The In-Line vs. Off-Line Finishing Battle
Well...it’s not really a battle, but the debate has gone on for as long as I can remember (and I have been on both sides of it).
Let’s look at the book industry, which is in a state of consolidation. Here, the debate has taken on new life because of
- a) the “digitalization” of the book industry, and
- b) the current reality of producing books in runs of 250 or less.
The reason why continuous-web inkjet presses are being installed by book printers is not that the machines are terrific bargains (they’re not). This trend is due to the fact that such presses are the only way book printers are able to produce work in small run lengths.
Inkjet presses can produce books of one. So how does one approach the binding aspect? The majority of inkjet-printed book work is soft-cover, perfect-bound products. Perfect binders have been installed in in-line configurations for some time now. Still, when trying to decide how to configure a press/finishing module, you need to ask the right questions. In order to do that, you need to understand both the print AND finishing side of the equation.
Here are my recommendations for what to consider in deciding between in- and off-line finishing:
What’s the final product?—Different end products require different levels of complexity. For example, producing folded signatures in-line (for binding later) is fairly straightforward. You either buckle fold and cut, or plow fold and cut. There are proven systems that do these operations very efficiently and reliably.
Putting the binder in-line is a different story. Book blocks have to be produced, then automatically conveyed to the binder and put into the binder clamp.
Hard cover books are even more complex. I have designed systems for in-line coil binding, side-stitching and punching, shrink-wrapping, you name it. ANYTHING is possible, but not necessarily efficient. The more complex the finishing steps are, the greater the potential for total system stoppages over the course of a shift.
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.
If you’re in need of further (free) advice, you can always contact us at: firstname.lastname@example.org