UCSF Biomed Shares Medical Device Breakdown
Watch this fascinating conversation with Richard Fechter, a principal developmental engineer at the University of California, San Francisco Medical Center. Richard shares his insights for better performing medical devices that are cleanable and serviceable and hold up to commonly and frequently used disinfectants. https://www.youtube.com/watch?v=5Om5qRX-ZmQ
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NN Roadshow Recap

On September 19, participants and vendors gathered in East Providence, Rhode Island, for Tritan on Tour: an exclusive event hosted by Eastman and NN, Inc. showcasing how new materials and manufacturing processes can improve medical device performance. Representatives from Henkel, PolyOne, Dukane, Manta, Goddard, and Ensinger were on hand to share the latest advancements in medical injection molding applications.

Attendees learned how to select the best materials and streamline the manufacturing process, and strengthen the future of health care. They also got the opportunity to network with manufacturers, design engineers, and distributors, and discuss solutions for working with Eastman Tritan™ copolyester.

Thanks to all who attended and made this a fantastic event! If you’d like more information please visit our website 
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Thank You for Asking.
We often receive great questions about molding with Eastman medical grade polymers and are always glad to provide answers and more information. Here is a response to a recent query from our inbox:
“What is the heat deflection temperature for Eastman MXF221 copolyester?”
Heat deflection temperature (HDT) is the temperature at which a polymer or plastic deforms under a specified load. The HDT of our latest offering, Eastman MXF221 copolyester, is outlined here.
Thermal properties
Deflection temperature  
  @ 0.455 MPa (66 psi) ASTM
D 648 
94°C (201°F)
  @ 1.82 MPa (264 psi) ASTM
D 648
83°C (181°F)
MXF221 is a biocompatible, fully compounded medical grade polymer that is uniquely suited for medical devices and electronic device housings. Developed from Eastman Tritan copolyester, MXF221 offers superior chemical resistance to stringent disinfectants and drugs, improved durability, and greater longevity.
Thermal control is critical for injection molding. Keeping temperatures cooled below the HDT of MXF221 helps ensure successful demolding with no dragging or sticking of parts. Preparing a cooling strategy early in the tool design process can pay big dividends in cycle time and processability. 
For more information on MXF221’s properties, check out its product data sheet.

Eastman Tritan™ copolyester: Innovative properties for medical devices
Eastman Tritan copolyester offers a unique blend of processing and performance properties, including clarity, toughness, and heat and chemical resistance. It can also often be substituted into existing molds with minimal adjustments to processing parameters. This total balance of performance and processing gives Tritan advantages and design flexibility over many other commonly used polymers. Some qualities that make Tritan an excellent choice when it comes to molding parts for the medical market include:
  • Toughness: Exceptional toughness and durability. Medical device housings made with Tritan are impact- and shatter-resistant and have the ability to withstand extreme conditions.
  • Clarity: Outstanding clarity and color retention before and after gamma and e-beam sterilization.
  • Chemical resistance: Maintains part integrity when exposed to a wide range of harsh chemicals and disinfectants. This excellent chemical resistance also means improved ESC resistance during solvent bonding and other secondary operations.
  • Heat resistance: Higher level of heat resistance, which some devices require to deliver their intended performance or for accelerated aging validation.
  • Reduced scrap rates: Less defects due to black specks, flow marks, cracking, and breakage.
  • No annealing required: Greater throughput and higher yield.
  • Sustainability: Made without BPA, halogens, or ortho-phthalates.
For more information on the benefits of molding with Tritan, check out these resources on the advantages of using it in renal and blood contact devices.
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Reducing stress in the assembly process
Parts made from Eastman Tritan copolyester can be assembled using a variety of joining techniques, including chemical, mechanical, or thermal methods. The choice of assembly method will depend on the end-user requirements of your application. With whatever method you choose, however, the assembly process can cause stress in devices.
The good news is that Tritan is an inherently tough material and can stand up to these stresses. Consider mechanical joining methods. In this technique, molded-in bosses are commonly used to accept screws or threaded inserts, while molded-in or postmold inserts are commonly used where a plastic cover or part must be removed repeatedly.
Tritan can be joined by using screws, rivets, threaded inserts, or snap-fit methods and can be molded into various shapes—such as bosses—that can accept screws or inserts. When a screw is tightly turned, it can put a lot of stress on the surrounding plastic. Excessive stresses can cause cracking of the boss or hole with or without exposure to chemicals in the end-use environment. Tritans superior durability and high chemical resistance ensures that parts made with the material will stay intact—even in the presence of harsh chemicals.
Special screws have been developed over the years that incorporate uniquely designed threads that help to reduce radial/hoop stresses in the plastic material and provide increased pull-out resistance. Bosses—or cored-out holes—require special care in their design to allow for proper flow of the plastic. Proper sizing of the boss and related gussets will help avoid sink marks and provide good structural strength. Adding a radius to all sharp corners will further reduce stress concentrations around the boss.
For more information, check out our Secondary operations guide for Eastman Tritan copolyester.

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