Key question
How does a flat sheet of cardboard become a sturdy box?
Most packaging on the shelves consists of folding cartons made of paperboard. They are printed flat, die-cut, creased, and glued, and are only erected during the filling process. Anyone who understands their construction can design seamlessly across all panels and avoid costly mistakes.
Learning objective: You can name the parts of a folding carton, read and create a die-cutter template with cutting and creasing lines, and calculate the flat development from internal dimensions.
First fold, then design.
3.1 / The folding box
One sheet, many parts.
A folding carton consists of a few standard components:
01
Torso
The four side panels that wrap around the product and usually carry the design.
02
Adhesive tab
Narrow strip that connects the start and end of the hull to form a sleeve.
03
Tuck flap
Closes the lid or base by tucking into the box.
04
Floor
Tuck-in flap, crash lock base or auto-lock bottom, depending on weight and filling.
A tuck-in closure is inserted just like the lid: affordable, but with low load-bearing capacity. An interlocking base is folded together by hand and supports more weight. The crash-lock base is pre-glued and automatically pops into shape when assembled.
Each tab has a purpose.
3.2 / Create cutting die
The dieline is a blueprint, not an image.
The cutting die, also known as a dieline or cutter guide, shows all the lines along which cutting, creasing, or perforating will take place. In the print file, it is placed on its own layer in a spot colour that is not printed.
Coloured areas and images should extend approximately 3 mm beyond the cutting lines into the bleed. Keep text and essential elements clear of crease and cutting lines, as die-cutting may shift slightly.
01
Cutter guide
Through-cut that separates the shape from the printed sheet.
02
Crease line
Embossed crease line where the cardboard folds cleanly.
03
Direction of travel
Direction of the fibres in the cardboard; it determines how well it folds and stands.
The cutting die is placed on a separate layer.
3.3 / Dimensions and processing
The internal dimension is the size of the product.
Boxes are defined by their internal dimensions: length × width × height, which must accommodate the product. Material thickness is added at each crease, which is why the flat layout is slightly larger than the sum of the internal dimensions.
The number of layouts that fit onto a printed sheet is called the 'number-up' or 'imposition'. More items per sheet reduce costs. The exact cutting die is created by the die-maker or CAD software; your calculation serves as a planning guide.
More items per sheet, lower price.
Exercise
Build a box
Task: Design a folding box for 20 "Alpenkraut" teabags and construct it out of cardboard.
STEP 1
Measure 20 tea bags and determine the inside dimensions.
STEP 2
Calculate the blank development in the tooling and draw it at a scale of 1:1.
STEP 3
Mark cutting and creasing lines in two colours and cut out the shape.
STEP 4
Score, fold and glue the box, and check that everything fits.
Evaluation: Does the product fit well, do the tabs close properly, and does the box stand upright?