So, why bother with them if they are expensive, mark the web and don’t spread. Well here the story gets a bit nuanced. I know a few people that I mostly trust that swear by them for very specific applications such as thin metal foil which is a bugger for wrinkles. If this is true, then the mechanism is likely based on double or compound curvature (rather than some new as yet undescribed principle based on grooving). When the grooves bend the web into troughs roughly in the CD, then wrinkles that are mostly in the MD will not form. We can get a similar effect using the big and slippery principle taught by the late great Dr John Shelton, so I still don’t quite get the motivation for herringbone rollers. Still, I try to keep my eyes and ears and mind open for further data points and am quite willing to change my mind should new evidence indicate the need for a 180 turn in thinking.
Tocomplete my reporting, I will mention another application that I am very familiar with is chevron grooving on two-drum winder drums used in the paper industry. Here the paper industry uses a different word, chevron, for what is essentially the same pattern that converting calls herringbone. This old school grooving was used on some front drums before my time as a traction element and I have seen many still in use when I first started work. I have little doubt that the grooving improved traction on wound rolls. However, the chevron grooved drums were very expensive to make, often marked the web, were very noisy at paper winder speeds and, more importantly, traction is almost never ever lost on that location. So again, why bother? Chevron grooved winder drums thus all but disappeared from new paper winders 40 years ago.
This is all I know or can guess. If any readers have experiences to add, please weigh in.