Standard Cut Length Gravimetric Methods for Line Flax Linear Density Testing
Standard cut length gravimetric testing uses strict pretensioning, razor sectioning, and moisture regain corrections to establish spinnable tex accurately.
Sliver Cohesion Drafting
Fibre Attachment
Internal resistance between parallel fibres in a bundle determines the force required to pull them past one another during processing. The sliver cohesion drafting value measures how well the flax strands hold together as they are thinned out on the spinning frame. Strong attachment prevents the sliver from breaking or sagging between the rollers.
The measurement is restricted to fibres that have been aligned into a continuous strand.
Machine Configuration
Rollers on the drafting frame are set with specific pressures to manage the sliver cohesion drafting characteristics of the current lot. If the resistance is too low, the sliver will pull apart prematurely and create a thin spot in the yarn. Higher humidity in the mill can increase this bond by activating residual pectins in the bast fibre.
Spinners adjust the distance between the nip points to account for these changes. Proper lubrication of the machine components ensures that the applied pressure remains constant throughout the work shift. Manual checks of the sliver weight per metre provide a secondary verification of the drafting consistency.
Quality Consequence
Inconsistent attachment leads to periodic thickness variations that are visible in the finished linen cloth. When sliver cohesion drafting is optimized, the resulting yarn shows a high degree of linear uniformity. This property is tested by measuring the force needed to draw the sliver at a constant speed.
It is a critical indicator of whether a batch of flax is suitable for wet spinning or dry spinning.