The document summarizes the pre-spinning carding process. It discusses that carding is used to convert tufted fiber material into a single fiber web by passing it between wire points or saw teeth. The objectives of carding are to open fibers individually, remove impurities and dust, disentangle neps, blend and orient fibers, and form slivers. It also describes the basic components and working of a carding machine, which uses cylinders and flats to open fibers that are then formed into slivers.
10. YM-2012 Card objectives n working principle.pdf
1. Pre Spinning Processes
(YM-2012)
M Irfan
Department of Textile Engineering
National Textile University Faisalabad
Reference:
The Rieter Manual of Spinning
3. What is carding
• The conversion of tufty material into a single fiber state (filmy web) by passing it
between two surfaces containing wire points or saw tooth is called carding.
M Irfan, PhD
• Machines used to carry out this work are
called cards
• Two famous saying about carding
demonstrate the importance of carding
process in the yarn manufacturing
• “Card is the heart of spinning”
• “well carded half spun”
4. Different types of card machines
• One classification is
• Revolving flat card
• Mostly used in ring spinning
• Roller card
• 3-4 inch diameter rollers instead flats
• Another classification is
• Single card
• Used in ring spinning
• Double or tendem card
• Improved quality and blending
M Irfan, PhD
Tendem card
Single revolving
flat card
6. Objectives of carding
• Fiber-to-fiber opening
• Fibers need to be opened to individual fiber level for cleaning
• Blowroom opens material to tuft level (very small tufts)
• Carding action opens the material to individual fiber level
• Elimination of impurities
• Foreign matter or impurities are removed at card
• Impurities mainly drop in taker-in region, only small amount is removed in flat
strippings or drop at other positions
• High degree of cleaning can be achieved at card (80-95 %)
• 95-99 % impurities can be removed both by blowroom and card
• 0.05-0.3 % impurities can still be present in card sliver
M Irfan, PhD
7. Objectives of carding
• Elimination of dust
• Card is a good dust removal machine
• Card can remove dust particles attached firmly with fiber surfaces
• Free dust removal also takes place as in blowroom
• Significant fiber/metal and fiber/fiber friction is present in card
• Neps removal or disentanglement
• A mass of entangled fibers is known as nep
• Neps increase in blowroom from machine to machine
• Due to rolling of fibers during transportation
• Neps are unentangled at card
• Small amount of neps are removed in flat stripping
M Irfan, PhD
neps
8. Objectives of carding
• Neps removal or disentanglement
• Factors affecting disentanglement at card
• Low fiber density at cylinder (larger cylinder width)
• Closer setting between different clothing surfaces
• Sharper clothing
• Optimal speed of take-in (not too low)
• Low doffer speed
• Low production or throughput
M Irfan, PhD
9. Objectives of carding
• Removal of short fibers
• Short fibers are removed in flat strippings at card
• Card removes 1-2 % flat strippings. Half of these strippings are short fibers
• Thus card removes less than 1 % short fibers from raw material which is not noticeable in
staple diagram
• Short fibers are removed if they are pressed in clothing
• Longer fibers have more contact with cylinder clothing, they are carried with cylinder
• Short fibers have less contact with cylinder clothing, they are caught in flat clothing
and are pressed into flat clothing and are carried away
M Irfan, PhD
10. Objectives of carding
• Fiber blending
• Short term fiber blending takes place on card
• Long term blending is not possible because fibers spend short time in card
• Transverse blending and fiber to fiber blending is achieved
• Fiber orientation
• Longitudinal orientation of fibers takes place on card machine
• Fibers are more parallel on cylinder but less parallel on doffer due to formation of
web
• Partial longitudinal orientation is obtained but not perfect orientation
M Irfan, PhD
11. Objectives of carding
• Sliver formation
• Formation of sliver takes place on card
• Sliver is the first intermediate product that is formed during yarn manufacturing
• Sliver is a thicker linear strand of fibers which is untwisted
M Irfan, PhD
12. Objectives of carding
• Fiber to fiber opening
• Elimination of impurities
• Dust removal
• Short fiber removal
• Fiber blending
• Fiber orientation
• Sliver formation
M Irfan, PhD
13. M Irfan, PhD
1 Conveying
duct
2 Feed Chute 3 Transport Roller
4 Feed Roller 5 Taker-In/
licker-in
6 Knife Grid
7 Suction duct 8 Cylinder 9 Front Carding
Segment
10 Flats 11 Cleaning Unit 12 Post carding segment
13 Cylinder
cover plate
14 Doffer 15 Stripping Device
16 Calender
Roller
17 Can 18 Coiler
14. Working of a card machine
• Raw material supply into the chute feed (2) via ducts (1)
• Compressed batt is formed
• Transport roller (3) feed the batt to the feeding arrangement (4) (feed roller and
feed plate)
• Feed assembly feeds material to taker-in (5)
• Taker-in opens the fibers, pass them overs grids (6) and transfer them to the main
cylinder (8)
• Impurities liberated at taker-in and card segments (9) are removed by suction
duct (7)
• Carding process takes place between cylinder and flats (10) and fibers are opened
to individual level
M Irfan, PhD
15. Working of a card machine
• Cleaning assembly (11) removes fibers, neps and trash from flats
• Grids or cover plate (13) is present under the cylinder
• Opened and aligned fibers on cylinder (9) are taken by doffer (14) in the form of
web
• Stripping unit (15) removes web from doffer and convert it into sliver
• Calendar roller (16) compress the sliver and coiler (18) deposits the sliver in cans
(17)
M Irfan, PhD
