Carding process, Carding process in spinning, Carding machine process, carding process in textile, carding machine, card machine, pkspiny.

CARDING

    GENERAL INFORMATION

    Introduction

 The carding operation is the most important phase of short staple spinning. “Well carded is half spun” is an old expression that applies equally today. In the modern carding process there are three basic functions that have to be considered, namely:

·    lap formation using the chute feeding system,

·   the carding steps to produce a sliver and the control systems to facilitate the production of high quality sliver at increased production rates

 

  Carding functions

 

• The chute should supply a matt to the card which is uniform in mass and consistent in fiber openness,

•  the card opens the fiber tufts into individual fibers,

•  removes a high proportion of the neps,

•  in the case of cotton, removes a majority of the trash,

•  blends fibers in the short term,

•  initiates fiber orientation,

•  produces a continuous sliver of controlled mass.

 

Needless to say, for the card to perform well it must be provided with well opened, well cleaned and adequately mixed/ blended material.

 Cards that are set and operated correctly are the most effective machines in the line for removing trash and neps, but it is erroneous to leave all of the work to the card.

 The blow room should function to:

•  mix and open the fibers,

•  remove an optimal amount of trash,

•  minimize nep formation

•  minimize fiber damage.

•  minimize the loss of good fiber in the waste.

 

A goal of the blowroom is to:

•  remove 70 to 75% of the trash in the bales,

•  not increase the nep level by more than 100%,

•  not increase the short fiber content (SFC).

•  not reduce the staple length of the fiber.

 

   Principal features

    Current carding machines

 The C 51 and the C 51 Hi•Per•Card represent the current line of Rieter’s cards that have evolved through many models over many years. No doubt there will be model changes in the future that will encompass new concepts.

The primary features of the A70 chute are:

 The aerofeed A 70 chute for cotton, man-made fibers and blends up to 65 mm (2.5•).

•  Mat weight - of Cotton from 400 to 800 g/m.
•  Man made fibers from 300 to 700 g/m.
•  A 70 Chute production rate up to 120 kg/h
•  Double chamber with fiber opener feeding the lower chute chamber to produce a controlled matt with feeding functions integrated with the carding requirements.
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     Aero feed system

 In the Rieter blow room one or two fine opener / cleaners open the fibers and feed them into the distribution system. The fibers pass through the fan and are blown into the transportation ducts that pass over the tops of the chutes.

The top chute of the A 70 has a perforated side sheet though which the transporting air flows.

 All of the transportation air has to pass through the perforated sheets, and depending upon the degree of chute filling the fiber passes to the chute with the least resistance to air flow.

 When all of the chutes are full there is reduced airflow and a pressure builds up in the ducts. A pressure sensitive switch, between the fan and the first chute detects the pressure increase and stops the feeding machine.

 Similarly, when the air pressure drops to a pre-set low level the feeding machine is again started.

    Function of the A 70 Chute

 The A 70 chute is part of the aerofeed pneumatic card feeding system. It can be used in a linear arrangement or in the “U” form.

 A cross-sectional view of the A 70 chute is shown in the illustration.

 The fan blows the fibers through the fiber duct (1). Gravity and the airflow cause the fibers to fill the upper feed chute (2).

 

The transport air passes through the perforated sheet into the extraction air duct.As fiber is fed to the lower chute, the perforated sheet is exposed allowing more air to flow bringing additional fiber to the upper chut.

At the bottom of the upper chute is a pair of feeding rollers (3) supplying fibers to the opening roller (4) that opens the material in tufts to feed the lower chute (5).

A photocell sensor monitors the material level in the lower chute a regulates the speed of the feed roller to maintain a controlled level and matt mass.

The matt weight is established by adjusting the positions of the ch walls. The matt is taken from the bottom of the lower chute by the feed rollers (6) and fed to the card.

 

   Features of the C 51 Card and C 51 Hi•Per•Card.

 

Carding production rate is up to 120kg/h with the Hi•Per•Card option depending upon the type of fibers being processed, the sliver weight and the end uses.

 The following diagram shows the elements of the card:

  Primary features include,

   Unidirectional feed and licker-in

 ·  Unidirectional feed to minimize fiber damage at the licker-in,

·  Adjustable nipping distance for short staple fiber,

·  Matt feed trough controls the fibers. Any change of matt thickness is detected as a movement of the trough and the leveling system responds by changing the card draft.

·  Modular licker- in section for all applications,

·  High performance trash separating knives and carding segments under the licker-in.

    Cylinder wire and flats

 

·         Cylinder clothed with high performance wire depending upon fibers and applications.

·         Improved setting and carding action using revolving flats with ground down heel,

      

·           TREX and TREXplus with stationary carding plates on the cylinder in positions before and after the flats carding zone.

·           Improved suction and flats cleaning,

·           “Cleanmaster” fixed flats system as an option instead

of revolving flats. Currently used only for man-made fibers.

Modular licker-in Unidirectional feed Flats with Ground down Heel TREXplus for Hi•Per•Card

   IGS-Classic

(IGS –classic)  programmable system to automatically sharpen the cylinder wire during production. Maintaining sharp wire extends the lifetime of the wire and maintains an effective nep removal performance. 

⦁ IGS – top   Automatic system to periodically sharpen the flats during production to minimize the deterioration of the carding action due to dull flats,

Automatically maintains the sharpness of the Flats.

   IGS-Top

⦁ Improved consistency of carding quality with the use of IGS – classic and IGS – top,

⦁   No machine down time or loss of production due to grinding the card clothing. (The flats have to be periodically reset to the cylinder to maintain carding performance)

   Automatic waste removal

Automatically maintains the sharpness of the Flats.

⦁   Separation of the licker- waste from the flats and fly waste in an automatic waste removal system to maximize the value of the waste.