How do you recommend performing dye penetration on a double package (i.e., inner and outer pouch)?
Dye penetrant testing techniques for testing double barrier packages, like a pouch within a pouch, often require removal of the inner package. In some cases, it is possible to cut the center of the outer package and remove the inner pouch. This must be done in a way which will not affect the ability of the outer to be tested. By leaving enough uncut material surrounding all seals this can be accomplished. The feasibility of this method is dependent on the packaging configuration.
Another way is to incorporate one of the newly proposed ASTM F1929 techniques, which expose the package to the dye solution from the outside of the package. Both the new edge-dip and eye dropper application techniques allow for external exposure of the seal to the dye solution. In this manner, the outer pouch can be tested with minimal dye exposure to the inner package. Once testing has been completed, then the outer package can be removed and the inner can be tested.