Various Types of Defects in Knitted Fabrics
Bands and Streaks
There are different kinds of bands and streaks that may occur in knitting. Some of the popular defects are as follows:
v Barrie Effect: A Barrie effect has the appearance of a stripe with shaded edges. It is horizontal in weft knits and vertical in warp knits. The barrie effect is caused by various factors like:
» Lack of uniformity in yarn size, color or luster.
» Mush tension on the yarns during knitting one section of the fabric.
» Uneven shrinkage or other finishing defects.
v Bowing: A line or a design may curve across the fabric. This bowing is the distortion caused by faulty take-up mechanism on the knitting machine.
v Streak or Stop Mark: A straight horizontal streak or stop mark in the knitted fabric is due to the difference in tension in the yarns caused by the machine being stopped and then restarted.
v Skewing: Skewing effect is seen as a line or design running at a slight angle across the cloth.
v Needle Lines: Needle lines or vertical lines are due to a wale that is either tighter or looser than the adjacent ones. This is caused by needle movement due to a tight fit in its slot or a defective sinker.
There are various kinds of stitch defects like:
v Boardy: The knitted fabric becomes boardy (a stiff or harsh hand) when the stitches have been knit very tightly.
v Cockled or puckered: If the knitted fabric is cockled or puckered, it is due to uneven stitches or uneven yarn size.
v Dropped Stitch: This is an un knitted stitch caused either by the yarn carrier not having been set properly or the stitch having been knitted too loosely.
v Run or ladder: A run or ladder indicates a row of dropped stitches in the wale.
v Hole: A large hole or a press off is the result of a broken yarn at a specific needle feed so that knitting cannot occur.
v Tucking: This is the result of an unintentional tucking in the knitted fabric. This is also called the bird's eye defect.
v Float: This is caused by a miss stitch which is the result of failure of one or more needles to have been raised to catch the yarn.