There are two widely used types of winding machine:
1.) drum winders (used to wind staple-spun yarns into random-wound packages)
2.)precision winders (for winding filament yarns into precision-wound packages).
1.) drum winders
They are also called as “Random Winders”. Drum-winding machines rotate the forming package through surface contact with a cylindrical drum, and the yarn is traversed either by an independent traverse, typically a wing cam, or by grooves in the drum. Figure 1 illustrates the two types of traverse systems
Fig 1: Winding traverse motion
There are several different independent traverse systems, but the simplicity of the wing cam makes it a useful example to describe. As shown, the end, A, of a yarn guide bar moves the yarn while the other, B, is made to move around the periphery of the cam, traveling one circuit of the periphery per revolution of the camshaft. As B makes one circuit of the cam, A reciprocates, moving the yarn through a return traverse (i.e., double traverse) along the length of the bobbin. The reciprocating yarn guide limits the winding speed because of the inertia on reversals. A very high rate of traverse is impeded by the mechanics of the guide system, since forces of 16 to 64 times the weight of the yarn guide can be present during the reciprocating action. The reciprocating guide can be replaced by a spirally grooved traverse roller, which moves the yarn along the traverse length. In this case, only the yarn undergoes reversal as it is held in the traversing groove of the rotating roller, and speeds in excess of 1500 m/min can be achieved. A further advantage of the grooved traverse roller is that, as a result of tension, the yarn being wound enters the groove without the need for threading up as is required with the independent traverse system.
With the grooved drum system, the surface speed of the drum, and the traverse speed are kept constant. A continuous helical groove (i.e., interconnected clockwise and counter clockwise helical grooves) around the drum circumference guides the yarn along the traverse length as the yarn is wound onto the bobbin. A continuous helix has points of crossover of the clockwise and counter clockwise helices. To retain the yarn in the correct groove during its traverse, particularly at the intersections, one groove is made deeper than the other, and the shallower groove is slightly angled.
They are also known as Spindle driven Winders. the Principle of precision winder is as shown in figure.
With precision winders, the package is mounted onto a drive spindle, and a reciprocating yarn guide, driven by a cylindrical cam coupled to the spindle drive, is used to move the yarn along the traverse length. The reciprocating yarn guide limits the winding speed because of the inertia on reversals.
The term precision refers to the control of positioning each layer of yarn as it is wound onto the bobbin. There is a precise ratio of spindle to traverse speed. Therefore, as the package diameter increases, the wind and TR are kept constant.