Loepfe - Triboelectric Yarn Clearing
Ltd. was founded in 1955 by the brothers Helmut and Erich
Loepfe. Innovative and reliable products, supported by
customer-oriented service, are the basis for the success
of Loepfe Brothers Ltd. Loepfe system solutions and
services for the textile industry are recognized as being
innovative and leading in application technology. Loepfe
solves textile problems with precision and are
characterized by new ideas and features. Loepfe’s
electronic control systems are used with success in
spinning, weaving and other textile industries.
Prevention of standstills during sectional warping and beam
warping as well as the following production steps reduces costs
and increases efficiency. However, machine standstills and the
resulting quality defects in the finished product can never be
100% prevented whereas standstills caused by deficient yarn can
be prevented. With the efficient triboelectric yarn clearer "YarnMaster
Zenit FP", contaminations can be prevented and thus expensive
faults in the finished product.
Equivalent to foreign matter detection in the nineties, PP
(polypropylene) cleared yarn is becoming the prerequisite for a
high quality standard. More and more markets specifically demand
yarn cleared from PP from their suppliers.
Cotton bales contaminated with synthetic foreign matter
result mainly from contaminated cotton fields and packaging
remnants. During processing in the spinning preparatory factory,
they are reduced to small pieces and evenly distributed during
folding. Foreign matter elimination when opening the bale
reduces the cutting count in the winding process by only approx.
Experience shows that every fifth machine stop during
sectional warping and beam warping is caused by PP contamination
(Fig. 1). Yarn strength is essentially reduced (Fig. 2) because
there are fewer fibers in the cross-section which causes yarn
breaks in further processing. In addition, hooking can also
cause machine standstills. The later the standstills occur in
the process, the higher the costs thereby incurred. For example,
raw-white PP becomes visible only after dyeing (Fig. 3).
Clearing this foreign matter improves the yarn standard
considerably and prevents costly complaints concerning the dyed
YarnMaster ZENIT yarn clearer
Correct method of detection
Polypropylene (PP) and other synthetic foreign matter that is
transparent and identical in color with cotton/wool can hardly
be recognized with conventional, optical foreign fiber clearing.
To solve this problem, LOEPFE developed the "YarnMaster
Zenit FP" triboelectric sensor. This sensor detects
synthetic foreign matter independent of the color of the yarn
and of the foreign matter, for example white and transparent
polypropylene in raw-white yarn as well as finest foreign fibers
and operates with maximum reliability thanks to many years of
When the triboelectric measuring principle is used, variable
amplifiers adjust the signal to a normalized
level. While the yarn passes the sensor, the fibers exchange
electrons with the sensor. This effect is referred to as the "triboelectric
effect”. It is continuously measured by state-of-the art
electronics. When a synthetic fiber passes the electrode of the
sensor, it is detected because of the triboelectric voltage
difference. The YarnMaster ZENIT FP yarn clearer thus detects
synthetic foreign fiber matter, such as polypropylene,
polyethylene, polyamide (nylon), etc.
Cotton and blends are tested, depending on material and
blending ratio, in various yarn counts. The elimination of 128
defined sources of error as well as IPI imperfections according
to international standards can be achieved. Desired effects are
maintained as non-disturbing. Reference lengths can be selected.
The classification of the splice connections is performed
relative to groups and also to spindles. In addition to
diameter-related imperfections, the SFI and SFI/D surface
characteristics developed by Loepfe are also monitored around
Materials testing with the efficient "YarnMaster Zenit FP"
triboelectric yarn clearer can prevent contaminations and
eliminate expensive faults in the finished product. This clearly
increases efficiency of downstream processes of the spinning
mill. In this production stage, undyed yarn particles would
result in costly faults. The yarn clearer reduces complaints
caused by foreign matter in the dyed end product.
A non-optical measuring system causes erroneous results in
the detection and clearing of yarn faults as well as foreign
fibers with different colors. The application of a measuring
system with limited possibilities and low reliability is
inadequate and therefore too expensive in any case.
The reference of all measuring systems is the human eye. The
finished yarn and the textile surface produced from it meet the
quality criteria of the human eye. In higher market segments,
yarns that are free from PP are a basic requirement for success.
Perfect yarn clearing allows the producers access to these
markets and more attractive prices. With the optical and
triboelectric measuring method, Loepfe provides optimum
solutions with high economic efficiency.