Questions from Calvin: I’ve been told that adding more wraps improves load containment. We also have differing opinions on how to load the film, and some believe it doesn’t matter. Is that true?
Hi Calvin,
Thanks for sending in your questions, I’m glad you took the time to ask. The short answers are yes, adding wraps can increase load containment, and yes, film orientation absolutely matters. Let’s take a closer look at why.
The best place to start is with how the film should be loaded onto the machine. Stretch films typically consist of at least three extruded layers. An additive is mixed in the resin on one of the outside layers that creates a tacky surface, just like that kitchen staple we all know as saran wrap. Importantly, the tack is only present on one surface of the film. Logically, that means orientation serves a specific purpose. If you don’t pay attention to how the film is loaded on the stretch wrap machine, you only have a 50/50 chance of getting it right.
The stretch film must be loaded so the tacky side faces the load. This is critical for several reasons. First, the tack helps the film adhere to the load as it is being wrapped. Second, if the tacky side faces outward, pallets can stick together during storage or transit. This can cause the film to tear when pallets are separated or shift during shipment, compromising load containment and damaging product. In extreme cases, it can even make loading and unloading almost impossible.
Third, because of its elasticity, as the film is stretched during the wrapping process, it will retract by some percentage. When the tacky side faces inward, the layers bond together as they are applied, effectively behaving like a single, thicker layer, multiplying the force that the film applies to the load (Force-to-Load) as it retracts.
Most film cores are marked to indicate the correct orientation when loading onto the machine. However, marking methods vary by manufacturer, so it’s important to verify orientation rather than assume it’s correct. When we characterize stretch film performance in our lab, we always check each roll before testing to ensure proper loading.
Now that we’ve settled the film orientation question, let’s return to your question about adding wraps.
Applying additional layers of stretch film to a load increases the effective thickness of the wrap. This added thickness improves resistance to further stretch during transportation, which enhances load containment. If the film continues to stretch during transit, it allows individual components of the load to move independently, which can result in a load failure.
However, there is a point of diminishing returns, where adding more wraps increases material cost without delivering meaningful improvements in containment. At that stage, you’re simply adding expense without solving the underlying issue.
We study the science of load containment, not only to understand where the “point of diminishing returns” is, but to move beyond it by developing a technology that provides exceptional load containment, while using significantly less stretch film. In many cases, this results in using roughly half the film you would normally, while also improving performance.
The benefits are twofold: reduced cost per pallet and increased production throughput, since fewer wraps are required. This means you can improve efficiency without adding more equipment or people. Truly a win/win. If load containment is an issue for you, we can tailor a solution that will achieve your objective and save you money!.
Thanks for asking!
