Drafting System
How much number of roller and it how way arrange is known drafting system. The drafting system is the heart of the draw frame and thus the part which exerts the most decisive influence on quality.
Drafting systems: ( Figures from W. Klein)
I) 4-over-4 roller drafting system.
II) 3-over-4 roller drafting system.
III) 3-over-3 roller drafting system.
IV) 4-over-3 roller drafting system.
V) 5-over- 4 roller drafting system (Rieter).
5-over- 4 roller drafting system (Rieter):
a) 5 top rollers on 4 bottom rollers (Two large, 90mm dia; and two small, 28mm dia)
b) Pressure rollers are suspended from two yokes and loaded pneumatically.
c) Break draft and main draft is carried out in field B and field A respectively.
d) Nip spacing is changeable through the roller 2 and 4.
e) A pressure bar ensures the firm guidance of material in main draft field and the curve alignment permits the proper guidance of web to forward.
Systems for Drafting Arrangement:
Dust is released in drafting zone and this is totally enclosed, so that cannot pass to the surrounding atmosphere. The dust laden air should be extracted by suction. For this each roller has an associated cleaning device and air passed via tubes directly to the exhaust ducts.
Causes of irregularities in drawn sliver:
a) Inherent properties of the material
b) Inherent short coming
c) Mechanical defective machinery
d) External factors – RH, temperature, workers, negligence, insufficient, management.
How much number of roller and it how way arrange is known drafting system. The drafting system is the heart of the draw frame and thus the part which exerts the most decisive influence on quality.
Drafting systems: ( Figures from W. Klein)
I) 4-over-4 roller drafting system.
II) 3-over-4 roller drafting system.
III) 3-over-3 roller drafting system.
IV) 4-over-3 roller drafting system.
V) 5-over- 4 roller drafting system (Rieter).
5-over- 4 roller drafting system (Rieter):
a) 5 top rollers on 4 bottom rollers (Two large, 90mm dia; and two small, 28mm dia)
b) Pressure rollers are suspended from two yokes and loaded pneumatically.
c) Break draft and main draft is carried out in field B and field A respectively.
d) Nip spacing is changeable through the roller 2 and 4.
e) A pressure bar ensures the firm guidance of material in main draft field and the curve alignment permits the proper guidance of web to forward.
Systems for Drafting Arrangement:
Dust is released in drafting zone and this is totally enclosed, so that cannot pass to the surrounding atmosphere. The dust laden air should be extracted by suction. For this each roller has an associated cleaning device and air passed via tubes directly to the exhaust ducts.
Causes of irregularities in drawn sliver:
a) Inherent properties of the material
b) Inherent short coming
c) Mechanical defective machinery
d) External factors – RH, temperature, workers, negligence, insufficient, management.
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