USTER HVI 900 - Uster SCI Regression Coefficients

USTER® HVI 900 Instruction Manual
Uster Technologies, Inc. Chapter 4
Version 4.0 (1.99) Status - Page 4-26
4.18 Uster® SCI Regression
Coefficients
Uster® Spinning Consistency Index (SCI) is a calculated value based on
multiple regression analyses that compare fiber properties to yarn
properties. Each equation takes into account all HVI properties, and
calculates one value to be used on each test sample. The standard
equation for SCI is based on the following information.
 Many samples that contain a wide range of fiber properties
 Yarn strength, appearance, elongation, neppiness, and spinning
potential yarn numbers
 The samples represent a wide range of cottons
Property Range
Length 15/16 - 1 3/8 inches (23.8 - 34.9 mm)
Strength 18 - 36 grams/tex
Micronaire 2.8 - 5.8
These ranges of fiber properties represents more than 90% of the
cottons produced worldwide. This equation can be used on cottons
produced in any growth area in the world. Several research institutes
also have done multiple regression analyses and have published results
for their specific varieties of cotton. Currently, the following equations
are used for SCI.
Uniformity Index (where UHML and ML in inches are used):
- 412.7 + 2.9 * Strength - 9.32 * Micronaire + 49.28 * Length
+ 4.80 * Uniformity + 0.65 * Rd
Uniformity Ratio
(where 2.5% Span Length and 50% Span Length in
inches are used):
- 412.7 + 2.9 * Strength - 9.32 * Micronaire + 49.28 * Length
+ 8.72 * Uniformity + 0.65 * Rd