Mark Plantier
(Admin)  Posts: 7
Registered:
2009-03-13 | Seal Integrity
Posted: 2009-06-01 |
QUOTE ( @ 2009-06-01, 09:51:47)
Is the vacuum applied to the inside of the test container (bottle, etc), drawing water into the container through leaks or is the vacuum applied to the water-filled tank? Thanks.
The vacuum test shown in our presentation and used in the Enercon lab pulls a vacuum on the water filled tank. If there are any leaks air bubbles releasing from the sealed container will appear. In the case of a weak seal the force of the vacuum will cause the seal to break away from the container.
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(Member)
 Posts: 2
Registered:
1970-01-01 | Seal Integrity
Posted: 2009-06-01 |
QUOTE ( @ 2009-06-01)
Can I feel comfortable vacuum testing immediately after I seal the package? A 24 hour hold before testing is not desired. And, do you have any general details on “how” the seal strength changes after 24 hrs?
This is completely dependent on the application. There is definitely a period of time that is needed for the liner to cool down and the heat seal layer or polymer to properly set. Once the liner has cooled down, you should be able to test the seal. However, the seal strength may change over the first 24 hour period. It’s partially dependent on the heat seal film composition and the resin of the container being sealed. However, the overall bond strength can increase over 24 hours which would result in a slight increase in the peel force required to remove the seal. Preliminary testing to see the difference between 2 minutes and 24 hours is would not hurt.
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(Member)
Posts: 2
Registered:
1970-01-01 | Seal Integrity
Posted: 2009-06-01 |
QUOTE ( @ 2009-06-01)
What does Enercon define as a good seal integrity?
We do not have a specific requirement that we test to each and every time. The customer determines what a good or acceptable seal is given their package. Each package is going to react differently under the pressure so to define a good seal integrity is very difficult. There is no ASTM guideline or industry standard that identifies a good seal. At Enercon, we have a conversion chart where we can convert our inches of mercury readout on our wet vacuum chamber into altitude so we get a good idea of what each package can handle in an unpressurized cabin or truck at any given altitude.
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(Member)
Posts: 6
Registered:
1970-01-01 | Seal Integrity
Posted: 2009-06-01 |
QUOTE ( @ 2009-06-01)
What is the vacuum pull rate for the leak test
We work with our customers to determine what the appropriate pressure to test to is. It will depend on a number of variables including: container, diameter of foil and materials involved. For example a recent customer asked us to test at a value of 8in. Hg, for 30 seconds. Unfortunately, there are no ASTM, or any other kind of specification concerning the testing of induction seals. Everyone seems to have their own method, including squeezing the bottle, to standing on it.
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