Troubleshooting in dyeing of woven fabrics on high-temperature jig machine

        SYMPTOMS

DIAGNOSIS

CURE

Listing

1.      High speed & speed variation (150 m/min i.e. 20 mints per cycle)

2.      Temperature variation side to side

3.      Dosing criteria

1.      Constant speed & Medium speed (80-100 m/min i.e. 30-35 mints per cycle)

2.      Control of temperature & proper winding of fabric through jig main rollers

3.      Follow the Dosing Criteria heading (given in below)

Tailing

1.      High Dyes / Chemicals Concentration

2.      Unknown disperse/reactive dyes properties profile

3.      Different migration of different disperse and reactive dyes

4.      pH Variation

5.      Liquor level variation

6.      Levelling issues

7.      Temperature (8-10 oC) variation during running of lot

8.      High speed & speed variation (150 m/min i.e. 20 mints per cycle)

9.      Extra length of fabric meters (more than the specified capacity of jig machine)

1.      Dyes Dosing should be dosed in portions (400 to 400 meters fabrics )

2.      Need to use Medium sublimation disperse dyes & medium substantive reactive dyes

3.      Balance migration properties in trichromatic shades

4.      Use of acidic buffer

5.      Liquor level can be controlled by variable dosing

6.      Use of dispersing / levelling agents

7.      Speed should be lower (increment in dwell time)

8.      Increase the dwell time (35-40 min per cycle) with constant lower speed

9.      Shorten the length of fabric i.e. 20%

Shade Variation

As it is an inherent problem with jig dyeing machine, it gives shade differences i.e. tailing and listing, if dye dosing and circulation of fabric through dye liquor are not controlled properly. There are some major reasons of shade variation, some of them are:

  • Temperature variation with width of the fabric or length of the fabric

  • Improper dye dosing

  • Uneven tension on fabric when end/cycle changes

  • Inconsistent speed of the fabric

Therefore, it is advisable to use closed jigger machine for consistent temperature throughout the dyeing process and standardized dye doing system.

Jigger Data:

NORMAL DOSING

SUGGESTED DOSING

     •1st end 1/2 dosing

     •2nd end 1/2 dosing

     •1st end 1/6 dosing

     •2nd end 1/6 dosing

     •3rd end 1/6 dosing

     •4th end 1/6 dosing

     •5th end 1/6 dosing

     •6th end 1/6 dosing

1^st Cycle

2^nd Cycle

1.     Fill the jigger bath 200 litres (or 50% of the total water level of machine) with water and add half quantity of buffer.

2.     Make stock solution of 200 litres in four drums or any suitable item with adding of disperse dyes.

3.     Add 17 litres solution from the stock solution in the bath and run the 400 meters fabric.

4.     Similarly repeat this procedure until the end of one cycle, so there will be six doses in single cycle after each 400 meters

1.     For 2^nd cycle add another half quantity of buffer & repeat the same procedure as done in 1^st cycle with remaining 100 litres stock solution.

2.     After completion of dosing and two cycles, now for initiating the 3rd cycle, first maintain the temperature up to 90 ^oC and then raise the temperature up to 130 ^oC Check the pH with suggested time & temperature.

3.     Run 4^th cycle @ 130 ^oC , 35

4.     Repeat reaming cycles same as given above

1^st Cycle

2^nd Cycle

1.     Fill the jigger bath 200 litres with water and add half quantity of salt

2.     Make stock solution of 200 litres in four drums with adding of reactive dyes

3.     Add 17 litres solution in the bath and run the 400 meters fabric

4.     Similarly, repeat this procedure until the end of one cycle, there will be six doses in each cycle after each 400 meters

1.     For 2^nd cycle add another half quantity of salt & repeat the same procedure as done in 1^st cycle with remaining 100 litres stock solution

2.     After completion of dosing and two cycles, now for initiation of 3^rd cycle, first maintain the temperature up to 60 ^oC and then add soda ash via checking the pH (9-11)

3.     Run 4^th cycle at the rate of 60 ^oC 35

4.     Repeat reaming cycles same as given above