Uster Technologies

Modern, industrial cotton gins often operate with sensors by Uster, to control their process and to the resulting fiber quality.

Cotton classing is required to measure and classify each cotton bale according to its specific physical attributes. Measurement information produced by Uster's HVI (High Volume Instrument) covers following parameters: fiber length, length uniformity, fiber strength, fiber maturity, short fiber content, micronaire (fiber fineness), color grade, leaf and extraneous matter.

When cotton is traded, its value is determined by the above-mentioned quality parameters, as measured by the HVI in the classing agencies. Hence Uster's HVI has defined a set of standards for a large part of all cotton trades worldwide.[3]

Uster products are used in the spinning mill for measuring and analyzing the quality of the raw materials (i.e., fibers of different materials), intermediate products (i.e., sliver, roving) and final product (i.e., yarn) along their entire manufacturing process.

Most important process parameters a spinning mill has to control are: quality of the incoming fibers, yarn evenness, hairiness, tensile strength and elongation, contamination with disturbing materials, twist, friction, etc. By measuring these parameters, the instruments can be used as tools for a mill-wide quality assurance process.[4]

An overview of Uster products applied in the spinning mills:

• The "Uster Tester", a laboratory system for the measurement of evenness, thick places, thin places, neps, hairiness, diameter, dust, trash, fineness of yarns
• Yarn tensile testers - at conventional (5m/min) and high speeds (400m/min)
• Yarn fineness tester
• Yarn strength tester (Tensorapid)
• Yarn twist tester
• Yarn friction tester
• Single fiber measuring system (AFIS = Advanced Fibre Investigation System)
• Fiber bundle measuring system (HVI)
• Yarn clearer (Uster Quantum), which is mounted in the automatic winding machine, i.e., "on-line"
• Defect classification instrument (Classimat)
• Cotton cleaning system (Vision Shield)

While developing these different testing instruments, often the first of their kind, Uster also had to invent either the measuring method or the suitable measurement parameters.[5] Some examples:[6]

For comparing such quality parameters in the spinning laboratory with those of other spinning mills worldwide, Uster established a number of benchmarks. The first so-called "Uster Statistics" were introduced in 1957 and have been periodically updated to account for the technical and regional changes in the industry. These statistics are an important element in the trading of yarns, as they allow yarns to be objectively specified and referred to a worldwide quality level.

Uster Technologies also runs the Usterizing certification program for spinning mills.