Sliver Verification
Formal quality assessment of carded or hackled flax ribbons confirms linear density, fibre cleanliness, and moisture content before drawing operations. Spinning mills conduct raw sliver qualification to ensure incoming sliver lots conform to spinning process specifications. Technical staff pull representative sliver samples from card cans to test for linear density variation and residual shive content.
Processing records log these initial quality values prior to roving creation.
Parameter Testing
Carded flax ribbons contain micro-variations in fibre mass that cause yarn irregularity if left uncorrected during drafting. Executing raw sliver qualification involves measuring linear density uniformity on electronic evenness testers alongside trash content analysis. Slivers with high mass variation require extra passage through auto-leveling draw frames to smooth out linear mass spikes.
Laboratory technicians tally shive counts per gram to prevent downstream yarn breakage.
Quality Threshold
Out-of-specification sliver causes drafting waves and high yarn break rates on wet spinning frames. When raw sliver qualification indicates excessive neps or uneven linear density, mill managers route the affected lots back for re-carding or re-blending with long staple fibres. The procedure assesses initial un-drafted sliver packages and does not evaluate spun yarn or finished woven cloth.
Mill quality control records register these audit results on raw material acceptance dockets before release to the drawing section.
