to understand the polymer structure and qualities of HDPE if you’re machining it.

 

Ever wonder about the differences in cost and process among 3D Printing, Injection Molding or Plastic Machining?

 

Check out our blog:
“Settling the Debate”

 

 

Properties of HDPE

 

HDPE is a high impact, high density crystalline thermoplastic.  It also has a low moisture absorption rate and good chemical and corrosion resistance.  Compared to its sister polymer LDPE, HDPE offers much greater impact resistance and tensile strength.  This polymer has a melt temperature of 266 F (130 C).  Its tensile strength is 20 MPa (2,900 PSI); to put this number into perspective, a slab of concrete may be able to withstand 3,000 PSI.

 

Oftentimes, people use HDPE in everyday home appliances and commercial containers.  Due to its strength and corrosion resistance, it’s a common candidate for garbage bins, laundry detergent cartons and cutting boards.  It is also safe to use for food contact such as milk cartons.

 

PE is available in sheet stock, rods, and even specialty shapes in a multitude of variants (LDPE, HDPE etc.), making it a good candidate for subtractive machining processes on a mill or lathe. However, colors are usually limited to white and black.

 

Machining HDPE

 

Annealing HDPE

Annealing greatly reduces the chance that surface cracks and deformation due to internal stresses will occur from the heat generated during machining HDPE. AIP uses computer controlled annealing ovens for the highest quality precision machining of all thermoplastics.  Talk to our engineers about any questions you have about the annealing of a specific polymer.

 

Machining HDPE

As a crystalline thermoplastic, HDPE can be machined at tight tolerances; remember dimensional stability and strength!  AIP recommends non-aromatic, water-soluble coolants because they are most suitable for ideal surface finishes and close tolerances. Keep in mind however that HDPE has a very low CTLE and therefore will move quite a bit with slight temperature changes.  Some examples are pressurized air and spray mists. Coolants have the additional benefit of extending tool life as well.

 

Some companies machine both metals and plastics, which has detrimental outcomes for clients. Many past experiences have shown parts going to customer without cracks, only to develop cracks over time due to exposure to metal machine shop fluids. Be sure to use a facility like AIP that only machines polymers.

 

Preventing Contamination

 

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

 

HDPE (High Density Polyethylene) Machining Guide: Supportive Information

 

Miscellaneous Materials Guide

ISO 13485:2016 Certification

ISO 9001:2015 Certification

Learn more about HDPE and its applications in other industries

 

Discover what HDPE can do

 

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An Informational Brief on Polymer Machining

 

Among the many plastics AIP precision machines, PSU (Polysulfone) is a high-performance thermoplastic made from UDEL Resin.  This particular thermoplastic is able to retain its properties in temperatures ranging from -150°F (-100°C) to 300°F (150°C).  This precision machined plastic also has excellent radiation stability, chemical resistance as well as hydrolysis resistance for continuous use in hot water and steam.

 

In many applications, PSU is used over stainless steel parts or aluminum as the material is seven times lighter than stainless steel and can also be steam-cleaned in areas like chemical labs.  For this reason, it has a wide range of uses in the following industries:  aerospace and defense, medical and life sciences as well as specialized industrial applications.

 

Our latest machining guide discusses what goes into machining PSU and how its considerations differ from other manufacturing options such as metal machining, injection molding, and 3D printing.

 

How does AIP approach PSU and its machining process? To start, we’ll explain the difference between machining PSU, a thermoplastic, and machining thermosets.

 

Machining Thermoplastics vs Thermosets

 

We’ve already said that PSU is a thermoplastic, but what does that mean exactly?

 

All polymers can more or less be divided into two categories: thermoplastics and thermosets. The main difference between them is how they react to heat. Thermoplastics like PSU, for example, melt in heat, while thermosets remain “set” once they’re formed. Understanding the technical distinction between these types of materials is essential to CNC machining them properly.

 

The table below outlines the main properties of thermoplastics versus thermosets:

 

Thermoplastics

Thermosets

  • Good Resistance to Creep
  • Soluble in Certain Solvents
  • Swell in Presence of Certain Solvents
  • Allows for Plastic Deformation when Heated
  • High Resistance to Creep
  • Insoluble
  • Rarely Swell in Presence of Solvents
  • Cannot Melt

 

From there, thermoplastics are categorized into amorphous or crystalline polymers per the figure below:

 

Source: https://www.ejbplastics.com
 

Based off of the chart, PSU is an amorphous, high performance engineering thermoplastic, meaning its molecular structure is randomly formed.  The result is that amorphous materials soften gradually with temperature increase, making them easy to thermoform.

