Moisture Regain Corrections in Gravimetric Linear Density Testing of Hackled Line Flax
Accurate gravimetric testing of line flax linear density demands dry mass weighing and standard twelve percent regain adjustment per ISO 6741.
Drawing Frame Draft
Fiber Attenuation
Linear stretching of the gathered fiber band reduces its mass per unit length before the spinning phase begins. Adjusting the drawing frame draft determines the degree of elongation and parallel alignment of the flax fibers in the sliver. This process converts a thick bundle of uneven fiber into a thin, uniform strand suitable for roving.
Mechanical Operation
Achieving the desired thickness relies on the difference in surface speed between the feed rollers and the delivery rollers of the machine. The drawing frame draft must be set precisely by changing the gear ratios in the drive train to match the average length of the flax fiber batch. When the delivery rollers turn much faster than the entry rollers, the fiber bundle is drawn out into a finer strand.
This mechanical action also helps to mix different flax lots to ensure a uniform color and strength in the final yarn.
Yarn Quality
Controlling the uniformity of the strand prevents thin spots and thick spots in the spun yarn. An incorrect drawing frame draft leads to frequent breakages on the spinning frame and produces an uneven fabric surface during weaving. This control ensures the yarn meets the buyer’s strength criteria.