University of Management & Technology, Lahore, Pakistan
“Card is the heart of the spinning mill” and “well carded is half spun” are two proverbs of the experts. Carding is one of the most important operations in the “spinning process” as it directly determines the final features of the yarn. High production in carding to economise the process leads to reduction in yarn quality. Higher the production, the more sensitive becomes the carding operation and greater danger of a negative influence on quality. The technological changes that has taken place in the process of carding is remarkable. Latest machines achieve the production rate of 60-100Kgs/hr, which used to be 5-10Kgs/hr, upto 1970.
THE PURPOSE OF CARDING:
- To open the flocks into individual fibers.
- Cleaning and elimination of impurities.
- Reduction of neps.
- Elimination of short fibers.
- Fiber blending.
- Fiber orientation.
- Sliver formation.
- Feeder Hopper
- Linker in Cylinder
- Revolving Slates
- Brushing Rollers
- Drawing Unit
- Trumphet Guide
- Grid Roller
- Sliver Cane
There are two types of feeding in the cards:
- Feeding material in the form of scutcher lap.
- Flock feed system (flocks are transported pneumatically)
POINT TO BACK ACTION:
Linear density of the lap is very good and it is easier to maintain (uniformity) the whole installation is very flexible deviation in card output will be nil, as laps can be rejected. Lap run out is an additional source of fault, as it should be replaced by a new lap. More good fibers loss during lap change more load on the taker-in, as laps are heavily compressed. The is opened in it and pass through small grids on it.
|Diagram of carding|
POINT TO POINT ACTION:
The cylinder get opened with sharp teeth and then pass over to doffer. High performance in carding due to high degree of openness of feed web. Cylinder is located below the plate is pressed against the cylinder by spiring force.
The cotton fibers that are on the teeth of cylinder are then cleaned by the brushes at the upper part of cylinder.
The fiber batt runs downwards without diversion directly into the teeth of the taker-in which results in gentle fiber treatment. This helps to reduce faults in the yarn. The revolving flates revolve the brushes on it, so the cotton on the cylinder teeth will eliminate the impurities.
BACK TO BACK ACTION:
The doffer take the cleaned cotton same way to cylinder from taker in, and passes to drawing unit.
The drawing unit stretched & parallelize the cotton and changes into individual fiber form, then pass to trumphet guide.
The straightened fiber collectively gets in trumphet guide and intermix in it to form a sliver.
The sliver cane stores the sliver in it for further processes.