A carton cutting die does more than cut the outer shape; it also decides how the product folds, how the lid closes and how the lock holds. Rule height, creasing line, counter channel and board grammage are therefore set up as one balance; when one changes the others are read again.
The cut line separates the product, the crease carries it
The cut line takes the box out of the sheet; the crease line gives the board a fold memory and lets the box keep its shape through its life. A clean cut with a weak crease opens up in use; a firm crease with a burred cut spoils the edge. Both have to be right in the same die, on the same stroke.
On the drawing the two roles come in separate colours and the fold direction is stated; critical points such as the lid, lock tab and glue flap are marked. Cutting rule and creasing rule sit in the same plywood at different heights; which is where is read from the drawing, not guessed.
- Cut and crease lines are given in separate colours or layers.
- Fold direction and print face are stated on the drawing.
- Lid, lock tab and glue flap are marked as critical points.
Board grammage changes the channel decision
Creasing presses the board between the creasing rule and the channel opposite it to form a groove; channel width and depth are chosen for the board thickness. Thin board wants a narrow channel, thick board a wide one; a narrow channel cracks the board, a wide one lets the fold line wander and the lid sits crooked.
Grammage alone is not enough: two boards of the same grammage can differ in thickness. Grain direction also changes fold resistance; a fold across the grain is more prone to cracking. Lamination, film or heavy ink coverage changes how the surface stretches, and that information belongs on the order.
- The real thickness is stated alongside the grammage.
- Grain direction is written on the drawing or in the message where possible.
- Lamination, film or heavy ink coverage is shared where present.
Rubbering helps the clean release
For the cut box to leave the die cleanly, the ejection rubber beside the rule pins the material before the cut and pushes it off after. Rubber of the wrong hardness, or missing rubber, holds the piece on the rule, crushes the board in tight areas or marks the surface; narrow details such as lids and flaps are the most sensitive zones for rubbering.
Rubber hardness and placement are chosen for material thickness, detail density and machine speed. Waste areas get separate attention: inner windows are filled completely with rubber so the cut piece does not stay in the window. When the machine type is known the rubber layout is built for its speed.
- Rubber pressure is checked in tight areas and around the lid.
- Inner windows and waste areas are handled separately in the rubber plan.
- Machine type and speed are stated for the rubber hardness choice.
The folded sample is the final decision
Even with a correct drawing, when the first product is folded the lid fit, lock tightness and any ink cracking on the crease line are checked. The sample is cut from the board that will be used in production; a sample from a different grammage does not represent the fold behaviour.
The feel of resistance as the lid is closed by hand, whether the box sits flat on the table and whether the corners are symmetrical are checked by eye and by hand. If needed, a crease revision is planned together at this stage; a problem caught after approval costs far less than one found after thousands of boxes have been cut.
- The first sample is cut from the production board and assessed folded.
- Lid closure, lock tightness and flat seating on the table are checked.
- Any crease revision is planned together before the production run.
Quote details we clarify together
When the file, material, quantity and deadline are clear, the quote conversation moves faster and with less back-and-forth.
- Current revision file
- Material and quantity details
- Critical dimensions or production notes
- Deadline expectation and delivery preference
