3. SAMPLE
• The sample is a relatively small number of
individual members which is selected to
represent that population. A sample must
consist of a number of individual. An individual
is one member of the population.
4. SAMPLING
• Selection of material from the whole bulk for testing.
• Selection or taking small and ideal part of raw
materials to check the quality of total raw material by
is called sampling.
5. Importance of Sampling
• To reduce the cost
• To prevent the wastage of time
• To know the perfect characteristics of the raw
material.
• To ensure the good quality
• To achieve the good result
7. Random sampling
• A method of selecting the individual where
every individual of a sample in the population
has an equal chance of being selected.
• -The number of sample must be sufficiently
large to include all variation of the individuals
in the population.
8. BISED SAMPLING
• In biased sampling method, the selection of an
individual is influenced by factors other than
chance.
• Hence the sample does not truly represent the
bulk.
• Depending on the position of the sampling person.
9. Factors affecting sampling methods
• The form of the material
• Amount of material available
• Nature of the test
• Type of testing instrument
• Information required
• Degree of accuracy required
10. Sampling methods for different textile materials
1. Sampling for the determination of fiber properties
2. Sampling methods for yarn
3. Sampling methods for fabric
11. 1. Sampling for the determination of fibre
properties
• It depends upon the form in which the fibre is available. Different
techniques for different form of fibres-
– Fibres in bale
– Fibres in sliver
– Fibres in yarn etc
12. 1. Sampling for the determination of
fiber properties
Some techniques / methods involved for sampling
fibres-
• The squaring technique
• The cut squaring method
• The zoning technique (for raw cotton)
• Dye sampling method (for wool)
• The tong sampling method (for wool)
• Core sampling method (for wool)
13. 2. Sampling methods for yarn
Samples are randomly selected by various methods which differ according
to the tests required.
• Sampling for the determination of yarn count (yarn from different
packages)
• Sampling for the determination of yarn count (yarn removed from fabric)
• Sampling for the determination of yarn twist (yarn from packages)
• Sampling for the determination of lea strength of spun yarn
• Sampling for the determination of single thread tensile test (from any yarn
package or from any woven/knitted fabric)
14. 3. Sampling methods for fabric
Points of consideration while sampling fabric:
• Fabric within 2 inches of the selvedge should not
be used. (Tension variation/strain on the yarns has effects)
• No two samples should contain the same thread.
• Form (narrow/wide) & amount of fabric available
for testing
