Woven Fabric Defects 1i134q

WOVEN FABRIC DEFECTS

Presented by: T. Srivani, Assistant Professor, DFT.

NATURE & CAUSES OF DEFECTS 1. YARN DEFECTS 1) Broken Filaments 2) Coloured Flecks 3) Knots 4) Slub

5) Slubby Weft

NATURE & CAUSES OF DEFECTS 2. WEAVING DEFECTS 1) 2) 3) 4) 5) 6) 7) 8) 9) 10)

Broken Ends Woven in a Bunch Broken Pattern Double End Float Gout Hole, Cut or Tear Lashing-in Local Distortion Missing Ends Oil or other Stain

NATURE & CAUSES OF DEFECTS 2. WEAVING DEFECTS 11) 12) 13) 14) 15) 16) 17) 18) 19) 20) 21)

Oily or Soiled Ends Oily Weft Reed Marks Selvedge Defect Slough Off Smash Snarls Stitches Untrimmed Loose Threads Weft Bar Weft Crack

NATURE & CAUSES OF DEFECTS 3. PILING & RAISING DEFECTS 1) Broken Pattern due to Defective Piles 2) Pile less Spot 3) Uneven or Loose Piles

NATURE & CAUSES OF DEFECTS 4. PROCESSING DEFECTS 1) Bleaching spot 2) Blurred or Dark Patch 3) Bowing 4) Defects caused by Hanging Thread 5) Dye Bar

6) Dyestuff Stain Misprint/ Absence of Print

NATURE & CAUSES OF DEFECTS 4. PROCESSING DEFECTS 7) Patchy or Streaky or Uneven Dyeing 8) Pilling

9) Shading or Listing 10)Uneven Printing or Tinting 11)Water Mark White spot

NATURE & CAUSES OF DEFECTS 5. MILLING DEFECTS 1) Mill Rigs

2) Uneven Milling

NATURE & CAUSES OF DEFECTS 6. EMBROIDERY DEFECTS 1) Embroidery Defects

1. YARN DEFECTS •The defects originating from spinning stage or winding stage.

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BROKEN FILAMENTS Occurs when the individual filaments constituting the main yarn are broken.

MAIN CAUSES: - During the process of winding etc. the yarn guide having sharp edges may cut individual filaments or abrasion caused at the time of weaving while ing through heald eye and reed dent

MENDING: - Non mendable

COLOURED FLECKS Presence of coloured foreign matter in the yarn.

MAIN CAUSES: - The cotton fibre gets contaminated during the ginning stage due to leaves, immature fibre, yellow fibre, tie yarn etc., which gets embedded into the yarn at the time of the spinning.

MENDING: - The coloured portion should be carefully removed from the yarn with a plucker. If that is not possible, then it should be cut with a thread clipper from both the sides carefully and the cut portion should be removed with a plucker. The resultant bare patch can be corrected by combing with a metallic comb.

KNOTS Occur when broken threads are pieced together by improper knotting.

MAIN CAUSES: - When the thread breaks during the process of winding, warping, sizing or weaving, if the knotting machine is not used, it results in thick knots. MENDING: - Non - mendable.

SLUB A slub is a bunch of fibres having less twist or no twist and has a wider diameter compared to normal spun yarn.

MAIN CAUSES: - Improper Carding/Combing. - Improper cleaning of the cans, top rollers, clearers in drafting, roving and ring frame.

- Broken tooth in the chain of the gear system. - Failure of the pneumatic suction system. - Careless piecing of the ends in the drawing, roving and ring frame. MENDING: - The slub should be cut with thread clipper from both the ends carefully and the cut portion should be removed with a plucker. The resultant bare patch can be corrected either by combing with a metallic comb or by the insertion of a separate thread with the help of a fine needle.

SLUBBY WEFT A slubby weft is the occurrence of slubs at frequent intervals in the weft yarn.

MAIN CAUSES: - Improper Carding/Combing. - Improper cleaning of the cans, top rollers, clearers in drafting, roving and ring frame. - Broken tooth in the chain of the gear system. - Failure of the pneumatic suction system. - Careless piecing of the ends in the drawing, roving and ring frame.

MENDING: Non – mendable.

2. WEAVING DEFECTS - The defects which originate during the process of weaving.......

BROKEN ENDS WOVEN IN A BUNCH This defect is caused by a bunch of broken ends woven in the fabric.

MAIN CAUSES: - Failure of the weaver in attending to the warp breaks properly.

