Why Is the Wrap-round Case Packer So Important?

Views: 5224 Author: Howie SUN Publish Time:
The packer sets the line rating more often than the filler does, because it is rated in cases per hour including film changes and seal cooling.
Key facts at a glance
TypesShrink wrap, wrap-around carton, carton packing, tray
RateMatched to the filler; usually the line bottleneck
Key controlFilm tension, seal temperature, case squareness
MaterialPE film, corrugated board, tray board
Key decisionShrink, carton or tray
Line positionAfter labelling, before palletizing

Shrink, carton or tray: which one fits the market?

Shrink wrap is the cheapest per case and the fastest, and it suits retail where the pack is the display unit. A wrap-around carton gives print area and stack strength for distribution. A tray with shrink is a compromise used where the pack needs both protection and visibility.

When is a carton packer worth the extra cost?

When the market needs print on the case, when the pack has to stack high in a warehouse, or when the product is sold through distribution rather than direct to retail. A carton costs more per case, and it protects the bottles and carries the brand where shrink film cannot.

Pack formatCost per caseWhat it protects
Shrink wrapLowestRetail display, short distribution
Tray + shrinkMiddleStacking and visibility
Wrap-around cartonHigherPrint area and long distribution
Regular slotted cartonHighest board useFragile packs and export

The specification sheet for the Wrap-round Film Shrink Wrapping carries the figures quoted here.

How is film width chosen?

From the pack footprint plus the wrap allowance and the tunnel shrinkage. A film that is too narrow leaves the base exposed; too wide and the pack gets a double layer at the seam. Width is a per-format setting, like the lane guides.

Throughput and change-part lists are on the Carton Packing page rather than in this note.

What is the cost of a wrong case pattern?

It reaches the pallet, the film width and the truck. A pattern that does not fit the pallet footprint wastes cube, and a pattern that does not match the retail unit costs the customer a repack. Pattern is a commercial decision as much as an engineering one.

The same question is worked through from another angle in What Does the Shrink Wrapper Do.

How to read the numbers. Treat the capacity figures as reference ranges from the product specification. A rated pack rate assumes one pack format; changeover and film-roll changes sit outside it, so size on 0.65-0.85.

Frequently asked questions

How many cases per hour is 24,000 BPH?

At 24 bottles per case, 1,000 cases per hour. The packer, the palletizer and the label supply all have to carry that number, and the line rating is the lowest of them.

What film thickness should a shrink pack use?

It follows the pack weight and the transport distance, and it is set with the film supplier. A thinner film saves cost per pack and fails earlier in a long distribution chain.

Can one packer run shrink and carton?

Not without a change of the packing module. Shrink and wrap-around carton are different machines with different board or film paths, so a plant running both normally has two packers.

What case pattern should a new line use?

The pattern that fits the pallet footprint and the retail unit. It is decided with the palletizer and the film width at the same time, because changing it later changes three machines.

Key takeaways
  1. The packer sets the line rating more often than the filler does.
  2. Shrink quality is film tension and seal temperature, and failures appear in transit.
  3. Case pattern is a specification item, not a changeover detail.
  4. Carton buys print and stack strength; shrink buys cost per case.
About the author
Written by the Sunswell engineering team - led by Howie SUN, Founder & CEO, with 14 years in filling and blow-moulding equipment R&D and turnkey project delivery across 71+ countries.
Last reviewed: 2026-08-28 . Reviewed by Sunswell engineering team
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