Last month we discussed where to find general information about web handling. This background is vital because it serves as a skeleton to support information specific to our processes. Without this background, our machinery and processes would be an unintelligible mess of unconnected data and observations. Having a web-handling background, however, is incomplete. So what if we know about the science of wrinkling? We need further information from our process to know which type of wrinkle we're battling at this moment. So what if we know about the science of winding defects? To proceed to a solution requires data to determine which telescoping case we have. Where do we get specific information such as this?

The most obvious source of web-handling data is from sensors. This would include load-cell tension readings, if not motor loads, nip pressure settings, and temperature, if heating or cooling were involved. Lab instruments can quantify strength, stretchiness, thickness, color and any number of important parameters. Some plants are record a lot of this type of information. One large paper mill continuously gathers and records measurements from over 10,000 sensors.

Unfortunately, many web-handling problems do not have practical or even usable sensors. For example, the most common problem in our industry, wrinkling, is not measurable by sensor. Baggy webs are barely measurable and only then at great cost or difficulty. The situation is no better with winding. Of the hundred or so types of winding defects, very few can be measured.

So, what are we supposed to do if we can't easily measure things we are most interested in? Simple: Open your eyes. While wrinkling is not measurable, it's easily observed. Your eyes can determine whether it's an MD wrinkle, diagonal-shear wrinkle, TD wrinkle or so on. Same thing with bagginess. While meaningful measurements are truly painful to gather, your eyes will clearly tell you the location, width and severity of a slack lane. Same thing with winding defects.

The problem is that technical people don't like that answer. They insist on measurements because that is how they were groomed. Operators, on the other hand, were not indoctrinated in measurements. It's natural for them to "notice stuff" because they've been sensitized from the very first day on the job to pay attention to how their product looks. It does not take them long to figure out that how their in-process product looks is no less important.

Thus, my most important troubleshooting tip: Talk to—and listen to—the operators. In at least half of my problem-solving missions, the key piece of data came from an operator rather than engineer, sensor or other source. Sadly, many technical people don't even know how to talk to an operator. They often look down at the less (formally) educated and their demeanor shows it. The operator may not respond well to this arrogance. When I work with an operator, they are not my equal. They are my superior. They know things I don't, and what they know is vital to figuring this problem out.

920/725-7671, drroisum@aol.com, www.roisum.com