The In-Line vs. Off-Line Finishing Battle
Format—Minimal size changes usually tip the scale towards in-line. Whether you’re producing one or several thousand copies of a product, if it’s the same size, the finishing system has fewer change parameters to deal with. For the printer, the web imposition remains the same, as does the paper size on the output end.
If you’re faced with several size changes during production, it’s best to keep the press running and finish the product off-line.
How many pieces in the puzzle?—Look at the number of separate components in the finishing system. The more there are, the higher the risk for (and number of) stops.
Controls and buffers—When separate finishing systems are employed, an “overall” control system may be necessary to manage them. This is a common practice in the offset printing world.
The READY and RUN status of each piece can feed back to a common controller, along with the necessary product sensors. Buffers are needed in order to enable the printer to keep running when a piece of the finishing system stops (hopefully) momentarily. A festoon buffer on a postpress cutter performs this function. Conveyors usually provide this for in-line binders. For in-line finishing systems, a well-designed buffer is critical.
Labor—What are the labor requirements of the in-line vs. the off-line set-up. How many times must the work be moved between (off-line) devices?
The labor component is HUGE. I have seen well-designed in-line saddlestitching systems produce booklets for hours on end, with the booklets being boxed and shipped at the end of the line with ONE operator crewing the printer and stitcher. You can’t get more efficient that that.
So the in-line vs. off-line factors are
- a) the effect of in-line vs. off-line on total throughput,
- b) labor (What is the total labor requirement for in-line vs. off-line?), and
- c) cycle time (How does each configuration affect cycle time for short, medium and longer runs?).
I hope this will help some of you facing these decisions.
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