RIGHTSPUN
Strength of yarn is essential primarily for two purposes.
1. To enable withstanding the spinning & winding tension in the Ring spinning machine.
2. To meet the stress levels that may arise in the downstream process for the yarn - such as knitting, weaving, preparatory for ply twisting etc
In both the instances the variations if narrowed down to lower levels ( CV% values) the performance is achieved. So we need to focus on reduction in variations, more than increasing the mean values of strength - @ a cost ofcourse (such as higher comber noils etc)
In the current scenario of gentler opening & effective drafting with modern machines, selection of process parameters such as HANK, MASS, DRAFT DISTRIBUTION all needs to be reviewed & optimised to the advantage of the spinner.
Many good spinners have successfully adopted these long back & many more are still to consider. Such acceptance will release so much of capital infrastructure, reduce recurring cost heads such as ENERGY , LABOUR etc.
There will be no compromise on quality of the yarn in any aspect , has been proved time and again, so no need to be concerned for the fairly modernised infrastructure spinning mills.
CONSIDER TO REDUCE COST , INCREASE PROFITS , RELEASE EXPENSIVE CAPITAL DEPLOYED . CALL US / E MAIL US..
Tuesday, June 2, 2009
Monday, February 16, 2009
RIGHTSPUN DUE CARE points – Understanding Yarn for Weaving and Weaving Preparation
1. Strength of weak place in yarn to be 70% of parent yarn strength – Any yarn lower than this strength to be stopped from further process
2. FLUCTUATION in strength is more and more important for weaving – NOT MEAN VALUE.
3. Single Yarn Strength CV% at 15% level- yarn will not be workable at all in weaving.
If it is 13% - looms/ warping stops will be 10/hr
If it is 11% -stops can drop down to 2/hr
The increase or decrease in performance is NOT PRO RATE but GEOMETRICAL for increased fluctuation / range / CV%
4. Reduction in CV% of strength means lesser thin places in the yarn.
5. Shuttle looms – @200 mpm requires, let us say –‘ n’ g as strength in the yarn
6. For shuttleless looms - @800mpm same yarn strength is sufficient – only the CV% of SYS to be lower by 20% than the previous.
7. Both the looms will have same performance efficiency with yarns as above. There is no need for increase in the mean yarn strength for shuttleless looms.
8. Hairiness in single yarn plays a key role in performance variations at weaving.
9. It is safer to use yarn with lower hairness & lower SYS CV%, than with higher hairiness, increased mean strength & uncontrolled higher SYS CV%. Cost of richer raw material need not result in consistently better yarn, without adequate process control efforts.
10. It is important always to check / review the cost of QUALITY REQUIRED Vs actually GIVEN. No need & no necessity for giving over quality.
11. Elongation at Break is very important for warp yarn. Any E% beyond 2% - no recovery will be there.
12. Dry E% vs Wet E% (will be higher normally in cotton yarn) also is an important factor.
13. Yarn stretch levels – in process can be as under
· Winding – Maximum 10 to 15% - to remove thin places, to get tighter winding / harder package density.
· Warping – Maximum 5% - Uniform sheet of warp essential for weaving – no sagging.
· Sizing –Maximum 15 to 20% - because the yarn is wet in sizing stretch is unavoidable
· Sizing machines of year 1980 and later will have 1 to 1.5% stretch
· Newer machines less than 5yrs old will have 0.8 to 1.0% stretch
14. Higher warping stops than expected indicates failure at Conewinding to eliminate thin places – consequently higher SYS CV%.
15. Conewinding breaks can ideally be between 2 to 2.5 per 100g of yarn.
16. Warping process is the best testing laboratory for the spun yarn.
17. Hairiness is fully a spinning (RM, Process) process related problem for the weaving.
18. Sizing machine stretch to be checked in case of excessive warp stops in looms despite good warping performance.
19. Cone base dia ideally to be 4” or above for good unwinding
20. Warping barrel diameter is larger than the weavers beam barrel diameter – this is to reduce the unwinding tension at Sizing(Larger diameter – lesser tension; Smaller diameter – higher tension)
