Airborne Ultrasound (ABUS): How 100% Automated Seal Inspection Works
Airborne ultrasound (ABUS) inspects a medical device pouch seal by transmitting an ultrasonic signal through the seal and measuring how that signal is transmitted or attenuated, a physical response that correlates directly to seal quality — bond strength, completeness, and material consistency — rather than to what the seal merely looks like from the outside.
How does airborne ultrasound detect a seal defect?
Seal defects change the seal's physical structure: an incomplete bond, a weak or under-formed seal, trapped contamination, or over-sealed and crystallized material all alter how sound energy passes through that section of the seal compared with a properly formed one. ABUS measures that signal in-line, non-destructively, at production speed, and does it on every seal rather than a sample — which is what makes 100% inspection operationally realistic rather than a theoretical ideal.
What can it catch that other methods can't?
Because it doesn't rely on optical transparency, ABUS works regardless of material color, transparency, or porosity — which matters enormously for medical device pouches, where Tyvek and other porous, opaque materials dominate the sterile barrier category and defeat most non-destructive optical methods outright. It is also non-destructive, which distinguishes it from burst, creep, and dye-penetration testing, all of which destroy the unit being tested and therefore can only ever sample, never inspect at 100%. ABUS is recognized as a validated method in both ASTM F3004 and ISO 11607.
Where does it fit relative to newer optical methods?
The inspection field is not standing still. Inline optical coherence tomography (OCT) systems have recently been demonstrated for packaging seal inspection, pushing detection thresholds down into the single-digit-micron range at competitive line speeds — a genuine and welcome advance. But that technology is currently built around transparent and semitransparent materials, which leaves the opaque, porous packaging that defines most medical device sterile barrier systems outside its reach. For that packaging — which is to say, for most of what actually ships in this category — non-destructive, 100%, in-line inspection today means airborne ultrasound.
How does this fit a broader QRM program?
ABUS is the detection method that makes the rest of a seal-focused QRM strategy operationally real: it lets a manufacturer validate against a defensible, geometry-correct target defect size, on every unit, with an objective and quantitative record rather than an inspector's visual judgment.