A paper cup carton compression test should evaluate the packaged product, not only the force reached by the outer carton. Cups at corners, top layers or closure zones may experience different loads. Mapping their positions before the test allows internal rim, sidewall and stack damage to be traced after opening.
A qualified packaging laboratory must select and perform the applicable compression procedure. This guide supports specimen preparation and damage mapping; it does not provide test loads, certification rules or a substitute for the complete current procedure.
Diagnostic decision table
| Test-planning question | Evidence to preserve | Decision risk |
|---|---|---|
| Which pack is being tested? | Cup, bag, carton, closure and pallet identity | A carton result covers other pack builds |
| Where did damage occur? | Layer, carton and orientation map | Loose damaged cups lose their history |
| What load applies? | Laboratory procedure and shipment inputs | A copied force fits every route |
| Was the product acceptable afterward? | Predefined cup and pack inspections | Outer carton appearance is enough |
Freeze the packaged-product specification
Record cup count and construction, stack arrangement, bag or sleeve, carton board, dimensions, closure and any internal supports. For palletized configurations, document layer pattern, pallet and restraint. Photograph assembly stages and identify every deliberate departure from routine production.
Use representative components with lot identity. Do not reinforce laboratory cartons with extra tape or corner pieces unless those items belong to the configuration being evaluated. A design alternative should receive its own identifier so its result cannot be mistaken for approval of the production baseline.
Create a position map before closing
Assign carton, layer, stack and orientation codes to the cup groups. Use labels or separators that do not materially alter load transfer. Retain a diagram showing where each group was placed. If individual cup identity is unnecessary, preserve at least the smallest location group needed to investigate the anticipated damage pattern.
Inspect representative cups and packs before testing using the agreed criteria. Keep companion baseline samples where appropriate. Do not open and rearrange the test carton after the initial record unless the laboratory procedure permits it and the change is documented. The pre-test map must still match the specimen actually loaded.
Let the laboratory select the procedure and load
Provide the distribution configuration, stack information and pack properties to a qualified laboratory. ISTA notes that compression calculations in its procedures depend on factors such as stack arrangement and packaged-product weight. The responsible laboratory must use the complete current method rather than a formula copied from a summary page.
Record the procedure, version, orientation, platen setup, force or conditioning sequence and any deviations. Confirm whether the test is screening, comparison, simulation or certification. A stronger-than-planned trial may be useful for development but should not be represented as the originally specified certification result.
Inspect internal damage by mapped position
At the permitted opening point, preserve the carton and internal arrangement before removing cups. Photograph bulging, crushing, closure movement and stack displacement. Remove groups in mapped order and record rim deformation, sidewall creases, base damage, blocking and changes in stack behavior.
Use the predefined functional checks and record denominators. An intact outer carton does not prove the cups are acceptable, while a cosmetic carton mark does not automatically establish cup damage. Compare position patterns with load paths and companion controls before naming a packaging component as the cause.
Verify a design change with new specimens
Review concentrated damage with the packaging engineer and equipment suppliers. An authorized change to carton construction, stack count, bag tension or internal support creates a new packaged-product configuration. Prepare new representative specimens and repeat the agreed comparison rather than rebuilding the already tested carton.
Document the scope of release and conditions that trigger retesting. Send HANNAI the pack specification, location maps and cup damage photographs when evaluating packing-line effects. This evidence helps distinguish packaging compression from upstream forming defects without claiming that one laboratory result guarantees every shipment.
Related equipment and next checks
Review the paper cup packing equipment and the related guide to packed-product vibration trial planning. The Engineering Notes archive connects these checks with wider machine planning.
Technical reference
- ISTA: compression depends on stack and packaged-product conditions — general reference; confirm applicability to the installed equipment.
- ISTA: select test procedures for the actual distribution system — general reference; confirm applicability to the installed equipment.
Frequently asked questions
Can the laboratory use a force copied from an online example?
Use the complete applicable procedure and qualified laboratory calculation.
Does an undamaged carton prove all cups passed?
No. Inspect the mapped internal product using agreed criteria.
Can one tested carton represent every packaging revision?
No. Review changes in components, counts, closure and arrangement.
Should cups be removed without recording location?
Preserve the position map so damage can be related to the pack load path.
Review the evidence with HANNAI
Send your machine model, component identification and the observations described in this guide. Include the drawing or material reference and any before-and-after measurements so the required next check can be identified.