What is stripping in die cutting? After the die cuts a sheet, the blanks are still held in a surrounding grid of waste paper. Stripping is the step that separates the two: the blanks go forward to gluing, and the waste is removed and baled. On a simple carton the waste is a few narrow strips; on a windowed or shaped box it can be much of the sheet, and the way it comes out decides how fast the line runs.
What are nicks and why do they exist? A nick is a small uncut bridge of paper left on the cutting rule, which keeps the blank attached to the sheet as it travels. Without nicks, blanks fall out on the press and jam the delivery. With too many or too heavy nicks, the operator has to break each one by hand, and the broken edge shows as a torn fibre on the finished carton. The number and position of nicks is a design decision, not an accident of the die.
How is waste removed? Manually, by an operator pulling the grid away from the sheet; semi-automatically, with a stripping station that pushes the waste out as the sheet passes; or in line, where the die cutter itself strips and stacks. Manual stripping suits short runs and complex shapes. In-line stripping needs a tool that matches the die, and it only pays when the volume justifies the tooling and the setup time.
What goes wrong? Waste left inside a counter, so the next impression is uneven. A grid that tears and leaves fragments on the blank, which then jam the gluer. Blanks that separate too early and arrive at the delivery out of register. On windowed cartons, the window aperture waste can pull the film with it if the nick pattern has not been planned around the patch. Each of these faults traces back to the die and the stripping plan rather than to the operator.
Why does it matter downstream? A folder gluer runs at speed and cannot tolerate loose waste. A fragment of board in the glue unit lifts the flap, the glue lands in the wrong place, and the carton is scrap. Lines that run windowed or shaped work often add an inspection point after stripping for exactly this reason. Buyers who see a run of glue failures should ask about stripping before they ask about the glue.
How is the nick pattern decided? It follows the shape and the grain. Nicks go where the blank is least visible on the finished pack, usually on a glue flap or a hidden edge, and they are kept small enough to break cleanly. Long narrow waste strips need more nicks to stay in the sheet; a heavily shaped blank may need a custom stripping tool. The die line drawing should show nick positions where the buyer has a preference.
What should a buyer specify? The nick positions if the pack is visible, the stripping method if the volume justifies in-line tooling, and the delivery condition , counted, banded, stacked or palletised. Add the requirement that no loose waste arrives with the blanks, because that single sentence prevents the jams a gluer will see. On a repeat order, keeping the same die and stripping plan is worth more, since tooling sits inside the post-press sequence than shaving a little off the tooling price.
Chengtop die cuts, strips and delivers folding cartons and shaped boxes from its Wuhan plant, with nick positions agreed on the drawing before the die is made. Send the shape and the quantity, and we will confirm the stripping route and the delivery pack.
