Textile Floor │Knitting Defects with causes & remedies

During knitting of Fabric there is a lot of defects can be formed. Here are some faults or defects of knit fabric are shown & described below: 

     1. Drop Stitche, 2. Pin hole, 3.  Grease stain, 4. Fly dust, 5.  Hole Mark, 6.      Sinker Mark, 7.   Dust stain, 8.  Needle Mark, 9.  Barre, 10. Contamination of Yarn, 11. Oil Spot, 12. Star mark, 13. Dust knit, 14. Set off, 15. Streakiness, 16. Snarls, 17. Spirality, 18. Surface hairiness, 19. Snagging, 20. Bowing, 21. Needle Line..

1. Drop Stitches:  

Causes:

• Defects of needle.
•  If yarn is not properly fed during loop formation i.e. not properly laid on to the
• Needle hook
• Take-down mechanism too loose
•  Insufficient yarn tension.
• Badly set yarn feeder.

Remedies:

• Needle should be straight & well.
• Proper feeding of yarn during loop formation.
• Correct take up of the fabric & correct fabric tension
• Yarn tension should be properly

                

2. Pin hole: 

Causes: 

• Due to break down or bend of the latch, pin hole may come in the fabric.

Remedies: 

• Change the needle

3. Grease stain:

Causes:

• Improper greasing
• Excess greasing

Remedies:

• Proper greasing as well as proper maintenance

4. Fly dust: 

Causes:

• In knitting section too much lint is flying to and fro that are created from yarn due to low twist as well as yarn friction. This lint may adhere or attaches to the fabric
•  Surface tightly during knit fabric production.

Remedies:

• Blowing air for cleaning and different parts after a certain time.
• By cleaning the floor continuously. By using ducting system for
• Cleaning too much lint in the floor.
• Over all ensure that lint does not attach to the fabric

5. Hole Mark: 

Causes:

• Holes are the results of yarn breakage or yarn cracks.
• During loop formation the yarn breaks in the rejoin of the needle hook
• If the yarn count is not correct on regarding structure, gauge, course and density.
• Yarn feeder badly set. 

Remedies:

• Yarn strength must be sufficient to withstand the stretch as well as uniform.
• Use proper count of yarn.
• Correctly set of yarn feeder
• Knot should be given properly

6. Sinker Mark:

Causes:

• When sinkers corrode due to abrasion then some times cannot hold a new loop as result sinker mark comes.
• If sinker head bend then sinker mark comes.

 Remedies:

• Sinker should be changed.

7. Dust stain:

Causes: 

• If any dust on the machine parts. 

Remedies: 

• If any dust on the machine parts then clean it.
• Proper maintenance as well as proper oiling.

8. Needle Mark: 

Causes: 

• When a needle breaks down then needle mark comes along the fabrics.
• If a needle or needle hook is slightly bends then needle mark comes on the fabrics. 

Remedies: 

• Needle should be straight as well as from broken latch.

9. Barre:  
A fault in weft knitted fabric appearing as light or dark course wise (Width wise) Stripe. 

Causes: 

• This fault comes from yarn fault.If different micro near value of fiber content in yarn.
• Different lustier, dye affinity of fiber content in yarn.
• During spinning different similar classes of fiber is mixed specially in carded yarn& these fibers have similar characteristics.
• In draw fame different similar classes sliver is mixed and make one sliver.

Remedies: 

• We can use this fabric in white color.

10. Contamination of Yarn:

Causes:  

• If yarn contains foreign fiber it remains in the fabric even after finishing.
• If lot, count mixing occurs. 

Remedies: 

• By avoiding lot, count mixing.
• Fault less spinning.

11. Oil Spot:

Causes: 

• When oil licks through the needle to the fabrics and make a spot.

Remedies:  

• Ensure that oil does not pass on the fabrics.
• Well maintenance as well as proper oiling. 

12. Star mark: 

Causes:  

• Yarn tension variation during production.
• Buckling of the needle latch.  
• Low G.S.M fabric production. 

Remedies:

• Maintain same Yarn tension during production.
• Use good conditioned needles.

13. Dust knit: 

Causes: 

• Clusteration Of cotton dust 

Remedies: 

• Keep the machine clean with blower

14. Set off: 

Causes:

• It can occur after a drop stitch when an empty needle with closed latch runs into the yarn feeder and remove the yarn out of the hook of the next needles. 

