Finishing Web Inkjet Printing, Part 2
Last week we discussed the components that you need to put together a finishing line for a web-fed inkjet system. So now you have a good idea of what you need. But now you have to look at your own workflow, customer requirements, and need for flexibility, and decide whether this is to be an inline system, or broken up into sections. So the question becomes more strategic, and it is one only you can answer. The answer is that it depends on your product mix, your service level requirements, and your operator skills.
If you ask the printer manufacturers, they often would prefer that you separate the printing from the cutting and finishing. The reason is simple: Most inkjet systems will run with little downtime if they are kept running smoothly from roll-to-roll. All systems will suffer productivity losses if they are stopped and started while in production. Some will experience more downtime and waste than others (an analysis for a different day), but they all will be less productive if the systems are stopped and started in synch with the needs of finishing equipment. And this may be your best choice. But it also may not be.
By separating the finishing from the printing systems you get both productivity enhancements and detractions. The price you pay for separating the two processes is that you need more labor to handle the printed roll transfer between printing and finishing, you can experience more product waste due to roll damage and setup, and you can lose time in getting the first piece out the door. You can also increase your risk of wasting a specific recipient’s piece, if your product is personalized, causing more pieces to be reordered. You also have extra costs of an additional extra unwinder and rewinder.
What you gain by separating print from cut is also important to look at: You get an important buffer between the printer and the finishing system, which allows your most expensive component to be as productive as possible. If you have many different product sizes or types, you get the flexibility of using one of several different finishing lines depending on the product type, without a time-consuming mechanical changeover. Although specs are changing all the time, usually finishing lines can run faster than the print engines, allowing them to “catch up” to production if there was a mechanical maintenance item on them that needed to be replaced, like knives or other wear parts.
The reciprocal discussion can be made for keeping everything in line. You gain in less labor, faster first-product out-the door, lower chance of losing a piece or damaging part of a roll in the process. But you give up finishing flexibility, and if any part of the entire system goes down, the entire line gets shut down.
That decision gets more complex due to the growing sophistication of in-line finishing systems. One firm has been a pioneer in developing multi-capability in-line finishing, and can saddle-stitch, cold glue, or adhesive bind in-line with most continuous printers. A recent installation in Italy, in-line with a continuous web ink jet printer shows that it can be a great choice, under the right conditions. The finishing portion can divert printed sheets to either the saddle-stitcher, or the adhesive perfect binder based upon a sheet barcode. This might be the ultimate in in-line finishing.
All of these pros and cons to inline vs. near-line discussion can be quantified, and your specific “best configuration” really depends on the financial and service level requirement set. Here again is an area that an independent expert can become an invaluable resource in helping you determine how you should approach your new venture.