Heat shrink tunnel specification

Shrink tunnels for sleeve sealer machines

Match the shrink tunnel to the sleeve sealer, film type, pack dimensions and required multipack finish.

Request a sleeve sealer quote Call 01494 623015

Why the shrink tunnel matters

The shrink tunnel is responsible for the final film finish. Even when the sleeve sealer is correctly specified, the pack can look poor if the tunnel aperture, temperature zones, airflow or belt speed are mismatched.

For PE shrink film and multipack applications, tunnel settings need to be matched to pack size, film thickness and required output. Belt speed and spacing affect how long the pack receives heat and how consistently the film shrinks.

Shrink tunnel specification checks

Tunnel aperture width and height clearance.
Belt width, belt speed and product spacing.
Temperature control and airflow direction.
Film type, film thickness and shrink performance.
Cooling, outfeed and operator handling after the tunnel.

Shrink tunnel quote data
Pack dimensions	Finished pack width, height and length through the tunnel.
Film	Material, thickness and shrink characteristics.
Output	Packs per minute, spacing and line speed.

Next comparison pages

Related sleeve sealing pages

Use these pages to narrow the sleeve sealer, shrink tunnel and line integration specification before sending an enquiry.

Sleeve Sealer Machines UK

Compare machine routes for bottles, cans, trays and grouped products.

Automatic Sleeve Sealers UK

Continuous automatic sleeve wrapping with shrink tunnel finishing.

Sleeve Sealer Specification Checklist UK

Prepare the pack data needed for a practical quotation.

Bottle Sleeve Sealers UK

Bottle and beverage multipack wrapping applications.

Shrink Tunnels UK

Heat tunnel considerations for PE shrink film and pack finish.

Sleeve Sealer Line Integration UK

Conveyors, infeed, outfeed and layout planning.

Quick answers

Sleeve sealer FAQs

What does a shrink tunnel do?

A shrink tunnel applies controlled heat so shrink film tightens around the pack after the sleeve has been sealed.

Can one shrink tunnel handle all pack sizes?

Not always. Tunnel aperture, airflow, belt speed and heat capacity must match the largest pack and required output.

What causes poor shrink finish?

Common causes include unsuitable film, incorrect temperature, poor airflow, wrong belt speed or insufficient pack spacing.

Lancing UK specification support

Need help choosing a sleeve sealing machine?

Send product dimensions, bundle layout, film type, target output and available space. Lancing UK will advise on the suitable sleeve sealer, shrink tunnel and conveyor route.

Request a quote Call 01494 623015

High-intent sleeve sealer searches

More ways to find the correct sleeve sealing route

These crawlable pages target the buying phrases customers use when comparing sleeve sealers, shrink tunnels, PE film and multipack wrapping machinery.

Sleeve Sealing Machine UK

Exact sleeve sealing machine guide for UK production lines.

Automatic Sleeve Sealer with Shrink Tunnel UK

Sealer and heat tunnel guidance for multipack wrapping.

Sleeve Sealer Suppliers UK

How to prepare a better quote enquiry for Lancing.

Sleeve Wrapper Machine UK

Alternative sleeve wrapper terminology and buyer route.

Shrink Tunnel Machine UK

Tunnel aperture, dwell time, belt speed and airflow guidance.

Bottled Water Shrink Wrap Machine UK

Bottle pack and beverage multipack wrapping guidance.

Shrink Wrap Machines for Cans UK

Can multipack wrapping and collation details.

Polythene Shrink Wrapping Machine UK

PE film sleeve sealing and transit pack guidance.

Tray Shrink Wrapper UK

Tray pack sleeve sealing and tunnel specification.

Tunnel process control

Heat, airflow, dwell and loading determine the finished sleeve

A shrink tunnel is not selected by aperture alone. The pack must receive controlled and repeatable heat across its surfaces while travelling at a speed and spacing that allow the film to shrink without damaging the product or destabilising the bundle.

Airflow and dwell time

Airflow should distribute heat around the pack rather than concentrating it on one edge. Conveyor speed changes dwell time, but it must be assessed with temperature, fan or airflow settings, pack mass and spacing. The LU-BSPN6040 reference tunnel lists a conveying-speed range of 0–15 metres per minute; this is not a guarantee of pack output or acceptable shrink at every speed.

Tunnel loading and energy

Warm-up, installed load, temperature, airflow, belt speed, heat loss, pack spacing and utilisation all affect energy use. A lightly loaded tunnel and a continuously loaded tunnel may behave differently. The final electrical load and operating duty must be confirmed from the supplied project documentation; it should not be derived from a generic machine description.

