Fabric Construction and Weaving
Fabric Construction and Weaving
This domain examines loom motions, the three basic weaves, and fabric mass per unit area. You should be able to identify a weave from its interlacing pattern and estimate GSM from sett and yarn count.
Loom and weave basics
- Three primary motions: shedding, picking and beating-up. Secondary motions include take-up and let-off.
- Plain weave has maximum interlacing, is firm and cheap; examples include muslin and poplin.
- Twill weave produces diagonal lines, as in denim and gabardine.
- Satin weave has long floats, low interlacing and high lustre.
- Warp yarns run lengthwise and are usually stronger; weft yarns run widthwise. The selvedge is the self-edge.
Fabric weight
GSM means grams per square metre. An estimate from sett and yarn count is: GSM = (ends/cm × warp tex + picks/cm × weft tex) ÷ 10. It ignores crimp and weave take-up, so treat it as an approximation.
Worked example
A plain fabric has 40 ends/cm of 20 tex warp and 30 picks/cm of 20 tex weft. GSM = (40 × 20 + 30 × 20) ÷ 10 = (800 + 600) ÷ 10 = 140 g/m². Reasoning: each metre-length warp end weighs 20/1,000 g, and there are 40 × 100 ends across a metre width; the same logic applies to weft.
Traps
Do not swap ends and picks. Do not use inches in the formula without converting. Do not call satin hard-wearing in every end use. Do not ignore crimp when comparing the estimate with a tested GSM.
Key points
- Shedding, picking and beating-up are the primary loom motions.
- Plain weave has the highest interlacing; satin has the lowest of the three basics.
- Twill is identified by diagonal wales.
- Ends/cm and picks/cm are not interchangeable.
- The GSM formula gives an estimate, not a finished-fabric test result.