Every winder is equipped with an adjustable tension. Most winders can taper this tension automatically as the roll diameter builds. Some winders can even program a curve. Whether we have a simple set-point, linear taper or arbitrary curve, we must choose how to set the tension. The best setting is determined the same way here as with any other adjustment: economics. Specifically, we choose a tension which avoids the most, but not necessarily all, defects. We can group defects into the following categories: low tension, high tension, taper tension or independent of tension. Examples of low-tension defects are out-of-round rolls, some rough roll edges and loose cores. Examples of high-tension defects would include blocking, gage bands and some crushed cores. Some defects are independent of tension, such as wrong diameter rolls due to an operator setup error. A couple of defects, namely subsets of starring and tension, are very sensitive to a lack of taper.
展开▼
