Avoiding Freight Damage & Using Empirical Stretch Wrapping Data to Troubleshoot Causes
Everyone hates damage claims. They’re time consuming to process and nobody ever wins. Whether the cost is lost opportunity, actual product damage, squandered time or even just emotional frustration, there’s a cost for everyone. The best solution is avoiding freight damage, but how do you measure for it?
A major contributing factor is the inherent difficulty in measuring and documenting packaging suitability for LTL and over-the-road pallet load shipments. Unlike small parcel carriage, for which standards can be explicitly established, documented and validated using ECT (edge crush test) for corrugated and drop testing, there’s little comparable for pallet loads.
Containment force is one measure that has the potential to change that though. Containment force is an internal standard can be used by shippers to confidently reduce damage in LTL and over the road shipments – and give companies clues to what might have caused any pallet load damage.
What is containment force and how do you measure it?
Let’s start with a definition and some background.
Containment force is the product of stretch film layers and film tension – cumulatively the force which stretch film exerts to hold a pallet load together. It’s a complex, multi-variable product of various factors which include film type, gauge and pre-stretch as well as the way in which the film is applied to a load.
Different loads require different containment force and different areas on some loads may require more or less than other spots on the same load. For general reference a uniform load of typical CPG products in column stacked corrugated boxes which doesn’t overhang a pallet typically requires about 5 to 7 pounds of containment force. Irregular loads such as commonly shipped by distribution centers require about 8 to 12 pounds and heavy, inherently unstable product like shrink wrapped bundles of bottled beverages typically requires about 17 to 20 pounds, as measured with Lantech’s CFT-5 containment force tool. Be aware, though, that there are different types and brands of containment force tools and they are not calibrated to a universal or uniform standard – different tools will report different containment force values if they measure the same load.
Containment force is usually manually measured using a device and process as shown. It’s a deceptively simple process with some potentially important implications. (For more on containment force, check out our on demand webinar on How to Properly Wrap a Pallet.)
Establishing and monitoring
It’s easy to “over” wrap a load. One could use extra containment force on every load for instance, and sleep well knowing that the risk of failing in shipment is low. However, too much containment force carries a number of negative consequences.
First is the fact that excessive containment force can damage freight by crushing them. So there is an upper containment force limit for most loads. Then there are cost and throughput considerations. Increasing containment force means the load must be wrapped with more film layers or more film tension or a combination of each. Adding more film layers increases wrap cycle time and reduces throughput since fewer loads could be processed through the stretch wrapping equipment during an hour, shift or day. Unless, of course, a thicker film applied with more film tension was used. Further, there is an actual bottom line cost of the film – especially when considered across thousands of loads shipped. And beyond the cost, there’s a range of sustainability implications. Using more film than necessary to ensure safe shipment results in excess plastic in landfills.
Since containment force has both upper and lower limits, it’s important to optimize it – and that takes a more than bit of trial and error – it’s a hard and tedious process. Experts can make informed recommendations which are more specific than our general guidelines above, but there’s no alternative to simply test shipping loads as part of an effort to reduce film use. In other words, once a reasonable base line is established, it’s possible to tweak variables on test loads that are then shipped and exposed to extended real world tests to determine suitability.
However, it’s not enough to simply establish and document a containment force standard. Too many variables exist. For instance purchasing may buy different film which seems to have similar specs, but performs differently. Operators on different shifts may have machine set-up preferences, and serial adjustments can result in drifting outputs. Efforts to reduce costs/volume of primary packaging like cases often changes the behavior of palletized loads. And film breaks – one of the dreaded killers of stretch wrapping OEE – typically prompt operators to decrease film tension. That single adjustment often leads to significantly reduced containment force unless effective countermeasures are taken.
Therefore, like any important operational parameter, it’s important to monitor containment force. This requires periodic sampling, and a consistent system for tracking and logging the data.
Referring to the data
Here’s where it gets interesting.
At Lantech we know from experience that proper containment force, the absence of lengthy film tails and loads locked to pallets with rolled film cables (vs. bunched film ropes), stretch wrapping eliminates about half of the un-salables that result in transit from Ineffective stretch wrapping. When a load is wrapped to these standards, it’s safe-to-ship from a stretch wrapping viewpoint and has the highest probability of arriving undamaged at its destination. Bear in mind however, that packaging materials, poor palletizer performance, load- to-pallet fit, and truck loading can also cause in-transit damaged freight. Although effective stretch wrapping can often help overcome deficiencies in these, it can only do so much.
So we think of monitoring containment force as a quality confirmation which ensures that standards are maintained without drifting – in other words, that every load leaves the dock in “safe to ship” condition.
If recorded, this historical data may have another potential use beyond confirming the maintenance of the standard on the production floor. When damaged freight does occur in shipment, the data can be referenced to confirm that a specific load, or a production run of similar loads, was actually wrapped according to a containment force standard which has been demonstrated to be adequate, through trial and error, for safe shipping.
This isn’t only theoretical. One of our innovative customers used containment force data and referred to documentation of containment force checks to support their theory that damaged freight in transit resulted from some other cause rather than inadequate stretch wrapping.
Implications of an empirical standard
Obviously this hasn’t been widely adopted, nor may it ever be. However, it has interesting potential implications as an empirical standard. Perhaps someday shippers could collect this data so that those bearing the risk of loss from in-transit damaged freight could refer to it to assert their claims. Similarly, carriers could use it to challenge claims. And finally, insurance providers could potentially create performance standards and minimum criteria to protect themselves.
And there are obvious benefits beyond reducing the squabbles over claims. Some research indicates that as much as .5% of all CPG products end up in landfills as un-salable due to damaged freight in warehousing, material handling and transit. The best solution is avoiding freight damage, and that’s the real power of containment force awareness, standards and tracking.
A Framework to Improve Outcomes of Avoiding Freight Damage
Every shipper can and should understand containment force, establish standards for their loads to be “safe to ship” and periodically check outgoing loads. Those are the simple but not necessarily easy basic steps which will likely make everyone’s lives simpler – especially the route drivers, depots and DCs that squander time trying to patch up poorly wrapped loads.
Beyond that we suggest awareness and a broader discussion. How heavily might you lean on your containment force data to troubleshoot shipping damage issues? It’s fair to say that nobody could definitively answer that today.
We do know that technology is evolving quickly to automate the collection of containment force data, monitor machine performance for consistency, and even automatically adjust to varying load configurations on the fly – adjusting stretch wrapping parameters and the resulting containment force dynamically.
For too many companies stretch wrapping is a “black box” and the standard is whether there’s a sheen of film on the outside of the load. We know that increases the likelihood of damaged freight in transit – and drives up a host of related costs as a result.
Want to learn more about how to incorporate containment force and other best practices for stretch wrapping into your process? Watch our free, on demand 30 minute webinar on the right way to wrap loads.