Pressure Regulation
Vertical pressure applied at the point of contact between two spinning cylinders controls the attenuation of the fiber assembly. The drafting roller nip force dictates how effectively the machine grips the flax sliver as it undergoes elongation. Proper calibration prevents the fibers from slipping or bunching during the transition from a thick bundle to a fine thread.
No fibers escape.
Operational Impact
Regulation of the load occurs via weighted levers or pneumatic springs that press the top roller against the bottom fluted drive. If the drafting roller nip force is insufficient, the resulting yarn shows thick and thin spots known as drafting waves. Pressure must be steady.
Excessive pressure conversely damages the delicate cellulose structure of the flax filaments. This balance is particularly hard to maintain when the moisture content of the mill atmosphere fluctuates throughout the day.
Maintenance Requirement
Measurement of the grip is conducted using a specialized gauge placed between the stationary rollers. Frequent checks of the drafting roller nip force ensure that the rubber coatings on the top rollers have not developed flat spots or wear patterns. Consistent force across all spindles in a frame is the only way to produce a uniform yarn lot.
