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.
packaging film
Sealing Over Extra Layers of Film at the End Seal (part 4 of 4): Optimizing Crimper & Sealing Jaw Design
There is no one-size-fits-all solution for the design of crimpers and sealing jaws on horizontal flow wrappers and vertical baggers; they should be specified according to the packaging film, products, and conditions of your packaging operation.
This post, the last in our four-part series, reviews design options for crimpers and jaws. The optimal combination of serration patterns, materials, and special features can dramatically improve seal quality and productivity when sealing across extra film layers at the end seal.
Transitions on the end seal between varying thicknesses of film created by the fin seal, lap seal, gussets, and wrinkles make it more difficult to maintain the operating window necessary for quality seals:
- Too little pressure leaves gaps, or leakers, at these transition zones.
- Excess pressure can easily crush or split the end seal.
- Overheating distorts the seal and can cause poor hot tack, where the film springs back open at transition zones or “moons,” before the seal can set.
The end results can be packages that fail to protect the product or have little appeal to consumers, as well as lost production time spent attempting to meet package quality standards.
Crimper and Sealing Jaw Design Options
Troubleshooting Extra Layers of Film at the End Seal (Part 2 of 4): Refining and Eliminating Wrinkles and Creases on Vertical Baggers
Varying thicknesses of film at the end seal can cause sealing problems, especially at the transition points of multiple film layers created by the fin or lap seal, gussets, wrinkles, creases, and at the corners. Applications of pressure and heat must be great enough to cause the sealant layer to flow into and seal off these voids. However, 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 second in a four-part series, will examine this process on vertical baggers; Part 1 covered these issues on horizontal flow wrappers.
Any impediment that disturbs the even flow of film can distort packages and create leakers; a combination of factors is often to blame. To find the causes of these problems and fix them we recommend a comprehensive analysis of design, condition, and adjustment, beginning with the film roll and following along sequentially as the film is unwound, formed, filled, and sealed.
Film Contact with the Forming Collar
The wing of the forming collar should completely and evenly support the film as the flat web is formed into a tube. Too much, too little, or uneven tension can cause wrinkles and creases.
Troubleshooting Extra Layers of Film at the End Seal (Part 1 of 4): Refining and Eliminating Wrinkles and Creases on Horizontal Flow Wrappers
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.
Case Study: Packaging Material Cost Reduction
Project Goals
The corporate engineering department at a large, international company commenced a project to reduce material costs for a variety of products that are individually packaged on horizontal flow wrappers. Greener Corporation was invited to participate in a series of meetings that defined the project’s initial goals:
- To reduce the cut-off length for each package by reducing the overall seal width, thus allowing the product envelope to remain unchanged.
- To achieve material savings without degrading seal integrity or productivity levels.
- To achieve a project payback period of twelve months or less.