Monday, 27 April 2009
Tsudakoma-ZAX Loom Settings for 14.5 Oz/Sq yd OE/OE Denim (EPI x PPI = 64 x 37) count (6s x 7s)
Back Rest- 125 mm (vertical)
-16th mark ( horizontal)
Dropper Box- 100 mm (vertical)
- 50 mm (vertical)
1st Frame- 99 mm
3rd Frame- 83 mm
4th Frame- 75 mm
Heald Frame Height:
1st Frame - 43 mm
4th Frame- 37mm
Shed Crossing Timing- 290 deg
Leno Crossing Timing- 290 deg ( LH Side), 0 deg ( RH side)
Temple- 15 rings- Medium Type
Sub Nozzle angle- 4 deg
Sub nozzle height- 3rd Mark
Machine Pulley- 220 mm
Motor Pulley- 113 mm for 760 rpm
Tension- 280 kgf
Upper Limit- 560 kgf
Lower Limit- 0 kgf
Pick Density- 37 pick
Arrvial setting - 240 deg
Filling insertion timing- 80 deg
No. of Sub groups- 5
Feeler H1- 200 deg to 290 deg
H2- 200 deg to 310 deg
Forward- 350 deg
Rev (others)- 180 deg/320 d eg
(Filling)- 290 deg
Dropper Setting: 10 th Volume
Pin: 50deg-200 deg
AUX Main: 60deg-100deg
Auxiliary Nozzle- 76 deg-176 deg
1st Pick- 86 deg
Stretch Nozzle- 200deg-300deg
STOP MARK Data
1. F Kick ( Filling) - 0 upto 7 steps
2. F Kick (Others)- 0 upto 7 steps
3. R Kick ( Filling)- 0 upto 7 steps
4. R Kick (Others) - 0 upto 7 steps
5. Kick Back Speed- 1. Low 2, Medium 3, High On
6. Kickback order- on 1
1. Rev to Forward
2. Forward to Rev
7. Down time- 5 min
8. Fell Control-8
9. Dia Comp-48
10. Let Off Avg-2
12. R.Gain- 0
13. Gain -1
14. Rush Torque- 1200%
15. change Picks-2
16. Change timing- 30 deg
17. 1 pick insertion- On
18. Autolevelling- On
Saturday, 25 April 2009
Critical Process Parameters- Denim Manufacturing
Machine Speed m/min= 600+-50
Tension on individual thread ( cN) 90+-30
Warping breaks ( Avg/10000m/400 ends) < = 0.2
1. Machine Speed = 30+-2
2. Size Viscosity ( Flow seconds) = 6+-1
3. Size Add on ( %)= 6+-2
4. Breaking Force (gf) sized yarn = >=1100
5. Tenacity ( cN/tex) ( sized yarn) = >13
6. Elongation ( %) of sized yarn >= 4.5
|Quality||7 x 6||7 x 6||7 x 7||7 x 9||7 x 6|
|Shrinkage ( %)||15+-1||14.5+-1||15.5+-1||16+-1||14+-1|
|Skew ( %)||5-11||5-11||5-11||5-11||5-11|
New Page 1
|Ideal Weight||14.5 Oz/Sq yd||13.75 oz/sq yard||12.5 oz/sq yard|
|Warp Count (Washed)||6.9 +-0.6||6.9+-0.5||6.9+-0.5|
|Weft Count (Washed)||6.0+-0.4||6.9+-0.5||9.0+-0.5|
|EPI ( Unwashed)||70+-2||70+-2||70+-2|
|PPI ( Unwashed)||43+-2||43+-2||43+-2|
|Wt ( Oz./ sq.Yd)||14.2||13.4||12.2|
|Rubbing Fastness ( Dry)||2-3||2-3||2-3|
|Fastness to Laundering||2||2||2|
If shade is getting:
Redder- Increase the conc. of Caustic , slightly decrease the conc. of Hydro
Redder, Duller- Increase the con. of hydro
Greener, Paler- decrease the con. of hydro
Greener, duller- Increase the con. of caustic
Bronzing- Increasing the con. of Hydro
In such denims, the polyester used in warp is kept low about 20-25%, because the blend is harder to dye than cotton . Polyester can be used in much higher percentage in filling. It has the advantage of being strong, durable and even in appearance.
Wednesday, 22 April 2009
Blending at Draw Frame
This method is normally used for binary blends only. The required blend proportion is adjusted by the number of slivers of each component and the hank of respective slivers.
The fleece blending is done on the blending Drawframes specifically designed for this purpose. They are fed with 16-20 slivers at the back and therefore provide a much greater flexibility as regards the blend ratios.
- Easier to obtain uniform blend ratio.
- During opening and carding, optimum settings fro each blend component can be used for better quality of output with less damage to the fibres.
- Easy working.
- Difficult to attain random arrangement of fibres in the yarn cross section.
- Additional drawing capacity needed.
- Separate opening lines needed for each component.
Blending of Combed Cotton Sliver and Polyester
Many Indian mills resort to this practice when the humidity control or conditions of machines is very poor.
- Produces very intimate blend
- Trouble free running and high productivity at card.
- Less yarn imperfections due to better fibre individualisation because of reprocessing of the cotton component.
- Reduced number of d/f passages.
- Lower end breaks due to fewer slubs.
-better uniformity of dyeing due to more intimate blend.
