USTER HVI 900 - Page 237

USTER® HVI 900 Instruction Manual
Uster Technologies, Inc. Chapter 10
Version 4.0 (1.99) Synthetic Fiber Testing - Page 10-25
5.4.4 Fineness Data
Micronaire is a measurement of specific surface [the ratio of surface
area (mm
2
) to the fiber volume (mm
3
)]. For cotton fibers, it is useful in
determining the cell wall thickness (volume of cellulose) within varieties
that have the same fiber perimeter. For Synthetic fibers, the
measurement is useful in determining if there is a change in denier, in
fiber finish, or in the cross-section shape (surface area). Therefore, it is
a useful measurement for screening variations in production. Unlike in
cotton where Micronaire is used for calculating strength, micronaire has
no influence on the strength measurement in Synthetic fibers.
The Fineness Data selection alternates between None, Micronaire and
keyboard.
 None — No fineness value will be required for testing.
 Micronaire — The fineness value will be determined by performing
the micronaire test. A message line is displayed on the test screen
requesting that the sample be weighed and tested. This value is not
used in strength calculation, but will be reported on the screen,
transmitted, and/or printed.
 Keyboard — The fineness value will be entered via the keyboard.
A message line is displayed requesting that you enter the
micronaire value to be used.
If you have determined fiber size using some other instrument, such as a
fibroscope, you can enter the test value via the keyboard. This value is
not used in the strength calculation, but will be reported, transmitted,
and/or printed.