Choosing the Right Cardboard Thickness for Crash Lock Boxes
How to pick the right board grade and thickness for your crash lock packaging needs.
Understanding flute types
Corrugated cardboard gets its strength from the fluted (wavy) layer sandwiched between flat liners. The flute type determines the board thickness, cushioning ability, and compression strength. Crash lock boxes are most commonly made from E-flute or B-flute board.
Quick answer
E-flute (1.5mm) for items under 2kg, B-flute (3mm) for 2-8kg, and EB double-wall (4.5mm) for heavier or fragile items. E-flute gives the best print quality and works well for cosmetics, clothing, and light electronics. B-flute provides superior cushioning and stacking strength for heavier products. Choose based on product weight, fragility, and whether the box needs to stack in warehousing.
Matching thickness to product weight
Lightweight items like clothing, cosmetics, and small accessories are well served by E-flute crash lock boxes.
Books, electronics, bottles, and medium-weight products need the extra cushioning and strength of B-flute.
Heavy items need EB or BC double-wall construction to prevent crushing and base failure.
Over-specifying thickness wastes money, increases shipping weight, and uses more material than necessary.
Concerned about strength? Read about how die-cutting affects box strength or the engineering behind crash lock boxes.
When to upgrade thickness
Signs you need thicker board0 / 4 checked
Cost implications
Thicker board costs more per unit and weighs more (increasing shipping costs). The key is finding the minimum thickness that reliably protects your product. Over-engineering wastes money; under-engineering costs more through damage claims and replacements.
Crash lock boxes in every thickness
From lightweight E-flute to heavy-duty double-wall, ProcuraPack offers crash lock boxes in the right grade for your products.
Browse crash lock boxesFrequently asked questions
E-flute (1.5mm) for items under 2kg, B-flute (3mm) for 2-8kg, EB double-wall for heavier items.
A thin (1.5mm) corrugated board that provides a smooth printing surface and adequate protection for lighter items.
A 3mm corrugated board offering excellent cushioning and compression strength for medium-weight products.
No, over-specifying wastes money and adds weight. Choose the minimum thickness that reliably protects your product.
Yes, many suppliers allow different board grades across different box sizes within the same order.
Part of our guide
Product Guide: Crash Lock Boxes
Expert insights on crash lock packaging, from materials and design to branding and sustainability.
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