Standard Cantilever Testing and Defect Scoring in Greige Cloth Inspection
Standard cantilever testing and four-point inspection verify greige cloth stiffness and fault densities to enforce contract specifications before finishing.
Slub
Structural Irregularity
An abrupt, localized enlargement in yarn diameter along an otherwise continuous strand constitutes a recognizable variation in textile mass distribution. In linen yarn spinning and subsequent cloth manufacturing, a slub appears as a thickened segment containing an excess accumulation of bast fibre bundles. While occasional mild diameter variations provide authentic rustic texture in decorative linen, pronounced and tightly bunched masses represent structural imperfections.
The phenomenon directly influences downstream processing behaviour and fabric appearance.
Formation Origin
Mechanical drafting irregularities and bundle entanglement during roving attenuation generate unwanted mass clusters. When flax roving passes through ring frame drafting rollers, unseparated bast fibres bound by residual natural gums resist drafting shear, sliding through the nip as an intact lump rather than a uniform ribbon. In wet spinning facilities, dirty water troughs or worn drafting flutes exacerbate the release of these undispersed flax clumps.
Electronic yarn clearers mounted on automatic cone winders monitor strand profile via optical or capacitive sensors, cutting out gross anomalies before yarn packaging. Chinese spinning mills tally clearing cuts per hundred thousand metres on quality reports, distinguishing standard flax diameter variation from intolerable mass lumps.
Acceptance Threshold
Visual grading standards distinguish between decorative character and rejectable structural faults. Fabric buyers define permissible slub dimensions, establishing limits on length and thickness multiples relative to nominal yarn diameter. Under international four-point inspection standards, excessive slubs in smooth shirting or sheeting fabrics trigger defect points that downgrade whole fabric rolls from grade A status.
Controlled slub frequency separates deliberate aesthetic surface effects from substandard yarn manufacturing.