Carding
The carding (also currycombs , sleeves , sometimes colloquially falsely also scratch , in Southern Germany Dachas or dätschen ) is used in the process of spinning or in the production of nonwoven fabrics for the first orientation of the loose textile fibers into a pile or fleece fabric. Machines for carding will be carding or carding or simply card called. The place where carding takes place is called carding or carding .
A distinction must be made between the combing of long fibers and the roughening of fabrics by scratching (weaver cards) or scratching machines .
Function description
The fiber flocks, which have already been cleaned well, are presented to the card or card as evenly as possible. The flakes are loosened by means of a feed roller (also known as a lickerin) and presented to the tambour (a roller of large size, fitted with tooth-like trimmings). The flakes are picked up by the toothed clothings of the rapidly rotating drum and conveyed to the upper area of the card. On the upper side of the drum there are boards (top bars) or small roller pairs, which are equipped also with teeth sets or with flexible hook - in the use of flat bars, the machine carding machine , with the use of pairs of rollers carding mentioned. Due to the different directions of rotation and the alignment of the clothings to one another, the flakes are opened and the fibers are parallelized. The teeth of the clothing can be oriented against each other (also known as carding position) or in the same direction. In addition, the high speed of rotation of the drum ejects dirt and dust, which is an important function of the card, especially when processing cotton.
The carding intensity, i.e. the measure of how strongly the fibers are parallelized, depends on the following parameters:
- the speed difference between the drum and the flat bars or roller pairs
- the density of the sets (the number of teeth per cm²)
- the distance between the drum and flat bars or roller pairs
These parameters are to be selected according to the type of fiber to be carded, because some fibers are damaged by excessive carding intensity.
When the fibers have completed half a turn on the drum, they are removed from the rear by a take-off roller. The take-off roller rotates in the same direction as the drum, but much more slowly. This means that the fibers are "unhooked" from the tooth sets on the drum. Since the fibers get caught up with one another and do not adhere well to the doffer roller, a wide sliver, the pile or fleece, can be pulled off the doffer roller.
When processing into a yarn, the pile is shaped in a funnel into a round ribbon, the card sliver, and placed in loops in a can. The card sliver is then stretched together with other card slivers in the draw frame (formerly stretch bench ) in order to compensate for irregularities in the individual card slivers. The drawn ribbon can then be spun into a yarn over several steps.
In the production of nonwovens, further processing can take place in various ways. The pile can be bonded directly to form a nonwoven (chemically, thermally or mechanically) or several pile layers are layered on top of one another before bonding. This can be done either by bringing together the pile layers of several cards or by stacking a single pile layer in a cross- stacker . The finished nonwoven is rolled up or, in the case of thicker nonwovens, cut into shorter pieces and stacked.
history
- In 1748 the Englishman Daniel Bourn from Leominster received a patent for a roller card.
- In the same year the Englishmen Lewis Paul and John Wyatt from Birmingham received a patent for a similar card with a hand drive.
- In 1769 the waterframe , the mechanical spinning machine, was invented. Because of their greater speed, carding became even more of a bottleneck in spinning.
- In 1775 Richard Arkwright received a patent for a card in which the rollers above the main cylinder were replaced by bars.
- This principle of both systems has been preserved to this day, only finer, more precise and more stable designs have enabled higher machine speeds and working widths. Productivity has increased many times over. A flat card with a working width of 1.5 meters can produce up to 200 kilograms of card sliver per hour, while a roller card with a width of 3 meters can achieve over 1.5 tons per hour in the production of geotextiles .
Smaller drum cards that are operated with an electric motor or a hand crank are used in the arts and crafts and hobby areas. In the case of hand cards, a tick cover is attached to two approximately 10 × 20 cm boards with handles. The fiber flocks are placed between the boards and the cards are pulled apart. A scratch or patch card is an even smaller hand card. It is used individually to loosen the wool, for example when hand spinning.
field of use
- Cotton and chemical staple fibers up to 60 millimeters in length are carded on machines with flat bars.
- Wool , chemical staple fibers from approx. 25 millimeters in length, vigogne , waste fiber mixtures , jute and bast fiber tow are processed on carding cards (also called roller cards).
- Linen and hemp fibers are often not carded, but only dissolved by panting .
literature
- Hermann Kirchenberger, spinning mill 2000 . Verlag Bondi, Vienna-Perchtoldsdorf 1986, ISBN 3-900008-10-8
- Nötzold: Handbook of the carded yarn and vigoga spinning mill . Fachbuchverlag, Leipzig 1970
