Conventional vs. digital finishing
In the conventional finishing process the sheets are first cut on a sheet cutter, then folded in a folding machine and finally collated in a saddle stitcher or bindery line, depending on if they have to be stitched, glued or sewn.
The highest productivity is normally obtained by using the sheet cutter for trimming and then use folding machines in the same sizes as the printing presses. Consequently bigger sized printing presses require bigger sized folding machines. This combination increases the production speed of f.ex. A4 pages per time. Using double-sized folding machines also halves the required number of saddle stitcher or bindery stations.
If big size printing presses are combined with middle sized folding machines, the sheet cutter can be used to split the big sheets into two smaller ones prior to folding.
New digital finishing lines, developed to handle products from the digital printing presses, opens up for an alternative way of finishing the printed products from offset presses. The digital finishing lines contains of an integrated combination of collators, stitching or gluing stations and 3-knife trimmers. In other words, folding, collating and trimming of the printed products are performed in one pass and the finished products come directly off the line.
The maximal production speed of conventional folding machines and saddle stitchers and bindery lines are higher than the production speed of the digital finishing lines, but the make-ready time of the digital finishing lines are faster, so above a specific number of copies the conventional process is faster, but for short run offset jobs, the digital finishing machines might be faster and more economical than conventional finishing processes.
The digital finishing machines have a maximum sheet size capacity of oversized A3, so all sheets from bigger offset presses must be reduced to A3 sheets in the conventional sheet cutter, before they can be processed by digital finishing equipment.
The leading conventional finishing equipment manufacturers are:
The leading digital finishing equipment manufacturers are: