There are two common ways to secure a full pallet and both use elastic film, but they apply it to the load in fundamentally different ways. That difference decides more than the machine: it shapes how the load behaves in transit, what it is protected against, how the end of the line is laid out and what has to be redefined when a format changes.
Two methods, two mechanics
In stretch wrapping, film arrives on a roll, is elongated through a pre-stretch unit and applied in a spiral by a turntable or a rotating arm. The load is held by hoop tension: the force acts horizontally and inwards, and it accumulates as overlapping layers build up turn by turn. At a stretch wrapping station, two variables decide the result, pre-stretch ratio and wrap pattern, and both are stored as a recipe per product and load height.
In stretch hood, gusseted film is cut and sealed into a cover, opened out on four sides, drawn down over the load and released so that it recovers around it. There is no spiral; the load is closed in a single application. Here the force comes from the recovery behaviour of the film rather than from accumulated turns: it acts on all four sides at once and on the top face with a downward component. Stretch hood uses no heat, so the cover seats through the elasticity of the film itself and both heating energy and flame risk leave the equation.
What each one protects against
A spiral wrap leaves the top of the load open unless a separate top sheet is applied, and even then the transition between sheet and side wall is not a closed surface. Rain, wash-down water and dust find their way through that transition and between spiral layers. A stretch hood forms a one-piece cover that includes the top face, giving a closed surface against dust and water without heat.
How much that is worth depends on where the load waits before dispatch. For pallets stored outdoors, carried on open trailers or handled in dusty areas, the closed cover is a protection layer in its own right. For a short trip in a closed trailer followed by covered storage, the same containment becomes a constraint you pay for and never use.
Load geometry and stability
Stretch wrapping tolerates irregular load profiles better: overhanging cases, varying pallet heights and mixed loads can run through the same station, because the film follows the outline of the load. Stretch hood expects pallet dimensions to stay within a defined range, because the cover is sized to the load; outside that range the cover either strains or sits loose.
In return, when the hood can be drawn below the pallet deck, it creates a strong tie between the load and the pallet itself. Stretch wrapping achieves the same tie by taking the first turns around the pallet foot, which is a separate parameter of the wrap recipe. Skip it and the load stands as one unit on top of the pallet without being attached to it, and the two behave separately the moment a forklift moves them.
Pack strength is the quiet limit
Film tension compresses the pack as well as the load. A case in the bottom layer already carries the weight of everything above it; add inward hoop tension and thin corrugated board can buckle at the corners. The behaviour shows up first on light, tall loads with voids inside, and the earliest sign is the pallet corners curving inwards.
At that point, chasing stability with more tension works in reverse: the load does not get tighter, it gets deformed. What restores the lost stability is usually not more film but a force in a different direction. Horizontal strapping presses layers together and stops individual cases from working their way outwards; vertical strapping ties the load to the pallet deck and holds it when handling tries to tip it. Neither replaces film; both work alongside it.
Rate, format changes and consumables
Cycle time behaves differently in the two methods. On a wrapper, time follows load height and the number of turns in the recipe: the taller the load, the longer the wrap. On a hood station the cover is applied in one pass, so cycle time is less sensitive to load height and stays more predictable on a continuously flowing line.
Consumable handling is not the same either. Stretch film is stocked as rolls and roll changes are a routine operation; hood film arrives gusseted and cover sizes are defined per product family. A new pallet size has to be defined in advance on the hood side, while on the wrapping side it is a recipe parameter. Film consumption in both methods varies with load height, the recipe and the stability level you are targeting: a plant-specific figure that should be measured against your current wrapping data rather than estimated.
How a wrong choice comes back
Most load securing failures are seen where the pallet is opened, not where it was wrapped, which is why the cause is usually attributed to the wrong step. The common return paths are these:
- An under-secured load slides or leans in the trailer; the damage appears at unloading and nobody can say which step produced it.
- Over-tensioned film deforms the pack; the bottom layer buckles and the stack goes out of line upwards.
- An open top takes on water in outdoor storage; moisture reduces case strength and labels and print degrade.
- A pallet outside the defined range reaches the hood station and the cover either falls short or sits loose; in both cases the load is not secured.
- With no plan for format changes the station stops at every product change, and the cycle time you gained is handed back in downtime.
Edge cases
The difference between the methods is clearest at the extremes. On tall, light loads with voids, film alone is not enough and the need for compression brings strapping into the picture. On loads with overhang and irregular profiles, wrapping is tolerant and hooding is selective. For pallets that wait outdoors, the hood makes a visible difference; for short trips in closed trailers, that same difference is a paid-for feature nobody uses. Where one line carries many different pallet heights, a wrapper needs no separate setup, while the hood side needs its size families defined in advance.
Questions worth asking on site
- Where does the load wait before dispatch, for how long, and is it under cover?
- Is the trailer closed, and how many times is the pallet handled before delivery?
- How many distinct pallet sizes and load heights are there, and is there overhang?
- Is the strength of the pack known, and has bottom-layer buckling been seen before?
- How many pallets leave per shift, and what does that number become in the peak hour?
- Is damage on arrival recorded, and at which point does it occur?
- Was the current wrap recipe measured, or has it run at the same setting for years?
Common misconceptions
"A stretch hood shrinks with heat." It does not. The cover seats through the recovery of the stretched film; heating energy and flame risk are not part of the application.
"More film means a more stable load." What decides the result is not how much film is used but where it goes and at what tension: pre-stretch ratio and wrap pattern. Plenty of film in the wrong pattern holds less than a little film in the right one.
"Stretch film protects the load against water." A spiral wrap covers the sides, leaves the top open and does not form a closed surface between layers.
"We have to choose one of the two." In some plants both run on the same line, selected by product family.
Making the call
Three questions are usually enough: what does the load face during transport and storage, how variable is the pallet geometry, and what rate does the line end need? Variable load profiles and moderate rates point towards stretch wrapping; outdoor storage, defined pallet sizes and continuous flow point towards stretch hood. When the answers cut across each other, the decision is not a method but a combination: film secures, strapping ties. That is exactly why the four systems in the pallet packaging family can be designed together on one line.