How Flax Fibre Is Graded into Linen Yarn
Flax fibre grading determines spinnable yarn count, where hackling yield and fibre fineness dictate wet-spinning efficiency and landed cost per metre.
Faller Bar Drafting
Mechanical Attenuation
The controlled extension of a sliver involves the use of moving pins to restrain and guide the individual fibres. During faller bar drafting, the material passes through a series of combs that travel at a speed between the feed and delivery rollers. This mechanical interaction prevents the uncontrolled movement of short fibres while the longer ones are drawn forward.
The process stops being effective if the pin density is too low for the fineness of the flax being processed.
Operational Control
Bars equipped with steel pins rise into the sliver as it enters the drafting zone and drop away as they reach the exit point. The speed of the faller bar drafting mechanism is set slightly higher than the input rollers to maintain tension. This lead ensures that the fibres stay taut and aligned as they move toward the front rollers.
Gilling frames often use two sets of bars to provide control of the fibre mass.
Quality Threshold
Drafting waves occur when the distance between the pins and the rollers exceeds the mean length of the fibres, causing clusters of untamed material to move through the zone as a single mass. Effective faller bar drafting produces a uniform sliver. Pin maintenance prevents tangles.