 

Properties of PSU (Polysulfone)

 

Amorphous thermoplastics are usually translucent in color, but the gradients vary.  PSU, for instance, is amber semi-transparent.

 

Since they are isotropic in flow, they have better dimensional stability than semi-crystalline plastics and are less likely to warp.  Thermoplastics like PSU offer superior impact strength and are best used for structural applications.

 

The materials bond well using adhesives. They also tend to offer excellent resistance to hot water and steam, good chemical resistance, stiffness and strength. PSU and PEI are especially good examples of amorphous thermoplastics offering these qualities.

 

Machining PSU (Polysulfone)

 

Annealing PSU

 

Like many amorphous thermoplastics, PSU is especially sensitive to stress-cracking, so stress-relieving through an annealing process is highly recommended before machining.  Annealing PSU greatly reduces the likelihood that surface cracks and internal stresses will occur from the heat generated. Post-machining annealing also helps to reduce stresses that could potentially contribute to premature failure.  AIP uses computer controlled annealing ovens for the highest quality precision machining of PSU and other thermoplastics.

 

Machining PSU

 

Non-aromatic, water-soluble coolants are most suitable for ideal surface finishes and close tolerances. These include pressurized air and spray mists. Coolants have the additional benefit of extending tool life as well.

 

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

 

Preventing Contamination

 

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

 

PSU (Polysulfone) Machining Guide Supportive Information

Amorphous Materials Guide

 

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An Informational Brief on Polymer Machining

 

One of the high-performance thermoplastics that AIP works with is NYLON:  a PA, or polyamide.  It is known for high strength, maintaining mechanical properties at elevated temperatures and chemical resistance.  This polymer was first introduced by DuPont in the 1930s following extensive research on polyesters and polyamides.  For this reason, polyamides comprise the largest family of engineering plastics with a wide range of applications.  Typical applications of nylon include, but are not limited to:  gears, industrial bearings, nozzles, sheaves and wear pads.  Oftentimes, it replaces metal because it is very lightweight, weighing 1/7th as much as bronze.

 

Our latest machining guide discusses what goes into machining Nylon and how its considerations differ from other manufacturing options such as metal machining, injection molding, and 3D printing.

 

How does AIP approach nylon (PA) and its machining process? To start, we’ll explain the difference between machining nylon, a thermoplastic, and machining thermosets.

 

Machining Thermoplastics vs Thermosets

 

We’ve already said that nylon (PA) is a thermoplastic, but what does that mean exactly?

All polymers can more or less be divided into two categories: thermoplastics and thermosets. The main difference between them is how they react to heat. Thermoplastics like nylon, for example, melt in heat, while thermosets remain “set” once they’re formed. Understanding the technical distinction between these types of materials is essential to CNC machining them properly.

 

The table below outlines the main properties of thermoplastics versus thermosets:

 

Thermoplastics

Thermosets

  • Good Resistance to Creep
  • Soluble in Certain Solvents
  • Swell in Presence of Certain Solvents
  • Allows for Plastic Deformation when Heated
  • High Resistance to Creep
  • Cannot Melt
  • Insoluble
  • Rarely Swell in Presence of Solvents

 

From there, thermoplastics are categorized into amorphous or crystalline polymers per the figure below:

 

 

Based off of the chart, nylon is a semi-crystalline, high purity engineering thermoplastic, meaning its molecular structure is highly ordered.  The highly ordered structure of a crystalline structure is what lends the polymer to strength and rigidity.  Generally speaking, crystalline structures are opaque since the structure tends to reflect light.  Here at AIP, we machine several different grades of nylon for multiple industrial applications.

 

Properties & Grades of Machined Nylon (PA)

 

As a thermoplastic, nylon offers industrial-grade resistance to pH changes due to varying thermal conditions, as well as solvent-resisting capabilities. This can be an advantage in petrochemical industries where fluoropolymer parts are in contact with or exposed to bursts of gases, oil or detergents.

 

It should also be noted that nylon (PA) is known for its high degree of crystallinity, which results in a stronger and strain-resisting component. Furthermore, applying nylon reduces the need for heavy lubrication, and dampens sound and eliminates galling, corrosion and pilferage problems.

