Different Types of knitted fabrics Structures:
- Plain knitted fabrics
- Rib knitted fabrics
- Purl knitted fabrics
- Interlock knitted fabrics
Plain knitted fabrics:
If a weft or warp knitted fabric has one side
Fig 1 : Plain knitted fabrics |
Rib knitted fabrics:
If on both sides of a relaxed weft or warp
Fig 2 : Rib knitted fabrics |
The longitudinal extensibility of the rib structure equals that of a plain knitted structure. The geometry of the yarn path influences the elastic behavior of the knitted structures. The change of direction of the interlooping of the stitches of neighboring wales (cross-over points) results in the wales of a rib knitted structure closing up. This gives rib structures better elastic properties widthwise than other basic knitted structures. With rib structures in the lateral direction,extensions up to 140% can be achieved. Other construction of rib structures include 2 x 2 rib, where two wales of face stitches alternate with two wales of reverse stitches. As the number of wales in each rib increases, the elasticity decreases as the number of changeovers from reverse to front reduces.
Purl knitted fabrics:
If on both sides of a relaxed weft knitted fabric
Fig 3 : Purl knitted fabrics |
only reverse stitches are visible, then this is defined as a purl knitted fabric. Generally, weft-knitting machines are used to produce these fabrics. Purl fabrics are produced by meshing the stitches in neighboring courses in opposite directions by using special latch needles with two needle hooks. When the fabric is stretched lengthwise, then the face stitches are visible. The fabric shrinks more in the direction of wales, and once it is released, it relaxes to hide the face stitches between the courses.
The inter-looping of the stitches of neighboring courses in opposite directions results in the courses of a purl knitted structure closing up. The structure, therefore, has a large longitudinal extensibility which is largely elastic.
Interlock knitted fabrics:
These could be considered as combination of two rib knitted structures.
Fig 4 : Interlock knitted fabrics |
The reverse stitches of one rib knitted structure are covered by the face stitches of the second rib knitted structure. On both sides of the fabric, therefore, only face stitches are visible, and it is difficult to detect the reverse stitches even when the fabric is stretched widthwise.
The geometry of the yarn path influences the elastic behavior of the knitted fabrics. The change of direction of the meshing of the stitches in neighboring wales results in the wales of a rib knitted fabric closing up-giving it better elastic properties widthwise over other basic knitted structure. The meshing of the stitches in neighboring courses in opposite directions results in the courses of a purl knitted fabric closing up. Thus they could be stretched lengthwise more than the other knitted structures. The combination of two rib knitted structures in the interlock structure gives very little or no room at all for the wales or courses to close up, and therefore the interlock fabrics shows very poor elastic properties in both directions.
The warp-knitted fabrics are generally classified according to the number of guide bars as well as lapping plan employed. Warp knitting is generally carried out with one set of needles, although two sets of needles are found on some Raschel machines for production of special kinds of fabrics such as cut plush.
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