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.
Shore Durometer
Measurement Tool
The resistance of elastomeric cot materials to surface indentation is a critical factor in the draft distribution of fiber bundles during yarn spinning. Spinning mills use a shore durometer to measure the hardness of the rubber covers on drafting rollers. Proper hardness ensures that the nip line remains stable, allowing the roller to grip the flax fibers evenly without crushing them.
The device provides a numerical reading on a standardized scale, with higher numbers indicating harder materials.
Hardness Application
Operation of the instrument involves pressing a spring-loaded indenter into the rubber surface to determine the depth of the resulting impression. In the wet spinning of linen, where the fibers are saturated with water to soften the natural pectins, softer cots are often used to increase the contact area. This larger contact zone helps control the short fibers and reduces hairiness in the finished yarn.
Conversely, dry spinning uses harder rollers to withstand the higher pressures needed for coarser flax strands. Technical specifications for the spinning line always list the required shore hardness for each drafting stage.
Roller Maintenance
Maintenance crews perform regular checks on the rollers to detect hardening caused by age, chemical exposure, or heat. Rollers that have become too hard cannot grip the fibers effectively, causing yarn defects and drafting failures. Replacing worn rollers based on these measurements ensures consistent yarn quality.