Statimat DS

Automatic Tensile-,
Evenness-, and
Count Tester

 

 

n the production of staple fi bre- or fi lament yarns
as well as in twisting or texturizing operations
quality control serves to secure material properties
which ensure trouble-free downstream processing
as well as fl awless fi nal products. On the other
hand, by routine testing of yarns it is possible to
recognize faults in the production process early
enough to analyze the causes of such defects and
to take corrective actions.
The most important properties of yarns are tensile
strength and elongation, mass unevenness, and
yarn count (linear density). Static tensile tests, yarn
evenness tests, as well as various methods of yarn
count testing, e.g. by means of wrap reel and
balance, serve for the assessment of these yarn
properties. The operation of different test equip-
ment to which the yarn samples are presented one
after another, results in high expenditure of labour
and, especially in case of modern automatic
computer-controlled testing equipment, in
considerable fi nancial investment.

 

Description

Tasks of the quality control
on yarns and threads

This new model of the well-proven STATIMAT series of Textechno combines testing of tensile
properties according to the CRE principle, unevenness,
and count of yarn and thread in one tester.
The essential advantage of such a combination
of different test methods lies in the common use
of peripheral components like package changer,
threading mechanism for inserting the yarn sample
into the test sections, yarn feeding device, waste
yarn disposal, instrument housing with protective
front panel, as well as control electronics including
the PC-based Textechno TESTCONTROL system.
The three tests on each package presented by the
package changer are performed in succession.
Optionally it is possible to test unevenness and
yarn count in one test run.

Tensile test

The essential features of this STATIMAT DS test
procedure are the high clamping force of the
pneumatic jaws for tensile tests up to 1000 N,
the long path of the draw-off clamp for breaking
extensions up to 1000 %, the quick yarn threading
reducing idle time to only a few seconds, the forcemeasuring
system with a range of 500 N (optional
1500 N), as well as high variability of the test
process and the evaluation of the measured data.
In addition to the static tensile test, for instance
according to ISO 2062 or ASTM D2256, D885,
alternating load tests (hysteresis tests) are
possible according to freely selectable programs,
as well as creep and relaxation tests.
A yarn feeding device enables high-speed take-off
of selected yarn lengths prior to starting the tensile
test on a new package or between individual
tensile tests. This means that tensile tests can be
carried out on yarn lengths both from the package
outer and inner layers.

Yarn evenness test

A new innovative capacitor system enables
capacitive testing of the mass unevenness
according to ISO 16549 within a wide yarn count
range by individual adaptation of the measuring
sensor to the properties of the yarn material. As
a new feature in yarn evenness testing the yarn
tension can be monitored in order to ensure proper
testing conditions. Measurable variables delivered
by the system are the coeffi cient of variation of the
mass distribution along the yarn length, the
spectrogram, and for staple fi bre spun yarns the
numbers of neps, thick and thin places.
In case of continuous multifi lament yarns, interlaces
(entanglements), too, infl uence the uniformity of
the yarn. A sophisticated optical sensor system
serves for measuring the number as well as the
regularity of interlaces both in fl at and textured
yarns.