Injection Molded and Machined PEEK Components
by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Injection Molded and Machined PEEK Components

PEEK (polyetheretherketone) is a high-performance thermoplastic available in various grades to suit a wide variety of applications. It is commonly used in bushings, medical implants, gears, gaskets, and more. However, what one of the aspects of PEEK that makes it stand out from other engineering polymers is that it can be machined or injection molded, making it suitable for the manufacture of an even more diverse group of components.

PEEK Components

There are a number of different types of parts and applications where machined or injection molded PEEK are used. These include …

It is also a common material in a variety of industries, including …

  • Oil & gas
  • Renewable energy
  • Nuclear energy
  • Chemical processing
  • Food & dairy
  • Medical
  • Pharmaceutical
  • Transportation
  • Electronics (including semiconductors)
  • Aerospace

PEEK: High Performance Polymer

PEEK is both stiffer and stronger than most plastics, retaining its mechanical strength even at high temperature. It also provides key characteristics such as dimensional stability, excellent wear resistance, and hydrolytic stability. It is also known for having a low coefficient of friction, self-lubrication, and a very low tendency to form stress cracks. PEEK also provides very good chemical resistance and is insoluble in most solvents. In addition, it provides both environmental and regulatory benefits because it is fully recyclable. Furthermore, PEEK lends itself to various processing methods.

PEEK is available in FDA-approved grades as well as implantable grades, where its biocompatibility makes it highly desirable for medical applications. In addition, PEEK grades are available that can handle gamma radiation exposure and even autoclaving as part of sterilization processes. It is ideal for very harsh, high temperature environments, including those found in the petrochemical industry and aerospace. Its low particle generation and outgassing make it well adapted to applications involving semiconductors where high purity is critical.

Fillers can also be added to PEEK to improve properties such as abrasion resistance, surface hardness, and friction. Common fillers include glass, carbon, and graphite fibers as well as PTFE and silicon dioxide. Glass fibers can increase compressive strength and enhance heat resistance while carbon and graphite fibers reduce weight while increasing overall strength. Adding PTFE to PEEK further reduces friction while silicon dioxide can be used to increase strength.

Injection Molded PEEK

Injection molding involves raising the temperature of a polymer to the point where it almost melts, which allows it to be injected under high pressure into a mold. Once the polymer has cooled, the components are removed from the mold and typically require minimal post-processing to prepare them for use.

Injection molding PEEK is much cheaper than machining for larger  production runs around 10,000+ components, and is a near-net-shape manufacturing method that results in minimal waste. It works extremely well when parts are needed that are too complex to machine efficiently. The most costly aspect of injection molding lies in the design and execution of the molds required; however, depending on the size of the part and the machine used, multiple parts can be injection molded with a single die.

When used in connection with PEEK, injection molding is often used to manufacture a replacement for metal bushing. Injection molded PEEK bushings can be found in various applications, including …

  • Citrus processing, where exposure to the acids in the fruit can lead to chemical compatibility issues
  • Pumps used in harsh environments that include aggressive chemicals and high temperatures
  • Applications where the presence of vibration accelerates wear

Note, however, that injection molding PEEK involves very high processing temperatures that not all facilities are equipped to handle. In addition, to achieve reliable part fabrication, there are certain cooling requirements that must be met to prevent issues such as warping and annealing may be required to eliminate residual stresses. Injection molding is also limited in its capabilities when there is a need for high precision parts or large parts.

Machined PEEK

Machining using cutting and grinding tools to remove unwanted material from a solid blank in order to produce the desired component. Most facilities use CNC (Computer Numeric Control) machining, which ties in well with CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) that allows a part to be first designed on a computer and then machined using tools that are computer controlled.

Machining is typically used when dimensions need to be extremely precise, the geometry of the PEEK component does not lend itself to injection molding, thin walls are needed, or the desired components are relatively large.

Machining is also more economical when a short production run (<5,000) is involved, which means it is also ideal for developing prototypes. It is faster than injection molding because there is no significant upfront time required for tooling such as molds / dies. In addition, machined PEEK parts usually have much better wear and mechanical properties than injection molded PEEK. And, unlike many thermoplastics, PEEK is easy to machine. Machining also works extremely well for achieving thin walls and fabricating parts with non-standard dimensions or shapes.

There are several industries that make use of machined PEEK components, including …

  • Oil and gas industry, where large PEEK bushings are often required
  • Medical applications where an FDA-approved material must be combined with high precision, customized parts
  • Arctic wind turbines, which require large bushings that can handle the aggressive environment 

Machining can be challenging when working with a filled grade of PEEK and not all machining companies have the skills and knowledge needed to fabricate a machined PEEK component. Finally, annealing may be needed to stress relieve machined parts.

Conclusion

For PEEK parts with a short production run that require a short lead time, machining works extremely well. It is also recommended when there is a need for thin walls or extreme tolerances. On the other hand, high-production volumes will benefit from the lower costs involved with injection molding. 

