5. Increase and decrease in the number of stitches

This process only concerns flat weft knitting machines.

To start with, the knitted fabric is carried out with a given number of needles in action. If the shape to be produced requires the knitted fabric to be widened, two solutions are possible. When this enlargement is small, it's possible to change the length of yarn in a stitch (named stitch length). This is what's applied, for example, to the upper part of socks, whose circumference varies between the ankle and the calf. In this case, the mechanical behavior of the knitted fabric varies as a function of the stitch length