 

There are two common grades of nylon that should be mentioned for their properties and applications, Nylon 6 and Nylon 6/6.  They can be used interchangeably for various applications, but there are some property differences to note:

 

Nylon 6:

 

Nylon 6 is usually produced in two forms:  for textile use and high-strength types for industrial uses.  It is usually formed into filament yarns and staple fiber.  Most of the time this nylon can be found in tire cords, parachutes, ropes or industrial cords.  In comparison to Nylon 66, Nylon 6 has these benefits:

 

  • A lower density
  • Better toughness
  • Better surface appearance
  • Lower processing temperature

 

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

 

Nylon 6/6:

 

Much like Nylon 6, Nylon 6/6 has many industrial applications, from thin walled components to large thick-walled bearings.  It is also an outstanding candidate for metal replacements. Compared to Nylon 6, Nylon 6/6 has the following advantages:

 

  • Higher temperature resistance
  • Higher strength
  • Higher stiffness
  • Lower moisture absorption
  • Better abrasion resistance

 

Besides Nylon 6 and Nylon 6/6, AIP offers wide-ranging machining expertise of Nylon® and Polyamide grades that provide different strength, thermal stability, and corrosion resistance. Our decades of experience with high-performance specialty plastics and thermoplastics can help you select the best grade of nylon for your application.

 

Machining Nylon (PA)

 

Annealing is a heat treatment that changes the properties of a material to make it easier to machine by increasing ductility and reducing hardness in the material.  The process of annealing and stress-relieving nylon reduces the likelihood of surface cracks and internal stresses occurring in the material.  For more information on AIP’s annealing processes for nylon and other materials, reference our annealing guide.

 

Annealing Nylon

Annealing is a heat treatment that changes the properties of a material to make it easier to machine by increasing ductility and reducing hardness in the material.  The process of annealing and stress-relieving nylon reduces the likelihood of surface cracks and internal stresses occurring in the material.  For more information on AIP’s annealing processes for nylon and other materials, reference our annealing guide.

 

Machining Nylon

Nylon offers ease of machining and tight tolerances due to its inherent strength, toughness and dimensional stability. Machining Nylon isn’t too different from machining metals as a result of this; pretend you’re machining brass. Unlike metal, though, nylon (like all thermoplastics) will deform if you hold it too tightly as it yields easily. We generally recommend Tungsten Carbide Alloy Tooling. Also, keep the part very cool and support it well. We also suggest non-aromatic, air-based coolants to achieve optimum surface finishes and close tolerances. Coolants have the additional benefit of extending tool life as well.

 

Case in point, Nylon (PA) can be manufactured into industrial equipment components that may include piping and tubing, valves, gears, nozzles, and wear pads—among many other formats. It can also be combined with other materials, helping customers innovate and create new product classes with utility that exceeds its original applications.

 

Preventing Contamination

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


Nylon (PA) Polyamide Machining Guide: Supportive Information

AIP Nylon Variants Guide

 

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An Informational Brief on Polymer Machining

 

Kynar®, Polyvinylidene Difluoride (PVDF) is a specialty fluoropolymer thermoplastic known for its ease of processing and its versatility in a variety of applications.  PVDF’s manufacturing not only ensures durability in its utility, but also delivers an innate resistance to acids, bases, high temperatures, and solvents.  Harsh industrial environments are no match for PVDF parts, which is why it is commonly used in environments requiring extreme resistance to a broad range of chemicals.

 

Additional demand for fluoropolymers like Kynar® PVDF is driven by the increasing trend of specialized, small-batch production for customized parts and components. Companies developing prototypes find it extremely convenient to have access to a fluoropolymer part manufacturer such as AIP.  Furthermore, AIP’s experience with custom-engineering plastics ensures our customers’ evolving needs are always met with the same level of innovation and excitement for creating new ways to deliver value in fluoropolymer applications.

 

Our latest machining guide discusses what goes into machining PVDF and how its considerations differ from other manufacturing options such as metal machining, injection molding, and 3D printing.

 

How does AIP approach PVDF and its machining process? To start, we’ll explain the difference between machining PVDF, a thermoplastic, and machining thermosets.

 

Machining Thermoplastics vs Thermosets

 

We’ve already said that PVDF is a thermoplastic, but what does that mean exactly?

 

All polymers can more or less be divided into two categories: thermoplastics and thermosets. The main difference between them is how they react to heat. Thermoplastics like PVDF, for example, melt in heat, while thermosets remain “set” once they’re formed. Understanding the technical distinction between these types of materials is essential to CNC machining them properly.

 

What type of thermoplastic is PVDF in particular? PVDF is a semi-crystalline, high purity engineering thermoplastic, meaning its molecular structure is highly ordered.

