1. Roving frame/Speed frame/Simplex

2. Function/objectives/What it does?
The chief function of roving frame is the attenuation of sliver.
Insertion of protective twist in order to hold the fine strand of sliver.
Winding of roving into a package that can be transported, sorted, donned on ring spinning machine.

3. Limitations/Draw backs
Complicated machine
Liable to faults
Causes defects
Add to production costs
Roving is sensitive in both winding & unwinding
Complicated winding operations
Spindle & flyer
A cone drive transmission
A differentiate gear
Builder motion.

4. Necessity of Roving Frame
There are two principle reason:
First reason is to apply drafting.
Sliver is thick, untwisted strand that tends to be hairy and to create fly. There fore, if we directly want to produce yarn from sliver by discarding simplex, we need 300 to 500 draft to do so. But the fine twisted roving is significantly better suited to this purpose.
Second reason is related with transportation and space limitation on ring frame.
Draw frame “can” is the worst conceivable mode of transportation and presentation of feed material.

5. Operating region of Roving frame
The creel
The drafting arrangement
Roller drafting system
The apron
Applying pressure to the top roller.
The condenser
The spacer
Winding of bobbin
Package build
Bobbin drive
Cone drive transmission
The lifter motion
The builder motion
Spindle & flyer
Imparting twist
Spindle
Flyer
Design of flyer
Pressure arm

6. Drafting arrangement of roving frame
Roller Drafting system
Conventional roller drafting system:
4 over 4 without apron.
Modern Roller drafting system:
3 over 3 drafting system with double apron (Lakshmi Rieter FS185P)
4 over 4 drafting system with double apron (SKF PK 1600)

7. SKF PK-1600 drafting system
Draft range: Total draft 5 to 20
Total draft is distributed in each zone as follows:
Back zone: Break draft is applicable in here. Amount of break draft is depends upon material.
Material
Break Draft
Sliver Coarse
Sliver Medium
Sliver Fine
Sliver MMF

8. Middle zone: Front zone:
Less amount draft is applicable in here.
Condenser is used in middle zone to condense sheet like sliver.
Front zone:
Maximum amount of draft is applicable in here. Apron is used in this zone.

9. Roller type: Top rollers are synthetic rubber coated
Bottom rollers are made of steel
Front, 3rd and back rollers (bottom) are spiral fluted.
2nd roller has granulated pin.

10. Roller dia: Roller Front roller 2nd roller 3rd roller Back roller
Top roller
28 mm
25 mm
Bottom roller
30-32 mm
25-27 mm

12. The Apron:
The upper aprons are short and made either of leather or more commonly of synthetic rubbers. They have a thickness of about 1 mm and are held by tensioning device.
The lower aprons are longer and usually made of leather. They run over the guide bar, usually known as nose bar, to position close to the delivery roller.
Function:
The aprons co-operated with each other t guide and transports the fibers during drafting and they exert a very significant influence on the drafting operations.

13. Applying pressure to the top roller
The top roller must be pressed with relatively high force against the lower rollers to ensure the guidance of fiber.
Pressure are in the range of 100 to 250 N per roller which may vary as per raw material and its volume.
Pressure is applied by spring pressure, pneumatic weighting, magnetic weighting.

14. Condenser
Feature:
Condensers are mounted on a reciprocating bar behind the drafting arrangement.
The second condenser is provided in break draft field.
And the 3rd one is located in main draft field.
Function:
Spreading sliver masses are condensed to improve evenness and lead to drafting zone.
Advantage:
Reduce the high fly level and hairiness of roving.

15. Spacer
As the top apron are forced by spring pressure against the lower apron, the arrangement of this apron should permit precise adoption of minimum distance to fibre volume. In order to be able to maintain this minimum distance, spacer are replace ably inserted between the nose bar of the lower apron and the cradle edge of top apron. Spacer size is 4 to 7 mm in accordance with roving hank.

16. Imparting Twist

17. The flyer Flyer is used to impart twist
Flyer has two legs, one with hollow path or slot and pressure arm another for balancing the flyer while rotating.
Flyer is placed on spindle, it gets motion by gearing.
Flyer speed has direct influence on production.
Flyer can be varying in sizes which are specified in inch. For example, 12”X 5.5”, 12”X6” and 14”X6”. First no. indicate maximum height and second no. indicate maximum dia of wound package.

18. Pressure Arm
A steel yoke attached to the lower end of hollow flyer leg is called pressure arm.
The roving is wrapped 2 or 3 times around the yoke.
The no. of turn determine the roving tension. For higher tension, a hard compact package is obtained and if it is too high false draft or roving breakage can be caused.
Therefore, the no. of wrap depends upon material and twist level.

19. Winding Principle Bobbin leading principle (For cotton spinning)
Flyer leading principle (For jute spinning)

20. Bobbin leading Principle
Bobbin speed is higher than flyer speed at all point of winding.
The winding on speed is constant throughout the process.
With the increase of bobbin dia, bobbin speed must be decreased.
The variation of bobbin speed with the increase of bobbin dia must be constant.
Less tension on roving.
Bobbin
Speed
Empty
Bobbin
Full
Bobbin
RPM
Flyer Speed d

21. Flyer Leading Principle
Flyer speed is higher than bobbin speed at all point of winding.
The winding on speed is constant throughout the process.
With the increase of bobbin dia, bobbin speed must be increased.
The variation of bobbin speed with the increase of bobbin dia must be constant.
Higher tension on roving.
Flyer Speed
Full
Bobbin
Empty
Bobbin
Bobbin
Speed

22. Comber

23. Function
Remove short fibre below a preselected length and there by reduce length variation in the cotton mixing.
Improve fibre parallelization and fibre to fibre separation and minimize the fibre entanglement and disorientation.
Remove neps and foreign matter form the cotton.

24. Excellence of fiber quality by combing:

25. Parameter/ Specification of comber
Feed/nips 6-8 mm
Nips/min
Lap weight grs/yd
Noil % %
Efficiency 90-95%

26. Line diagram of comber Top nipper Top comb Detaching Feed roller
Lap
Feed Plate
Cylinder
Bottom nipper
Delivery
roller

29. Machine Setting Depends on Noil Extraction%
Feed Distance
Type of feed
Detachment setting
Point density on top combs
Piecing

30. Feed Distance: Feed distance means feed per nip.
Feed distance has a influence on
Noil
Quality of combing operation
Production rate.
High feed distance increase the production rate but causes deterioration in quality.
Feed distance approximately correlated with fibre length.

31. Type of feed
Forward feed has been chosen for higher production rate when quality requirement is not rigorous with a noil % of %.
Backward feed has to use for higher quality requirement with a noil % of 12 to 25%

32. The detachment setting
This is the distance between the bite of the nippers and the nip line of detaching rollers.
Higher detachment setting bring the high elimination of noil
The detachment setting normally lies in the range of 15 to 25 mm.

33. The no. of points on comb
Point density and the fineness of needle have to be adopted to the material.