21. Warping – Flange diameter : Barrel diameter – Ratio to be between 3:1 to 4:1 (Normally 40” flange has 12” barrel)
22. Weavers beam barrel diameter of 210mm and above is good for lesser let off tension.
23. Cone hardness – ideally to be 70’
24. Conditioning is done for and expected to maintain CONSTANT MOISTURE CONTENT in the yarn.
2. FLUCTUATION in strength is more and more important for weaving – NOT MEAN VALUE.
3. Single Yarn Strength CV% at 15% level- yarn will not be workable at all in weaving.
If it is 13% - looms/ warping stops will be 10/hr
If it is 11% -stops can drop down to 2/hr
The increase or decrease in performance is NOT PRO RATE but GEOMETRICAL for increased fluctuation / range / CV%
4. Reduction in CV% of strength means lesser thin places in the yarn.
5. Shuttle looms – @200 mpm requires, let us say –‘ n’ g as strength in the yarn
6. For shuttleless looms - @800mpm same yarn strength is sufficient – only the CV% of SYS to be lower by 20% than the previous.
7. Both the looms will have same performance efficiency with yarns as above. There is no need for increase in the mean yarn strength for shuttleless looms.
8. Hairiness in single yarn plays a key role in performance variations at weaving.
9. It is safer to use yarn with lower hairness & lower SYS CV%, than with higher hairiness, increased mean strength & uncontrolled higher SYS CV%. Cost of richer raw material need not result in consistently better yarn, without adequate process control efforts.
10. It is important always to check / review the cost of QUALITY REQUIRED Vs actually GIVEN. No need & no necessity for giving over quality.
11. Elongation at Break is very important for warp yarn. Any E% beyond 2% - no recovery will be there.
12. Dry E% vs Wet E% (will be higher normally in cotton yarn) also is an important factor.
13. Yarn stretch levels – in process can be as under
· Winding – Maximum 10 to 15% - to remove thin places, to get tighter winding / harder package density.
· Warping – Maximum 5% - Uniform sheet of warp essential for weaving – no sagging.
· Sizing –Maximum 15 to 20% - because the yarn is wet in sizing stretch is unavoidable
· Sizing machines of year 1980 and later will have 1 to 1.5% stretch
· Newer machines less than 5yrs old will have 0.8 to 1.0% stretch
14. Higher warping stops than expected indicates failure at Conewinding to eliminate thin places – consequently higher SYS CV%.
15. Conewinding breaks can ideally be between 2 to 2.5 per 100g of yarn.
16. Warping process is the best testing laboratory for the spun yarn.
17. Hairiness is fully a spinning (RM, Process) process related problem for the weaving.
18. Sizing machine stretch to be checked in case of excessive warp stops in looms despite good warping performance.
19. Cone base dia ideally to be 4” or above for good unwinding
20. Warping barrel diameter is larger than the weavers beam barrel diameter – this is to reduce the unwinding tension at Sizing(Larger diameter – lesser tension; Smaller diameter – higher tension)
21. Warping – Flange diameter : Barrel diameter – Ratio to be between 3:1 to 4:1 (Normally 40” flange has 12” barrel)
22. Weavers beam barrel diameter of 210mm and above is good for lesser let off tension.
23. Cone hardness – ideally to be 70’
24. Conditioning is done for and expected to maintain CONSTANT MOISTURE CONTENT in the yarn.
Tuesday, January 20, 2009
RIGHTSPUN DUE CARE POINTS for SPINNING MILLS
RIGHTSPUN TIPS on ROLL ROOM CARE
1. Buffing - restoration of smooth surface, to get a smooth and even surface.
2. The cut given during buffing should ideally even out / remove
i. the material passage groove
ii. the surface nicks, burrs
iii. any cuts
iv. surface wax and
v. any decomposed surface coating.
3. The three equally important elements of buffing are –
i. the grinding wheel & speed,
ii. the clamp holder for the arbor,
iii. the exhaust arrangement for liberated fine dust
4. Higher the cutting speed (than recommended) – arbor will get overheated, not good for the bearing lubrication inside the arbor
5. Worn / improper clamp holding of the arbor – results in uneven buffing.
6. Daily mild dressing of the grinding wheel is essential to ensure the quality of buffing.
7. Diamond tipped dressing tool, diamond tip size selection, tip worn out tool periodic discarding and replacement are all very very important.
8. Lesser depth but more frequent buffing is better than deeper and wider frequency of buffing.
9. Lesser depth cutting does not disturb the polymers in the rubber cot. More cut results in surface hardness increase.
RIGHTSPUN TIPS on TOP ROLLER COTS CARE
1. For Ring frames - with ever increasing spindle speeds, consequently the drafting pressure, force & delivery speeds – the buffing needs to be planned more scientifically based upon delivery rate – ideally @ 1000 english hanks delivery (appx.770km ).
