Warp End Density Calculation and Loom Shed Geometry Calibration
Calibrating warp end density within cover factor limits and aligning loom shed geometry prevents thread chafing, maintains loom efficiency, and controls metre cost.
Beat up Dwell Angle
Crank Timing
Mechanical timing governs the forward stroke of the reed assembly during the flax weaving process. Beat up dwell angle designates the precise crank rotation interval in degrees during which the sley rests against the fell of the cloth while the pick inserts across the warp shed. Adjusting this arc determines whether the falling wire meets the newly woven cloth under high dynamic pressure or gentle contact.
Loom operators record these positional degrees in the mill machinery logbook alongside warp tension values.
Sley Mechanics
Rotary motion from the main crankshaft transfers through eccentric arms to swing the heavy wooden sley sword back and forth. Beat up dwell angle controls the duration of rest at the forward dead centre before the return sweep begins. Lengthening this rotational window allows the reed extra time to pack individual weft yarns tightly against the preceding picks without deflecting the shuttle box.
Shortening the interval creates a rapid impact that suits lightweight linen cambric but risks warp breakage on heavy canvas grades.
Cloth Density
Fabric firmness depends entirely on how accurately the final positioning matches the instantaneous warp relaxation point. Beat up dwell angle dictates the final squareness of the intersection between warp ends and wet spun weft picks. Mill technicians check this parameter whenever air humidity shifts because dry flax yarn shrinks and alters the required packing interval.
Poorly synchronised sley stops produce uneven reed marks that inspectors mark down during final grey cloth grading.