Airborne Ultrasound for Medical Device Packaging
Airborne ultrasound is used across medical device pouch and tray packaging to inspect seal formation quality non-destructively, at production speed, on materials — like Tyvek — that most other non-destructive methods can't evaluate at all. For Class III devices specifically, it addresses a category of seal-formation defect that a leak test alone is not designed to catch.
Why does medical device packaging need this in addition to a leak test?
A leak test confirms whether gas or microbes could pass through a completed package. It does not, by itself, confirm that a seal was formed correctly across its full width, at a consistent bond strength, free of wrinkles, inclusions, or localized over- or under-sealing. Those seal-formation defects are exactly what airborne ultrasound is built to see, which is why device programs increasingly deploy it alongside, not instead of, a leak-test method.
How does this apply to pouch seals specifically?
Premade Tyvek and foil pouches typically carry a single final seal, and because Tyvek is a delicate, fibrous material, over-sealing to guarantee a strong bond isn't a safe option the way it might be with a more forgiving film. Most real-world pouch seal defects come from under-sealing or a cold seal rather than a gross breach, which is precisely the kind of defect ultrasound's acoustic signal is sensitive to and visual inspection is not.
How does this apply to Tyvek-lidded trays?
Tray seals present a harder geometry problem: the seal runs around the entire tray perimeter, and the seal flange must be uniform, flat, and accessible to the sensor as the tray is rotated or moved past it. This is a newer and more demanding application of the technology than pouch inspection, and for the most sensitive leak-detection requirements on trays, vacuum decay (with the Tyvek lid masked off) remains a complementary, and in some cases preferred, method for the container-integrity side of the equation, while ultrasound targets the seal-formation side.
Does this replace manual visual inspection?
For any sterile barrier system where reliability matters, yes, it should. Manual visual inspection's own governing standard, ASTM F1886, only covers transparent and semi-transparent materials in the first place, and documents a 60-100% probability of detection that degrades further with time on task. Airborne ultrasound provides an objective, quantitative, 100%-capable alternative for exactly the material types — foil, Tyvek, opaque films — where visual inspection is weakest or inapplicable.