When you think of shrink wrapping, you may not think of how your product is being sealed and how that will impact the presentation of your product. Understanding the different vertical shrink wrapper methods will make you better educated on making the right decision.
Vertical shrink wrapping systems are used when products must be standing upright and sealed either by a bottom or top trim seal leaving the side panels of the package uninterrupted for a cleaner appearance or to allow clear space for graphics. Using a side seal wrapper is not be the best solution as the package would not be visually appealing for graphics on the printed film.
Lap seals is NOT the right vertical shrink wrapper solution
Conventional vertical wrappers use a bottom lap (overlap) seal. Whether a drag wire thermal seal or a static seal, lap seals are not generally as secure as full trim seals. Drag wire seals, while more secure than static seals are notoriously sensitive to wrapper speed changes. As the wrapper slows for any reason, the temperature may be too hot and, as it speeds up, the temperature may not be hot enough for select packages. As a result, packages are poorly sealed and may require constant monitoring to ensure they are inspected and removed from the line.
Trim seal is the way to go
A trim seal is the most secure seal available in the market. Bottom trim seal wrappers use the same device to seal the film and remove the trim as a side seal except that the seal is on the bottom of the package.
For some vertical shrink wrapper applications, sealing the package on top rather than on the bottom is the perfect answer.
Let’s say your multipacking and sleeving several cold products and notice condensation on the surface. As moisture flows to the bottom of the package, it would wet the film and contaminate the bottom seal.
Another case where the top trim seal would be necessary is where the vertical package arrives at the wrapper with the bar code on the bottom of the package and a seal of any type could risk making the code difficult to read.