Textile Testing and Quality Control
Standards and sampling
Testing follows recognised standards and uses representative sampling. Understand the difference between accuracy and precision, and between random and biased sampling. Control charts (X-bar and R) and acceptance sampling (AQL) are core quality tools.
Fibre and yarn tests
Fibre length, fineness, maturity and strength are measured by instruments such as fibrograph and micronaire. Yarn tests include count, twist, strength (single yarn and lea), elongation, evenness and imperfection counts. Uster evenness and hairiness are commonly examined.
Fabric tests
GSM, thickness, tensile and tear strength, abrasion, pilling, colour fastness (washing, rubbing, light, perspiration) and dimensional stability are standard. Fastness is graded against grey scales.
Traps
- Confusing strength units (cN/tex is specific strength; kgf is force).
- Mixing CV% with standard deviation.
- Assuming a higher evenness CV% is better; lower is better.
Worked example
If mean yarn strength is 250 cN and standard deviation 12.5 cN, CV% = 100 × 12.5/250 = 5%. For a 20 tex yarn, specific strength = 250/20 = 12.5 cN/tex. Always state the count basis when quoting strength.