Packing is the last line on the specification and the first thing that fails in transit. A container of moulded parts that arrives crushed, damp or unidentifiable has failed commercially even though every part passed inspection at the factory, and the cost lands on the buyer's line, not on the freight. This note covers the three parts of an export pack that decide whether the parts arrive usable.
The carton has to survive the stack
A carton in a container is loaded by a stack of cartons above it, and the stack can be several metres high in a hot hold. The specification that matters is the edge crush strength of the board, and double-wall corrugated is the default for dense plastic parts, where a single-wall carton bulges under its own contents. Part geometry decides the rest: sharp edges and heavy parts need interior protection, and parts with cosmetic surfaces need a layer that does not abrade in transit. A carton marked with the part number, quantity and lot turns the packing into the traceability record, which is what the receiving dock actually counts against.
Hygroscopic grades need a barrier, not just a carton
Nylon, PET and TPU take moisture from the air, and a part that ships dry and sits in a humid hold arrives at the wrong moisture content. The consequence is not visible: the parts look identical and mould badly, because the moisture flashes to steam in the barrel and the surface degrades. The standard protection is a barrier bag with desiccant, sometimes with a humidity indicator card, for any grade that ships with a moisture specification. Programmes that skip it discover the problem at the customer's moulding line, three weeks and one ocean away from the factory that packed it correctly.
| Part family | Packing requirement | Transit risk if skipped |
|---|---|---|
| PA, PET, TPU parts | Barrier bag plus desiccant, indicator card | Moisture uptake, moulding defects at destination |
| Dense structural parts | Double-wall carton, edge protection | Carton crush, part damage in stack |
| Cosmetic surfaces | Non-abrasive interleaf, no direct contact | Scuffing that reads as a quality failure |
| Small loose parts | Bagged with count, lot card inside | Count disputes, mixed lots at receiving |
Shipping marks and the wood question
Shipping marks are the customs and receiving interface, and they carry the consignee, the part and lot identity, the carton count and the weight. Wood pallets and crates entering most markets need ISPM-15 treatment, the heat or fumigation mark that proves the wood was treated, and an unmarked pallet is a customs hold rather than a packing detail. Where the programme can standardise on plastic pallets or slipsheets, the ISPM question disappears from every shipment, which is why repeat programmes usually migrate there.
Unitisation is the last specification
The pallet pattern decides whether the container is full or full of air. A pattern that stacks to the container height without crushing, with corner boards where the stretch wrap bears and a wrap tension that does not deform the cartons, is part of the quotation, not an afterthought. Programmes that let the factory choose the pattern get a pattern that suits the factory; programmes that specify the pattern, the carton and the marks in the purchase order get containers that arrive the way they left.
Related reading
Our bagged and kitted parts programme with lot traceability covers the small-parts packing route, and the discreet packaging sourcing guide covers the retail-facing side of the same question.
Related product categories
The materials and part types discussed above are grouped in our sourcing directory:
