Inter-Ply Bond Measurement Standards in Recycled Paperboard Production
Inter-ply bond standards mandate TAPPI T 541 or ISO 16260 testing under strict ISO 187 conditioning to prevent converting delamination on recycled paperboard.
Platen Compression Dwell
Pressure Application
The duration of maximum pressure application during the die-cutting and creasing cycle ensures the permanent deformation of the paperboard. In carton converting, the platen compression dwell holds the board between the male creasing rule and the female matrix for a fraction of a second to prevent spring-back. This phase is critical for achieving consistent fold lines in stiff carton boards.
Deformation Settlement
When the platen closes, the creasing rule forces the board into the groove, which stretches the outer liner and compresses the inner plies of the board. Holding the pressure at this point allows the paper fibers to relax and adjust to the new shape, which reduces the internal stresses that cause the crease to open up. If the dwell time is too short, the board retains its elastic memory and the crease becomes weak, which makes it difficult to fold on high-speed gluing machines.
The dwell time is controlled by the mechanical design of the press and the operating speed of the line.
Crease Setting
Increasing the dwell time can improve crease quality but reduces the overall production speed of the die-cutter. The converter must find the optimal balance between crease stability and throughput.