Abstract:
Pirn winding is an operation of winding yarn
from supply yarn package onto pirns which are used for shuttle
weft insertion. Firm and coherent winding tension is required to
maintain in the pirn winding process to withstand the high forces
produced by the deceleration of the shuttle at the end of each
pick and to avoid permanent strains in yarns which will appears
as fabric defects in weaving. The package size and its diameter
vary due to subsequent winding of pirns. Hence the balloon effect
varies and caused to change the thread tension at the winding
point of the pirn. The thread tension variation is considerably
significant from the first pirn wound from a package to the last
pirn wound from the same if no tension controlling mechanism is
devised. Placing dead weights on the disc tension controller
which adds a tension to take off tension may help to compensate
the yarn tension variation to some extent to combat with this
problem. However, this is a stepwise manual compensation
technique which needs the correct timing of compensation to
avoid significant tension variations in pirn windings. The author
attempted to theoretically analyze the tension variation in the
yarn path of the pirn winding machine and theoretically model
the tension variation with and without deadweight placement on
the tensioners. Author also verified the accuracy and the validity
of the model developed through the experimental results obtained
at different locations along the yarn path..
