Standard Operating Inspection Protocol for Four Point Greige Scoring
ASTM D5430 four-point scoring normalises greige defects per 100 square yards, capping penalties at four points per yard to decide lot acceptance.
Slub Detection
Mechanical Oversight
High-speed photoelectric sensors monitor passing yarn strands during the spinning stage to identify irregularities in diameter. Slub detection triggers an automatic machine stoppage or yarn diversion when a section of material exceeds the predetermined tolerance for thickness. Each automated device operates by comparing the incoming strand profile against a reference gate that defines acceptable yarn uniformity.
Such equipment prevents thick imperfections from entering the final warping or weaving operation where they cause breakage or visible defects in finished fabric rolls. An operator records these events on the daily production log to track machine performance and maintenance intervals for specific spinning frames. Spinning mills maintain quality levels by integrating these sensors into every frame.
Inspection Protocol
Sensors function through an optical barrier where a light source project beams toward a receiver. Interference occurs as the yarn passes between these two points. A micro-controller calculates the duration and intensity of the shadow cast by the strand to determine whether a thickening event meets the criteria for a reject.
Deviations beyond the allowed limits force an immediate cutter engagement that severs the yarn. This mechanism ensures that knots or thick segments do not proceed to the winding stage. Factory technicians calibrate the sensor gates based on the specific count of the flax fibre currently processed.
Fine yarns require smaller tolerances than coarser counts, so staff reset the threshold parameters during every changeover. A failure to perform this calibration results in either excessive waste from unnecessary cutting or defective material passing through to the loom. Accurate settings support consistent output quality across different production runs.
Measurement Boundary
These systems regulate local yarn consistency rather than overall fibre composition. The monitoring process stops at the completion of yarn winding and does not oversee the chemical properties of finished goods. Mill standards for this task remain separate from buyer requirements for fabric integrity, although both systems influence the final export grade.
Each sensor unit operates independently to ensure total coverage across all spinning spindles in the plant. Slub detection provides a hard barrier against batch contamination.