What is Warping in Textiles?
After finishing the yarn winding, selected cones are transported to next process, i.e. this process is called warping. Warping is an essential weaving preparatory process in weaving unit. The warping process is intermediate between the winding and the sizing processes. It is said that good warping finishes fifty percent weaving. It produces the warper beams that are combined together as a single weaver’s beam in the next process of sizing. A warper beam may contain about 500-1000 warp ends. The main purpose of warping process is to prepare a warp sheet of the required length with a specific number of yarns. During this process, the warp sheet is wound onto a flanged beam while ensuring that the tension of each yarn and the density of the yarn mass remain within acceptable limits throughout the entire warp beam. The process of warping is dedicated to the conversion of cones into a beam of given specifications.
Warping Defects in Textiles:
Warping defects in textiles are problems that occur during the process of preparing yarn for weaving process, affecting fabric quality and production efficiency.
Following are some of the warping defects in textiles and their common causes and remedies.
- Variation in tension within and between beams
- Missing ends
- Crossed ends
- Poor quality of beam preparation
- Production loss due to some cones running out early
- Pattern not proper
- Lost end
- Section mark
- Draw back
- Lapped end
- Piecing
- Soft ends on the warping beam
- Incorrect form of build
- Slacks & irregular yarn tension
- Broken ends on the beam
- Conical winding on the beam
- Improper length of warping
Common causes and remedies of above warping defects are briefly discuss below:
1. Variation in Tension Within and Between Beams:
This problem occurs when the yarn tension is not uniform either along a single beam or between different beams, causing uneven fabric quality and processing issues.
Causes:
- Change in balloon heights as the cones run out
- Reduction in unwinding diameter of the package as the unwinding progresses
- Difference in the lengths of yarn between respective first thread guide and the head stock
- Number of guide points for the yarn in the creel
- Angles of deflection in the path of yarns from the axis of the respective packages to the first guide roll in the headstock
- Variations in the weight of tension discs and package diameters
Remedies:
- Proper control of balloon heights as the cones run out
- Maintain uniform unwinding diameter of the package as the unwinding progresses
- Equalize the lengths of yarn between respective first thread guide and the head stock
- Keep uniform number of guide points for the yarn in the creel
- Maintain equal angles of deflection in the path of yarns from the axis of the respective packages to the first guide roll in the headstock
- Use uniform weight of tension discs and package diameters
2. Missing Ends:
Missing ends occur when one or more warp yarns fail to run properly during warping or sizing due to mechanical or operational faults.
Causes:
- Improper functioning of stop motions
- Bent drop wires
- Fluff accumulation in stop motions
- Entanglement of broken yarn with drop pin
Remedies:
- Proper functioning of stop motions
- Straight drop wires
- Remove fluff accumulation in stop motions
- Prevent entanglement of broken yarn with drop pin
3. Crossed Ends:
A crossed end is an end broken during warping that when repaired was not free or was tied in with an adjacent end or ends overlapping the broken end. The end draws or pulls back when unwound on the slasher and is also referred to as draw back.
Causes:
- Broken ends not drawn correctly
- Improper insertion of lease rods
Remedies:
- Draw broken ends correctly
- Proper insertion of lease rods
4. Poor Quality of Beam Preparation:
Poor quality of beam preparation occurs when the beam build, yarn surface, or unwinding process is not proper, leading to tension variation, yarn damage, or stoppages in subsequent processes.
Causes:
- Uneven beam build due to improper tensioning
- Ridges on yarn surface from uneven winding
- Incorrect comb spacing, flange misalignment, or non-concentric flanges
- Ineffective stop motion or brakes
- Frictional damage from rough drum surfaces or machine parts
- Variation in warp length between beams or sections
- Unsuitable warping speed for yarn type and count
Remedies:
- Uniform tensioning with required weights for firm beam build
- Even winding of yarn, free from ridges
- Correct comb spacing, aligned and concentric flanges, minimum tension variation
- Ensure effective stop motion and brakes, proper mending of broken ends
- Smooth drum surface, no cuts on contacting parts, suitable warping speed
- Accurate length measuring system for consistent warp length
- Maintain prescribed barrel diameter to minimize tension variation
5. Production Loss Due to Some Cones Running Out Early:
Production loss occurs when some cones run out before others, causing machine stoppage and increase in hard wastes.
