Use of high-performance fiber lasers introduced at NPE 2012 may significantly advance use of a variety of clear plastics in medical applications, such as fluid bags now made from polyvinyl chloride.
Eastman Chemical announced at MD&M West held in Anaheim, CA last month that the technology developed by IPG Photonics (Oxford, MA) has significant potential for advancing its clear copolyester plastics.
One major reason is that the fiber laser process developed by IPG Photonics (Oxford, MA) does not require energy-absorbing additives. Medical device OEMs are pushing suppliers to remove as many chemicals from formulations as possible. Eliminating additives, such as Clearweld inks or Lumogen dyes also saves money.
The laser process is also very clean because no tools come into contact with the medical device material.
"Welding techniques typically require an energy-absorbing additive to be added to the polymer, and with medical applications, there is always the question of biocompatibility with the polymer and any additives," said Gopal R. Saraiya, global segment leader, medical devices, Eastman Chemical Co.
The IPG Photonics technology is based on fiber lasers that use semiconductor diodes to pump light into specialty optical fibers infused with rare earth ions.
In an interview with Plastics Today, IPG VP Bill Shiner said: "The beauty of our technology is that it is very cost-effective and you can shift the wavelength depending on the plastic." All types of thermoplastics regardless of polarity can be welded with the technology. Polarity is a significant limitation in some other plastics welding systems. Conventional, nonproprietary radio-frequency (RF) welding of films has been limited to polar resins with high dielectric loss factors-particularly flexible PVC and thermoplastic polyurethane.
According to the IPG executive responsible for the medical market, there are many prospective applications using the process for Eastman's copolyester, as well as other clear plastics.
"There are numerous applications made with Eastman Tritan copolyester in multiple markets in various stages of development that would not be possible without IPG Photonics' new welding technology," said Tony Hoult, senior applications manager, IPG Photonics, Silicon Valley Technology Center. "For medical device manufacturers, the benefits of this welding technique include fully hermetic leak-proof precision joints that have a smooth weld that will not entrap bio-burden."
Unrelated to the Eastman announcement, Shiner said that IPG Photonics recently shipped a welding system to a medical catheter manufacturer.
Hoult told Plastics Today in an interview that the potential use of a clear polymer needs to be first confirmed by checking its light absorption rate under fixed conditions. This is done by placing a sheet of the material above a laser power meter that has been calibrated for the 1.5 or 2 μm laser wavelength.
Founded in 1990, IPG pioneered the development and commercialization of optical fiber-based lasers for use in a wide range of applications such as materials processing, advanced applications, and telecommunications and medical applications. Work with medical plastics is under active development.