 

Properties & Grades of Machined Kynar® (PVDF)

 

As a thermoplastic, Kynar® PVDF offers industrial-grade resistance to pH changes due to varying thermal conditions, as well as solvent-resisting capabilities. This can be an advantage in petrochemical industries where fluoropolymer parts are in contact with or exposed to bursts of gases, oil or detergents.

 

It should also be noted that Kynar® PVDF is known for its high degree of crystallinity, which results in a stronger and strain-resisting component. Add to that a natural resistance to fungus, ozone and weather, which makes Kynar® PVDF a great fluoropolymer for coatings and manufactured parts exposed to the elements.

 

Finally, adding to its versatile performance in industrial environments, Kynar® PVDF provides excellent resistance to nuclear radiation, allowing it to be used in both Power Generation and military applications.

 

AIP offers a range of Kynar® and PVDF grades that provide different strength, thermal stability, and corrosion resistance and can help you select the best grade of PVDF for your application..

 

Machining Kynar® (PVDF)

 

Annealing PVDF

 

The process of annealing and stress-relieving PVDF reduces the likelihood of surface cracks and internal stresses occurring in the material. Post-machining annealing also helps to reduce stresses that could potentially contribute to premature failure.

 

Machining Kynar

 

PVDF offers ease of machining and tight tolerances due to its inherent strength, toughness and dimensional stability. Machining PVDF isn’t too different from machining metals as a result of this; pretend you’re machining brass. Unlike metal, though, PVDF (like all thermoplastics) will deform if you hold it too tightly as it yields easily.

 

We generally recommend Tungsten Carbide Alloy Tooling. Also, keep the part very cool and support it well.

 

We also suggest non-aromatic, air-based coolants to achieve optimum surface finishes and close tolerances. Coolants have the additional benefit of extending tool life as well.

 

Case in point, Kynar® PVDF can be manufactured into industrial equipment components that may include piping and tubing, valves, tanks, nozzles, and fittings—among many other formats. It can also be combined with other materials, helping customers innovate and create new product classes with utility that exceeds its original applications.

 

Preventing Contamination

 

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

 

Kynar® (PVDF) Machining Guide: Supportive Information

 

Chemical Resistant Materials

 

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An Informational Brief on Polymer Machining

 

Vespel Polyimide (PI) is a high-performance polymer frequently machined for end-use in aerospace, semiconductor and transportation technology. This material thrives in extreme environments with high strength, chemical resistance, high temperatures, and a low coefficient of friction. It also has impressive sealing and wear properties.

Our latest machining guide discusses what goes into machining Vespel and how its considerations differ from other manufacturing options such as metal machining, injection molding, and 3D printing.

How does AIP approach Vespel and its machining process? To start, we’ll explain the difference between machining PI, a thermoplastic, and machining thermosets.

 

Machining Thermoplastics vs Thermosets

 

We’ve already said that Vespel is a thermoplastic, but what does that mean exactly?

All polymers can more or less be divided into two categories: thermoplastics and thermosets. The main difference between them is how they react to heat. Thermoplastics like Vespel, for example, melt in heat, while thermosets remain “set” once they’re formed. Understanding the technical distinction between these types of materials is essential to CNC machining them properly.

What type of thermoplastic is Vespel in particular? PI is a semi-crystalline engineering thermoplastic, meaning its molecular structure is highly ordered.

 

Properties & Grades of Machined Vespel

 

Combining heat resistance, lubricity, dimensional stability, chemical resistance and creep resistance, Vespel works well in hostile and extreme environmental conditions. Vespel is able to overcome severe sealing and wear. As we mentioned before, these properties allow Vespel to be commonly machined for semiconductors and transportation applications.

Unlike most plastics, Vespel doesn’t produce significant outgassing, even at high temperatures. This makes it useful for lightweight heat shields and crucible support. Vespel also performs well in vacuum applications and extremely low cryogenic temperatures. However, it does absorb a small amount of water, which results in a longer pump time while placed in a vacuum.

Although there are polymers that surpass individual properties of this polyimide, the combination of these factors is Vespel’s primary advantage.

We regularly machine various grades of Vespel at AIP Precision Machining, including the Vespel SP and Vespel SCP family of products from DuPont. The former group is known for their durability and exceptional thermal resistance, while the latter is known for its mechanical properties and thermal stability.

 

Machining Vespel

 

Annealing Vespel

 

The process of annealing and stress-relieving Vespel reduces the likelihood of surface cracks and internal stresses occurring in the material. Post-machining annealing also helps to reduce stresses that could potentially contribute to premature failure.

