Heat tunnel engineering
The conveyor must support the real wrapped pack through entry, heating, discharge and cooling while providing the required speed range, load distribution and interaction with airflow.
Direct answer
A shrink tunnel conveyor is not selected by width alone. Confirm the wrapped product footprint, weight distribution, base stability, film contact, allowable surface marking, actual speed range, tunnel loading, transfer levels and downstream cooling. The chosen support must carry the product without snagging, tipping or distorting while allowing the required heat and airflow to reach the film.
Use the area that actually contacts the conveyor after film presentation. Feet, recesses, curved bases, trays, loose fins and unstable groups can create point loads or snagging. Include the least stable orientation in trials.
A published conveyor load is a preliminary limit. A small contact area or concentrated mass may behave differently from a broad stable pack of the same weight. Confirm the proposed conveyor and transfers with the machine supplier.
For a fixed heated length, conveyor speed influences exposure time, but film response also depends on airflow, product load, temperature, spacing and recovery. Record actual accepted speed with the production pack rather than relying only on the drive setting.
Level, gap, friction and guide transitions can move a wrapped product before or after shrinking. Warm film needs support and cooling before close accumulation, compression or a sharp transfer.
Verified model references
The values below are already published on this website. They do not replace a product and film trial.
| Model/page | Published conveyor or tunnel data | Application use |
|---|---|---|
| LU-BSP6040 heat tunnel | 0–15 m/min conveying speed; 1800 × 600 × 400 mm furnace; maximum 50 kg conveyor load | Screen wrapped dimensions, required dwell, distributed load and line layout before trials |
| LU-SPL6 wrapping route | 600 mm conveyor belt; 1800 × 750 × 400 mm tunnel; POF/PE film reference | Check pack support, guide clearance, film route, cooling and sustained accepted output |
| LU-SPL4 bottle wrapping system | Maximum package 400 × 120 × 330 mm; payload up to 20 kg; 0–6 packs/min | Assess bottle-group stability, pack weight, transfers, film and cooling around the automatic bundle route |
Buyer questions
Not necessarily. Guides, structure, film movement, required side clearance and product stability can reduce the practical envelope. Check the wrapped pack, including loose film and expected movement, against the final machine configuration rather than treating a published belt width as guaranteed usable clearance.
Total weight, distribution and contact area all matter. A concentrated load, narrow feet or an unstable centre of gravity may need a different support or transfer arrangement from a broad pack of the same mass. Confirm the proposed duty against the machine’s published load and final specification.
Contact pattern, heat, film tension, product weight and movement can produce visible marks or distortion. Include the required display face and base finish in the acceptance standard, then inspect after full cooling rather than only at tunnel discharge.
Common causes include an unstable base, transfer gap, height difference, excessive guide pressure, loose film contacting the structure or product pitch that creates pressure from behind. Correct the presentation and transfer before using heat settings to treat a mechanical movement problem.
For a fixed heated length, increasing actual conveyor speed generally reduces time in the heated zone and decreasing it increases exposure. Effective shrink still depends on airflow, temperature, film, product thermal load and spacing. Record actual speed and accepted pack evidence together.
Test the smallest, largest, heaviest and least stable packs; normal pitch; highest tunnel loading; a production gap and restart; transfer into and out of the tunnel; full cooling; and the next handling operation. Record product movement, film marking, pack quality and rejected-pack reasons.
Lancing Ltd publishes this guide for preliminary conveyor and tunnel selection. The final duty must be confirmed against the supplied machine documentation, production film, real pack and site layout. Send the pack and line information.
Conveyor review
Include wrapped footprint, weight distribution, product stability, film, output, transfers and downstream cooling.