Friday, July 14, 2017

Carding Process in Spinning

Carding section:
Carding is the one of the most important process in cotton spun yarn manufacturing, because it determine the quality of yarn. This is the process, by which fiber are prepared to manufacture a yarn. In this process, fibers are opened at almost single, removal of dust, trash, neps and short fiber to produce a continuous strand of fiber called sliver. Carding machine is called mother or heart of spinning, because it prepares the fiber in such a way, which is ready to manufacture yarn because disentanglement, cleaning and intermixing of fiber are happened here.

Carding machine
Fig: Carding machine
Objects of carding:
  1. Opening and individualization of fibers.
  2. Elimination of remaining impurities that are not removed in blow room.
  3. Reducing neps of fiber.
  4. Fibre mixing and blending.
  5. Elimination of short fibres.
  6. To produce a thick sliver.
Carding machine mainly consists of feeding unit, taker-in, cylinder, doffer and a set of revolving flat-bar. The surface of taker-in, cylinder, doffer and flats are clothed with pin or wire. There are also many supporting arrangement presence in carding machine to assist the carding machine for better performance, e.g. mote knifes and carding segment etc. after opening and cleaning of fiber a condenser converts the carding web into sliver shape, which is suitable for the next subsequent process.

Card clothing:
The word card clothing mean the placement or arrangement of wires a definite angle and density in a base material, which is suitable to cover the surface of taker-in, cylinder, doffer and flats. Among all the individual components of the card, the clothing has the greatest influence on sliver quality and productivity of the carding machine. There are mainly three types of card clothing, which are following:
  1. Flexible clothing
  2. Semi-rigid clothing
  3. Metallic clothing
Now a days metallic clothing is used in taker-in, cylinder and doffer but flexible clothing is used in flats. Card clothing is needed to regular grinding for its effectiveness. Grinding is a process of sharpening the wire point of card clothing.

Action in carding machine:
Mainly four types of action happen in carding machine, these are following:

1. Combing action: This action take place between feed roller and taker-in.

2. Carding action: This action take place between cylinder and flats.

3. Stripping action: This action take place

   (i) Between taker-in and cylinder
   (ii) Doffer and stripper.

4. Doffing action: This action take place between cylinder and doffer.

Function of Flat: 

The chain of flats revolves on the surface of cylinder and its functions are following:
  • Opening the flocks of fiber into individual fibre.
  • Orientate the individual fiber in longitudinal direction.
  • Elimination of impurities, short fiber and dust.
  • Untangling neps.
Function of doffer:
  • Collection of individual fiber from cylinder and condensed them into web.
  • Straight fiber is converted into hook at the end of fiber.
  • Supply the fiber web at condenser and delivery roller.
Product of carding machine:
The product of carding machine is called sliver. Sliver is a thick untwisted continuous rope of fibers, which is uniform in weight per unit length and suitable for subsequent process. The English count of card sliver is 0.1-0.14

Characteristics of card sliver:
The characteristics of card sliver is as following:

  • Fibers in card sliver are oriented in different direction.
  • Hook and also projected fiber present in card sliver.
  • The uniformity of sliver is not very good.
  • In the web there are 50% fiber exhibit tailing hook, 15% leading hook, 15% both ends hook and a small portion without hook.
Cleaning efficiency of carding machine: 80-90%

Draft necessary at carding machine: 80-120

Production per carding machine: 30-70 Kg/hr

Recent development: The following process are associated recently in carding machine.

  • Metal detector
  • Auto leveling
  • Continuous suction
  • Electronic control system and display necessary quality report.
You can also like: 
  1. Cotton Yarn Manufacturing Process
  2. Machinery of Blow Room Section
  3. Jute Yarn Manufacturing Process
  4. Analysis of Textile Filament Yarn and the Yarn Size System
  5. Properties of Cotton Yarn
  6. How to Identify the Substance of Textile Yarn
  7. Yarn Consumption Calculation for Woven Fabric
  8. Yarn Faults in Spinning | Common Types of Yarn Faults
  9. Yarn Count Numbering System and Conversions
  10. Yarn Count Measurement System