Determining Dry Cellulosic Mass Yield in Wet Flax Roving Processing
Dry cellulosic yield in wet flax roving requires gravimetric tare subtraction, moisture regain adjustments, and chemical boil-off loss corrections per lot.
Bobbin Package Density
Volumetric Compactness
Mass ratios define the proportion of yarn weight to the total volume occupied on a spinning or winding bobbin. Achieving a target bobbin package density prevents the deformation of the yarn layers during subsequent handling or dyeing. This value is calculated by dividing the weight of the yarn by the measured volume of the package.
It dictates how many kilograms of flax can be processed in a single autoclave cycle.
Winding Mechanics
The tension of the yarn during winding and the pressure applied by the package cradle determine the final hardness of the bobbin. If the bobbin package density is too high, the dye liquor cannot penetrate the inner layers, resulting in uneven colouration. Low density leads to unstable packages that may collapse or slough off during high-speed unwinding.
Mills use durometers to check the surface hardness as a proxy for density across the entire lot. Adjusting the traverse speed relative to the bobbin rotation helps maintain a uniform structure from the start to the finish of the winding process. Stable density ensures that the yarn does not stretch or lose its elasticity while stored.
Liquidity Permeability
Dyeing cycles rely on a specific flow rate of chemical solutions through the yarn. Correct bobbin package density allows for a consistent pressure drop across the package. This uniformity is required for high-quality export linen.