What happens, especially with sword plates, is the ablation can build up inside the platesetter and land on the lens. The Kodak machines tend to have the huge vacuum cabinets with a filter, where the Screen machines have a smaller system, which is fine for most plates. It's especially bad with the 8600 machines, which have 64 lasers instead of 32, but have the same debris removal system as their 32 beam systems. When you open up a 64 beam machine running Sword plate, it makes me want to cry. It's such a nice stable workhorse, and now it looks like someone lit off a smoke bomb in it. Brown powder everywhere. I've seen it interfere with optical sensors and create malfunctions.
So, what happens is the ablation coats the optics and now the laser power has to increase to make up for the losses due to the dirt on the optics to end up with the same power hitting the plate. So you're running your laser system harder, for nothing. Also, the dirt doesn't just block laser light, but scatters it, and our goal is not just power, but power density to expose properly. With the dirty optics, it's more of a felt tip pen than a sharp fine pen that you're imaging the plate with. So a cleaning of the optics is like sharpening a pencil, as I tell my customers, and lines go away. There shouldn't be a need to increase power every month, as some have said. The power of the lasers is a very stable system, and the emulsions aren't changing all the time, and if they were, they might need LESS power sometimes, right? Why always up and up? So, you can guess I'm not a fan of the Sword, except for the money I make doing the service.
