Stretch wrapping looks simple: wind film round the pallet until it seems secure. But a pallet that shifts or collapses in transit costs far more than the film saved, and a pallet wrapped with too much film costs money on every load. This guide explains how stretch film holds a load, how pre-stretch reduces film use, and the settings that matter on a wrapping machine.
How stretch wrapping holds a load
Stretch film is stretched as it is applied. As it tries to return to its original length, it pulls the load together, the way a rubber band holds a bundle of pens. The holding force on the load comes from three things:
- How far the film is stretched, which sets how hard each layer pulls;
- How many layers are applied, and where;
- How the film is anchored to the pallet, so the load and the pallet move as one.
Get these right and the load stays square through braking, cornering and forklift handling. Get them wrong and film is either wasted or not doing its job.
Machine film vs hand film
Hand-wrap film is designed to be applied by a person walking round the pallet, who can only stretch it a little. Machine-grade stretch film is made to be stretched much further by a machine, and gives better grip and holding strength. On a pallet wrapping machine, use machine-grade film; hand film on a machine tends to break or under-perform.
Pre-stretch: the biggest lever on film use
A powered pre-stretch carriage stretches the film between two rollers turning at different speeds before it reaches the load. The film goes onto the pallet already elongated, so each metre of film on the roll covers more of the load. That is how a machine with pre-stretch reduces the film used per pallet compared with wrapping by hand, while applying the film evenly.
Pre-stretch also means the holding force comes from the film, not from pulling hard against the load. That matters for light or fragile products that would be crushed by a high wrapping tension.
Wrap patterns: where the film goes
Bottom wraps
Extra wraps at the base, taken slightly down onto the pallet, lock the load to the pallet. Without them, the load can slide off the pallet as one block even if it is well wrapped above.
Body wraps and overlap
As the carriage climbs, each band of film overlaps the one below. Too little overlap leaves weak bands; too much wastes film. The carriage speed sets the overlap.
Top wraps
Extra wraps at the top hold the top layer, which is the most likely to shift. Some loads benefit from a top sheet to keep dust and rain off.
On most wrapping machines the operator sets top and bottom wrap counts, carriage speed and film tension from the control panel, and can store a pattern for each product.
Film tension and fragile loads
Tension is how hard the film pulls as it wraps the load. Too little and the load is loose; too much and cartons are crushed, bottles are pulled over and corners are damaged. Set tension to the weakest part of the load, and use corner boards where cartons are light or the edges are soft.
Turntable, rotary arm and automatic
- Semi-automatic turntable: the pallet turns, the carriage climbs. The operator attaches and cuts the film. Suits warehouses wrapping up to a few dozen pallets a day.
- Rotary arm: the arm moves round a stationary pallet. For loads that are unstable, very heavy or very light and should not spin.
- Automatic: pallets arrive and leave on conveyors, and the machine attaches, wraps, cuts and clamps the film itself. Suits continuous lines, often after a robotic palletizer.
Common stretch wrapping mistakes
- No bottom wraps onto the pallet: the load and the pallet part company.
- Adding more film instead of fixing the settings: more layers at low stretch cost more and often hold less than fewer layers correctly pre-stretched.
- One setting for every product: a pallet of bottled water and a pallet of light cartons need different tension and wrap counts.
- Using hand film on a machine.
- Uneven stacking: film cannot fix a load that overhangs the pallet or leans. Stack square first.
Checking your wrapping works
- Push the load at the top: it should move with the pallet, not on its own.
- Watch loads arriving at customers: shifted or damaged pallets tell you where the pattern is weak.
- Track film use per pallet over a month, before and after a settings change.
Frequently asked questions
Is stretch wrap the same as shrink wrap?
No. Stretch wrap is stretched around a pallet cold and holds the load by its own tension. Shrink wrap is heated so it shrinks tightly around individual products or packs, using a shrink tunnel or heat gun.
How many pallets a day justify a wrapping machine?
For operations wrapping more than about 15 to 20 pallets a day, a wrapper usually pays for itself through less film, faster wrapping, lower labour and fewer damaged loads. Below that, it can still be worth it for load consistency.
Can the machine wrap different pallet heights?
Yes. The film carriage travels to the height of each load, and the start and end heights can be set by the operator for different load sizes.
Load stability starts before the wrapper
Film holds a load together; it cannot make a bad stack good. Cases should be stacked square to the pallet edges with no overhang, heavy items at the bottom, and an interlocking pattern where the case sizes allow it, so each layer ties the layer below. A robotic palletizer repeats the same pattern on every pallet, which is one reason automated lines produce more consistent loads. Get the stack right, then wrap it.
Wrapping machines and film, supported locally
Welpack supplies turntable, rotary-arm and automatic wrappers with powered pre-stretch, installs and commissions them on site, and stocks machine-grade stretch film and spares in Malaysia. See the stretch film wrapping machine range or our palletizing and end-of-line solutions, or ask us to review your wrapping.