In short: seven families of cardboard packaging insert cover almost every industrial shipping need: dividers, layer pads, honeycomb blocks, edge and corner protectors, cradles, bracing wedges and void fill. Selection rests on three criteria — product mass, the dominant stress mode (vibration, shock, compression) and the cost of failure you are willing to accept. Well-chosen inserts cost 2–6% of the value shipped and typically cut breakage by a factor of five to ten.
The last thing anyone designs, the first thing that costs money
In most manufacturing businesses, protective packaging is handled at the end of a project, once the product and the case are already fixed. That sequence is a costly methodological error: the insert determines the useful internal dimensions, so it should be designed alongside the case.
The consequence of the inverted sequence is familiar. Oversized cases, full of air, into which catch-up void fill is added. Material cost rises, shipped volume rises, and protection stays poor because the product still has room to move.
The seven insert families
1. The divider
A grid of slotted blades creating one cell per item. The reference solution whenever several identical units travel in one case: bottles, flacons, jars, machined parts. See our page on made-to-measure partitions.
2. The layer pad
A simple sheet between two product layers. Cheap, it prevents interlocking and makes layer-by-layer picking easy. Used heavily on cans, drums and flat components.
3. The honeycomb block
A cut block of honeycomb paperboard shaped to the product. It combines load bearing with cushioning and replaces foam on heavy parts.
4. Edge and corner protectors
Edges are the most exposed part of any pack. A case corner concentrates handling impact; protecting it costs pennies and prevents most crush damage.
5. The cradle
A U- or V-shaped former that receives a cylindrical or irregular product. Essential for reels, tubes, shafts and parts of revolution.
6. The bracing wedge
Placed between load and container wall, it removes lengthwise movement. It is the fibre alternative to inflatable dunnage bags, with better temperature behaviour and simple recycling.
7. Honeycomb void fill
Blocks or strips that occupy residual space. Less elegant than the six above, but very effective for mixed single-parcel shipments.
Selecting by dominant stress
| Dominant stress | Recommended solution | Avoid |
|---|---|---|
| Long-duration vibration | Divider, close-fitting cradle | Soft fill that settles |
| Drop impact | Honeycomb block, corner protectors | Layer pad alone |
| Stacking compression | Tall-blade divider, honeycomb | Perimeter packing only |
| Lengthwise movement | Bracing wedge, void fill | Strapping alone |
| Surface abrasion | Solid board divider | Smooth plastic, direct film |
| Point puncture | Honeycomb load spreader | Direct contact on thin liner |
Five questions that build a specification
- Where is the product weak? An edge, a connector, a label, a neck ring. That, not total mass, dictates the insert.
- What does the flow actually do to it? A full-truckload direct run is nothing like multi-hub parcel. The second demands two to three times the protection.
- What does a failure cost? Add product value, return freight, reprocessing and the commercial cost of a failed delivery.
- How much packing time is acceptable? A perfect insert taking 40 seconds per parcel is not viable on a 300-parcel-per-hour line.
- What happens at the customer’s end? An industrial customer forced to sort three different materials will eventually charge you for it in the tender.
Three worked configurations
Heavy mechanical parts, daily flow
Reinforced case, 30 mm honeycomb base pad, tall-blade divider, corner protectors. Loads up to 300 kg per case with near-zero residual breakage.
Glassware, sea-freight export
Moisture-treated solid board divider, top and bottom pads, reinforced corners, container desiccant. The most demanding configuration, and the one where good and bad packing differ most visibly.
B2B e-commerce, single parcels
Digitally cut honeycomb insert matched to the product, assembled in one movement. The governing criterion here is not material price but preparation time and unboxing experience.
From prototype to production line
An insert validated in the design office is not yet an industrial insert. Scale-up trips over the same obstacles every time.
The packing station
Every component adds a movement. Three distinct parts to place in a set order generate errors and slow the line. Practical rule: aim for two components maximum per parcel, even if that means paying more for one part that replaces two.
Supply and storage
Flat-supplied inserts occupy five to ten times less space than pre-erected ones. On a space-constrained plant that gap often decides the choice regardless of unit price. Conversely, a plant short of labour will prefer pre-erected.
Operator training
A divider assembled inside out, or a wedge placed on the wrong side, cancels the protection. A visual work instruction at the station — one photo of correct assembly, one of incorrect — costs minutes and removes most errors.
Documenting the solution
An insert that works should be written up as a packaging file: dimensioned drawing of every component, illustrated assembly sequence, specified material and grammage, supplier and part number, and transit test results. Without that file, the solution degrades with every change of supplier or personnel.
The file also serves as a contractual basis. In a transit claim, a complete packaging file backed by standard test results transforms your negotiating position with a carrier or insurer.
Measurable gains from redesigned packing
Three effects recur across insert redesign projects. Case volume falls by 8–20%, which translates immediately into pallets saved. Transit claims typically drop by a factor of three. And packing time falls by 10–25% when improvised packing is replaced by designed packing.
These gains compound and are measurable. Payback on a packaging study is normally counted in months, rarely in years.
Matching the insert to the distribution channel
The same product shipped through different channels needs different protection. Applying one specification everywhere means over-packing the easy lanes and under-packing the hard ones.
Full pallet, direct delivery
The gentlest channel. The pack is built once, moved by forklift and unloaded once. A basic divider plus layer pads usually suffices, and stacking compression is the governing constraint.
Groupage and parcel networks
The harshest channel. A parcel typically sees five to eight extra handling events, including automated sortation with slides and drops. This is where corner protection, full-height blades and a tighter clearance earn their cost.
Direct-to-consumer
Here the pack must survive parcel handling and then present well at unboxing. Single-material, quickly assembled inserts win, because packing time per order dominates the economics.
Intercontinental sea freight
Humidity, long duration under load and container movement combine. This is the only channel where moisture-treated grades and desiccants are routinely justified.
Rationalising an existing insert range
Companies that have grown by adding one insert per new product usually end up with dozens of near-identical references. A rationalisation exercise typically follows four steps.
First, list every insert with its annual volume, unit price and the SKUs it serves. Second, group by function and by dimensional family rather than by product. Third, identify the two or three sizes that could absorb the long tail, accepting slightly more clearance on some SKUs. Fourth, quantify the trade-off: marginally more material on a few references against fewer tooling sets, lower inventory, simpler ordering and better volume pricing.
In practice a range of thirty references usually reduces to eight or ten with no measurable loss of protection, and the saving comes mostly from complexity rather than from material.
Frequently asked questions
Should every SKU have its own insert?
No — that should be actively avoided. The aim is to cover product families with a limited number of insert references. Standardisation cuts inventory, station errors and unit price simultaneously.
Do cardboard inserts survive sub-zero temperatures?
Yes, better than most plastics, which turn brittle. The watch point is condensation when returning to ambient, not the cold itself.
Are there standards for testing an insert?
Yes. ISTA 3E and 6-AMAZON.COM cover palletised and e-commerce flows, and the ASTM D4169 series offers full distribution sequences. These do not replace a real-route test but give a comparable baseline between two solutions.
Can cardboard and foam be combined?
Yes, and it is often the best technical and economic answer: honeycomb structure with small foam pads only at critical contact points. Keep the two hand-separable to preserve recyclability.
Key takeaways
Protective packaging is not a consumable — it is a designed part. Specified alongside the case and dimensioned on your real flow, it simultaneously lowers material cost, freight cost and failure cost.
Estic-Maillot’s technical teams have designed industrial packaging inserts since 1924. Describe your flow for a costed proposal.