Random versus Precision winding

Lets talk about the geometry of making good yarn packages. Most home winders for fiber artist create a random wound package. What is a random wound package you ask? It has no discernible patterning like you see in the above packages. There are air gaps in the lay of the yarn and paying off it is more consistent in tensioning, especially in high speed applications. There is a drawback however, the amount of yarn on a cob or empty cone is reduced. Precision cross wound packages like in the picture above are primarily wound on high speed industrial winders, and will have a distinct patterning, notice the diamonds it creates on the package. When the package is running on a winder you will notice distinct fields or bands appear and when the machine is stopped you will see diamonds, very large diamonds or small. A crossing or traverse ratio dictates what winding pattern you have created. It is basically, a ratio of the spindle speed versus traverse speed x 2. For example, if we have a 5-1/3 winding ratio, it would be expressed in decimal at 5.333333. The amount of fields is 16 while running, you get this number by multiplying the denominator 3 by the 5 and then add the numerator, 1. The denominator represents the reversal points on the package at each end. You will in this case have 3 reversal points. Now you will never have a true fraction it will always be a little over or a little under under. If we ran this wind completely like it is, we would create a "dead wind", this is when the yarn lays directly on top of each other on every layer, and see you see a staircases effect and will see holes in the package, and eventually it will make a hexagonalish package. So we always go a little over or under the wind. We call this in winding, a fore or aft wind. For example, 5.326677 would be a fore wind, and a 5.349877 would be an aft wind. The patterning of diamonds will be the same on a fore and aft wind, however, when viewed from the side of the package, the trailing edge of strand of the yarn on the diamond will be reversed and vice versa. There are infinite amount traverse ratios possible to create different patterns. I have been the industrial yarn winding process for many years, so I wanted to share a little technical knowledge with you in the winding process.