Denim Dyeing With Indigo Dyes | Slasher Dyeing Process

Indigo Dyes

Indigo dyes are widely used dyestuff of all time in the denim coloration process. However, indigo dyes are the common choice of the denim manufacturer for their extremely wash fastness property. However, during the 13th century, Marco Polo saw indigo being prepared in China. Historically, this dyes was used many centuries before the Christian era in the Far East.


Denim or jeans products are commonly used in the modern time. However, it is the oldest, most widely used, most fashionable and most versatile fabric of the world. Basically, this products have great demand to the young generation as well as other people.

Denim Dyeing Process

There are four denim dyeing process with Indigo for denim dyeing. They are-

  1. Rope/ Ball warp/ Chain dyeing
  2. Slasher/ Open warp/ Sheet dyeing
  3. Loop dyeing
  4. Beam dyeing
Slasher Dyeing Process 1
Denim Dyeing With Indigo Dyes Slasher Dyeing Process

Denim Dyeing With Indigo Dyes Slasher Dyeing Process

The slasher dyeing dyes the yarns in the warp beam form. Basically, it is a continuous process which combines dyeing and sizing in a single operation. Dyeing is consequently done by continuously passing warp yarns through several (at least 5) troughs of indigo dye liquor. The dyed yarns are then sized and wound onto a warp beam to be ready for use in the next weaving process. The slasher dyeing is usually of inferior quality as compared to rope dyeing shade evenness or side-to-side shade variations. Moreover, in the slasher dyeing, the penetration of dyestuff is poorer, and it is easily reveals an uneven pick-up along its width with the distortion of the pad-roll.

Characteristics of Slasher Dyeing Process

The following are the characteristics of slasher dyeing process. They are-

  • Firstly, as each yarn is independently subjected to treatment it require less time. It needs 6-10 dye-baths per vat.
  • Secondly, warp yarns are supplied from warp beams. Most of the machine capacity is 9500 warp yarns having 300-750 warp yarns per beam.
  • After that, the number of total warp yarns are determined by yarn count and denim fabric design.
  • Lastly, the yarn count which is used in this process are ranges from 1-30 Ne.      

Flow Chart of  Slasher Dyeing and Sizing:

The following are the flow chart of slasher dyeing and sizing process. They are-

Warper’s Beam

Pretreatment (Scouring) bath

Dryer- wash bath (1, 2, 3)

Color box – 1

Dryer – 1

Color box- 2

Dryer – 2 (Air oxidation is done here)

Color box – 3

Steam box

Color box – 4

Yarn pass between a set of guide roller for oxidation

Color box – 5


Color box – 6

Guide Roller

Color box – 7


Color box – 8


Wash box (1, 2, 3)


Sizing box





Weaver’s beam

Advantages of Slasher Dyeing Process

The following are the advantages of slasher dyeing process. They are

  • Firstly, it needs less space because of  compact design.
  • Secondly, it needs less Oxidation and immersion times.
  • Thirdly, it facilities continuous dyeing process.
  • After that, it has flexibility to color changing.
  • Lasly, it requires less production cost.

Disadvantages of Slasher Dyeing Process

The following are the disadvantages of slasher dyeing process. They are

  • Possibility of cross-shade variation
  • Possibility of yarn rupture
  • Productivity and flexibility in production are low
  • Extra time needed for lot change
  • No versatility in denim production
  • Reducing agent consumption is high
Features of Beam Creel Section:

The following are the features of beam creel section. They are-

  1. Type- Sliding creel
  2. Arrangement- Two creels are placed parallel to each others.
  3. Creel capacity-16 warp beams can be placed in each creel.
  4. Electronic motor is available to slide the creel as well as mount the beams.                   
Sizing BATH and Sizing parameter:

The following parameter are require to maintain during size preparation in the size bath. They are

  1. Capacity of cooking tank
  2. Cooking Temperature
  3. Cooking time
  4. Pick up%
  5. Cylinder temperature
  6. Squeezing Pressure
  7. Delivery squeeze pressure: Lowest and Highest
  8. Stretch
  9. Refractro reading
  10. Viscosity
  11. Sizing Temperature         

In sum, slasher dyeing process is on of the best choice of dyeing specialist.

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