Cooling after the heated zone

Allow the film to stabilise before the pack meets close accumulation pressure, a bend, a lift or a pallet. Cooling may use ambient travel or controlled airflow depending on the pack and line. Acceptance should include the condition of the bundle after representative downstream handling.

Shrink tunnel troubleshooting boundaries
Defect	Possible process areas	Safe next check
Loose lower film	Airflow distribution, dwell, pack clearance, belt or support contact.	Compare the approved setup and inspect airflow and pack position without bypassing guards.
Burn holes or film thinning	Excess heat, local airflow, long dwell, sharp edges or unsuitable film.	Stop and inspect the film and pack; restore validated settings and assess edge protection.
Wrinkles on one side	Uneven airflow, off-centre pack, film overlap or unstable collation.	Verify guides, pack centreline, film position and airflow balance.
Product or tray distortion	Heat sensitivity, excessive dwell or temperature, unsupported product.	Review product materials and approved process limits before further trials.
Bundle fails after discharge	Insufficient cooling, tight accumulation or inadequate pack support.	Increase controlled discharge space and retest the cooled pack.

For broad heat-tunnel categories beyond grouped-pack sleeve sealing, use Lancing's specialist heat tunnel machinery page. This site remains focused on tunnels used with sleeve sealers and multipack systems.

Tunnel FAQs

Heat, airflow and cooling questions

Does a higher tunnel temperature always improve shrink?

No. Excess heat can split film, distort products or create uneven shrink. Temperature must be balanced with airflow, dwell, spacing and the film specification.

What is dwell time in a shrink tunnel?

It is the time the pack is exposed to the heated process. Conveyor speed, tunnel length and pack movement influence dwell, while airflow and temperature determine how that exposure acts on the film.

Why does the same setting behave differently during a long run?

Tunnel loading, warm-up state, ambient conditions, product temperature and spacing can change the heat balance. Validate the process under representative sustained conditions.

How can tunnel energy use be estimated?

Use the confirmed installed load and a measured production duty that includes warm-up, operating temperature, airflow, utilisation and shutdown practice. Conveyor speed alone is not enough.

When is extra cooling required?

When the film remains soft at the next transfer, accumulation or handling point. The need depends on film, pack mass, tunnel settings, ambient conditions and downstream pressure.

Can tunnel airflow be adjusted without a trial?

Use only the permitted controls and machine instructions. Any change should be checked against pack quality and product safety, with accepted settings recorded for the SKU.

Control the complete heat process

Assess tunnel loading and the cooled pack, not one hot sample

Provide the production film, bundle and target output so heat, airflow, dwell, spacing and discharge can be validated together.

Request tunnel advice Review PE film

Repeatable tunnel process window

Record the conditions that produced the approved cooled bundle

A temperature set point is not a complete shrink-tunnel recipe. Warm-up state, airflow, conveyor speed, spacing, loading, film and cooling must be recorded together so an accepted result can be reproduced.

Process-window record for each approved pack
Variable	What to record	Why it changes the result
Warm-up state	Ready indication, stabilisation period and any approved start-up checks.	The first packs after start-up may see a different heat balance from a continuously loaded tunnel.
Temperature and airflow	Permitted operator settings and any format-specific fan or damper positions available on the supplied machine.	Heat must reach the relevant film surfaces evenly without local overheating.
Conveyor setting and dwell	Conveyor control value, pack orientation and the corresponding accepted exposure.	The listed LU-BSPN6040 conveying-speed range is a machine reference, not a guarantee of shrink quality at every setting.
Pack spacing and loading	Normal pitch, row arrangement and whether the test represents sustained production.	Large gaps and dense loading can change heat recovery and airflow around the pack.
Product and film	Product temperature, bundle mass, support tray or pad, film supplier, grade, width and thickness.	Thermal mass, geometry and material response affect the required process window.
Cooling and discharge	Cooling method, stabilisation distance, ambient conditions where relevant and downstream pressure.	Film that looks sound at the tunnel exit may move or split while still hot.

Review energy from measured project duty, not a generic assumption

Meaningful energy assessment requires the confirmed installed electrical load, warm-up duration, production temperature, airflow setting, loaded operating time, idle time and shutdown practice. Product mass, spacing and heat loss also affect how the tunnel cycles. These values should come from the final supplied documentation and measured duty; a conveyor-speed range or wrapper power figure cannot be converted into a reliable site energy cost on its own.

Use the cooled pack as the final acceptance point

Inspect the seal and sleeve before the tunnel, the film distribution at the exit and the pack again after cooling. The final check should include any close accumulation, turn, transfer gap, lift or manual handling expected in production. For wider heat-shrink machinery that is not specific to grouped sleeve wrapping, use the Lancing shrink wrapping machinery route rather than duplicating that broader intent here.

