Dr. Jimmy Lam Institute of Textiles & Clothing Woven Fabric Analysis Dr. Jimmy Lam Institute of Textiles & Clothing

What you can find from a woven fabric Believe it or not, you can find at least ten items from a piece of fabric. What are they?

Information from a woven fabric Weave (structure) Order of coloring in warp and weft (if applicable) Sett – ends (warp) and picks (weft) per cm Yarn particulars Counts (tex) Twist per cm S or Z twist Single or fold yarn

Information from a woven fabric (2) Crimp% in warp and weft Width of warp in reed Warp length for a given finished fabric length (m) Weight of fabric per unit area (gm/sq. m) Type of material for both warp and weft Type of finishing applied Other factors: tensile strength, resistance to abrasion, drape, shower resistance, color fastness

Items Units Weave, drawing-in and lifting plan - Fabric width Cm Warp density Ends/cm Weft density Picks/cm Warping (Colour pattern) Wefting (Colour pattern) Warp crimp % Weft crimp Warp count & material Tex Weft count & material Fabric weight Gm/sq. m

Face and back of woven fabric In defining which is the face or back of woven fabric, it is mainly accorded to type of material, yarn count, arranging of yarn, dyeing and printing, weave pattern, finishing effect. Typical for fabric surface are: Smoother; Soft handle; The face with solid jacquard pattern, pattern weave or printed weave It is always with higher warp float proportion of fabric Fabric with special effects, the effects usually appears on the face.

Distinguish of warp and weft (1) With reed mark No reed mark End spacing is more uniform Pick spacing is more irregular Higher tension Lower tension Parallel to selvedge - Higher sett (ends/cm) Lower sett (picks/cm) Higher strength Lower strength than warp If folded yarn is used, warp is always with fold yarn Weft is single yarn

Distinguish of warp and weft (2) Warp Weft If both are with same yarn, warp is finer, higher twist, with longer staple yarn Weft is coarser, lower in twist, shorter in staple Usually sized No sizing Warp is Z twist Weft is S twist Usually lower crimp% Higher crimp% For stripes of fancy yarn, introduced in warp - For leno (selvedge), threads are warp For cotton twill, twill run up from left to right when warp is vertical

Finding crimp% and yarn count Crimp%=[(extended length) – (sample length) x100%] ÷ (sample length) For yarn count, it is determined through the weight of specific length and then calculate the count. Yarn count (tex) = yarn weight (gm) per 1000 meter.

Yarn count (tex) Calculation Total length= no. of yarn sample x length of each sample Weight of these samples=by directed weight and unit in gm. Weight of 1 km in length = by calculation in gm Yarn count= weight in 1 km in length and unit in tex Example: No of yarn sample taken=12 Length of each yarn sample=6 cm Total yarn length=(12x6)÷100 m =0.72m Weight of these samples =0.060gm Weight of 1 km in length=(1000 x 0.06)÷0.72 =83.3gm Therefore, yarn count =83.3 tex

Fabric Weight Calculation This is done by calculation of fabric size 1 m x 1 m. The formula for warp weight: Warp weight (gm/sq m.) = [ends/cm x 100 x tex x (1+warp crimp%)] ÷ 1000 The formula for weft weight: Weft weight (gm/sq m.) = [picks/cm x 100 x tex x (1+weft crimp%)] ÷ 1000 Fabric Weight (gm/sq. m) = warp weight + weft weight

Fabric weight classification Weight Range Typical examples Sheer: 0-50 g/m2 (0-1/2 oz/yd2) Lingerie, women”s hosiery, sheer cutrains Light: 50-150 g/m2 (1-4 1/2 oz/yd2) “Top weight”, shirts, blouses, dresses, linings Medium: 150-300 g/m2 (4 1/2 – 9 oz/yd2) “Bottom weight”, shirts, suits, sports denim, terry towels Medium-Heavy: 300-600 g/m2 (9-18 oz/yd2) “Bull denim”, workwear, best terry towels, overcoats Heavy : 600 g/m2 (18 oz/yd2) and up Winter coats, upholstery, mats, carpets

Satin & Sateen Weaves In these weaves, the warp faced ones are termed as “satin” and those of weft faced are termed as “sateen” weave. For either one, the interlacing points of two adjacent threads are so arranged that each only has one interlacing point and then floats across the width of the repeat. The results with a maximum degree of lustre and smoothness of no prominent weave features. Also, such arrangement of interlacing points of threads with each other lets them with much freedom, and therefore, more close packing of threads is possible

Sateen of repeat number of 8 Which moves number is not possible, why?

Sateen Weave For M=1 and 7, weaves of opposite twill lines are formed For M=2,4, and 6, some threads are without any interlacing points For M=3 and 5, regular sateen weaves, with the above mentioned features are formed.

Rules for the Move Number of Sateen Weave Some rules should be followed in the construction of regular satin or sateen weaves: The selected move number should not be either one or one less than repeat number of weave; or with a common factor of the repeat number

Examples of Sateen Move Number Repeat No Move no. excluded Possible move no. 5 1,4 2,3 6 1,2,3,4,5 None 7 1,6 2,3,4,5 8 1,2,4,6,7 3,5 9 1,3,6,8 2,4,5,7 10 1,2,4,5,6,8,9 3,7 11 1,10 2,3,4,5,6,7,8,9 15 1,3,5,6,9,10,12,14 2,4,8,11,13

Sateen Repeat Number Possible Move Number Repeat =5, Possible M=2 and3 Repeat =7, Possible move M=2,3,4 or 5

Sateen Repeat Number Possible Move Number Repeat=9, M=2, 4 or 5 Repeat=10, M=3 or 7 Repeat=11, M=3 or 7

Irregular Satin & Sateen

Discussion What information you can have from a piece of woven fabric? Discuss the sateen weave and the rules for sateen movement?