Materials
Materials3 min readUpdated
Paperboard basics
Paperboard is the thin, stiff board most shop boxes are made of: tuck boxes, sleeves, cosmetic cartons. Here is what the grade names mean, and how a board's weight relates to the thickness you type into a dieline.
Paperboard or cardboard?
Many people use the two words for the same thing. Packaging makers don't. Paperboard is one solid sheet, well under a millimetre thick. It folds cleanly and takes fine print, so it is the board of shop shelves.
Corrugated boardCorrugated board A wavy sheet, the flute, glued between flat liners. Light, stiff and hard to crush: the board of shipping and mailer boxes. is a sandwich: a wavy layer glued between flat sheets. It is thicker and stronger, built for shipping, and it is what a box maker hears when you say cardboard. For most box types the editor's Board list offers both, paperboard first, then the flutesFlute The wavy layer inside corrugated board. Its letter (F, E, B, C, A) tells how tall the waves are..
The main grades
Paperboard is sold by grade. The grade tells you what the fibre is and how the surface looks.
| Grade | What it is | Often used for |
|---|---|---|
| SBS solid bleached board | Bleached virgin pulp all the way through, white inside and out. The smoothest print surface. | Cosmetics, medicines, premium food |
| FBB folding boxboard | Layers: a bulky middle between bleached outer layers. Light and stiff for its weight. | Cosmetics, medicines, food cartons |
| WLC white-lined chipboard | Mostly recycled fibre with a white top and a grey back. The cheapest. | Cereal, biscuits, shoes, dry goods |
| CUK coated unbleached kraft | Brown kraft fibre under a white coated top. Tough, and holds up when damp. | Can and bottle multipacks, frozen food boxes |
Names differ by country and mill. When the exact board matters, ask for its data sheet.
Weight and thickness
Board is sold by weight, in grams per square metre (g/m², often written gsmGrammage A board's or paper's weight in grams per square metre (g/m², gsm). It hints at thickness, but only loosely.). A dieline needs its thickness, called caliperBoard thickness How thick the board is, in mm, also called caliper. Type it into a box's dieline and the details around the folds follow it.. The two are linked, but loosely: boards of the same weight can differ by a tenth of a millimetre or more, by grade and by mill.
| Weight | Thickness, about |
|---|---|
| 300 g/m² | 0.3–0.4 mm |
| 350 g/m² | 0.45–0.5 mm |
| 400 g/m² | 0.45–0.6 mm |
US printers give caliper in points. One point is a thousandth of an inch, so 16 pt is 0.016 in, about 0.4 mm. That is for reference: the editor takes the thickness in mm or in inches, whichever units you work in.
Thickness on your dieline
Type the caliper, not the weight. Your sizes run crease to crease, and the thickness never moves those creases. It moves the details around the folds: flap insets, tucks, locks and slots. Where a wall folds right back on itself, the dieline draws two creases twice the board's thickness apart. Below 0.6 mm one crease is enough.
The paperboard entries in the Board list, 300 g at 0.4 mm and 400 g at 0.6 mm, are a starting point. If your printer quotes another caliper, type that. More in How thick should the board be?
Board thickness on your dieline
Pick your board in the Board list, or choose Custom… and type its caliper. The details around the folds follow it.
- Cut
- Crease
Which grade for your box
- Bright white and fine print, for food or cosmetics: SBS. More in SBS board: C1S and C2S.
- Stiff and light, for everyday cartons: FBB.
- Lowest cost and recycled, for dry goods: WLC.
- Strong and fine with damp, for cold drinks and frozen food: coated kraft.
- Heavy or shipped products: corrugated board, not paperboard.
Your printer knows which boards their press and die-cutter run well. Ask them before you choose.