Finished Shrink Wrap Problems: Splitting Seals

Effect: After the product has been shrink wrapped and heat sealed, the shrink film opens at a seam or parts of the seal fall away from its opposite. This is called splitting seals or weak seals.

While a great many of the common shrink wrap problems are harmless and unnoticeable to the end user or customer base. Splitting seals can affect your business both from a trust standpoint and a noticeable issue with spoiled goods or lost revenue.

If you are shrink wrapping multiple loose items in trays, tamper proofing bottles or protecting fresh food, is a seal is open you may lose parts of a product and a client may refuse receipt of any delivery that isn't fully secure. Split seals in shrink film are not Fish Eyes which can be fixed tomorrow, they require urgent attention immediately.

    1. If you are using a conveyor, consider that the sealing cycle is too fast. You are dealing with a form of plastic, it requires time to respond to the heated environment and shrink and attach to itself sufficiently.
    2. If only parts of the seal are splitting, rather than the entire length you can check the sealing wire for causes. Does it need cleaning, is it hot enough, or perhaps maybe the sealing wire is too hot? Test to negotiate.
    3. It may be that the clamp pressure on the sealing wire is not set high enough or a part is causing the pressure to be placed unevenly. So check the seal pad or seal tape is not worn too.
    4. Lastly or first of all, check shrink film compatibility with your machine. Up gauge and make use of a thicker shrink film product - which is determined by microns or check the quality of the shrink wrap you have been used to, is it a faulty product?

Don't panic, yes the reasons are numerous and the splitting seals and weak seals have a variety of sources attributed to them. If you have a contract for a regular machine service, consider using it now. Or calling someone in to check and give your shrink wrap machine a once offer to correct and find the problem if you cannot ascertain the cause yourself.


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