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.
Drafting Nip Spacing
Roller Position
Mechanical spacing defines the physical distance between the pairs of rollers that draw out flax roving into fine yarn on a spinning frame. Adjusting the drafting nip spacing allows a mill to accommodate different average fiber lengths without creating excess waste. Proper settings ensure that the drawing rollers grip the longest fibers while the short fibers remain controlled.
Fibre Control
Adjustments to this roller gap correspond to the staple length of the flax consignment currently being processed through the drawing frame. A mill technician changes the drafting nip spacing by moving the lower and upper drafting rolls along a slotted guide rail, locking them into position with a calibrated bolt assembly. If the gap remains too wide, shorter fibers lack guidance and bunch together, causing periodic thick places in the spun yarn.
Conversely, when the gap is narrower than the longest fibers, the roller pressure shears the flax strands, creating broken ends and machine down-time.
Spun Quality
Final yarn consistency suffers if the mechanical settings are not updated for each batch of raw roving. Variations in fiber length distribution demand a corresponding shift in roll clearance to maintain even drafting. The measurement is validated by analyzing the drafted ribbon under a optical sensor for draft-related faults.