Flute profiles, walls and what they carry.
Export cartons are specified by flute profile and wall count before anything else. The flute sets cushioning and stacking behaviour; the wall count sets thickness and compression strength.
| Flute | Flute height | Flutes per metre | Character | Use in cosmetic packaging shipments |
|---|---|---|---|---|
| A | 4.5-5 mm | ~115 | Best cushioning, lowest flat-crush | Fragile glass, heavy jars — usually as one wall of a double-wall board |
| C | 3.5-4 mm | ~125 | General-purpose balance of cushioning and stacking | Standard export outer for plastic components |
| B | 2.5-3 mm | ~154 | Highest flat-crush strength; flattest print surface | Retail-ready outers, inner boxes, die-cut dividers |
| E | 1.1-2 mm | ~286 | Smooth surface for fine print; little cushioning | Folding cartons and gift boxes — not shipping cases |
| Board | Layers / flutes | Thickness | Typical duty |
|---|---|---|---|
| E-flute (micro) | 3 layers, one E flute | 1.5-2 mm | Printed folding cartons, sleeves |
| Single-wall | 3 layers, one flute (B or C) | 3-5 mm | Light plastic components, caps, pumps |
| Double-wall | 5 layers, two flutes (A/B, B/C, E/B) | 6-8 mm | Glass bottles, heavy jars, any stack over 1.5 m — our default for glass |
| Triple-wall | 7 layers, three flutes (A/B/A, A/C/B) | 8-12 mm | Pallet-size cases, very heavy or long-haul multi-handling shipments |
Flute shape matters as well as height: U-flutes bond better and recover from crushing; V-flutes are stiffer but bond poorly and do not recover; UV-flutes are the usual compromise. Offset-printed liners that are laminated to board after printing cost about 10% of box-compression strength compared with direct flexo printing — worth knowing when a retail-ready outer is also the shipping case.
Grammage, thickness and burst — a worked selection.
A board specification reads as liner weight + flute + inner-liner grade. A 250 g liner with E-flute over a C-grade inner liner is written "250 g E/C"; the inner-liner grades weigh about 126 g/m² (B) and 115 g/m² (C). The table gives the resulting board weight and burst strength for common combinations.
| Specification | Board thickness | Board weight | Burst strength |
|---|---|---|---|
| 250 g E-flute, C inner | 1.9 mm | 545 g/m² | 8.2 kgf/cm² |
| 250 g E-flute, B inner | 1.9 mm | 575 g/m² | 10.0 kgf/cm² |
| 250 g B-flute, B inner | 3.0 mm | 555 g/m² | 8.4 kgf/cm² |
| 300 g E-flute, C inner | 2.0 mm | 590 g/m² | 9.8 kgf/cm² |
| 300 g E-flute, B inner | 2.0 mm | 600 g/m² | 11.5 kgf/cm² |
| 300 g B-flute, B inner | 3.0 mm | 590 g/m² | 11.0 kgf/cm² |
| 250 g double E-flute, C inner | 3.4 mm | 860 g/m² | 10.5 kgf/cm² |
| 250 g double E-flute, B inner | 3.4 mm | 875 g/m² | 11.0 kgf/cm² |
| 250 g E/B-flute, C inner | 4.1 mm | 820 g/m² | 9.5 kgf/cm² |
| 300 g double E-flute, B inner | 3.5 mm | 885 g/m² | 13.7 kgf/cm² |
| 300 g E/B-flute, B inner | 4.2 mm | 885 g/m² | 11.5 kgf/cm² |
The four strength measures that go on a carton specification: edge crush (ECT — load along the flutes, the number that predicts stacking), burst (Mullen — the hydraulic burst value above), puncture (a pyramid striker at 250-1,000 N), and box compression (BCT — the whole carton under a platen, with no crushing). A fifth, folding endurance (150 × 15 mm strip folded at 135° to failure), is specified for cartons that will be opened and closed on a retail floor. For a stacked pallet the BCT must cover the load on the bottom carton with a safety factor of 3-5 for sea freight.
FEFCO styles and what a carton has to pass.
| FEFCO series | Style | Where we use it |
|---|---|---|
| 02xx (0201 regular slotted) | Slotted case, one-piece, glued or stitched, tape-closed | The standard export shipping case for bottles, jars, pumps |
| 03xx (0300 series) | Telescope box — separate lid and base | Heavy glass, display sets, where a full-depth lid adds crush protection |
| 04xx (0427 and similar) | Folder / die-cut mailer, one piece, self-locking | Sample shipments, e-commerce inners, retail-ready trays |
| Check | Acceptance threshold |
|---|---|
| Staple pitch | Single row ≤60 mm; double row ≤80 mm; evenly spaced; joint tab ≥5 mm; score-line to edge 13 ± 7 mm |
| Corner gaps | ≤5 mm per corner; box square at 90° |
| Print position | ±1 cm; no splice in outer liner, ≤2 in inner liner |
| Delamination | ≤20 cm² per m²; edge lift on laminated board ≤2 mm |
| Moisture content | ≤8% (dried at 100-105°C to constant weight) |
| Print rub resistance | 500 g weight, 2-4 layers of white cloth in 95% ethanol, 50 strokes over ~30 mm — no board exposed, no colour change |
| Fold endurance | 180° fold at score line ×5, no cracking; edge tear ≤1 cm |
These are the checks the OQC gate on our QC standards applies to the outer carton, in addition to the tests on the components inside it.
