By Lynne H. Barton and Kent A. Hevenor
The market for sterile pouches is growing along with the demand for
improved strength, puncture resistance, and barrier properties of new
materials used to make the pouches. As medical device companies
develop new products requiring different levels of protection, the
selection of a medical pouch sealer becomes more critical.
Companies want a strong, repeatable seal that won’t expose it or its products to the risk of an FDA recall.
A consistent sealing process that is easily validatable; a seal that is affordable to produce and won’t result
in costly rejects; and a sealer that requires less maintenance, less downtime, and a lower total cost of
ownership (TCO) is desired. Is throughput a key factor? The ability to seal a range of materials? Each
company will have a different set of criteria that may impact which sealer is most appropriate.
Types of Medical Pouch Sealers
There are three major medical pouch sealing technologies—impulse heat, constant heat, and continuous
band sealers. All sealers work by either activating an adhesive layer or melting the pouch material under
pressure to form a seal.
The most important considerations are the quality/consistency of the seal, the repeatability of the process,
the ability for the process control system to be calibrated, and the sealer and process to be validated. To
ensure that the seal is formed under the proper temperature and pressure, sealers should operate within
a temperature and pressure alarm range.
Once sealed, the pouch is subject to manual inspection; it’s important that the pouch not only be sealed,
but that the seal look perfect in order to avoid rejection. Rejection can occur for incomplete sealing,
wrinkled seals, channels/gaps in the seal, or seals that have been burned through. While high rejection
rates cost the manufacturer money, the failure of a seal that has avoided rejection, and a potential
subsequent FDA recall, can cost millions.
Impulse Heat Sealers
Impulse heat sealers were the “original” heat sealers used for sterile packaging in the 1970s. Impulse
heat sealers run a timed impulse of electricity through a nichrome wire element that heats up rapidly and
seals the pouch. The heating process can take anywhere from a fraction of a second to a few seconds,
depending upon the thickness and temperature requirements of the material being sealed.
