Presentation
on
fibre sampling

Q. What is textile testing?
• Testing can be defined as the process of determining
the properties of different kinds of substances.

Q. What is purpose of taking sample?
• To draw conclusions about populations
from samples, we must use inferential
statistics which enables us to determine a
population`s characteristics by directly
observing only a portion (or sample) of the
population.

SOME BASIC TERMS :-
• Sample: Is relative small fraction which is select to
represent a population sampling method.
• Test specimen: this is the one that is actually used for
the individual measurement and is derived from the
laboratory sample. Normally, measurements are made
from several test specimens.

Type of Sample:-
• Numerical sample :- A sample in which proportion of
long medium and short fibre would be same in sample
as in population.
• Random sample :- In this type of sample every
individual in the population has an equal chance of
being included in it.
• Biased sample :- when the selecting sample is
influenced by other factor other then chance then sample
is not true representative.

Sampling method for fibre:-
From bulk there are two methods :-
1. Zone technique.
2. Core sampling .
From combed / sliver roving :-
1. Numerical sample.
2. Length biased sample .
3. Random draw method.(for sliver)
4. cut square method.(for yarn)

Zoning technique :-

Zoning techniques :- is popular techniques for
testing method of fibre, where the property may
vary considerably from place to place.
Procedure:-
• Collect handful of fibre randomly from at least 40 bales.
• Each handful is divided into 2 parts out of which one is
discarded and other is retain.
• Again divide the retain part into half.
• Repeat the process until about 5 grams of fibre remain in
handful.
• Treat each handful in similarly manner and collet all the fibre
from 40 zone to have the final sample of 5 gram.

Core sampling :-

Core sampling:-
Procedure:-
• Cutting tip dia. is lesser than coring tube.
• helps sliding the core upside the tube penetrates.
• helps retaining the core as it is withdrawn.
• No. of cores are extracted and combined.
• Different sizes of tube 14, 15, and 18mm.
• After removal cores are kept in air tight container
immediately.
• Hydraulic coring machine for large number of samples.

Fibre sampling from combed sliver/Roving
& yarn :-
• Numerical sample :- the removal of one sample does not
effect the composition of remaining sample then it can be
considered as numerical sample and each segment is
representative of hole.
• Length-biased :- Prepare a length-biased sample in
such way that the bias can be allowed for in any
calculation (based on some assumptions).
• Remove all fibres which are started left of A (X zone)
.The green fibres will be unaffected.
• Again remove fibres, the fibre will be unchanged.

If the removal of one sample does not affect the
composition of the remaining samples, then it can be
considered as “ numerical sample” and each segment is
representative of the whole.

RANDOM DRAW METHOD :-
• Take out fibre (2mm at each stage) and discard until a
distance equal to that of the longest fibre in the sliver has
removed. After that each draw will be of numerical
samples.

CUT SQUARE METHOD:-
• Cut all the projected fibres and discarded. The glass
plate is then moved back few mm, exposing more fibres
with “natural length” without cut. In each case projected
fibre ends must be removed.

• Thank you