 

Machining Vespel

 

Vespel offers ease of machining and tight tolerances due to its inherent mechanical strength, stiffness and dimensional stability. Machining Vespel isn’t too different from machining metals as a result of this; pretend you’re machining brass. Unlike metal, though, Vespel (like all thermoplastics) will deform if you hold it too tightly.

We generally recommend Tungsten Carbide Alloy Tooling, although we recommend diamond tooling for large volume runs or work requiring close tolerances. Be wary of overheating Vespel when you machine it. It shouldn’t become so hot that you can’t grasp it with your bare hands.

We also suggest non-aromatic, air-based coolants to achieve optimum surface finishes and close tolerances. Coolants have the additional benefit of extending tool life as well.

 

Preventing Contamination

 

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

 

Vespel Machining Guide: Supportive Information

DuPont Machining Vespel Guide

Aerospace Market Materials

Energy Sector Materials

Extreme Performance Materials

 

 

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An Informational Brief on Polymer Machining

 

Celazole, known as Polybenzimidazole (PBI), is a synthetic fiber characterized by exceptional thermal and chemical stability. PBI is commonly used in electrical insulators and high strength situations, where it shines due to its compressive strength and insulation properties.

Our latest machining guide discusses what goes into machining Celazole and how its considerations differ from other manufacturing options such as metal machining, injection molding, and 3D printing.

How does AIP approach Celazole and its machining process? To start, we’ll explain the difference between machining PBI, a thermoplastic, and machining thermosets.

 

Machining Thermoplastics vs Thermosets

 

We’ve already said that Celazole is a thermoplastic, but what does that mean exactly?

All polymers can more or less be divided into two categories: thermoplastics and thermosets. The main difference between them is how they react to heat. Thermoplastics like Celazole, for example, melt in the heat, while thermosets remain “set” once they’re formed. Understanding the technical distinction between these types of materials is essential to CNC machining them properly.

What type of thermoplastic is Celazole in particular? PBI is an amorphous engineering thermoplastic.

PBI is characterized by high strength; it exhibits excellent thermal stability, is hydrolytically stable after exposure to high-pressure steam or water, is broadly resistant to hydrocarbons, alcohols, weak acids, weak bases, hydrogen sulfide, chlorinated solvents, oils, heat transfer fluids and many other organic chemicals.

 

Properties & Grades of Machined Celazole

 

Celazole PBI is one of the highest performing thermoplastics on the market today; it has the lowest coefficient of thermal expansion of all unfilled plastics. At above 400°F (204°C), Celazole possesses the highest mechanical properties of any thermoplastic. By itself, PBI offers a continuous use operating temperature of 1,004°F (540°C). Even after being submerged in hydraulic fluid at 200°F (93°C) for thirty days, Celazole retains 100% tensile strength.

When you combine those exceptional qualities with excellent wear and frictional properties, as well as extreme resistance to chemicals and hydrolysis, it’s no wonder that Celazole excels in industries that require high-performance in hostile environments. For example, semiconductor parts made with Celazole can last twice as long as those made with polyimides.

Other applications that Celazole is commonly machined for include gas plasma equipment, aircraft engine components and other applications for “hot” section areas or environments with harsh chemicals. Whenever dielectric properties are required or high-strength situations arise, Celazole PBI is an ideal material for your application.

We regularly machine various grades of Celazole at AIP Precision Machining, including Celazol U-60 and Duratron PBI.

 

Machining Celazole PBI

 

Annealing Celazole

The process of annealing and stress-relieving Celazole reduces the likelihood of surface cracks and internal stresses occurring in the material. Post-machining annealing also helps to reduce stresses that could potentially contribute to premature failure.

 

Machining Celazole

 

Celazole is known for its extreme hardness, which poses a challenge to HSS machining. Instead, carbide and polycrystalline diamond tools are recommended for machining Celazole PBI.

Keep in mind that Celazole PBI is notch sensitive as well and that high tolerance components machined from this thermoplastic should be stored and sealed to prevent any dimensional changes from moisture absorption.

We also suggest non-aromatic, air-based coolants to achieve optimum surface finishes and close tolerances. Coolants have the additional benefit of extending tool life as well.

 

Preventing Contamination

 

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

 

Celazole PBI Machining Guide: Supportive Information

 

Extreme Performance Materials

Aerospace Market Materials

Energy Sector Materials

 

 

 

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