Similar to tex and
denier, yield is a term that helps describe the linear density
of a roving of fibers. However, unlike tex and denier, yield is the
inverse of linear density and is usually expressed in yards/lb.
A roving is a long and narrow bundle of
fiber. Rovings are produced during the process of making spun yarn from
wool fleece, raw cotton, or other fibers. Their main use is as fibre
prepared for spinning.
Linear density is the measure of a quantity of any
characteristic value per unit of length. Linear mass density (titer in
textile engineering, the amount of mass per unit length).
The SI unit (International System of Units) of linear mass density is
the kilogram per meter (kg/m). Linear density of fibers and yarns can be
measured by many methods. The simplest one is to measure a length of
material and weigh it. However, this requires a large sample and masks
the variability of linear density along the thread, and is difficult to
apply if the fibers are crimped or otherwise cannot lay flat relaxed. If
the density of the material is known, the fibers are measured
individually and have a simple shape, a more accurate method is direct
imaging of the fiber with SEM to measure the diameter and calculation of
the linear density. Finally, linear density is directly measured with a
vibroscope. The sample is tensioned between two hard points, mechanical
vibration is induced and the fundamental frequency is measured.
fabric utilization which is also referenced at times as the yield of