Question

The number of coils /D.T$_t$ remains constant from D$_0$ to D$_{max}$ in

• A. Drum winders
• B. Precision winders
• C. Ply winders
• D. Doubler winder

Hint:

• Precision Winding Characterized by a fixed gear ratio between spindle drive (package rotation) and traverse drive (yarn guide movement).
• This results in a constant number of coils per double traverse and a constant winding angle throughout the package build.
• Produces dense, stable packages ideal for subsequent processes or dyeing.
• Random (Drum) Winding Results in varying coils per traverse and varying winding angle.

Answer 1

The Correct Option is B

The term "number of coils / D.T$_t$" (coils per double traverse) remaining constant throughout package build-up (from initial diameter D$_0$ to maximum diameter D$_{max}$) is a defining characteristic of precision winding.

• (a) Drum winders (Random winders): The package is friction-driven by a drum. The relationship between package rotation and traverse motion is not precisely fixed, leading to a varying number of coils per layer and varying winding angle as the package diameter increases. This results in a "random" lay of yarn.
• (b) Precision winders: The package is spindle-driven, and the traverse mechanism is positively geared (synchronized) with the spindle rotation. This ensures that the number of coils laid down for each double traverse of the yarn guide remains constant. Consequently, the winding angle (helix angle of the yarn on the package) also remains constant. This produces very stable, dense packages with a highly regular structure.
• (c) Ply winders & (d) Doubler winder: These terms describe the function of winding multiple ends together. The winding mechanism itself (which dictates coil lay) can be either random or precision, depending on the machine design and application.

Therefore, the condition of constant coils per double traverse is a hallmark of precision winders. \[ \boxed{\text{Precision winders}} \]