Faults of Woven and Knit Fabric
Faults of woven fabric: Bar: It is a band running across the full width of cloth. Pick bar due ti difference in pick spacing Tension-bar due to difference in weft tension Weft-bar due to difference in material count, twist etc Box marks: The causes of box marks are – Dirty box Shuttle riding over the weft Dirty shuttle Dirty picking and ticks Broken pattern: It occurs due to wrong drawing of threads insertion of thee pick, incorrect lifting of warp threads. Broken pick: A pick missing of the fabric, due to rough shuttle eyes, poor winding and weft yarn breakage.
Defective selvedge: Curled selvedge
Cut selvedges Loppy selvedges Slack selvedges Pulled selvedge Tight selvedge Uneven selvedge Float stitches: A place where warp and weft yarns escape the required interlacement. If occurs for improper warp stop motion. Fuzzy: it occurs for the present of hairy and abraded yarns. Hang pick: A pick which is out of line and is a triangular shape. Missing ends: Gap of warp yarns is the main causes Reed marks: Due to this fault cloth shows irregular spacing between groups of warp yarns across the fabric width. Shuttle marks: Width way marks due to abrasion of warp yarns by the shuttle. Stain:
Major problems on woven fabric Oil, Dust, Soil, Carbon particles in the air may cause stains. Uneven cloth: It produced when take up motion is faulty, broken ratchet wheel is also responsible. Some mechanical faults: Reed marks Shuttle flying out Shuttle trapping Loom hanging Loom stopping Weft cutting Bumping Knitting Faults: Holes: Holes are the result of yarn breakage. It occurs for the following causes – Uneven yarn Badly set of yarn feeder Knots, slubs etc in yarn Yarn tension is too high Yarn is too dry Drop stitches: Those are the result of a defective needle. It also occurs when a yarn is not properly fed during stitch formation.
Cloth fall –out: it is an area consisting of drop sitiches lying side by side. Snags: It occurs when filament yarns are processing. It occurs for higher twist and lesser crimp elasticity. Double stitches: These occur due to badly knitted or non-knitted loops. Vertical stripes: It is observed as longitudinal gaps in the fabric. When the space between Wales is irregular it occurs. Horizontal stripes: Horizontal stripes are caused by unevenness in the courses. Soil stripes: Soil stripes can appear both in the direction of Wales as well as courses. Color fly: Color fly consists of singe fibres, brunches of fibre of yarn pieces in varying colors.
Distorted stitches: Due to it if become unsettled fabric and fabric appearance is skitter. Write about BAN (Barium Activity Number): Barium activity Number = (? Ba(OH)? _2 Absorbed by mercerised cotton material)/(? Ba(OH)? _2 Absorbed by unmercerised cotton material) BAN is always greater than 100 Standard range of BAN 115 – 135 Highly mercerized range 140 – 150 possible If BAN < 115, Mercerization wille be uneven Write ablout Water Hardness: Hardness is a term applied to water denoting a measurement of its PH and metal salt contest. Classification of water according to hardness – DescriptionTotal hardness (Degree)
Very soft 0 – 40 Soft 5 – 80 Shild 9-140 Fairly hard 15 -180 Hard 19 -300 Very hard > 300 Determination of water hardness: The following Reagents are required for hardness measermet Buffer solution EDTA (Ethelene Diamine Tetraacetate ) (. 02 N or . 01 M) Indicator solution 0. 05 gm (Solochromo black WDFA) Mixture of alcohol and tri-ethanol amine Calcium solution – Take 1 gm CaCO3 and dried at 1650C Cover with clock glass and add water (50-100 ml) Add 20. 5 ml HCl Warm and next Cool Transfer to one litre volumetric flask Determination of total Hardness: Total Hardness = (T? 1000)/V mg/L CaCO3 Where, V = Wt. f solution (50 -100) into conical breaker T = Total amount of EDTA used to get reddish tinge disappear. Weight loss in Pre-treatment: The weight of unscoured and scoured were taken separately at the same moisture content and then weight loos is measured in %. Weight loss = (Wt. of Unscoured fabric-Wt. of Scoured fabric )/(Wt. of Unscoured fabric) ? 100% Standard range of Weight loss = 4 – 8% Fabric and knit: (Questions) Faults of woven and knit fabric. Different variables of woven fabric. BAN (Bariem activity number) Hardness measurement of H2O. Wt. loss in pre-treatment (Scouring, bleaching, desizing etc)