- Poor tenacity and evenness in blend yarn.
- High cotton nep content in blend due to reprocessing
- Need of additional b/r and card capacity
- Slightly higher waste in b/r and carding.
Optimum Blending Method of various Blends
1. For blends like P/V , blowroom blending is effective as they need similar b/r sequence.
2. For blending of manmade stack blending method is generally used.
3. The polyester /cotton or acrylic/cotton are generally blended at d/f because cotton component needs a severe opening and cleaning action
4. Where there is a problem of running 100% polyester on card, stack blending of polyester stock and combed cotton may be resorted to.
5. In case of v/c blend, they should be blended at the draw/frame as they need quite a different opening sequence.
Tuesday, 21 April 2009
Blending at blowroom
There are three methods of blending at blow room:
a. Feeder blending
In this method the blends are prepared by feeding different fibres to different hopper feeders with feeds adjusted to the required blend ratio.
The amount of material taken from each bale for feeding these blenders should not exceed 2-3 kg.
This method is generally employed when more than two components are required to be blended.
b. Stack Blending
In this method the blend components from the bale or bale breakers ( pre opened ) are weighed and laid down in alternate layers
This stack which is laid horizontally is then withdrawn vertically for feeding.
Advantage of Feeder and Stack Blending
a. More intimate and homogeneous blend achieved.
b. Only one opening line needed.
c. Provides simplest control on the use of recovered fibre waste.
d. Requires minimum man hours for blending
a. Difficult to attain uniform blend ratio
b. Demands greater skill on the part of the operator.
c. Labour intensive and somewhat slow.
c. Lap Blending
In this the laps of the components fibres made at the breaker skutcher generally 3 to 4 are blended by feeding them together to the finisher scutcher in the desired ratio.
Advantages of Lap Blending
a. Ensures good blend homogenity
b. Easy to work.
c. Good control on the use of recovered fibre waste.
d. Uniform blend ratio is achieved
a. Opening line has to be modified to provide for both breaker and finisher scutchers.
b. Need for proper control on lap weights.
Monday, 20 April 2009
How to select Blend Constituents
Selection of Blend Constituents depends upon the following factors:
1. Type of Fibre
- Depending upon the end use of the fabric, blend constituents are chosen.
- For example, it is well known hat a polyester-cotton yarn looks fuller as compared to the lean look of polyester-viscose yarn.
- Therefore for light constructions like shirtings, polyester-cotton blend is used.
- However polyester-viscose blend is preferred for medium and heavy construcitons such as suitings.
2. Compatibility of blend fibres
Compatibility must be there in terms of the following properties:
a. Length and Denier of Fibres:
- As a general rule, these two fibre properties should be nearly the same for all the constituents.
- For example in a viscose rayon cotton blend, the rayon staple of 1.5 denier and 29-32 mm length is generally used since the cotton component used has a denier of around 1.5 and a length of 28mm.
- A large difference in the breaking elongation of the fibres in a blend adversly affects the yarn tenacity.
- The blend fibres should prefereably have the same density. Any large differences on this account will lead to selctive separation while conveying the blended stock through ducts under the influence of air suction in the blow rooms.
d. Dispersion Properties
- This property describes the ability of an individual fibre to separate from its group and disperse thoroughly within the fibre matrix of the blend to produce an intimate and homogeneous blend.
e. Drafting Properties
- Some fibres like viscose are outstanding it terms of draftability. These fibres, when blended with other fibres act as good carriers to obviate the trouble relating to drafting.
f. Dyeing Properties
- In case the blend yarn or fabric is to be dyed subsequently, due consideration should be given to the dyeing properties of individual fibre components.
CHARACTERISTICS DESIRED IN A BLEND YARN
A. The constituent fibres should be arranged at random in the yarn cross section.
B. The ratio between the blended fibres should be uniform at any cross section of the yarn.
C. There should not be any long-term or short-term irregularity in blend ratio of blended fibres.
Saturday, 18 April 2009
Neither natural or manmade fibres are optimally suited to certain fields of use, but a blend of these two fibres types can give the required characteristics.
1. Improvement in Functional Properties
A 100% single fibre yarn cannot impart all the desired properties to a fabric.
For example 100% viscose rayon suffer from low tensile strength, poor crease resistance and low abrasion resistance.
Similarly 100% polyester fabrics are not desirable as they are prone to static accumulation, hole melting and pilling. They are moisture resistant, difficult and expensive to dye and have a poor hand.
These negative attributes of polyester and viscose can be reasonably neutralised by addition of a certain percentage of each fibre.
2. Improved Process performance
Some fibres like polyester at times are quite troublesome to work in 100% form especially at cards. Addition of fibres like cotton or viscose rayon in the previous process has been seen to facilitate the smooth carding of such fibres.
The blending of manmades which are longer and finer to cotton which is shorter influences the spinnablility as well as productivity.
The price of manmades is much more stable than that of natural fibres like cotton. Price stability can enable the mills to pursue optimisation of their fibre purchase programme.
Blending could also be used for reducing the mixing cost. For example, a fibre like viscose can be blended with cotton for producing specific yarns with reduced raw material costs.
4. Fancy Effect
Fibres with a variety of colour mixture or shades can be produced by blending different dyed fibres at the blowroom, drawframe or roving stage.
The aesthetics of a fabric can be developed by selecting specific blend components and their properties.