Metric Fibre Number Claims and the Test Method behind Them
Metric fibre number claims require ISO 2370 gravimetric verification because airflow instruments skew up to fifteen percent across retting types and moisture regains.
Optical Projected Width
Profile Measurement
Optoelectronic sensor systems measuring yarn silhouettes during high-speed winding provide dimensional profile data for textile quality control. The optical projected width of a running yarn corresponds to its shadow image cast across a high-resolution linear sensor array. Measuring profile shadows enables continuous assessment of yarn diameter without physical contact.
Automated yarn clearers process these dimensional signals to detect structural yarn faults at production speeds.
Irregularity Detection
High-frequency optical scanning identifies thick places and thin places along the yarn axis. Bast fiber yarns exhibit natural thickness variations due to irregular fiber bundle division during drafting. When optical projected width exceeds pre-set thresholds, automatic yarn clearers cut out the defect and splice the thread.
Optical sensors differentiate between flattened ribbon-like yarn sections and round yarn cores by analyzing light occlusion intensity. Continuous profile tracking flags periodic yarn variations caused by eccentric drafting rollers or worn apron bands. System software categorizes detected anomalies into standardized yarn fault matrix classes for mill quality reports.
Yarn Grading
Statistical evaluation of profile width measurements generates coefficient of variation values for yarn evenness grading. Quality assurance teams use optical profile data to classify yarn lots for weaving suitability. Consistent yarn width minimizes filling bands and surface defects in woven linen fabrics.
Inspection records document mean optical projected width to certify yarn lot conformance with buyer specifications.