Determining Flax Staple Profile Using Manual Comb Sorting
Manual comb sorting by ISO 2370 isolates technical flax bundle length profiles to prevent drafting waves, control short fibre content, and enforce purchase contracts.
Roving Draft Mechanics
Longitudinal Attenuation
Mechanical thinning processes reduce the thickness of a fibre assembly before the final spinning stage. The roving draft mechanics involve the coordinated movement of multiple sets of rollers rotating at increasing speeds. This action slides the fibres past one another to create a finer strand.
Proper roving draft mechanics are essential to prevent the formation of thin spots or bunches.
Roller Influence
The distance between the drafting rollers must be set slightly longer than the longest fibres in the bundle. If the roving draft mechanics are poorly calibrated, the rollers will crush the fibres or fail to draw them at all. Pressure on the top roller ensures that the fibres do not slip prematurely.
This grip is necessary for maintaining the integrity of the strand. When the grip is too tight, the fibres are crushed. Correct alignment of the roller axis prevents uneven pressure across the width of the roving.
Bundle Stability
Cohesion between the fibres provides the necessary resistance to the drafting force. Without a small amount of twist, the roving draft mechanics would cause the bundle to fall apart under tension. This temporary strength allows the roving to be wound onto a bobbin for transport.
The draft ratio determines the final fineness of the roving.