Dynamic Resistance
The surface characteristics of flax yarn during high speed processing are critical to maintaining yarn tension and avoiding friction-induced heat. The kinetic friction coefficient defines the ratio of the friction force to the normal force when the yarn is in motion against a solid surface. This value is measured by drawing the yarn over a cylindrical pin at a specified velocity and measuring the change in tension before and after the pin.
High speed winding requires a low coefficient to prevent fiber damage.
Process Lubrication
Uncoated flax yarn has a high and variable friction level that can cause tension spikes and breaks on the loom. Measuring the kinetic friction coefficient helps mills evaluate the effectiveness of yarn lubricants such as paraffin wax or silicone emulsions. The measured coefficient is documented in the yarn test certificate to verify process compliance with spinning standards.
Lower friction values allow the yarn to glide smoothly through guides and knitting needles.
Product Quality
Frictional variations across a yarn package can lead to tension bands and uneven stitch density in knitted or loose linens. Monitoring the friction coefficient across the package length ensures that the yarn behaves consistently in subsequent loom or knitting stages. Uniform yarn surface properties prevent localized stress points and fabric deformation.