Causes:
- Uneven cone lengths despite length measuring units
- Early run out of some cones
Remedies:
- Use full cones for warp and send remnants to weaving as weft
- Keep some 20 gm cones to replace run out cones without stopping the machine
6. Pattern Not Proper:
Pattern is not proper when yarns are creeled in incorrect positions, leading to design defects in the fabric.
Causes:
- Incorrect creeling of dyed yarns
- Mistake in following the design card
Remedies:
- Creel yarns exactly according to the design card
- Double-check positions while creeling
7. Lost End:
A lost end is an end on a section or tricot beam broken during warping and not repaired by a knot.
Causes:
- End breakage during warping
- Broken end not mended
Remedies:
- Properly mend broken ends using knots
8. Section Mark:
A section mark is a fabric defect with marks running warp-wise in a repeating pattern, caused by improper section setting in silk or indirect warping.
Causes:
- Improper setting of sections in warping
Remedies:
- Correctly set sections according to warping requirements
9. Draw Back:
Draw back is a crossed end broken during warping, repaired by tying with an adjacent end, causing it to pull back when unwound on the slasher.
Causes:
- Broken ends not drawn correctly
- Improper insertion of lease rods
Remedies:
- Draw broken ends correctly
- Proper insertion of lease rods
10. Lapped End:
A lapped end occurs when a broken end of yarn is not tied to the end on the warp beam and overlaps the adjoining yarn.
Causes:
- Broken end not tied to the warp beam
- Beam not properly brake or signal hook fails
Remedies:
- Tie the broken end to the warp beam
- Proper signal hook
11. Piecing:
Piecing occurs when one broken end is joined to another yarn end on the warping beam.
Causes:
- Broken end joined incorrectly
Remedies:
- Proper joining of yarn ends
12. Soft Ends on the Warping Beam:
Soft ends occur when a group of ends break and are pieced in a bundle or by lapping.
Causes:
- Breakage of ends and improper piecing
- Carelessness of the operator
Remedies:
- Careful operation
- Proper piecing of broken ends
13. Incorrect Form of Build:
Incorrect form of build occurs due to non-uniform spreading of ends in the guide reed, improper setting, or conical winding from uneven warping beam pressure.
Causes:
- Non-uniform spreading of ends in guide reed
- Improper setting
- Conical winding from uneven beam pressure
Remedies:
- Uniform spreading of ends
- Appropriate setting
14. Slacks & Irregular Yarn Tension:
Slacks and irregular tension occur when yarn is improperly threaded, ejected from under the tension device disc, or the tension device is of poor quality.
Causes:
- Improper threading into tension device
- Ejection from under the tension device disc
- Poor quality tension device
Remedies:
- Proper threading of tension device
- Use good quality tension device
15. Broken Ends on the Beam:
Broken ends occur when a group of ends break and are tied as a bunch or worked-in with overlapping.
Causes:
- Breakage of a group of ends
- Ends tied as a bunch or overlapped
Remedies:
- Remove broken ends
16. Conical Winding on the Beam:
Conical winding occurs when the pressure roller applies incorrect load.
Causes:
- Incorrect load by the pressure roller
Remedies:
- Correct load applied
17. Improper Length of Warping:
Improper length of warping occurs due to malfunction of the counter or brakes of the measuring device and warp beams.
Causes:
- Malfunction of counter
- Malfunction of brakes of measuring device and warp beams
Remedies:
- Use good measuring device
Conclusion:
Warping faults / defects arise from mechanical faults, improper handling, or incorrect settings during the warping process. Issues such as variation in tension, missing ends, crossed ends, poor beam quality, and soft or broken ends can affect fabric quality, cause production loss, and increase waste. Most warping defects can be prevented by careful operation, proper maintenance of machinery, correct creeling, uniform tensioning, and accurate measurement. Overall, attention to detail and strict process monitoring are essential for high-quality warping and subsequent fabric production.
References:
[1] Purushothama, B. (2016a). Handbook on fabric Manufacturing: Grey Fabrics: Preparation, Weaving to Marketing. Woodhead Publishing India in T.
[2] In, M. K. S. P. (2015). Industrial practices in weaving preparatory.
[3] Purushothama, B. (2012). Training and development of technical staff in the textile industry. In Woodhead Publishing Limited eBooks. https://doi.org/10.1533/9780857095848
[4] Gokarneshan, N. (2009). Weaving preparation technology.
[5] Banerjee, P. K. (2014). Principles of fabric formation. In CRC Press eBooks. https://doi.org/10.1201/b17804
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
