Lap preparation for combing in spinning:
Blow-room, 1st drawing machine, and after carding or pre-comb drawing machine is used in spinning a line to make combed yarn. The sliver obtained from carding or drawing is used to prepare the mini lap with the help of a sliver lap machine or super lap machine. The preparation of the slivers before feeding to the combing machine is called preparation for combing. Since this preparation is preceded by lap preparation, this preparation phase can also be called lap preparation. https://bdfabric.com/the-parameter-influencing-the-combing-operation/
Lap preparation for combing in spinning. The main purpose of the combing process is to remove the short-length fibers remaining in the processed cotton fibers from the original sliver. Therefore, to achieve this purpose, the fibers i.e. the slivers have to be prepared a bit before feeding in the combing machine. The fibers of the carded sliver are scattered in different directions, due to which feeding such sliver in the combing machine can remove the fine fibers along with the small fibers. There may also be damage to some small parts of the combing machine, such as the cylinder comb or the needle of the cold comb. Etc. To eliminate the problems, mini lap or sliver lap of more balanced, straight, and parallel fibers are prepared and fed to the combing machine.
The necessities of lap preparation before combing:
The reasons why it is necessary to prepare a mini lap with a carding/drawing sliver before feeding to the combing machine are described below.
1. The parts of the sliver first obtained from the carding machine are scattered in different directions, it is driven in one passage or two passage drawings for alignment and parallelism. Prepared by drawing and parallel fibers from the drawing, it is first prepared for feeding in sliver and later in mini lap combing.
2. When the fibers are straight and parallel, it is easy to remove short fibers from the mini lap sheet.
3. It is easy to control the appropriate amount of waste (noil) from the mini lap sheet.
4. If the fibers are not straight and parallel, the larger fibers may be removed along with the shorter fibers, thus increasing the production cost.
5. If the mini lap is not of balanced weight, the cylinder comb and top comb will not be able to combine the mini lap sheet well. On the one hand, such waste will increase. The needle of the comb, on the other hand, may break.
6. Feeding on the sliver combing machine alone is not useful if the lap is not generated.
7. The combing sliver is not likely to be irregular after combing as a result of the preparation of parallel fibers and balanced mini lap.
8. Above all, the mini lap is prepared by the sheet according to the thin wave, so there is no extra pressure on the combing machine to feed and operate. The combing process is perfect.
The importance of the number of passages of drawing frame used before combing:
For the following reasons the number of drawing frames before combing is more or less i.e. 1, 2, or 3 uses are determined by considering the following factors.
1. The fibers of the existing hook in the sliver or mini lap are not fed into the combing machine as the leading hook.
2. The number of drawing frames is determined by the need for the mini lap to have more parallel fibers fed into the combing machine.
3. When the number of drawing frames is more, the fed mini lap is very balanced.
4. The cost of making yarn should be taken into consideration. Using more drawing frames will increase the cost.
5. Low rate of a lap in the produced yarn. If there is a leading hook in the mini lap fed to the combing machine, the number of yarn naps will be more.