Dye Penetration Testing
Sometimes it is the most simple test methods that give us the most value. Although Dye Penetration does have its limits, it can be a fast way to evaluate seal value on a busy day during processing. The feedback gained can give quality managers a quick glance at possible machine or material issues. Dye Penetration Testing is a methodology that utilizes visual inspection. ASTM-F1929 is the standard test method for detecting seal leaks in porous medical packaging by dye penetration. Harmful biological or particulate contaminants may enter a device through leaks, and these leaks are frequently found at seals between package components. Leaks can also result from a pinhole in the packaging material.
A dye penetrant solution is applied locally to the seal edge to be tested for leaks. After contact with the dye penetrant for a specified time, the package is visually inspected for dye penetration. This test method is for use on packages with edge seals formed between transparent film and a porous sheet material. The dye penetrant must have good contrast to the opaque packaging material.
The dye solution used in penetration testing will wick through any porous material over time, but normally not within the suggested maximum time. If wicking does transpire, it may be verified by observing the porous side of the subject seal area. The dye will have discolored the surface of the material.
There is no general consensus regarding the level of leakage that is likely to be detrimental to a particular package. However, since ASTM F1929 testing is designed solely to detect leakage, components that illustrate any indication of leakage are usually rejected.
- ASTM F1929 testing is limited to porous materials which can retain the dye penetrant solution and prevent it from discoloring the entire seal for a minimum of 20 seconds.
- Prior to ASTM F1929 testing, all test specimens must be conditioned.
- If ASTM F1929 testing is used as the quality control method, the test specimen must consist of a complete packaged device.
- Packaging must be free of condensation or any other source of liquid water. Water already in the seal defects may render them undetectable with a dye penetrant.
- ASTM F1929 procedure requires that the dye penetrant have good contrast to the opaque packaging material.