An Informational Brief on Polymer Machining

 

Since it was first polymerized in 1954 by Karl Rehn and Giulio Natta, polypropylene (PP) has become one of the leading polymer choices for a wide array of applications from automotive to commercial to medical.

 

Polypropylene plays a significant role in medical applications due to its high chemical resistance, lightweight, radiolucency and repeated autoclavability. Furthermore, medical grade PP exhibits good resistance to steam sterilization and moisture resistance. Disposable syringes, instrument or implant caddies and fluid delivery systems are the most common medical application of polypropylene. Other applications include medical vials, diagnostic devices, petri dishes, intravenous bottles, specimen bottles and surgical trays.

 

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AIP has over 35 years of experience machining complex components from thermoplastics like polypropylene. In this insightful technical brief, we will discuss what goes into machining polypropylene and how it differs from other manufacturing options such as metal machining, injection molding, and 3D printing.

 

Homopolymer vs Copolymer – What’s the Difference?

 

The two main types of polypropylene available on the market are homopolymers and copolymers. Although they share many properties, there are some differences that help guide machinists and engineers in choosing the right material for their PP application. For the purposes of this blog, we will briefly review the differences between PP homopolymer and PP copolymer.

 

PP Homopolymer PP Copolymer
  • High strength to weight ratio and stiffer & stronger than copolymer
  • Good chemical resistance and weldability
  • Good processability
  • Good impact resistance
  • Good stiffness
  • Food contact acceptable
  • Suitable for corrosion resistant structures
  • Bit softer but has better impact strength; tougher and more durable than homopolymer
  • Better stress crack resistance and low temperature toughness
  • High processability
  • High impact resistance
  • High toughness
  • Not preferable for food contact applications

 

Properties of Polypropylene

 

Keeping information about the properties of a thermoplastic beforehand is always beneficial. This helps in selecting the right thermoplastic for an application. It also assists in evaluating if the end use requirement would be fulfilled or not. Here are some of the key properties of polypropylene:

 

Polypropylene is characterized by excellent chemical resistance in corrosive environments, resistance to cleaning agents and solvents and by a high heat deflection temperature.

 

It also has great dimensional stability and is fairly easy to machine. As noted above, it is available in heat-stabilized homopolymer and copolymer grades. At AIP, we machine POLYSTONE P, PROPYLUX HS and HS2, PROTEUS LSG HS PP from MCAM, TECAPRO MT and TECAFINE PP from Ensinger. Interesting to note is that both the PROPYLUX and TECAPRO heat stabilized PP grades are available in both standard and custom colors for medical sorting and sizing organization. Whatever your application, our machinists can help you in material selection, sizing and manufacturing techniques from concept to completion.

 

Melting Point of Polypropylene – The melting point of polypropylene occurs at a range.

 

Homopolymer: 160 – 165°C
Copolymer: 135 – 159°C

 

Density of Polypropylene – PP is one of the lightest polymers among all commodity plastics. This feature makes it a suitable option for lightweight\weight saving applications.

 

Homopolymer: 0.904 – 0.908 g/cm3
Random Copolymer: 0.904 – 0.908 g/cm3
Impact Copolymer: 0.898 – 0.900 g/cm3

 

Machining Polyproylene

 

Annealing Polypropylene

Due to its low annealing temperature, PP, like any polymer under heat and pressure, has a tendency to deform during machining. The annealing process at AIP greatly reduces the chances of these stresses occurring from the heat generated during machining PP and other polymers. Our machinists use computer controlled annealing ovens for the highest quality precision machining.

 

Machining Polypropylene

As a part of the polyolefin family, PP is semi-crystalline, which means that it can be machined at tight tolerances. We recommend non-aromatic, water-soluble coolants because they are most suitable for ideal surface finishes and close tolerances.

 

Bear in mind that polypropylene has variable levels of thermal expansion and will move a great deal 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 and medical 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.

 

Polypropylene Machining Guide: Supportive Information

 

ISO 13485:2016 Certification
ISO 9001:2015 Certification

 

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An Informational Brief on Polymer Machining

 

Machining High Density PolyethyleneAmong 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

 

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Learn about the re-useable capabilities of precision plastics

 

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

 

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

 

Everyday Sustainable Precision Plastics
Polymer Properties AIP’s Machined Applications
PPS Broadest chemical resistance; zero moisture absorption; dimensional stability; ultra-low wear factors and structural strength

*available in several grades

Case Study: High-quality PPS wheel bushings for a theme park water ride.

  • Reduced ride downtime
  • Saved on maintenance and inventory costs
  • Lower energy cost
  • Efficient design
  • Low-wear
TORLON Highest performing, melt-processible plastic; maintains strength and stiffness up to 500 F; chemical, thermal and stress resistance

*available in several grades

Ideal for critical mechanical and structural components for severe levels of temperature and stress

  • Jet Engine Components
  • High Temperature Electrical Connectors
  • Automotive Transmission components
  • Wear Rings in Oil Recovery
  • Valve Seats
PEEK Biocompatible; abrasion and chemical resistant; low moisture absorption; very low smoke and toxic gas emission

*available in several grades

Case Study: PEEK Dynamic Telescopic Craniotomy (skull plate for brain traumas

  • Reduced ride downtime
  • Saved on maintenance and inventory costs
  • Lower energy cost
  • Efficient design
  • Low-wear
RADEL Impact resistance; hydrolytic stability; excellent toughness; chemical resistance; heat deflection temperature of 405 F (207 C)
ULTEM Excellent heat and flame resistance; high rigidity and strength; low thermal conductivity; highest dielectric strength

*available in several grades

Used as structural components in several industries

  • High-voltage circuit-breaker housings
  • High-temperature bobbins, coils, fuse blocks and wire coatings
  • Jet-engine components
  • Aircraft interior and electrical hardware parts
  • Microwave applications
  • Replaces glass in medical lamps

 

Thermoplastics – The Green Plastic

 

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

 

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

 

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

 

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

 

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

 

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

 

Unrivaled Expertise. Unparalleled Results

 

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

 

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

 

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

 

 

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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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Key Moments in Aircraft & Aerospace Innovation

 

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

 

The Pioneers of Aviation

 

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

 

 

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

 

The Golden Age

 

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

 

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

 

 

Plastic’s Mettle: Wartime Materials Take Flight

 

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

 

 

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

 

The Race for Space

 

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

 

 

Plastics of the Future

 

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

 

 

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

 

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

 

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

 

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

 

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

 

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

 

Benefits Across the Board

 

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

 

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

 

Plastics are more resistant to chemicals than their metal counterparts.

 

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

 

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


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

 

Let’s Break It Down by Industry

 

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

 

Aerospace & Defense

 

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

 

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

 

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

 

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

 

Learn More

 

Medical & Life Sciences

 

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

 

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

 

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

 

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

 

Learn More

 

Specialized Industrial

 

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

 

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

 

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

 

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

 

Learn More

 

Power & Energy

 

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

 

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

 

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

 

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

 

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

 

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