Welcome to the latest Kenray Blog looking at the 6 Key Principles of forming, filling & sealing quality packages on VFFS Packaging machines. We are delighted to be joined by our Corporate Partners Greener Corporation.
1. Product Flow
Let’s start at the beginning with Product flow. Problems occur most often when the product is:
• large in relation to bag size
• inconsistent in size or shape
• oddly shaped
• or with rough outer surfaces
Bottlenecks occur when product strings out as it moves from the inlet cone into the narrower confines of the forming tube. In extreme cases individual product “charges” can bridge together. These product flow issues slow down production speeds, create blockages, and cause leakages when product gets trapped in the seal.
On forming tubes with integral cones, the product dose is slightly staggered, so it passes through the bottleneck faster and stays more compact.
2. Forming Set Design
Forming sets should be designed according to your product, package design, machinery, and film specifications. Make sure that this optimal design is accurately and consistently replicated when you order replacement parts or specify formers for multiple machines, lines, or locations.
3. Roller Position
Machine adjustments are also critical for producing quality packages. Misaligned film rollers prevent the film from making full contact with the forming shoulder, causing wrinkles, creases, and package distortions that reduce shelf appeal and cause seal problems.
4. Film Drive
Poor package quality is caused by film drive issues such as belt adjustment and forming tube alignment
5. Former Wear and Damage
Wear or damage to the former lip or shoulder can also distort the package.
By fine-tuning your forming and filling operations you will improve both package appearance and seal quality.
The end seals on packages produced by vertical baggers typically vary in thickness. Most have a lap or a fin seal, and some are designed with gussets. Unintended wrinkles or pleats may, at times, be unavoidable. Leakages, when they occur, often follow channels at the intersections between two and multiple layers of film and at the corners.
Sealing jaws must transfer enough pressure and heat to seal across these channels without crushing, cutting, or distorting the end seal.
In order to create uniform sealing pressure, the serration profile of your sealing jaws should be designed according to your package specifications, machinery, and running conditions.
Sealing jaw temperatures are often increased to improve seal quality, but this can create hot spots that overheat and distort the package.
Jaws manufactured from Dura-Therm material provide more responsive, consistent heat transfer across the package to help seal off-channel leakages without overheating the film.
• Wear and Damage
Jaws that are worn, damaged or contaminated with products also create inconsistent pressure and heat transfer that cause seal problems.
To learn more about forming and filling on vertical packaging machines, contact Kenray Forming on +44 (0)1530 400 100. We can also offer remote training and consultancy to help you optimize your packaging operations.
For further information, please contact Mark Evans on +44 (0) 1530 400 100 or email firstname.lastname@example.org