Standard Defects and Ratios
Mostly seen errors are hole, rupture and needle signs. On 20 Kg roll fabric maximum;
If woven by cotton yarn 3-4 pieces, if by carded yarn 5-6 pieces defects can be.
We can show fabric error codes and meanings on computer shown like on below;
Possible Defects that can be on Woven Fabrics
On fabric; because of yarn, worker, machine parts, foreign matters and operation, seen and rated errors that ruined and lowered quality of fabric is called as defect.
On woven fabrics; because of used yarn, preparation step before woven, on woven step, on dyeing and finishing step, on storage step, various defects can occur. Producers have to sell these defect fabrics as lower quality products.
Classification of Defects on Woven Fabrics
1.Weft Defects
2.Warp Defects
3.Woven Preparation errors
4.Woven Defects
Weft Defects
Weft Defects; cause from yarns, preparation of weft or process of woven. On the width of fabric, some part as pointedly or on the edge of fabric can be seen.
– Weft Leak: because of missing a weft yarn on the width of fabric defect is seen as a gap. It is cause from defected weft bobbin, defected batten, and unsmooth weft yarn. To prevent this error, weft bobbins and machine adjustment must be controlled.
– Broken Weft: because of breaking a weft yarn on the width of fabric defect seen as a space occur. Cause of this is wrong selvedge cutter margin adjustment and defected weft bobbins. Feeders, breakers (filtering devices), edge devices must be controlled.
– Weft Band: Weft band defect, because of different reasons, seen as different visual on the width of fabric. Periodic unsmoothness on yarn and unsmooth twist is the error reason. Because of that weft material have to be chosen rightly. Also; error can be occur because of wrong machine start/stop and frequency adjustments.
– Thin Weft: result of long period unsmoothness on weft yarn. This occurs from mix of different thick parties on weft yarn. Because of that, have to be careful on weft preparation and transportation on woven plantation.
– Floating Weft: On Fabric; result of Weft yarn is more floating than regular weft floats. Result of frame lifting or lowering devices problem or irregularness of weft timing. Adjustment of timing of weft guide elements must be controlled.
– Tense Weft: Because of more than normal tense on weft yarn, on fabric edge and width a track is seen as like thin weft. This is cause of tense yarn winding on bobbin. For his error, Weft yarn bobbins and filtration devices tense adjustments must be controlled.
– Loose Weft: Because of less than normal tense on weft yarn, on fabric width seen as amplitude. This is cause of irregular adjustment on weft bobbin winding. Have to control the filtration devices tense adjustments.
– Weft Beading: on fabric surface twists because of weft yarns separated from texture. Looseness on shuttle brakes and disordered shed adjustment is the cause.
Warp Defects
On woven fabrics warp defects; cause from yarns, preparation of warp or from weaving processes. these errors can be seen different long on fabric length, can be on all roll length and can be pointal. Most of the warp defects continues on fabric length till the warp beam is finished.
– Warp Leak: from various reasons as one warp yarn is snapped, error will be seen on fabric length. Cause of this is from unsmoothness on warp yarns, defected knots and insufficient slashing. Because of this slashing process must be done carefully.
– Warp Band: from one group of warp yarns, on fabric length, as a band visual, track can be seen. These errors can be from preparation of warp using different parties of yarns, irregular winding on warp yarns or on draft wrong twine occurs while passing heald.
– Thick Warp: because of one warp yarn more thick than other warp yarns, on fabric length defect can be seen as a line. Cause of this is; thicker warp bobbin is mixed to yarn. For this reason while creel is prepared bobbins must be checked.
– Thin Warp: because of one warp yarn thinner than other warp yarns, on fabric length defect can be seen as a line. On preparation of warp while creel is prepared bobbins must be controlled one by one.
– Tense Warp: this error is result of; on warp yarns, one or one group warp yarns are more tense than normal. On this more tense part of fabric, on lengthwise wefts, like light curve band, error will be seen. Cause of error is from the wrong adjustment of one or more brakes on warp creel.
– Loose Warp: because of less tense one yarn on warp yarns, as knot and inner like defects will be seen on fabric length. Cause of error is from the wrong adjustment of brakes on warp creel. For this reason all adjustments of brakes of creel must be as constant and desired tense.
– Dirty, Oily Warp: usually from not care of cleanness regulations, from oil and dirt stains on warp yarns, defects will occur on fabric. These defects are from; putting warp beads on unclean places, while knotting split yarns with dirty-oily hands, on slashing plantation oil stained to warp beads.
Weaving Preparation Defects
Defects caused from preparation processes on woven fabrics, usually seen on warp lengthwise. Caused from processes like warp preparation, slashing, draft and preparation of weft. On today weaving Technologies, weaving preparation defects are seen rarely.
On automated draft machines, with zero error, work is done and possible errors can be detected before beads are sent to weaving.
– Pattern Defect: Wrong heald draft cause; by shifted sequence of warp yarn, resulting ruin on weaving, track will be seen on length or width of fabric. Cause of these; on report of draft, warp yarns are passing from healds in wrong sequence. To prevent this error, draft must be done carefully and draft report and weft report must be controlled.
– Comb Draft Defect: Wrong heald draft cause; from empty, less or more yarn are situated on comb teeths, on fabric length, track will be seen. Cause of this; while putting warp yarns to comb, by mistake more, less or none yarns are passed from comb teeths.
Weaving quality control process is done on rolls that are taken from weaving machine. After error check on rolls, party no and total length are registered to control notebook. Then rolls are stored, and will be sent to factory for other processes.
On control notebook, defects of fabric roll, in which meter defect is, and defect type is written. If defects are too much, fabric will be separated as second quality.
Other defects on fabric can be classified as like these;
- Width difference
- Length difference
- Weight error
- Pile shrinking
- Floor shrinking
- Needle shrinking
- Missing warp
- Double warp
- Warp color report error
- Different warp
- Bordure pattern error
- Comb track
- Selvedge rupture
- Normal rupture
- Roll beginning error
- Dirt stain
- Oil stain
- Mottled raw yarn
- Mottled dyed yarn
- Floss
- Bordure weft points
- Color points
- Wrong wire
- Weft, warp difference
- Half weft
- Double weft
If fabric is jacquard, additionally;
– earring error
– module error
– wrong report
– floating
– malyon-cotton split , likewise defects can be added.
Ekrem Hayri Peker
Chemicals Enginer
