A. Introduction
Non-destructiveA careful external visual examination of containers and their seals is the primary means of detecting container defects.
To visually observe defects in food packages.> 100 μmOn-line
B. Operation
Representative samples are obtained from production line. External
surfaces are examined for holes, abrasions, delamination, and correct design. Critical dimensions are measured and observations
recorded.
- Strong light without glare, for visual inspection of packages
- Measuring devices, such as ruler, calipers, micrometer
- Scissors or knife
Refer to examination procedures for paperboard packages, flexible pouches, plastic packages with heat-sealed lids, and plastic cans with double-seamed metal ends.
Positive
Visually detected defect.
Negative
No visually detected defects.
False positive
Visual identification of defect not actually present.
False negative
Defect is present, but not visually detected.
C. Application
PACKAGE TYPES AND DEFECTS
| PACKAGE TYPE | ||||
|---|---|---|---|---|
| DEFECTS | Flexible Pouch | Semi-rigid and Rigid plastic container | Plastic Can (Double-seam Metal End) | Paperboard |
| Abrasion |  | | | |
| Corner Dent | | |||
| Crushed | | | ||
| Cut (Fracture) | | | | |
| Delamination | | | | |
| Double Seam Defects* | | |||
| Flexcracks | | | ||
| Foreign Matter Inclusion | | | ||
| Gels | | | ||
| Hotfold | | |||
| Label Foldover | | |||
| Leaker | | |||
| Leaker (Channel) | | | | |
| Leaker (Corner) | | |||
| Leaker (Notch) | | |||
| Leaker (Perforation) | | |||
| Leaker (Pulltab) | | |||
| Leaker (Seal) | | |||
| Loose Flap or Ear | | |||
| Malformed | | | ||
| Puncture (Pinhole) | | | | |
| Seal Defects (Blister) |  | |||
| Seal Defects (Blocked) |  | |||
| Seal Defects (Burnt) | | |||
| Seal Defects (Compressed) | | |||
| Seal Defects (Contaminated) | | | | |
| Seal Defects (Convolution/Embossing) | | |||
| Seal Defects (Creep) | | |||
| Seal Defects (Crooked) | | |||
| Seal Defects (Incomplete) | | |||
| Seal Defects (Misaligned/Deformed) | | | ||
| Seal Defects (Nonbonding/Weak) | | |||
| Seal Defects (Plastic Lumps) | | |||
| Seal Defects (Seal-width Variation) | | |||
| Seal Defects (Stringy) | | |||
| Seal Defects (Uneven Impression) | | |||
| Seal Defects (Uneven Juncture) | | |||
| Seal Defects (Wrinkle) | | | ||
| Swell (Swollen Package) | | | | |
| Waffling | | | ||
Visual inspection has a sensitivity of 10-2 Pa m3s, and is generally a gross leak detection technique. This method is time consuming, expensive and its monotonous nature may induce operator fatigue.