ANALYSES OF REAL TIME WARP YARN TENSIONS IN SIZE-FREE WEAVING

1
ANALYSES OF REAL TIME WARP YARN TENSIONS IN
SIZE-FREE WEAVING Kumar Vikram Singh1, Paul S.
Sawhney2, Jayaram Subramanian3, Brian Condon 2,
and, Su-Seng Pang3 1Miami University, Oxford, OH,
45056, 2Southern Regional Research Center,
ARS/USDA New Orleans, LA 70124, 3Louisiana State
University, Baton Rouge, LA, 70803
OBJECTIVES
DYNAMIC TENSION DATA
CONCLUSIONS, FUTURE DIRECTIONS

• The real time yarn dynamic tension data can be
  obtained and the range of tension oscillations
  can be the basis for minimizing yarn abrasion.
  For example, if the relationship between the peak
  tension and the rate of yarn abrasion can be
  established, then by controlling the range of
  dynamic tension oscillations, the warp yarn
  abrasion can be minimized.
• The experiments were conducted while weaving a
  cotton twill fabric with a size-less warp. The
  weaving speed ranged from 250-550 picks per
  minute (ppm) and the pick density varied from
  30-50 picks per inch (ppi). The following results
  correspond to 550 ppm and 50 ppi experiments
• The peak tension corresponds to the pick beat-up.
• The dynamic tension varies from 12 cN to 90 cN
  during a weaving cycle.
• The frequency response analysis indicates that
  the peak tension occurs at the rate of 2.28 Hz.
  (which means that during 1 cycle of crank
  rotation the yarn is (falsely) shown to
  experience the peak tension 2.28 times (instead
  of actual once).
• The higher harmonics of the frequency graph
  indicate that the peak tension repeats itself at
  the said frequency.
• The actual frequency of the peak tension were
  9Hz. (corresponding to the weaving speed of 550
  ppm). Hence the results presented here are
  aliased due to the limited capabilities of the
  data acquisition card used.
• Also, the tensiometer used for dynamic tension
  data acquisition has limited sampling rate (i.e.,
  27 samples/second). Hence, in order to identify
  the detailed tension fluctuations in yarns
  corresponding to small crank rotations (produced
  by the 550 reciprocating motions of heddles and
  reed per minute) and peak tensions during the
  beat-up process, we need to acquire tensiometer
  with high sampling rate (at least two time faster
  than the maximum weaving speed of 550 ppm, or
  20 Hz.).
• Tensiometer with high sampling rate will produce
  data that will help in better understanding of
  any correlation between the yarn dynamic tension
  and its abrasion resistance when the yarn is
  subjected to fatigue-frictional forces.
• A lab-scale yarn-endurance tester will be used to
  correlate the yarn dynamic tension, the beat-up
  frequency, and the yarn abrasion resistance
  (damage).

• Study the real-time tensions of single strands of
  an 100 cotton, size-less common warp, during
  weaving on a high-speed weaving machine.
• Study the dynamic tension behavior of individual
  warp yarns for various weaving speeds and fabric
  constructions (viz., picks per minute and
  picks/inch).
• Experimental determinations of the tension
  variations of a single yarn strand within a
  weaving cycle, the tension fluctuations among
  different yarn strands, and the overall warp
  tension variations.

HYPOTHESIS
A cotton spun yarn consists of multiple cotton
fibers that are twisted together in a spinning
process. Thus, the intra fiber cohesive and
mechanical forces keep the yarn structure intact.
In the conventional weaving process, the
traditional sizing of warp yarns further protects
the yarns from losing their twist during the
harsh weaving conditions, in which the yarns
experience repeated dynamic tension-compression
cycles. However, in case of size-free weaving the
dynamic tension-compression cycles due to the
reciprocating motions of heddles and reed may
lead to a certain degree of twist loss in the
interlaced fibers and consequently in the yarn
structure/integrity. The loss of twist in the
yarn leads to some separation of some individual
fibers in the yarn structure. These few,
relatively loose fibers progressively lead to
formation of protruding fibers on the yarn
surface. These projecting fibers ultimately form
the tiny soft ball-like defects that are
observed in the fabric.
Figure 2 Snapshots of dynamic tension of single
warp yarn at different positions on the loom beam
EXPERIMENTAL SETUP
Real Time Data Acquisition Hardware (ROTHSCHILD
F-METER R-2068)
Electronic Tensiometer
Figure 3 Average dynamic tension of single warp
yarn at different positions on the loom beam
Notebook Computer with Data Acquisition Software
Dynamic Tension Data Analysis in MATLAB
REFERENCES
2.28 Hz.

1. Sawhney, A. P. S., Price, J. B. and Calamari, T.
   A. A successful weaving trial with a size-free
   cotton warp. Indian Journal of Fibre Textile
   Research. 29(2)117-121. 2004.
2. Sawhney, A.P.S., Dumitras, P.G., Sachinvala,
   N.D., Calamari, T.A.., Bologa, M.K. and Singh,
   K.V., Approaches for Reducing or Eliminating
   Warp Sizing in Modern Weaving An Interim
   Report, AATCC Review, Vol. 5, No. 9, pp.23-26,
   September 2005.
3. Sawhney, A.P.S., Singh, K.V., and, Sachinvala,
   N.D., Calamari, Preliminary Assessments of
   Size-Free Weaving and Fabric Quality, AATCC's
   2005 International Conference Exhibition,
   Boston, October 25-27, 2005.
4. Sawhney, A. P. S., Singh, K. V., Sachinvala, N.,
   Pang, S.-S., Condon, B., and, Li, G. Size-Free
   Weaving of Cotton Fabric on a Modern High-Speed
   Weaving Machine A Progress Report. Beltwide
   Cotton Production and Research Conferences.
   National Cotton Council of America. pp.
   2491-2496, San Antonio, 2006.

6.84 Hz.
4.56 Hz.
9.12 Hz.
Figure 4 Frequency response indicating the
harmonics of the peak dynamic tension of single
warp yarn
Figure 1 Experimental Setup to acquire time
series dynamic tension data of single warp yarn
on the running loom