PROCESS PARAMETERS IN SPEED FRAME
|MATERIAL||YARN COUNT||HANK||TOTAL DRAFT|
|COTTON combed||36s to 40s||1.2||10|
|Cotton combed||24s to 30s||1.0||10|
|Cotton combed||14s to 24s||0.7 to 0.8||9|
|Cotton karded||36s to 40s||1.3||9|
|Cotton karded||24s to 36s||1.1||8|
|Poly/cotton||36s to 45s||1.2||11|
|Poly/cotton||24s to 36s||1.0||10|
|Poly/viscose||36s to 40s||1.0||11|
|Poly/viscose||24s to 36s||0.85||10|
|Poly/viscose||16s to 20s||0.7||8|
The above said details are for producing a good quality yarn.
This is suitable for 4 over 4 drafting
system with front zone as a condensing zone without a draft.
- With 4 over 4 drafting system, the toal draft can be
upto 13, whereas in the case of 3 over 3 drafting
system , the draft can not be more than 11.
- The Roving thickness and Roving hairiness(yarn
hairiness) will be less with 4 over 4 drafting system
compared to 3 over 3 drafting system.
- In 4 over 4 drafting system, since the fully drafted
material is just condensed in the front zone, if
the stikiness in case of cotton or static in case of synthetic is high, then the lapping tendency will be
very high on second top roller or second bottom roller. But in case of front roller, since the twist is
penetrating upto the nip, lapping on the front bottom or top roller will be less.
- As long as stickiness, honey dew in cotton and static in synthetic fibres is less, 4 over 4 drafting system with front zone as condensing zone, will give better results upto even 51 mm fibre.Of course the humidity conditions should be good.
- 4 over 4 drafting system can be described as follows
- bottom roller diameter is 28.5 mm
- Top roller diameter is 28 mm
- Break draft is between 4th roller and 3rd roller
- Main draft is between 3rd roller and 2nd roller
- Bottom apron is run by a 3 rd roller
- between front roller and 2nd roller is a condesning zone
- front zone setting 35 mm( even for 51 mm fibre)
- Main draft zone setting is 48 mm
- Back zone setting depends on break draft, but it is
normally 5o mm for cotton and T/c and
55 mm for synthetic fibres(44 to 51mm)
- 3 over 3 drafting system is good for fibres longer than 51 mm. 30 or 32 mm bottom roller diameters will be used with this system.
- Feed hank depends upon the total draft in speed frame. The drafts mentioned in the above table can be consdiered as a guide line.
- While processing 51 mm synthetic fibres, if the delivery
hank is coarser,and the delivery speed is
verh high, the break draft and the back zone setting to be widened. Break draft and break draft setting
does not depend only on T.M and fibre properties, it depends on the total production also. If the total
production is very high, with low break draft and closer setting, roving breaks due to undrafted strand
- Therefore, for very high production rate , higher break
draft and wider break draft setting is required. This
will result in very high "H" and "I" classimat faults(long
thin faults). Therefore the breakage rate in
spinning will increase.
- Break draft setting and break draft should be nominal.
Abnormal break drafts and wider break draft
settings indicate that there is a major problem in the process.
- Some times draw frame coiling is a very big problem with
synthetic fibres . If kinks are formed in the
sliver, the kink has to be removed before entering the draft zone.
- Kinks in the drawframe sliver depends upon
- drawframe delivery speed
- delivery can diameter
- coiler type
- Higher the delivery speed, more the chances for kinks to be formed in the sliver. Lower the can diameter more the kinks. If a coiler which is meant for cotton is used, the kinks in the sliver will increase in case of synthetic fibres.
- While processing synthetic fibres if kinks are more, it would be better if the creel is stopped. Sometimes it would be recommeded to use a rod between top arm and the first creel roll, so that the sliver takes a 90 degree bend before entering the top arm. This will help to remove the the kinks in the sliver. Otherwise, slubs in the roving will be more and the breakage rate in speed frame due to undrafted strand in the drafting zone will be more.
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