Advanced EMC has the skill and equipment needed for precision machining and injection molding of PEEK components. To learn more about what we have to offer or to get advice on which process would work best for your application, contact us today.

 

Mexican Plastics Industry During COVID-19
by Jackie Johnson Jackie Johnson No Comments

The Mexican Plastics Industry During COVID-19

With COVID-19 spreading across the globe, one company in Mexico City has created a rotomolded solution to help curb the infection in one of the world’s largest food markets. In fact, Mexico’s plastics industry has played a large part in COVID-19 relief.

The Mexican plastics industry is a relatively young one. However, it has quickly become one of the fastest developing sectors in the country. In 2016, the country was the tenth largest worldwide plastic producer, with a market of $33 billion.

Because it is so new, the Mexican plastics industry has the unique advantage of having new machinery that is on par with, and even superior to, those in Europe, where equipment could be 50 years old. Which means there are fewer problems to contend with which in turn allows for rapid production and innovation when the country needs it most.

So, in this week’s blog post, we will cover how the Mexican plastics industry has combated COVID-19.

Hospitals and Hand Washing Stations

The Mexico City based company Grupo Rotoplas SAB de CV has teamed up with toilet cleaning brand Harpic as well as the Mexican Red Cross to install a field hospital at the Central de Abastos, an open-air food market in the borough of Iztapalapa in central Mexico City, which was considered in the early days of the pandemic to be one of the main sources of contagion in the city. The hospital has been able to provide tests and care for sufferers of COVID-19.

Developed in the 1970s, Iztapalapa is one of Mexico City’s sixteen municipalities, and with a population of 1.8 million it is the most populous. The borough is heavily working class, and the people of Iztapalapa have been still working on the streets even while the threat of the Corona virus looms. When COVID hit the Central de Abastos, it spread rapidly, with one testing center testing 15,000 people with 1,347 testing positive.

In response, in addition to the field hospital, Rotoplas has installed multiple hand washing stations across the market, which covers 800 acres, as well as hanging banners offering advice on preventative action. Because of this it is estimated that 12,000 people have benefited from the new sanitary measures.

Rotoplas is best known for manufacturing large water tanks. They have a 27 product lines operate a score of manufacturing facilities across North and Central America and employs about 3,000 people.

From Coca-Cola to Face Masks

Like most of the world, Mexico has had a hard time procuring masks for hospitals and other medical facilities. One company, food-grade PET recycler PetStar SAPI de CV, stepped up to the plate by donating around 212,000 20-calibre face shields made from 1-million plastic bottles, which in turn were donated by Arca Continental, a company that is part of the Mexican Coca-Cola industry.

The process of recycling plastics is a labor intensive one. The plastic must first be washed to remove impurities that could impede operation. Then the plastic is fed into shredders which break down the plastic into much smaller pieces. These smaller pieces can be processed into the next stages for reuse. Before that, they must be checked again for any remaining impurities and given a second wash. After the plastic is further tested and identified by class and quality, they are melted down and crushed together to form pellets. These pellets can then be molded to form items such as face shields.

Recycling plastic bottles not only helped provide more masks to frontline workers, it also kept plastic bottles out of landfills and the ocean, where they could linger for generations. Not only did PetStar provide life-saving face masks, they also helped reduce plastic waste by recycling bottles.

Much Needed Protection

Dow Inc. contributed 25,000 protective gowns to the health sector of Mexico. For healthcare professionals battling COVID-19, isolation gowns are among the most used personal protective equipment right behind masks. And like masks there has been a shortage. In response, DOW, Inc. collaborated with nine key partners across a multitude of industries to develop donate 100,000 isolation gowns to frontline workers in Texas, Louisiana, and of course, Mexico.

Michelle Boven of Dow, Inc. had this to say on the subject:

“Many companies have shown tremendous ingenuity and speed in changing over production to meet the needs for respirators, masks, face shields, hand sanitizer and other products critical to fighting this pandemic,” said Boven from Dow. “With the accelerated product development, testing and certification of these medical gowns, Dow is proud to be among these innovators and we will continue to look for ways to use our vast material science expertise to address the needs of frontline workers around the world.”

Other Examples

  • Chemical manufacturer Alpek SAB de CV donating 500 gallons of hand sanitizing gel to public hospitals.
  • Polyethylene maker Braskem Idesa S.A.P.I. donated 12 metric tons of PE for the production of one million bottles of disinfectant.

In Conclusion

Mexico’s plastic industry is relatively young, but still booming despite the pandemic. It has expanded rapidly to become a $33 billion industry. With the increase in growth the Mexican plastic industry has been in the unique position to help the people of Mexico withstand the deadly pandemic.

Whether it’s providing lifesaving protective equipment or simply placing banners with tips on how to stay safe, the plastics industry has stepped up to help during these uncertain times.