5.4 Palletizing & Container Loading

Palletizing and container loading transform dozens of cartons into a single stable unit that can withstand forklifts, braking trucks, and ocean voyages. The goal is simple but unforgiving: keep weight balanced, cartons supported, and the load locked so it moves as one. Pallet choice, stack pattern, and restraint methods decide whether shipments arrive intact or collapse under pressure. Moisture, temperature swings, and route conditions add further demands, making packaging a true engineering discipline rather than a final afterthought.

5.4.1 The goal (in one line)

Build a single, rigid unit (pallet + cartons) that survives forklifts, brakes, bumps, humidity, and time—then lock it safely inside a truck or container.

5.4.2 Pick the right pallet (size, strength, compliance)

Choice	When to use	Notes
48×40” (GMA)	North America	4-way entry; common racking size
1200×800 (EU)	EU flows	Check racking beam spacing
1200×1000 (ISO)	APAC/EMEA mixed	Good for cube of 40’ containers
Wood (ISPM-15 HT)	Export	Must be heat-treated & stamped; no bark/nails proud
Plastic/presswood	Closed loop, damp routes	Clean, light; check deck stiffness/rack rating

Rating: know the pallet’s dynamic/load rating and don’t exceed it. No overhang—cartons must sit fully on deck boards.

5.4.3 Stack pattern & height (strength vs stability)

Column stack (aligned corners): max strength (best for ECT); use when cartons are strong and uniform.
Interlocked (brick): more stable, but reduces column strength—use only if needed.
Slip sheets/anti-slip between layers minimize shear.
Height & CG: heavier layers low; keep center of gravity near pallet center; target H ≤ 1.5× base unless spec’d otherwise.
Clearances: leave ~50 mm (2”) from skid edge to wrap; nothing should hang out.

5.4.4 Lock the load (wrap, strap, protect)

Stretch-wrap recipe (starter)

Rope band the film and trap under deck with 2–3 passes to tie load to pallet.
Bottom: 3–5 wraps with 50% overlap.
Mid: 2–3 wraps; add cross “X” if tall.
Top: 2–3 wraps; capture top cap if used.
Film tension consistent; no film tails.

Add-ons (choose by risk)

Corner boards (full height) to stop edge-crush and give belts something to bite.
Top cap (corrugated or hardboard) spreads strap pressure; protects from overhead dust.
Strapping: PET/PP for most loads; steel only for very heavy/rigid items. Always use edge protectors under straps.
Void fill: honeycomb blocks/airbags inside the pallet footprint (not sticking out).

5.4.5 Carton & pallet labels (traceable and readable)

Carton: SKU/Variant, quantity, unit SN range if serialized, orientation/fragile graphics.
Pallet: pallet ID, SKU(s), count, gross weight, destination, stack limit, and handling icons on two adjacent faces.
Mixed pallets: diagonal band or big MIXED placard; pack list in a clear sleeve.

5.4.6 Forklift reality (design for handling)

Fork entry: 4-way preferred; fork pockets clear (no wrap covering them).
Fork spread ≈ outer third of pallet; no tip-lifting one edge.
Do not pierce cartons (keep forks level, travel low).
No double-stack unless cartons and pallet are rated—if allowed, use slip sheets and corner boards between stacks.

5.4.7 Container loading (build a safe, quiet cube)

Plan the load

Create a load map: rows, layers, and aisle (if needed) before the door opens.
Weight forward & low, centered left/right; avoid heavy bias at the doors.
Keep even floor loading; spread concentrated loads with dunnage boards.

Block & brace

No overhang at container walls; leave 20–50 mm breathing gap.
Use chocks, cribbing, and load bars to stop fore–aft slide.
Dunnage airbags fill side gaps—inflate to spec; protect with corrugated.
Build a false bulkhead (honeycomb/corrugated) at the doors; strap to lashing rings.

Moisture control

Desiccant sized to route/climate; hang high and spread along the length.
Use container liners/VCI for corrosion-sensitive goods.
Close doors with seals; record seal number on paperwork.

5.4.8 Environmental & legal notes (fit for route)

Temp swings: avoid films that embrittle in cold; keep desiccant away from direct water; avoid air-cell cushions at altitude unless spec’d.
Regulatory: hazmat/UN boxes follow their own rules; lithium batteries need the correct marks and packing (if present in your product).
Weight limits: confirm axle/legal weights with logistics; heavy pallets can tip you over—better to split.

5.4.9 Quick tests that prevent headaches

Push test: a firm hip-push shouldn’t shift the top layer.
Tilt test: pallet tilted ~10–15° briefly—nothing slides.
Wrap test: pluck the film; it should feel tight and springy, not slack.
Short ride: forklift over a speed bump—no sway, no strap chatter.

5.4.10 Acceptance cues (fast table)

Area	Accept	Reject
Footprint	No overhang; even clearance to edges	Boxes hanging off; wrap covering fork entries
Stack	Column (or controlled interlock); heavy low	Random brick; tall light box on bottom
Wrap/strap	Rope banded to pallet; tight film; edge-guarded straps	Film tails; straps cutting cartons; no pallet tie
Protection	Corner boards/top cap as needed	Crushed corners; strap marks
Labels	Pallet ID, weight, destination on two faces	Handwritten mystery; one-side only
Container	Blocked/braced; gaps filled; desiccant hung	Free-to-slide stacks; no moisture control

5.4.11 Common traps → smallest reliable fix

Trap	Symptom	First move
Overhang to “use all space”	Crushed corners, failed ECT	Zero overhang; re-cut foam or change pallet
Brick stack by habit	Column strength lost	Use column stack; add anti-slip for stability
Wrap not tied to pallet	Load walks off deck	Rope band under deck; 3–5 bottom wraps
Straps without edge guards	Carton damage lines	Add corner boards/edge protectors
Heavy up high	Tip, sway, collapsed lower boxes	Re-layer: heavy low; limit height; top cap
No brace in container	Shift, door avalanche	Build bulkhead; use airbags/load bars
Wet/weak pallets	Breakage, nails through cartons	Inspect & reject bad pallets; use ISPM-15 HT

5.4.12 Pocket checklists

Before build

Pallet size/rating fits route; ISPM-15 for export
Carton stack plan picked (column preferred); heavy low
Corner boards/top cap/anti-slip staged; film & straps ready

Build

No overhang; ≥ 50 mm from edges to wrap
Rope-band film under deck; bottom 3–5 wraps; top 2–3 wraps
Straps with edge guards; labels on two faces with pallet ID & weight

Container

Weight centered; rows blocked/braced; airbags used where gapped
Desiccant/liner as required; seal applied & number recorded
Photo of load map and first/last rows (if customer/audit requires)

By stacking smart, tying loads firmly to the pallet, and blocking or bracing inside containers, shipments stay secure through handling and transit. This discipline minimizes damage, prevents safety hazards, and ensures products arrive exactly as packed, ready for customers without rework or loss.