Tunnel operating discipline

Hold a stable operating window through real production loading

Pack quality and energy use depend on warm-up, airflow, dwell, spacing, line stops and cooling. A temperature value without those conditions does not define a repeatable tunnel process.

Evidence for the approved tunnel window

Film supplier, grade and thickness
Pack dimensions, weight and support
Tunnel zones or temperature settings
Conveyor speed and actual pack spacing
Warm-up and ready condition
Airflow or fan settings where adjustable
Cooling distance and first handling point
Accepted packs, rejects and defect location

Where a result changes, compare the current production condition with this evidence before increasing heat. Obstructed airflow, damaged curtains, wide spacing, product changes or a different film may be responsible.

Open the energy and airflow guide

Tunnel process questions

Questions about operating windows, production loading and cooling

A shrink tunnel should be approved as a repeatable process window for the real film, bundle and line loading rather than as one temperature setting.

What is the correct shrink-tunnel setting for a new pack?

There is no universal setting; establish a controlled operating window using the actual PE film, bundle geometry, conveyor loading and finished-pack acceptance standard.

Start from the machine and film supplier guidance, then change one variable at a time while recording temperature, conveyor speed, airflow adjustments, pack spacing and cooling. Approve the cooled pack across repeated production, not one hot sample.

Use the tunnel energy and airflow guide.

Why can a tunnel perform well when lightly loaded but poorly at production rate?

Production loading changes the heat demand, airflow path, pack spacing and recovery time, so a setting that works for isolated packs may not remain stable during continuous running.

Test the expected pack gap and sustained load after full warm-up. Include stop and restart conditions and observe whether shrink quality changes across the belt or over time. The accepted rate should be based on stable cooled bundles under representative loading.

Read what affects accepted output.

When should extra cooling or discharge length be considered?

Consider additional cooling or supported discharge when the film remains soft at the first transfer, packs accumulate hot, labels or products are heat-sensitive, or handling loads disturb the bundle before it stabilises.

Assess the real ambient conditions, line speed, bundle mass, conveyor surface, downstream gap and longest blocked period. The requirement should be demonstrated during trials rather than assigned from a generic cooling time.

Use the cooled-bundle acceptance checks.

How should tunnel warm-up and restart be checked?

Define the conditions that indicate the tunnel is ready, then verify the first packs after start-up, a short stop and a longer interruption against the same acceptance standard.

Record displayed values, elapsed warm-up, fan and conveyor condition, pack spacing and any temporary setting change. A line that produces acceptable packs only after undocumented operator adjustment is not yet a repeatable approved process.

Review the FAT and trial guide.

Provide the film, pack, expected loading pattern, current tunnel settings and cooled-pack evidence for a process review.

Send application details

Tunnel terminology and selection

A shrink tunnel machine is specified by the pack, film and production duty

Heat tunnel, shrink tunnel and PE film tunnel may describe the same process stage, but tunnel aperture alone does not establish suitability. The accepted result depends on heat input, airflow distribution, conveyor support, dwell time, pack spacing, loading density and cooling after discharge.

Tunnel evidence to record during a representative trial
Area	Record	Why it matters
Starting condition	Warm-up state and stabilisation time before the run.	A cold start and a stable production condition can produce different shrink behaviour.
Pack loading	Normal spacing, bundle size, weight and packs per minute.	Tunnel heat load changes with product density and gaps.
Operating settings	Temperature zones, airflow settings and conveyor speed.	Accepted settings must be repeatable for each format.
Finished result	Seal condition, wrinkles, holes, loose areas, distortion and pack stability.	Appearance alone is insufficient if the bundle fails during handling.
Cooling and discharge	Cooling distance, accumulation pressure and handling point.	Hot film can stretch or tear before it stabilises.

Use the energy and airflow guide for the variables that affect heat use, and the quality acceptance guide to define what an approved bundle must withstand.

Tunnel process window

Use the shrink tunnel to finish an approved film and pack route

A shrink tunnel should complete the PE film shrink without overheating the film, distorting the pack, slowing discharge or making warm bundles fail during handling. Temperature, airflow, belt speed, aperture loading and pack spacing must be set around the actual product and film.

If shrink is loose or uneven, the cause may be film width, seal position, pack shape, tunnel loading, airflow, dwell or cooling. A tunnel adjustment is useful only when it solves the correct process variable without creating another defect.

Use tunnel energy and airflow guidance before changing settings.
Use running-cost factors for warm-up, idle and reject considerations.
Use bundle acceptance guidance to define the cooled standard.

Tunnel and air release

Link tunnel settings to film air escape and cooled pack evidence

A shrink tunnel recipe should be approved against the cooled bundle, not only against the pack as it leaves the hot zone. Air escape, perforation, film width, pack spacing and tunnel loading all affect the final result.