Yarn Count and Evenness Checks before a Cone Lot Ships
Verify conditioned skein count, capacitive CVm evenness, and cone hardness against ISO tolerances to stop defective flax yarn before freight release.
Spectrogram
Analytical Chart
A graphical representation that plots the frequency of mass variations against the wavelength of yarn defects provides a diagnostic tool for analyzing yarn spinning quality. This analysis, known as a spectrogram, helps mill engineers identify the exact mechanical or draft issues causing periodic yarn faults. Unlike random mass variations, periodic faults repeat at regular intervals and can cause severe visual defects in the finished linen fabric.
The chart displays these periodicities as peaks or chimneys rising above the normal curve.
Fault Identification
The position of a peak along the wavelength axis corresponds directly to the mechanical component responsible for the error. Short wavelengths, measuring a few centimeters, point to issues in the drafting zone, such as damaged roller covers or fiber slippage. Longer wavelengths, spanning several meters, usually indicate faults in the gears, belts, or drive motors of the spinning frame.
By calculating the gear ratios and roller circumferences, technicians can match the peak wavelength to the specific part that requires replacement or adjustment. In flax wet spinning, a worn eccentric drafting roller typically produces a distinct, high-intensity peak.
Mechanical Resolution
Mills generate these charts as part of their daily quality control routine to monitor the wear of spinning components. If a peak begins to emerge, maintenance is scheduled before the yarn can be spun in large quantities. This preventive approach prevents the weaving of fabrics with periodic banding that would otherwise be rejected by the buyer.