How Are Pirns Wound? - Trim Engineering Services

Pirns are rods onto which weft thread is wound for use in weaving. While they sound
similar to bobbins, but they are different in that they are fixed in place and the thread is
delivered off the end, rather than from the center. They are not wound evenly from end to
end in order to ensure snag-free thread delivery. Pirns are generally made of plastic or
wood, and are slightly tapered for most of the length, tapering at the end. Pirns are
generally used with power looms that have automatic changing mechanisms, which
remove the used pirn from the shuttle and replace it with a fresh one, thus allowing
uninterrupted weaving.
Having enough pirns in hand can help make your weaving time more effective and free of
time wastage. Also, by pre-loading pirns, you can change colours and transition projects
more easily and quickly. Thus, it is advised to have a good number of pirns in stock before
commencing your project. You can approach Trim Engineering Services, one of the
renowned pirn manufacturers in India, to get the best quality pirns for any kind of
project.
Pirns are basically of three types, namely plain tapered, full-base, and partly-formed-base
pirns. All these pirns are long and thin, but the dimension of each of these pirns is
controlled by the dimension of the shuttle it needs to be placed in. Whatever the kind and
size of pirn, the winding process is same for all.
Pirn winding is generally done on special automatic pirn winding machines consisting of
spindles. In case of regular winding, the cross-wound package results in tension variation
during weaving, while the parallel-wound package results in instability. This is why
winding of pirn involves overlapping short cross-wound sections in conical patterns. The
winding process begins from the conical base of the pirn, and slowly advances towards the

tip. Instead of travelling back and forth along the package, the yarn that is transferred from
the larger package to the smaller pirn is wound on one part of the package at a time. This
mechanism maintains uniform tension of the thread on the pirn and reduces ballooning
effects that are seen in bobbins, which reduces the possibility of slough-off. This winding
mechanism also cleans the pirns from any kinds of slubs or other faults during weaving
itself, which is why no additional yarn cleaning operation is required while winding pirns.
When a pirn is filled, the machine automatically removes it from the spindle and replaces it
with an empty pirn to be filled again, thus allowing uninterrupted weaving. All kinds of silk,
cotton, woolen, synthetic fiber, and terrycot yarns can be wound in this way. When a ready
pirn is used to weave, it is put into a shuttle that travels back and forth across the width of
the shuttle loom. This movement unwinds the yarn from the pirn through the eye or slot of
the shuttle.
This is how simple the winding and weaving mechanism of a pirn is. But, isn’t it interesting
to know how pirns and bobbins are so different from each other, while they perform the
same task!
For more information, visit: http://www.trimengineering.in/