How to Do Leak Testing for Sachets and Stick Packs?
Sachets and stick packs can be difficult to test because they often contain very little air, which reduces the pressure difference needed to make leaks visible during vacuum immersion testing.
When ASTM D3078 immersion testing does not provide enough sensitivity, internal pressurization according to ASTM F2096 can be used by injecting air into the sachet and observing for bubble emission.
Why Are Sachets Difficult to Test?
With little headspace, only a small number of bubbles may escape before the internal and external pressures equalize. Products with low viscosity can also block small defects, making leaks harder to detect.