Some people just don't get it. I sat through a conference call the other day where a purported expert in our field was talking about converting "graphics" (read: newsprint) papermachines to linerboard or medium production. Yes, there will be two or three of these, worldwide, that are successful, but the number that will be tried and will fail, if this person's advice is followed, will be in the scores.
While this may sound like a great idea, let's see what it will take.
Assuming the newsprint mill was a recycled mill, we'll have to start in stock prep. First, we can throw out the deinking equipment and all of its auxiliaries. Next, we'll have to check the pulper for size, rotor design, and drive specification. We may need a different bale loading system. Then the screens, cleaners, and refiners will have to be checked, reworked, or replaced. And while you are doing that, there may be some stock piping and pumps incorrectly sized now. Since this mill was making newsprint, that means it was probably losing money, and all the control systems, from stock prep, through the machine, are obsolete and parts are not available. So we'll need a modern control system from one end to the other.
On the machine, we'll have to take a look at the headbox, and if it is not multi-ply, we'll need to add at least one new top ply. The table elements will need review and probably replacing. The press section was not designed to handle linerboard, so add a new press section, two pass, long nip, to the shopping list.
We'll be needing some more dryers to dry the heavier sheet of linerboard. This will affect building ventilation, too, and we'll need to check the machine drive to see if it can handle the increased load.
The calender stack may need new rolls and the reel is probably not equipped to handle the heavier rolls of product. The winder is unsuitable and needs replacing. If we had a wrapping system, we'll want to take that out and put in a bander.
Oh, and did you remember to check the trim width? In fact, you may want to do that first thing, for when you do, this idea will likely be over in an hour or less.