What glass container and forming defects are found during vial inspection?

Glass container defects are flaws in the vial itself, created during glass forming and tube-to-vial conversion rather than added as foreign matter. They include stones, airlines, blisters, marks or discoloured glass, heel stickers, lack of concentricity, surface abrasions, metal running down the neck, and cracks or checks.

Stones are solid, unmelted inclusions in the glass --- graded critical when internal and protruding, because they interfere with processing and can shed, and minor when external and above 1.0 mm. Airlines are elongated air inclusions drawn into a line during tube forming, and blisters are gas bubbles in the wall, typically a defect above 1.0 mm. Marks, spots or discoloured glass and metal running down the neck of the vial arise from the forming and conversion process, while a heel sticker (tubing), lack of concentricity (uneven wall thickness), and scratched surface abrasion with depth are conversion defects on the finished vial.

Cracks and checks are graded two ways: by whether they penetrate the wall and by location --- body, heel, or shoulder/neck. A crack or check that penetrates the wall is critical because it breaches container integrity; one that does not penetrate is less severe. A bruise with a check that penetrates the wall is an impact defect with an associated crack, also graded by location.

FTI reproduces these glass-forming and crack/check defects by location and severity in its challenge sets and limit-sample defect libraries, and supports glass delamination and container characterization analysis when forming defects turn up in production.