MENDING: - The broken ends woven in a bunch can

be removed by using a plucker and the resulting loose threads should be cut with a trimmer. As a result, a bare patch occurs and combing in both directions with a metallic comb can fill this up.

BROKEN PATTERN A broken pattern is the non-continuity of a weave/design/pattern.

MAIN CAUSES: - Wrong drawing of threads in the colour pattern. - Inserting a pick in a wrong shed. - Incorrect shedding.

MENDING: - Non - mendable

DOUBLE END When two or more ends unintentionally get woven as one. This defect is characterized by a thick bar running parallel to the warp.

MAIN CAUSES: - Mixing up of threads during the process of spinning/ winding/warping/sizing. - Wrong drawing, taking more ends in heald eye.

MENDING: - This fault can be corrected by pulling out one extra end with the help of a needle. The resultant loose end can be clipped with the help of clipper. A bare patch if formed can also be filled, by combing in both the directions with the help of a metallic comb.

FLOAT A float is the improper interlacement of warp and weft threads in the fabric over a certain area.

MAIN CAUSES:

- Healds touching each other, causing some ends to remain on top. - Shed not divided so that the shuttle has the chance to leave some ends up or down. - Broken heald/heald eye. - Tight ends in the weaver’s beam cause a few ends to remain up rather than in the normal warp - Heald strap slack. - Heald hanging. - Cotton fluff between warp layers. - Broken end entangled with other ends. - Improper sizing: the ends sticking. - Crossed-ends from sizing or in loom shed.

FLOAT Continued.... Mending: Minor floats can only be rectified. The floating threads may be cut with a clipper from both the ends. Combing in both the direction with the help of a metallic comb may rectify the resultant bare patch formed.

GOUT Gout is a foreign matter usually lint or waste accidentally woven into the fabric.

MAIN CAUSES: - Improper loom cleaning.

- Unclean environment in the weaving department. MENDING: - The extra foreign matter can be pulled out with a needle and trimmed with the help of a trimmer. Combing in both directions with the help of metallic comb can fill up the resultant bare patch.

HOLE, CUT OR TEAR This is self-explanatory.

MAIN CAUSES:

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Sharp edges on the cloth roll or front rest.

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Hard substance between layers of fabric in the loom cloth roll.

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During removal of hard particles like, leather parts or iron particles woven in the cloth.

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The cloth roll striking against a sharp pointed edge during transport or when it is being doffed.

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Coarse temples used for fine fabric.

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Temple rolls not properly set, i.e., very high or low.

HOLE, CUT OR TEAR This is self-explanatory.

MAIN CAUSES: - Right hand temple used in place of left hand and vice versa. - Very coarse hooks at grey folding. - Wrong weft fork timing in case of centre weft fork, which causes small holes at the centre of the fabric. - Carelessly placing the shuttle on the cloth while changing the pirn. - Faulty emery roll. - Cloth not gaited up on the cloth roll properly.

MENDING: Non - Mendable

LASHING-IN An extra piece of yarn woven into the fabric in the vicinity of the selvedge.

MAIN CAUSES: - Defective setting of the shuttle box, rough edges in the front plate of the shuttle box. - Harsh picking. - Extra weft yarn left hanging at the change of weft pirn. - Warp too tight or too slack.

- Picking early or late. - Weft fork going too far through the grid. - In case of auto loom, weft cutters worn out or not properly set. - Worn out pickers.

LASHING-IN Continued....... MENDING: - This defect can be corrected by pulling out the extra pick from the selvedge end, which can be clipped with the help of a clipper. Combing in both the directions with the help of metallic comb can fill up the resultant bare patch.

LOCAL DISTORTION Distortion occurs when there is displacement of warp and/or weft threads from their normal position

MAIN CAUSES: - The emery roll in weaving is worn out. - In filament fabrics having low reed picks.

MENDING: - This defect can be corrected by pulling out the extra pick from the selvedge end, which can be clipped with the help of a clipper. Combing in both the directions with the help of metallic comb can fill up the resultant bare patch.

Streaks across the width of the fabric may occur. Reed marks or spaces between groups of warps at intervals or continuously due to crowding or improper spacing of warp yarns as they through the reed A tight selvedge, indicated by a puckered or wavy edge, may be caused by Excessive tension in the warp yarns

Bow: The weft not perpendicular to the warp and taking a direction of bow in the Center, wherein the weft lies adjacent to the previous pick at the selvedges Skew ness: a diagonal pick, touching the previous pick at one side of the fabric selvedge and staying distant at the other end, which disturbs the grain in the fabric.