The ultimate quality of the packages produced on horizontal flow wrappers requires a complex series of events to form and fill each package and move it through the packaging process. In the following post and “Tech Bites” video we explore the many steps that occur before and after packages are cut and sealed—from the product feed and film unwind through to the discharge belt—that must be fine-tuned to optimize seal integrity, package appearance, and productivity.
Varying thicknesses of film at the end seal can cause sealing problems, especially at the transition point between two and four layers created by the fin seal, gussets, wrinkles and creases, as well at the corners. Applications of pressure and heat (if applicable) must be great enough to cause the sealant layer to flow into and seal off these voids. Excess pressure can easily crush or split the end seal, while overheating distorts the seal and can cause poor hot tack, where the film springs back open, or “moons,” before the seal can set.
The operating window for creating quality seals can be elusive, resulting in packages that leak, are distorted, and have little appeal to consumers.
An important step in troubleshooting these issues is to eliminate unintended wrinkles and creases. This post, the first in a four-part series, will examine this process on horizontal flow wrappers; Part 2 considers these issues on vertical baggers.