Remedies:

• Make sure all the latches of needle are closed with feeding yarn after a drop stitch.

15. Streakiness:

Causes: 

• Yarn slippage on the IRO Pulley, due to the yarn slipping in & out from underneath the IRO Belt, due to a tilted IRO Pulley.
• Worn out IRO belts, yarn guides & eyelets etcFaulty winding of the yarn packagesYarn running out of the belt, on the IRO Pulley.

Remedies: 

• Ensure very smooth, clean & obstruction free passage of the yarn, through the eyelets, yarn & tension discs etc.
• No cuts or rough surfaces, in the Porcelain Eyelets, Yarn Guides & the Yarn Feeder holes etc.
• Flawless winding of the, Yarn Package (The yarn coils should unwind smoothly, without any obstruction)       

16. Snarls: 
Snarls appear on the fabric surface, in the form of big loops of yarn getting twisted, due to the high twist in the yarn (Unbalanced twist yarn).
Causes: 

• High, twist in the, yarn, Hosiery yarns are soft twisted. High, twist in the yarn, is the cause of snarling.
• (Snarls cause, fabric defects & needle breakages) 

Remedies:  

• Ensure using Hosiery Yarns, of the recommended T.P.M. only. (Hold a few inches of the yarn in both the hands, in the form of a ‘U’. 
• The yarn has a balanced twist, if it doesn’t tend to rotate or turn, in the form of a snarl.

17. Spirality: 
Spirality appears in the form of a twisted garment, after washing. The seams on both the sides of the garment displace, from their position & appear on the front & back of the garment. 
Causes: 

• Spirality is caused, by the Twisting Torque as a result, of the high yarn T.P.M.
• Hosiery yarns are soft twisted, whereas the Warp yarns are hard twisted.
• Uneven Fabric Take down tension, on the Knitting machine. 

Remedies: 

• Use the Hosiery yarns of the recommended TPM level for Knitting.
• Hosiery yarns are soft twisted, in comparison to the Warp yarns.
• Fabric pull or the Take Down tension, on both sides of the grey fabric tube, on the knitting machine, should be equal. 
• Ensure uniform rate of feed of the dyed fabric, on both the edges, while feeding the fabric to the Calendar, Compactor or Stenter machines.

18. Surface hairiness:

Surface hairiness appears in the form of excess superfluous fibers, on the surface of the knitted fabrics, which have either been reprocessed, or tumble dried. Pilling appears as, small fiber balls formed on the fabric surface, due to the entanglement of loose surface fibers. Factors such as, the fiber staple length, low T.P.M. & fabric construction (with long yarn floats) etc. also contribute to pilling.

Causes: 

•  Abrasion due to the contact with rough surfaces.
• Excessive surface hairiness caused, due to the abrasive tumbling action.
• Fabric friction in the Tumble Dryer.
• Rough Dyeing process & abrasive machine surfaces (Soft Flow Machine tubes, Tumble Dryer drum etc.) 
•  Reprocessing of the fabric is, also a major cause of piling.

Remedies: 

• Avoid using the Tumble Dryer.
• Control shrinkage by maximum fabric relaxation & over feed in the processing.
• Regularly inspect the fabric contact points on all the machines, for any rough & sharp surfaces.
• Rectify, if found rough.Avoid repeated reprocessing of the fabrics.

19. Snagging:
Snagging appears on the knitted fabric surface, as a pulled up yarn float, showing up in the form of a large loop.

Causes:

• Caused by the pulling or the plucking of yarn from the, fabric surface, by sharp objects. 

Remedies:

• Inspect & rectify the fabric contact points on all the machines (Soft Flow Dyeing, Tumble Dryer & Centrifuge etc), on which snagging is taking place.

20. Bowing:
Bowing appears as, rows of courses or yarn dyed stripes, forming a bow shape, along the fabric width. 
Causes:

• Uneven distribution of tensions, across the fabric width while, dyeing or finishing the fabric. 

Remedies: 

• Owing can be corrected, by reprocessing the fabric, by feeding it from the opposite end.
• A special machine (MAHLO) is also available for, correcting the bowing in the knitted fabrics.

21. Needle Line:

Causes: 

• Caused by bent needle, catching yarn usually vertical line.

Remedies: 

• Checking the fabric during knitting