CARDING FAULTS, SLIVER DEFECTS, REASONS OF SLIVER DEFECTS:
If the carding process goes out of control due to any reason, the sliver resulting after carding gets faulty. The linear density of the sliver gets varied , there may be other problems too. The following are the some common defects which generally occur in the sliver during carding process:
VARIATION IN SLIVER WEIGHT PER UNIT LENGTH (LINEAR DENSITY):
Possible causes of variation of linear density of a sliver are given below:
• The weight per unit length ( linear density) of a sliver gets affected due to variation in the draft in carding machine.
• If the draft gets varied during carding process due to mechanical or any other reasons, the high variation in sliver’s linear density (weight per unit length) is resulted.
• When card clothing doesn’t work properly or it gets worn out, the high variation in weight per unit length of sliver results.
• If the feed roller bearing gets worn out, the constant feeding rate of cotton mat is affected, so that draft variation results. Thus variation in weight per unit length of sliver results.
• The auto leveller always helps to keep the linear density of a sliver during carding process. When auto leveller gets failed due to any reason, the linear density carries.
The possible causes generating neps in the carding process are given below:
• if the doffer does Insufficient stripping of fibres, it results in the form of neps generation during the carding process.
• When the under casing of the carding machine does not get cleaned properly, it result in the form of nep generation.
• Improper flat top setting causes nep formation in the carding machine.
• When the waste gets accumulated in the under casing and it becomes chocked due to carding waste, neps formation takes place.
HOLES OR PATCHES IN CARDING WEB:
The main possible reasons creating holes in the sliver web are given below:
• The poor stripping of the fibres from flat top causes holes or patches in the carding web.
• When the clothing wires of flat top get damaged or bent, patches or holes in carding web result.
• When the cylinder wires get worn out , holes or patches in the carding web generate.