Troubleshooting hub
Select the symptom that appears first and follow the relevant feed, cut, placement or tunnel checks.
Open guidance →Fault isolation
How Do You Identify Where a Shrink Sleeve Defect Starts?
Find the first process point where the pack differs from an approved sample. Check the sleeve reel and feed path, then the cut sleeve, the pre-tunnel application, the tunnel exit and finally the cooled pack. Record the condition before changing settings. This staged method separates causes that can look similar on the finished container.
ReelCutPlacementTunnelCooled pack
Answer in brief
Inspect the line in sequence and find the first point that differs from an approved sample.
Start with the reel and feed path, then inspect the cut sleeve, the pre-tunnel application, the tunnel exit and the cooled pack. The first unacceptable stage narrows the cause: film tracking or cutting, container presentation and placement, or heat transfer and post-tunnel handling. Record the condition before changing settings.
Retain photographs and physical samples from each stage, together with reel identity, artwork revision, machine settings, tunnel recipe, pack spacing and the time the fault occurred. Change one controlled variable at a time and compare it with the approved condition; otherwise several adjustments can hide the original source without producing a repeatable correction.
Information to provide Lancing
- Container and closure samples with controlled dimensions
- Sleeve material, lay-flat, cut length, seam and artwork revision
- Required finished position, perforation and barcode details
- Target good output, batch pattern and format range
- Existing line layout, conveyor, utilities and adjacent machinery
Decision framework
Defect isolation sequence
Use this as a project-control framework. Final suitability depends on the actual container, closure, sleeve and production condition.
Check pointIf acceptableIf not acceptable
Sleeve reel and feedProceed to registration and cut checkConfirm material, tracking, static, tension and splice condition
Unshrunk cut sleeveProceed to application checkInvestigate registration, cut timing, blade and feed stability
Pre-tunnel packProceed to tunnel and cooling checkInvestigate height, twist, transfer, spacing and container handling
Tunnel exitAllow defined cooling before final acceptanceCheck gross shrink distribution, water marks, burn or pack movement
Cooled finished packRelease against agreed criteriaCompare recipe, shrink curve, container and sleeve batch
Buyer question
Which checks separate reel-feed faults from cutter faults?
Inspect reel identity, unwind direction, web tracking, tension, static, splices and the registration signal before blaming the cutter. Then examine unshrunk cut pieces for length repeat, edge condition and print position. If the incoming film position is moving, the cutter may be responding correctly to an unstable feed rather than creating the original error.
Keep a sequence of unshrunk samples rather than only one finished pack.
Buyer question
How can you distinguish placement faults from tunnel faults?
Measure the sleeve immediately before tunnel entry. If height, twist, seam orientation or cut edge is already wrong, investigate application and handling. If pre-tunnel placement is controlled but the cooled sleeve pulls, wrinkles or distorts, investigate film shrink behaviour, container geometry, tunnel distribution, speed and cooling. A tunnel cannot reliably correct an uncontrolled starting position.
Use fixed container datums so the comparison is repeatable.
Buyer question
Why should only one process variable be changed at a time?
Changing several settings together hides which action affected the result and can introduce a second defect. A controlled investigation records the baseline, changes one variable, runs enough packs to observe the response and then decides whether to retain or reverse the adjustment. This is slower than random adjustment for one pack but faster for establishing a repeatable production setting.
Protect the approved recipe and record every temporary trial change.
Buyer question
What evidence should be kept when a recurring defect is investigated?
Keep good and faulty packs, pre-tunnel samples, reel and artwork references, container and closure batches, applicator settings, sensor and fault logs, tunnel recipe, line speed, stop and restart events and photographs or video of the first failed stage. Without that context, a later investigation may compare different materials or production conditions as though they were the same fault.
Use the quality-control guide to define the record.
Continue the decision
Related sleeve applicator guidance
Use the connected pages to turn the answer into a controlled machine and trial brief.
Quality inspection
Define stage checks, cooled-pack acceptance and retained evidence that can be repeated in production.
Open guidance →Shrink tunnel settings
Record the complete process window, including pack spacing, conveyor condition, cooling and drying.
Open guidance →Application review
Send the actual pack, sleeve and line condition.
Lancing can review the container, closure, sleeve reel, required position, shrink route, output condition and integration boundary before recommending an applicator configuration or sample trial.