Saddle Stitchers — A Stitch In Time
One widely adopted solution to this challenge is to impose the job multiple-up in four-page flat signatures, then run it on a small-format press (33˝ or smaller). The sheets are cut to flat-sheet, four-page signatures that are loaded into a high-speed vacuum collator equipped with in-line stitching, folding and face-trimming accessories (see accompanying photo on page 74).
More and more printers are realizing significant advantages to the vacuum collator/saddle stitching approach. First, there are fewer off-line bindery steps and reduced material transport between the steps. With flat-sheet collating, you print, cut, load the collator, and the stitching, folding and face trimming are quickly completed in-line. With the traditional method, you print, perforate/fold, then load the signatures into an in-line system that gathers them onto a saddle and stitches them. In-line or off-line three-side trimming completes the process.
Another plus to this method is less spoilage. State-of-the-art collator and bookletmaking accessories designed for heavy-duty use come with digital controls, and stepper motors drive all guides and stops to the proper position for changeovers. This results in first-book-off quality, which is more important on shorter runs. Wasting 100 units setting up a saddle gathering line is insignificant on a run length of 50,000, but that same 100 units is 2 percent of the total job on a 5,000-piece run.
Most importantly, the off-line vacuum collator/saddle stitching system can be set up and changed over between formats in just minutes. This represents considerable labor cost savings compared to changing over saddle gathering and three-knife trimming lines. Changeover speed is critical, because shorter run lengths don't afford the luxury of amortizing setup costs over many units.
The same customers who are driving the business toward shorter run lengths are also pushing for faster delivery. They want next-day or same-day service. Using the cut-collate-stitch-fold-trim method, the printed sheets are ready to ship much faster than with the traditional process. An added bonus is you can offer customers partial delivery of the finished job as soon as the first booklet exits the trimmer. You needn't wait until all sheets are printed and signature folded before you can begin producing the finished, saddle stitched product.
