The Fabric count is the number of warp and weft yarns per unit distance while the fabric is held without tension and is free of folds and wrinkles.
In the woven fabric the warp yarns are referred to like ends, i.e., the number of warps ends per inch is known as ends per inch (EPI). The threads of weft are called picks and the number of weft threads per inch is known as picks per inch (PPI).
Determination of Threads per inch:
Fabric count is determined in the following ways:
Use of Counting Glass (Pick Glass).
Traversing Thread Counter.
Fabric Dissection (Unravelling the cloth).
Parallel Line Grating.
Tapper Line Grating.
Use of Counting Glass (Pick Glass):
The counting glass is a small magnifying glass in a stand over a square exactly one inch each way. The number of threads in the field directly gives the number of threads per inch. This is the method generally used.
Method of Using Counting Glass:
If the counting glass is used, it is convenient to use a light table, a box with a ground glass top and containing several electric bulbs. The EPI and PPI should be counted in five different places, not counting the same threads twice and, of course, not near the selvedge, because the spacing of the threads near selvedges is often a little different than in the body of the cloth. If there are fewer than 25 threads/inch, the number of threads is 3 inches wide the total number of ends should be counted and divided by the width.
In the case of pile fabrics, another pair of counts is of importance. The number of tufts or loops per inch, counted in the warp wise direction, known as row, the number of tufts or loops per inch, counted in the weft wise direction, is known as the pitch.
The construction of cloth is usually designated by a combination of figures such as 100x60. This means 100 ends per inch and 60 picks per inch. Fabric count is also expressed in the same manner as 100x60. The result should be read as one hundred by sixty, not as 6000.
Traversing Thread Counter:
This is also called a mechanical pick counter, it consists of a small microscope arranged to travel horizontally on a calibrated track. The microscope is fitted with a pointer to aid counting. The microscope is placed on the cloth with the pointer at zero and made to traverse on the cloth, counting the yarns as they pass under the needlepoint for a known distance. Then the number of yarns per inch is calculated.
Fabrics Dissection (Unravelling the Cloth):
In this method, a known with is unravelled and the threads counted. This method is used where the threads are difficult to distinguish as in felted threads or where the structure is complex, as in pile fabrics.
Parallel Line Grating:
It is a very rapid optical method and this can be straight away taken for the determination of ends per inch and picks per inch.
Taper Line Grating:
It is an optical method and is a development of parallel line grating.
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