Vol 7 No 3
Tested: Two-piece 12oz (355ml) carbonated beer cans; CO2 or LN2 Dosed with 202 can end.
Inspection Desired: Leak detection
Tested with: TapTone T4000 FS
The purpose of this test is to prove the effectiveness of the TapTone T4000-FS in testing carbonated and LN2 dosed beverage cans for pressure loss and leak detection. Cans are manufactured today using less raw material in an effort to decrease manufacturing and shipping costs. The reduction in materials, referred to as light-weighting or thin walling, renders them more susceptible to damage and leaks at production speed with damage due to twists and conveyor side rails. Traditionally, these cans have been tested with fill level or proximity systems. Fill level testing is only capable of detecting gross leaks and proximity testing is less accurate at pressure detection.
The challenge with Proximity inspection is that the can end retains some of its expanded (pressurized) shape even when the pressure has been lost, and since proximity testing relies on measurement of the can end’s shape (lid deflection) it may not be rejected. Therefore, pressure resolution (10-12 psi for the proximity sytem) remains the major shortfall for a standalone proximity sensor, whereas the resolution of force technology is capable of pressure detection to within 1-2 psi. Proximity inspection is best suited for lid deflection measurement for gross leak inspections as a “dud” detector for beverage cans, but will not provide linear data with pressure changes compared to the resolution of Force inspection.