Difference between drum and precision winder.pptx

Difference between drum and precision winder.pptx

1. Difference between drum and precision winder

2. Sl no Drum Winder Precision winder 1 The drum rotates at constant rpm; hence, its surface speed is constant. The package rotates by spindle at constant rpm; hence its surface speed increases as package diameter increases. 2 RPM of package reduces as package diameter increases. RPM of package is same as drum which is constant throughout the process. 3 Yarns of smooth and delicate surface should not be wound on surface driven machines, as the unavoidable slippage between the drum and the layers of yarn would not only damage the yarn surface but also disturb the winding process leading to defective packages. Yarns of smooth and delicate surface can be wound safely on precision winding because the possibility of slippage and friction is zero in this process.

3. 4 Since grooved drum is used for winding, the wind angle remains constant through the process. As package rpm and traverse ratio remains constant, wind angle diminishes as the package diameter increases.

4. 6 Ribbon formation may occur at certain points within the package when diameter of package reaches to a certain ratio to drum diameter. Possibility of ribbon formation is negligible because traverse guide movement is controlled separately. 5 The number of coils per turn of the package decreases as the diameter of the package increases ; consequently the package remains softer at the outer layers. The number of coils per turn of the package remains constant as the diameter of the package increases; consequently the package remains harder at the outer layers.

5. Tensioner Objective To remove weak places To maintain package density To remove the adhering impurities present in the yarn Amount of tension on the yarn Medium to high speed machine (650 m/min) 10% of single thread strength High speed machine (more than 650 m/min) 12.5% single thread strength

6. Tension measurement There are two ways of measuring yarn tension in textile industry. • Measuring with hand-held tension meters • Using an active device that measures a feedback of the yarn tension in real time using sensors

7. Additive type tensioner In additive-type tensioner , the yarn passes through two plates in which one plate is base plate and the other is weighing plate as shown in Fig. 1.32. The outgoing tension in additive-type tensioner depends upon the coefficient friction between the weighing plates and the yarn (μ), and the force applied to the yarn by weighing plate is F F = mg The relationship between incoming and outgoing tension in an additivetype tensioner is T2 = T1 + 2 μ F T2 = T1 + 2 μ mg Advantage: Easy threading Tension variation in the input tension is not multiplicated . In autoconers , the top disc is positively rotated so that the wear and tear is prevented and also is provides cleaning action. Disadvantage Risk of yarn coming out of the disc. Disc may deflect, when thick places run in the yarn.

8. Post or capstan or multiplicative tensioner In this type of tensioner , a yarn is wrapped round or deflected by a post, giving an output tension which is multiple of the input tension. The output tension in this type of tensioner depends on coefficient of friction (μ) between yarn and post and angle of wrap of yarn on capstan denoted by θ . If the incoming tension is T1 and outgoing tension is T2, then μ = μ1 + μ2 + μ3 θ = θ 1 + θ 2 + θ 3

9. If all posts are made of same material, then μ = μ1 = μ2 = μ3 If yarn is making same angle of wrap in radians around all posts, then θ = θ 1 = θ 2 = θ 3 The outgoing tension is T2 T 2 = T 1 e μ 3 θ Where e = 2.718 Advantage Less danger of affecting twist Tension is applied gradually Self compensation of tension is achieved. Disadvantage Incoming tension variation multiplied. Threading is difficult.

10. Combined tensioner This is the most common tensioning device found on warping machine. This type of tensioner consists of a post and a disc. The yarn passes round a capstan post and at the same time passes between springs or dead weight loaded discs mounted on the post or capstan as shown in Fig. 1.33. The discs mounted over post provide the effect of additive type tensioner , while the partial wrap of yarn around post adds multiplicative effect on outgoing tension. Both additive and multiplicative effects are shown in Fig. 1.34. T 2 = T 1 (e μ q ) + 2 μ F

11. Different mechanisms to impart tension Ball type tensioner

12. 1. The tensioning system shown in Figure is being used in a winding system. The input and output tensions are 10 cN and 98 cN respectively. If disc (additive) type tensioners A and B are identical then calculate the weights used in tensioners A and B.

13. Let the weight of the discs is  N   cN So, the weight of each of the discs is 34 cN .