2. A cut depth of 0.1mm or less per buffing is enough and practicable.
3. For draw frames – considering the drafting pressure, force & delivery speeds – the buffing needs to be planned more scientifically based upon delivery rate – ideally @ 4000 english hanks delivery (appx.3000km).
4. For speed frames – buffing schedule basis can be similar to RF.
5. Comber detaching roller cots buffing is quite tricky and depends upon far too many variables, since the rollers handle very thin fine oriented fleece of fibres. Customised schedules to be evolved by individual mills themselves based on external factors such as RH control, surface treatments practiced, speed of the machine, type of raw cotton etc. Draw box roller cots can practice based upon drawframe top roller buffing.
6. Surface treatment – such as irradiation, varnishing etc helps in covering up the buffed pores of the rubber cots after buffing. This again depends upon many variable factors and differs from mill to mill.
7. Natural sunlight radiation also is good enough but not practicable in reality.
8. Acid treatment – better to avoid until inevitable, all other means are attempted and exhausted. Such necessity may arise in synthetics, definitely not required for cotton processing. Due to polymer decomposition the rubber cots become harder and tend to allow fibre slippage, consequently increase in IPI.
1. Buffing - restoration of smooth surface, to get a smooth and even surface.
2. The cut given during buffing should ideally even out / remove
i. the material passage groove
ii. the surface nicks, burrs
iii. any cuts
iv. surface wax and
v. any decomposed surface coating.
3. The three equally important elements of buffing are –
i. the grinding wheel & speed,
ii. the clamp holder for the arbor,
iii. the exhaust arrangement for liberated fine dust
4. Higher the cutting speed (than recommended) – arbor will get overheated, not good for the bearing lubrication inside the arbor
5. Worn / improper clamp holding of the arbor – results in uneven buffing.
6. Daily mild dressing of the grinding wheel is essential to ensure the quality of buffing.
7. Diamond tipped dressing tool, diamond tip size selection, tip worn out tool periodic discarding and replacement are all very very important.
8. Lesser depth but more frequent buffing is better than deeper and wider frequency of buffing.
9. Lesser depth cutting does not disturb the polymers in the rubber cot. More cut results in surface hardness increase.
RIGHTSPUN TIPS on TOP ROLLER COTS CARE
1. For Ring frames - with ever increasing spindle speeds, consequently the drafting pressure, force & delivery speeds – the buffing needs to be planned more scientifically based upon delivery rate – ideally @ 1000 english hanks delivery (appx.770km ).
2. A cut depth of 0.1mm or less per buffing is enough and practicable.
3. For draw frames – considering the drafting pressure, force & delivery speeds – the buffing needs to be planned more scientifically based upon delivery rate – ideally @ 4000 english hanks delivery (appx.3000km).
4. For speed frames – buffing schedule basis can be similar to RF.
5. Comber detaching roller cots buffing is quite tricky and depends upon far too many variables, since the rollers handle very thin fine oriented fleece of fibres. Customised schedules to be evolved by individual mills themselves based on external factors such as RH control, surface treatments practiced, speed of the machine, type of raw cotton etc. Draw box roller cots can practice based upon drawframe top roller buffing.
6. Surface treatment – such as irradiation, varnishing etc helps in covering up the buffed pores of the rubber cots after buffing. This again depends upon many variable factors and differs from mill to mill.
7. Natural sunlight radiation also is good enough but not practicable in reality.
8. Acid treatment – better to avoid until inevitable, all other means are attempted and exhausted. Such necessity may arise in synthetics, definitely not required for cotton processing. Due to polymer decomposition the rubber cots become harder and tend to allow fibre slippage, consequently increase in IPI.
Sunday, January 18, 2009
Spin profits the right way thro RIGHTSPUN
RIGHTSPUN - since 2003
Experienced and Proven professional consultancy team for Techno-Commercial operations consultancy of spinning mills.
Unique ABC (activity based costing) approach to process control & product planning using "RIGHTCOST - CBS" , a software tool developed inhouse and successfully employed for focusing on profitability of spinning mills.
The company also operates in value addition process for yarn and facilitating, sourcing & trading in textiles.
Through this blog we intend to share with the textile friends and fraternity our experience & views periodically.
Let us share & spin together through our - R news fortnightly bulleteins
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