Book wraps: specifying a crease pattern that covers a whole product range

A book wrap is the most efficient pack in corrugated for anything flat. One blank, no glued joint, no assembly, and a pack that folds down to the height of what is inside it rather than the height of the box you happened to pick. The reason one wrap can serve a whole product range, and the reason some wraps are miserable to use, is the same thing: the crease pattern.

What the crease pattern actually does

The wrap has a set of parallel creases running across it, usually three to five. Each one is a depth the pack can fold to. The packer puts the product in, folds the side wings up and over, breaks the wrap at whichever crease sits closest to the top of the contents, and seals it.

That is the whole trick. One blank covers a span of product heights, and each pack is only as deep as it needs to be. Specify the creases well and a single line covers most of a range. Specify them badly and the pack is either loose around thin items or will not close over thick ones.

Start from what you actually ship

The common mistake is to set crease positions from the product catalogue. Set them from dispatch data instead.

Pull a few months of orders, plot them by the thickness of what went out, and the clusters are usually obvious: a dense band of thin items, a second band around the most common product, and a thinner tail of thick ones. Put crease positions at those clusters, not at even intervals. An evenly spaced wrap looks tidy on a drawing and wastes board in practice.

Two details decide whether the pattern works on the bench:

• Board thickness eats depth. Each fold consumes material, and the thicker the flute, the more it takes. E flute wraps fold tighter and closer to the product than B flute, which matters when the gap between crease positions is small.
• The top crease sets the maximum. Above it there is no fold left. If a meaningful share of orders is at or near that limit, the range needs a second wrap size rather than an optimistic crease.

Width, length and the wings

Internal width and length come from the product plus a working clearance: enough to drop the item in without fighting it, not so much that it slides. The side wings need to be deep enough to cover the contents at the deepest crease position, which is why a taller crease set makes the blank wider as well as longer.

That is worth knowing before you ask for “one more crease”. Extra depth capacity is bought in board area across every unit, including the thin ones.

Design to the carrier band

For most senders the postage band matters more than the board. A wrap that folds to the product is the easiest way to keep a flat item inside a cheaper band, which is exactly why the format exists.

Fix the band first, work back through board thickness and closure, and design the crease positions so that the common orders land comfortably inside it rather than a millimetre under. Our guide to sizing mailers to carrier bands covers how the thresholds interact with board and closure, and letterbox packaging covers the shallow formats designed to stay in the cheapest band of all.

Closure, returns and opening

The closure is an inline peel and seal strip: no tape, one motion, a consistent seal. Two additions are worth considering at the specification stage, because both are cheap on the blank and expensive to retrofit:

• A tear strip, so the recipient opens the pack cleanly without a knife and without damaging the contents.
• A second seal strip, so the same wrap can be resealed and sent back. For books, media and apparel, where returns are a normal part of the model, this is usually the cheapest returns solution available.

Where a wrap is the wrong answer

Wraps suit flat, rigid, reasonably robust goods: books, media, prints, framed items, documents, flat-packed accessories. They are not the answer for anything fragile that needs clearance on all sides, anything heavy enough to need a double wall case, or any product where the presentation of opening a box is part of the proposition. For those, a 0427 mailer or a bespoke die-cut format is the better route.

Rationalising a range

The attraction for a distributor is stockholding. A well-specified wrap range is short: two or three sizes, each with a crease set covering a span of heights, rather than a long tail of near-identical boxes that a packer has to choose between under time pressure. Fewer lines, less working capital, fewer decisions at the bench, and the same coverage.

Specifying one with us

Send the product dimensions, the spread of heights you ship, the carrier band you are aiming at, whether you want a tear strip or a return seal, and the annual volume. We design the blank and the crease set on CAD, cut samples on the digital flatbed so you can wrap real product and test the fold positions, then manufacture in pallet quantities with the peel and seal strip applied inline.

See peel and seal book wraps for the format as we make it, or send us the details and we will quote.