Wednesday, December 28, 2016

Specification of Knitting Machine

Knitting machine is a device which is used to create knitted fabric. There are different types of knitting machine. Each knitting machine contains various parts. The needle beds and needle bars, and thus the knitting machines, are specified with three features, namely:
  1. The working diameter (Circular needle beds and needle bars)
  2. The working width (Fiat needle beds and needle bars)
  3. The needle gauge or needle pitch.
1. The working diameter:
The diameter of a knitting machine is measured at the bottoms of two opposite: needle grooves in a cylinder or at the tops of two opposite needles in a circular bar, and is usually expressed in inches.

2. The working width
The working width of the machine should not be misused with the “actual working width”. The working width of a knitting machine is a measure (in cm or inches) describing the distance between the first and last needle in a flat needle bed, whilst the “actual working width” is the distance between the first and last needle actually used in the needle bed during knitting.
Fig: Knitting machine
3. Needle gauge or needle pitch
The needle gauge of a knitting machine (also called cut or gage) is a measure expressing the number of needles per a unit of the needle bed (bar) width.

Gauge, N = How many needles are used in one English inch.

          Number of needles
N = ………………………………………..
           One English inch

Highest needle gauge is about 60 and lowest needle gauge is about 2 to 2.5.

The needle pitch is the distance between two neighboring needles in the same needle bed (bar), from the center of a needle to the center of the neighboring needle.

Relationship between the needle gauge and the needle pitch is as follows:

                                                                               1
Needle pitch (Length units/needle) = ………………………………………………….
                                                              Needle gauge (length unit)

The pitch or distance between one needle and another is proportional to the needle gauge or thickness and therefore to the space available for the yarn. As the diameter of a yarn is proportional to its count, a relationship exists between the range of optimum counts of yarn which may be knitted on a particular machine and its machine gauge. Machine gauge thus influences choice of yarn and count, and affects fabric properties such as appearance and weight. For a given machine diameter or width, finer gauge machines tend to knit a wider fabric as more wales are involved. For example a 30” diameter circular machine might have 1716 cylinder needles in 18G and 1872 cylinder needles in 20G.Coarse gauge machines have latch needles with larger dimensions requiring greater movements. During knitting the size of the knitting cams are correspondingly large so less cam systems can be accommodated around a given machine diameter (for example 30”) so therefore coarser gauge machines often have fewer feeders.