PROCESS PARAMETERS IN SPEED FRAME

Roving machine is complicated, liable to faults, causes defects, adds to production costs and delivers
a product that is sensitive in both winding and unwinding.The following parameters are very important
in SPEED FRAME. They are

• Feed hank
• Delivery hank
• Roving tension
• break draft
• Drafting system
• Bottom roller setting
• Top roller setting
• condensers and spacers
• Twist in the roving
• Bobbin content
• flyer speed
• Creel and creel draft
• Drawframe sliverand can
• Bobbin height
• Breakage rate
• Piecings                                                                                                                                                     DRAFTING SYSTE                                                                                                                 Since modern Ringframes are capable of handling higher drafts in ringframe without quality detrioration
  It is better to have coarser hanks in the speed frame. This helps to increase the prodction in speed frame.
  Investment cost will also be less,because the number of speedframes required will be less and the cost per mchine
  is also high. The following table can be a guidle line for speed frame delivery hank  
  

  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
  1. bottom roller diameter is 28.5 mm
  2. Top roller diameter is 28 mm
  3. Break draft is between 4th roller and 3rd roller
  4. Main draft is between 3rd roller and 2nd roller
  5. Bottom apron is run by a 3 rd roller
  6. between front roller and 2nd roller is a condesning zone
  7. front zone setting 35 mm( even for 51 mm fibre)
  8. Main draft zone setting is 48 mm
  9. 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
  will increase.
• 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
  1. drawframe delivery speed
  2. delivery can diameter
  3. 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.