Question from Candice: How do we create a universal load containment standard to use across multiple SKUs and multiple facilities to ensure brand consistency and safety in transport?
Hi Candice,
Thank you for sending in your question! I appreciate that you recognize the importance of selecting the right load containment standard and that you have the vision to apply it consistently across your entire platform. However, as you’ve discovered, this is no small challenge.
Think of a one-size-fits-all sweater. If you’re of average size, it works well, but if you’re either larger or smaller, not so much. It is no different with load containment. That being said, with a thoughtful approach and a willingness to accept some degree of compromise, I believe you can achieve your goal. To get there, we need a clear roadmap to follow, using science as our compass.
There are many factors that affect load containment. To achieve the process capability required for a single, universal load containment standard, each factor must be controlled as much as is practical. Process variation, (the variance that is outside of practical control), is where the compromise in load containment comes into play.
Quickly reviewing some of the obvious factors that affect load containment, which cannot always be tightly controlled, we have pallet quality (important because you wouldn’t build the Empire State Building on quicksand), optimized stacking patterns, which must provide an even distribution of weight from top to bottom, the design and construction of the primary and secondary packaging, which must withstand the weight of the load, and finally, machine condition, because optimal load containment isn’t possible if the equipment can’t perform consistently.
Once these elements have been optimized and their limitations acknowledged, we can move on to the next phase in pursuit of a practical, scalable load containment solution. The challenge then becomes defining a wrap configuration or “recipe,” that will contain the load without crushing it. With a wide range of SKUs, this isn’t easy, but it is absolutely achievable.
Loads are comprised of individual components such as boxes, bags, pails, etc. The first objective of load containment is to unitize those components, so they respond to transportation forces as a single mass. If the individual components of the load are allowed to move independently, then load failures are just around the corner.
However, if you apply enough tension to properly unitize the load as it is being wrapped, the force to load (the amount of force the film applies around the load) may crush, or deform, the corners of the packaging. The obvious answer would be to reduce the applied tension and add more wraps. While that sounds like a logical solution, like most things in life, it’s not that simple.
As stretch film is stretched, its elasticity is reduced by some percentage while its resistance to puncture and tear is also proportionally reduced. If you wrap with insufficient stretch to keep the force-to-load from crushing contents, there will be significant elasticity remaining in the film. After the load has been wrapped, because it is still in an elastic state, the film will retract by some percentage, much like a stretched rubber band returns to its original size once you release it. Over time, the force-to-load exerted on the contents will gradually increase. Adding more wraps compounds this effect. A load may look perfectly fine immediately after wrapping, only to be crushed 48 hours later.
If you continue reducing the wrap tension to prevent crushing from happening, the remaining elasticity provides little resistance to continued stretch during transit. In other words, during transportation, the forces applied to the load will cause continued elongation of the film, allowing individual component movement within the load and ultimately leading to load failures. This illustrates the delicate balancing act that’s required to optimize load containment.
We’ve developed technology that, when applied properly, allows a single load containment standard to span multiple SKUs and facilities. The key is stretching the film enough so it becomes stiff and resists any additional stretch. This can be achieved through applied tension, pre-stretching the film before application, or a combination of both.
We target between 275% and 300% total stretch, achieved primarily through pre-stretch. This provides the unitizing force necessary to properly contain the load while leaving virtually no residual elasticity in the film after wrapping. As a result, the film neither retracts to crush the load nor continues stretching to allow independent movement of individual components.
Achieving this level of performance is difficult, if not impossible, with conventional stretch film. As traditional films are stretched, they become brittle and prone to web breaks. These breaks can be highly disruptive to production, and the common countermeasures operators use to reduce them typically involve lowering tension and applying more film, which increases cost while reducing load containment.
To overcome this limitation, we incorporate reinforcement filaments into the full web of stretch film. This allows the high levels of stretch required for maximum performance without web breaks, delivering superior load containment with fewer compromises. We have proven that one load containment standard across a broad range of SKUs and throughout multiple facilities is not only doable but may even outperform what you have in place currently.
We strive to bring solutions to the challenges that have long been accepted in the industry by thinking outside the box and applying basic physics.
Thanks for asking!
