Defects in Carding:
Sliver variation
Cloudy web
Hole in web
High nep count
Web slagging
More cylinder loading
Broken or malformed selvedge
Excessive blowout
Disappearing web
Flat strip too heavy
Taker-in snatch
Loss in yarn strength
Causes for Defects in Carding
Important causes for defects in carding are mentioned below:
Causes for Neps Formation
Insufficient stripping
Dirty under casing ( grid bar)
Uneven flats setting
Under casing chocked with fly ( waste)
High roller speed
Causes for Holes or Patches in Card Web
Poor flat stripping
Hooked or damaged wires on flats
Damaged cylinder
Cluster of cotton embedded on cylinder wires
Preventive Action in Carding Process
In order to avoid sliver variation draft calculation should be correct. Testing of sliver must be on time at least 3 times during shift.
High sliver variation problem may also be due to maintenance problem. So concentrate on maintenance. If our maintenance of machine will be there, then it will get more efficiency and better quality will be achieved. If expiry time of some part of the machine is there, then on time it must be replaced.
Now a days in advance technology the cards, auto leveler are electronic which adjust thesliver weight automatically. For getting better result with automatic auto leveler, it is also necessary to check sliver weight manually as well.
Preventive Action for Nep Formation
Over hauling of machine must be on time. During over hauling, setting of every part of the machine has to be checked. Flat setting play very important role for reducing nep formation. So flat setting must not be uneven.
Suction waste point should be properly working. This point must not be chocked. If there will be chock then neps formation will take place. Suction waste point also to be checked manually as well.
This problem is also related to maintenance. Over hauling of every machine must be on time. Wire of flats and cylinder have specific time limit of production. After that specific time limit it must be changed. As these play very important role by quality point of view.
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