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November 2017

What are the important setting points in a flat card?

What is the setting you will recommend for low grade cotton/for 1.25" cotton /for fine mixing/ for coarse, medium mixing and describe their influence on production & waste?

Carding Machine Settings
Carding Machine Settings

The Knowledge of optimum setting of the various organs of card and their effect on quality are essential for successful maintenance of carding process. The optimum settings are influenced by the following factors.
  1. The staple length of the material.
  2. The amount of trash to be removed,
  3. The hank of lap fed.
  4. The expected waste percentage.
  5. Type of clothing
  6. Mechanical condition of the machine.

Settings:

1. Feed plate to licker -in

0.009 inch to 0.012 inch

The object of this setting is to detach cotton in very small tufts from the lap without damaging the fibres. If the setting is too close, the longer fibres will be damaged and the waste increased. If it is too wide, the cotton will be detached from the lap fringe in large tufts or even lumps. When this setting is correct the cotton is evenly distributed on the main cylinder surface.

2. Licker - in to mote knives

  1. Upper knife -10 Thou (10 Thou means 0. 010 inch)
  2. Bottom knife- 12 to 15 Thou.

The object of this setting is to extract vegetable impurities like seed hits, 1 eaves, husks and other foreign impurities from cotton.
If the setting is too close, loss of good cotton may occur and if it so too wide, the mote knives operate inefficiently.

3. Licker in to under grid

5/16 inch.

The object of this setting is to hold the good fibre on the Licker in and fall down the dust, dirt, short fibres through under grid.
Close setting increases the fibre extraction with the waste.

4. Licker in to cylinder

 0. 007 inch

The object of this setting is to transfer the fibres to the cylinder.
The settings may be as close as 0. 005" for effective transfer of fibres, if the condition of taker-in is good (i. e) dynamically balanced, an unreasonably wide wetting will fail to transfer the fibres leading to formation of neps.

5. Back plates

  1. Lower edge: 0.022 inch
  2. Upper edge: 0. 017 inch

The object of the back plate setting is to control air currents and to some degree licker-in fly.
Wider setting other than given above will result in cloudy web due to uneven distribution of the fibres across the cylinder because of the uncontrolled air currents.

6. Cylinder to flats

0. 010 inch

The object of this setting is to card the fibres well so as to produce a clean web.
A close setting tends to produce cleaner web whereas wide settings results in more neps in the web.

7. Front plate

A.  Top % plate:

  1. Upper edge- 10 thou to 60 thou.
  2. Lower edge-32 Thou

B. Front bottom plate:

  1. Upper edge:32 thou.
  2. Lower edge:15 thou.

The object of Top % plate setting is to control flat strip waste. Wider front plate setting causes more flat strips waste and good cotton is lost as flat waste. If the setting is very close flat waste will be deposited on the cylinder causing poor web. The object of bottom plate setting is to transfer cotton from cylinder to the doffer evenly. Wider settings will cause uneven web due to uncontrolled air currents.

8. Cylinder to doffer

0. 005 inch

The object of this setting is to take off all good cotton from the cylinder by doffer. The setting may be wider as much as 0. 007" for heavier laps. Wider settings will result in patchy or cloudy web.

9. Cylinder to cylinder under casing

  1. Back 0. 012 inch
  2. Middle-0. 032 inch
  3. Front -0. 064 inch

Object of this setting is to keep the fibres on the cylinder and to let the dirt, dust and short fibres fall out. These settings influence air currents and production of fly and too wide settings causes loss of fibre.

10. Doffer to doffer comb

12 to 15 thou

The object of this setting is to remove as much good fibres as possible without touching. For heavy slivers and production the settings may be little wider.

11. Plats to flat stripping comb

32 thou

The correct setting is that the comb should not touch at any point and remove the strips effectively.


Ring Spinning Open-end Spinning
Bobbin rotates constantly for insertion of twist Spool does not need to be rotated to insert twist
Cannot handle spools of bigger size Much larger spools can be wound
Can spin finer yarns 3-5 times faster than ring spinning
Uniform and strong yarn Uniform but flexible yarn with better dye ability
Combed yarns (finer) Carded yarns (coarser)
Yarns for varied applications Yarns for heavier fabrics such as denims, towels and poplins
Stronger 20% more twisted but 15-20% weaker as the yarn is coarser
Suitable for all staple fibres Not suitable for man-made staple fibre spinning except rayon as the fibre finish clogs the rotor


Ring Spinning vs. Open-end Spinning
Ring Spinning vs. Open-end Spinning




Open-end or Carded or Break or Rotor Spinning

  1. The twist in the yarn being determined by the ratio of the rotational speed of the rotor and the linear speed of the yarn.
  2. The production rates of rotor spinning is 6-8 times higher than that of ring spinning and as the machines are fed directly by sliver and yarn is wound onto packages ready for use in fabric formation.
  3. The yarn is a lot cheaper to produce.
  4. Rotor spun yarns are more even, somewhat weaker and have a harsher feel than ring spun yarns.
  5. Rotor spun yarns are mainly produced in the medium count (30 Ne, 20 Tex) to coarse count (10 Ne, 60 Tex) range.
  6. End uses include denim, towels, blankets socks, t-shirts, shirts and pants.
  7. The use of this system has two basic advantages. It is fed by sliver, not as with the ring frame by roving, and so eliminates the speed frame from the process line. It can also be modified to remove any remaining trash, thereby improving the yarn quality.
  8. Open-end yarns tend to be more uniform, lower in strength, more extensible, bulkier, more abrasion resistant and more absorbent. It is likely then with all of these differences, only some of which are beneficial, that open-end spinning will not replace ringspun yarn as originally thought, but will be a complimentary product.
  9. Open-end spinning operates at a rate up to five times that of ring spinning and can be effectively used for cotton, polyester-cotton blends, as well as other short and medium staple systems.
  10. Synthetic staple fibers such as polyester alone can not be effectively open end spun due to dusting of oligomer from the fibers that interferes with the spinning action of the rotor.
  11. Advantages of Ring Spinning
  12. Production of high strength yarns.
  13. Spinning of fine count yarns.
  14. Proper for special yarns.
  15. It is universally applicable (any material can be spun).
  16. The know — how for operation of machine is well established accessible to everyone.
  17. It is flexible as regards quantities (blend and lot size).
  18. Since the speeds in drawing section are best controlled, yarn evenness is excellent. But if short fibers are too much, yarn unevenness occurs.
  19. Fine yarns can be produced as compared to open-end system.


Disadvantages of Ring Spinning

  1. Process stages are more numerous. Roving stage exists as an extra process compared to the other systems.
  2. Yarn breakages are more numerous as a result of ring traveler friction and yarn air friction. Interruptions, broken ends and piecing up problems exist because of the yarn breakages.
  3. The high speed of the traveler damages the fibers.
  4. The capacity of the cops is limited.
  5. Energy cost is very high.
  6. Low production rate.
  7. New spinning processes have difficulty in gaining widespread acceptance. Owing to their individual limitations, the new spinning processes are confined to restricted sectors of the market.
  8. The ring frame can only survive in longer term if further success is achieved in automation of the ring spinning process. Also, spinning costs must be markedly reduced since this machine is significant cost factor in spinning mill.
  9. The cost structure in ring spinning mill is shown in the graph.

Ashish Hulle

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