CARDING PROCESS

Carding is a mechanical process that breaks up locks and unorganised clumps of fibre and then aligns the individual fibres so that they are more or less parallel with each other. Carding can also be used to create blends of different fibres or different colours. Carding plays a crucial role in all spinning cycles particularly in the woollen spinning cycle, in which it incorporates different functions, all essential in order to obtain the level of quality required of the product.

The card used in woollen spinning is traditionally the sort with cylinders (covered with clothings that are angled to varying degrees), which rotate at different speeds, effecting the three cardinal actions: carding, stripping and raising. Appropriately combined, these three actions allow opening of the tufts, continuous detachment of the fibres from the card clothing, which would otherwise soon become clogged up, and delivery of the material from the machine at the end of a processing cycle.

Functions of Carding

Carding fulfils a series of precise objectives. They are given below:-

to open the blend fibres fully and definitively

1. To arrange (as far as their length allows) the fibres parallel with one another
2. To remove impurities
3. To blend the raw material further
4. To reduce the blend to a web of fibres and to divide it up into rovings of the required count, suitable for feeding to the spinning machines. 

Carding plays a crucial role in all spinning cycles, and its role is never more central than in the woollen spinning cycle, in which it incorporates different functions, all essential in order to obtain the level of quality required of the product. 

Basically, passing the material over the card undoes tangles of fibres and therefore makes it possible to remove all kinds of impurity. This is achieved thanks to the action of the spikes covering the surfaces of cylinders that rotate around parallel axes.

 

The equipment also fulfils another function, which is both delicate and fundamental: it has to guarantee the accuracy and evenness of the web count and subsequently of the roving count. Indeed, the definitive spinning machines that operate within the woollen spinning cycle can impart only a very low draft, which means that there is practically no possibility, at this stage, of intervening to correct the yarn count.

The carding room equipment thus performs the same operations already carried out in the preparation stage, this time more thoroughly, supplying the divider with rovings of the right count.

Defects In Carding
Causes of high sliver variation

1. Nep formation
2. Holes or patches in card web
3. High sliver variation in due to difference in draft between card
4. Worn clothing and feed roller bearing also create variation in card sliver
5. If auto leveler is not working properly than this will also create high sliver variation. If auto leveler is off then check the wrapping of carding after every 30 minutes.