Shrink vs Stretch, How to choose the right pallet wrapping method?

Shrink vs Stretch, How to choose the right pallet wrapping method?

 -Shrink Wrap

 -Stretch Hood

-Stretch Wrap

Cost of Ownership:  Properly evaluating the choice of pallet packaging method goes far beyond comparing equipment acquisition costs. Several factors can significantly impact the cost of ownership and, consequently, the return on investment.

Equipment cost:  Spiral stretch-wrapping equipment is available in multiple speed ranges and varying degrees of automation. With prices ranging from below $10,000 for semi-automatic low-speed models to $120,000+ for high-speed rotary-arm or satellite models, there is generally a spiral stretch-wrapping model for every budget.

Heat shrink-hooding equipment also comes in both semi- and fully automatic models. The price range is generally between $50,000 for semi-automatic models (where the operator applies a pre-made shrink bag over the pallet load) and $200,000+ for fully automatic, high-speed models.

The price of stretch-hooding equipment has come down somewhat over the past couple of years due to increased competition and the development of simpler equipment. Prices range from roughly $140,000 for single-format equipment to $200,000+ for multi-format equipment. For high-output facilities, it is important to realize that one single stretch-hood machine can replace multiple spiral stretch-wrap machines due to the higher achievable speeds.

Film cost. If protection and stability are secondary, the film cost for spiral stretch-wrapping a pallet load can be very low because of minimal film thickness and comparatively high pre-stretch percentage. Where protection and stability are critical, however, multiple layers of stretch-wrap film must be applied for stability, and a top-sheet added for protection. This can increase film cost per pallet.

Heat shrink-hooding is significantly more expensive in film cost per pallet than either of the other two methods because of the need to oversize the film hood prior to shrinking. The film cost per pallet for shrink-hooding can easily exceed that of stretch-hooding by 40 percent or more. And substantial energy costs associated with heat shrink-hooding add to the cost-disadvantage of this method.

For stretch-hood film, recent developments have enabled the use of thinner films with significantly higher pre-stretch percentages than was previously possible. This makes stretch-hooding competitive with spiral stretch-wrapping in terms of film cost per pallet load for applications where moderate load stability and protection is required.

However, for low speed/low product value applications where output/product value does not justify investment in fully automatic equipment, stretch hooding is not an option as no semi-automatic models are available.

Labor and maintenance cost: Spiral stretch-wrapping equipment is simple to operate and maintain. Semi-automatic models, in particular, require little training for operation. Maintenance costs, however, tend to the high side because of the quantity of moving components.

The drawback of spiral stretch-wrap equipment is that the relatively low-volume film rolls require frequent replacement at higher throughputs. Some manufacturers do offer an automatic film change option; however, this can be an expensive option, adding complexity to the equipment. Having to replace the film roll at short intervals reduces line availability and increases direct labor costs. The resulting costs from outdoor storage, or measures to protect from the weather, can be significant and must be included in a total cost-of-ownership analysis.

Heat shrink-hooding equipment is moderately maintenance-intensive in comparison with spiral stretch-wrapping and stretch-hooding, as heat shrink-hooding involves more wear parts that require replacement at regular intervals.

With stretch-hooding the film roll can be up to 39-inches in diameter, easily allowing for 10 times longer film change intervals and increasing line availability. The roll change typically taking no more than 10 minutes to return the machine to production. Unlike stretch-wrapping, adjustments to machine settings are rarely necessary, thus ensuring consistent high-quality packaging results. 

Moreover, with fewer wear parts than stretch-wrap machines, stretch-hooding equipment requires little maintenance, and five-sided pallet protection eliminates the need for protective tarps.

Keep in mind, however, that handling equipment (i.e. a forklift) is needed for stretch hood film handling due to the size and weight of the film roll.  Film rolls for stretch wrapping are smaller and lighter and can be handled without equipment. Also, a stretch hood machine is not portable as some low budget stretch wrap machines are. This means that there are costs associated with moving the machine, should this become necessary in the plant.

More info at: www.quickpakinc.com