When it comes to shipping, one of the most common elements is stretch wrap. This film is used to wrap items on pallets, securing them to themselves and the pallet during the shipping process or for storage purposes, reducing product damage and loss, as well as discouraging pallet tampering and pilferage.
Typically, stretch wrap is used to hold boxes together on a pallet for transportation. But, it can also be used to protect products during both transportation and storage. Stretch wrap comes in a variety of sizes (or gauges); is manufactured in different ways; and is applied differently (hand stretch wrap versus machine stretch wrap). It is also offered in a many different specialty wraps.
The two most commonly used types of stretch wrap are cast stretch wrap and blown stretch wrap.
Here are the major differences between the two, as well as the major advantages of each.
Cast stretch wrap is manufactured using a cast extrusion process. The cast extrusion process is a continuous process by which a thermoplastic material is melted and extruded through a flat die onto a chill roll, where it is quenched and re-solidified. Cast stretch film has excellent clarity, requires less force to stretch and an increased tear resistance, unwinds quietly from machines, and offers a superior cling. There are both machine grade and hand grade cast stretch film available.
Blown stretch wrap is manufactured using the blown extrusion process. The melted plastic material is extruded through a die, usually vertically, to form a thin walled tube. Air is introduced via a hole in the center of the die like a balloon. On top of the tube an air ring blows onto the stretch film to cool it as it comes off the line. This process allows blown wrap to be tougher and more resilient than cast stretch wrap. Blown stretch film typically has a greater load containment force.
No matter whether you use cast or blown stretch wrap or whether you employ a manual system of application or stretch wrap equipment, using a stretch film to secure your pallets for shipment offers a host of advantages.
The SaranTM wrap that you use at home is approximately the same as 40 gauge stretch wrap. That gauge of stretch wrap could secure around 1,000 pounds on a pallet load.
The Ziploc(R) bag that you use at home is approximately the same as 150 to 200 gauge stretch wrap. That gauge of stretch wrap could secure up to a 3,500 pound pallet load.
Traditionally, manufacturers made a standard gauged stretch film for customers to use that was affordable and worked well to secure a variety of loads. That standard came between 60 gauge and 150 gauge, able to secure between 1,500 and 3,500 pound loads. Over the years, 80 gauge stretch film became the industry standard and became known as being the most versatile thickness on the market.
The most common options on the market now include:
For years, before petroleum prices got out of hand, standard or true gauged wrap was what manufacturers produced; today, you have to specifically request it. This standard stretch wrap offers a great amount of stretch, tear resistance, and strength. However, using standard hand stretch also comes with unnecessary waste because users cannot reach the maximum stretch potential of the wrap. Better, more economical options are found in the other types versus this traditional wrap.
This film is typically called different things by manufacturers, but, in general, is considered an equivalent film. It typically comes in a 57, 60, or 63 gauge. The main differences between this stretch wrap and traditional wrap is the thickness of the material and the amount of stretch potential. A micron stretch wrap is often stiffer and will not stretch as much as standard wrap. However, the micron stretch wrap is more affordable, stronger, and often promotes less waste.
Hybrid stretch wrap is also considered an equivalent stretch wrap and replaces lower gauged wraps, typically coming in a 47, 51, or a 53 gauge. It is stiffer and has less tear resistance than the micron film. The major benefits include a lower purchase cost, lighter rolls, less physical exertion when applying, and a stronger wrap. The multilayers make the film stronger than a true gauged film of the same thickness, but does not come in higher gauges.
A great green option for users wrapping lighter loads is pre-stretched stretch wrap which is a true 80 gauge film that has already been stretched up to 90% of its potential before being placed on the roll and shipped to the customer. This makes it an affordable film that promotes less waste because users can reach the full stretch potential when applying the film with little physical exertion, equaling less film usage for maximum protection. Pre-stretched wrap is typically recommended for loads no heavier than 1,200 lbs.
Occasionally you’ll hear about the potential to save money by “down-gauging” your stretch film. This is something that should only be undertaken with a professional because every situation is different. Lowering your gauge may cause you to use more wrap, meaning you'll see no savings and you may actually be putting your pallet loads at risk for damage. Truthfully, there is the potential that you might get more benefit and realize more cost savings by actually increasing the gauge.
It’s important to remember that there are many hidden costs associated with down-gauging, which is why we only recommend you undertaking the process with a packaging professional.
Lighter gauge stretch films are more likely to experience breaks, either from machine variations, edge damage during handling, or defects. Will you have to spend more in labor costs because you have to keep starting the wrapping process over due to breakage? Will you need to have multiple wraps to cover those film nicks and ensure the load integrity? All costs have to be considered.
Thorough testing should be completed before considering changing to a lower gauge: weight, pallet configuration, and packaging environment must play a role in considering a lower gauge wrap. Loads can change over time which will affect your packaging, either in storage or during shipping. If your pallets and, ultimately your products, can't be protected, then down gauging hasn't saved a thing.
If you are ready to start looking into including stretch wrap equipment at your facility, IPS Packaging has put together an eBook with all the essential information you will need to make the most informed decision.
Stretch wrap machines save money through material and labor savings, as well as improve load stability and decrease damage rates. And if money is the biggest concern, know that when correctly utilized, most equipment pays for itself in less than a year.