Calculating Wet Spinning Scrap Deductions for Mass Balance Ledger Verification
Verify wet spinning mass ledgers by adjusting raw inputs to standard moisture regain, deducting verified chemical bath extraction losses and weighed mechanical scrap.
Bath Dissolution Loss
Chemical Yield
Gravimetric measurement determines the percentage of non-cellulosic material removed from flax yarn during chemical boiling. During wet spinning, the bath dissolution loss represents the weight reduction of the roving as pectin and lignin dissolve in the hot alkaline spinning bath. This loss occurs when the roving passes through the trough before reaching the drafting zone, where the elevated temperature softens the gummy substance that holds the flax fiber bundles together.
The resulting value is recorded in the mill test report before the yarn proceeds to the drying stage.
Spinning Efficiency
Alkaline treatment in the trough must be closely regulated because excessive temperature or treatment time leads to high yarn breakages. When the bath dissolution loss exceeds the target limit, the yarn loses its cohesion and begins to break during the drafting phase. Spinners adjust the bath concentration to maintain a steady drafting force across the draft zone.
Quality Threshold
Standard acceptance criteria for high-grade Chinese linen export yarns specify a maximum value for this loss to preserve structural integrity. The buyer’s inspection docket rejects batches that show highly variable values because uneven dissolution causes thick and thin places in the woven fabric. Mill records confirm that consistent values correlate with stable yarn counts across the entire batch.