Types of tensioning device
There are basically three types of method by which tension is applied to yarn. They are as follows
Capstan method
Additive method
Combined method
Capstan Method
This is the simplest form of yarn tensioning device where the yarn is passed around posts where the tension on the yarn is provided from the friction between the posts and yarns.
This follows the classic law of
Output tension = Input tension x eµθ
Additive method
In this method the yarn is passed through the middle of two surfaces in contact. The force is applied from above to give suitable tension to the yarn.
Combined method
The combined system is a combination of capstan and additive method. This device is a complicated system which on allows the addition of tension. We cannot decrease the tension with this device. It is seldom used.
Important effects of tensioning device
If the tension is too high then
The yarn can be damaged
The rate of yarn breakage will be high
The elongation property of yarn will change
If the tension is too low then
It can lead to unstable or loose package formation which will cause problems during unwinding
Variation in yarn in different parts of a wound package will cause undesirable effects
For man made filament yarn improper tension will cause
Change in molecular structure
Variation in colour shades
For staple or spun yarn too high tension will cause
Yarn breakage at thin places
Factors influencing the selection of Tensioners
The device must be reliable to control uniform tension
The device must be easily thread able
It must not introduce or magnify tension variation
It must not introduce variation in twist
It must not be affected by wear
It must be easily adjustable
It must not be affected by oil and dirt
It must not encourage dirt collection
It must be easily cleanable
The operating surface must be smooth
It must be cheap
No Comments
***www.TextileTune.blogspot.Com***