Tape adhesives and the H-seal.
| Adhesive | Strengths | Weaknesses | Use |
|---|---|---|---|
| Acrylic | Ages well, weather- and damp-resistant, high shear at temperature | Lower initial tack; weaker on non-polar surfaces (PE, PP); higher cost | Sea freight and long storage — our default for export cartons |
| Natural rubber | High initial tack, sticks to almost any surface, good hot shear | Poor ageing and humidity resistance; cost | Short domestic transit, recycled or dusty board |
| Synthetic rubber (hot-melt) | Low cost, bonds to most materials | Poor heat, ageing and weather resistance | Warehouse and short-haul only; not for containers crossing the equator |
| Silicone | Soft, clear, resists heat, acid and alkali | Slow cure, leaves residue | Special applications, not carton sealing |
Tape bond builds after application — adhesion typically rises 15-150% within the first 24 hours — so a container loaded straight off the taping line is at its weakest. Supplier tiers as toolmakers rank them: first tier 3M, tesa, Nitto (all with Chinese plants); second tier Scapa, Sekisui, Teraoka; third tier Taiwanese and mainland converters. Cartons are closed with an H-seal — one strip along the centre seam and one along each end seam — which is also what the OQC gate looks for before a container is loaded.
Glass bottles: the protection system and the breakage target.
| Layer | Specification | Purpose |
|---|---|---|
| Suspended tray + air-column bag | Compression rating ≥200 kg; tested to ISTA 3A | Bottles held off the carton walls and floor; shock absorbed by air, not glass |
| Dividers | B-flute or moulded pulp partitions, one cell per bottle | No glass-to-glass contact |
| Inner liner | Polythene bag inside each carton | Dust, damp and sea-air protection for necks and decoration |
| Outer carton | Double-wall, B/C or A/B, 6-8 mm | Stacking and puncture resistance |
| Pallet | Stacking limit printed on the carton; stack tested to GB/T 4857 (ISO 2234 equivalent); glass no more than 2 layers where cartons are stored loose | Predictable loads on the bottom carton |
Target breakage on arrival: ≤0.3%. The cautionary case: glass bottles shipped loose in dividers without suspended trays arrived with 18% breakage, and the emergency air replacement cost about 30% more than the sea freight it was meant to save — after which the buyer's transport-protection agreement made the shipper liable for 200% of losses on any deviation. For tubes, a honeycomb-board layer and a moisture barrier holding humidity ≤50% RH; for printed cartons, laminated outers with corner protectors and a stacking limit of 1.5 m. Breakage allowance is agreed up front in the specification, not argued afterwards — see glass bottles and how we work.
Shipping marks, and sea versus air.
Every export carton carries: product name and item code; quantity per carton; batch or lot number (matching the inspection report and the retained sample); inspection status with the inspector's code; gross and net weight; carton dimensions; carton sequence number; destination; handling marks (this way up, fragile, keep dry). A carton without a batch number is a complaint that cannot be traced to a shift, which is why the OQC gate rejects it.
| Question | Sea freight | Air freight |
|---|---|---|
| Cost | Baseline; empty packaging is volume, not weight, so sea is typically 5-8× cheaper per m³ | Emergency air adds about 30% to landed cost in the cases we track |
| Transit | 25-40 days to Europe or the US East Coast, 15-20 days to the West Coast, plus clearance | 3-7 days door to door |
| Packing | Double-wall cartons, palletised, ISTA 3A-style protection for glass | Lighter outers acceptable; volumetric weight (1:6,000) decides the bill |
| When | Anything planned: use a 1.3× buffer on quoted lead time and add 15 days around Chinese New Year and environmental production curbs | A launch date that cannot move — and then only the quantity that protects the date |
One honest boundary: we are a sourcing partner working with vetted partner factories, and the packing specification above is what we require of them — it is written into the order, checked at OQC, and the breakage target is agreed with you before the container is booked. Small first orders on the low-MOQ routes ship to the same standard.
Frequently asked
Get the packing specification with the quote.
Tell us the components, the quantity and the destination. Your quote comes with the carton specification, the pallet plan and the breakage target written in.
Related reading.
- Our QC standards, with the numbers — the OQC gate that checks the carton, the marks and the pallet before loading.
- Glass bottles — formats, decoration and the MOQs that go with custom glass.
- Factory audit checklist — section H, warehousing and logistics, is where packing discipline is audited.
- Real minimum order quantities, by route — small orders ship to the same packing standard.