Viva Questions and Answers for Weaving and Knitting

Viva Questions and Answers for Weaving and Knitting

Mazedul Hasan Shishir
Production Officer at Intramax Group
Email: mazadulhasan@yahoo.com




Introduction:
Some years ago textile engineers had many scope for doing job. But now a days huge no of textile engineers are entering into textile job sector. So ultimately result is that, scarcity job in textile sector. But scarcity from other department of textile, weaving and knitting are comparatively less. So fresh textile engineers have opportunity to do job in weaving and knitting mill. I have written this article for preparing themselves to get job in weaving and knitting industry.
Interview Questions and Answers for Weaving and Knitting

1. What is weaving?
Ans. the process of interlacing two sets of yarns namely warp and weft, at right angle to make a fabric, according to design.

2. What is knitting?
Ans. It is the process of producing fabric by transferring continuous yarns into interlocking loops, each row of loop hanging from the one immediately preceding it.

3. How many sets of yarn are used in knitting?
Ans. One set (warp or weft).

4. How many sets of yarn are used in weaving?
Ans. Two sets (warp and weft).

5. Is sizing required in knitted fabric?

Ans. No.

6. Write down the types/ classification of knitting.
Ans. Two types,
  • Warp knitting & 
  • Weft knitting.
7. Is yarn preparation is needed in knitting? 
Ans. No.

8. Is knitting fabric produce by inter looping? 
Ans. Yes.

9. Is weaving fabric produce by interlacing? 
Ans. Yes.

10. In which knitting, a fabric is produce by single yarn?
Ans. Weft knitting.

11. What is the other name of warp yarn? 
Ans. Ends

12. Write down the loom driving system?
Ans
  • Hand driving (hand loom) & 
  • Electric motor driving (power loom)
13. Write down/ what are the different types of shed?
Ans. 
  • Bottom close shed
  • Center close shed
  • Semi-open shed
  • Open shed
14. What is shedding?
Ans. Shedding is the act of dividing the warp threads according to design into two parts, to allow the passage of shuttle/weft inserting element from one side of the loom to the other.

15. Write down/what are the types of shedding mechanism?
Ans. 
  • Paddle/treadle shedding (used in hand loom)
  • Tappet shedding (used in power loom)
  • Dobby shedding (used in power loom, at past used in hand loom)
  • Jacquard shedding (both hand & power loom are used now)
  • Combined shedding
16. Normally tapped shedding mechanism produces square design (e.g. 4x4, 6x6, 7x7, etc.) (Yes /no)
Ans. Yes.

17. We can produce basic weave structures (i.e plain, twills satin) in tapped shedding (yes/no)
Ans. Yes

18. Where open shed is used?
Ans. Tapped loom
 
19. What is fabric?
Ans: Interlacement of two or more thread of yarn.


20. What are the primary motion?
Ans. The primary motion are as follows-
  • Shedding
  • Picking
  • Beating
21. What are the secondary motion?
Ans. The secondary motion are as follows :
  • Let off
  • Take-up
22. What are the tertiary motion
Ans. The tertiary motion are as follows-
  • Warp stop motion
  • Weft stop motion
  • Warp protector
  • Weft protector
23. Where bottom & center close shed are used?
Ans. Hand jacquard looms to produce delicate fabrics.

24. Where semi-open shed is used?
Ans. Double lift dobby & Jacquard.

25. One shedding + one picking + one beating =?
Ans. One weaving cycle/ loom cycle/picks cycle

26. One picking tapped insert one pick(True or False)?
Ans. True

27. What is the result of unequal shedding?
Ans. Wrong design & stitching

28. What are the maximum numbers of heald frame controlling capacity in tapped shedding mechanism?
Ans. 14

29. Dobby shedding mechanism can produce both square and rectangular size design (yes/no)
Ans. Yes

30. What types of design can be produced by Jacquard looms?
Ans. Any design

31. What are the maximum numbers of warp threads controlling capacity in Jacquard loom?
Ans. 1800

32. What is sizing?
Ans. Sizing is the process of giving a protective coating on the warp yarn to minimize yarn breakage during weaving.

33. What materials form the base of the size?
Ans. Starch or gum

34. What are the types of loom?
Ans. 
  • Hand loom & 
  • Power loom
35. What are the types of power loom?
Ans. 
  • Modern/shuttle less loom & 
  • Conventional/shuttle loom.
36. What is picking?
Ans. To propel the shuttle or any other weft inserting elements.

37. Write down the faults of picking

Ans
  • Early picking 
  • Late picking 
  • Smash or Bang-off
  • Short picking 
  • Harsh picking 
  • Shuttle flying out
38. Some meaning
Ans. 
  • PPM = picks per minute
  • PPI = picks per inch
  • EPI = Ends per inch
  • RS = Reed space
39 Actual production of a m/c is always less than that calculated production (True/False)
Ans. True

40. What is the object of beat-up mechanism?
Ans. To push the newly inserted weft yarn (last pick) to the fell of the cloth.

41. What is the function of take-up mechanism?

Ans. To wind the already woven fabric on the cloth roller with the progress of weaving.

42. What is pick spacing?
Ans. The space occupied by a pick in fabric

43. What is let-off mechanism?
Ans. To unwind the equivalent length of warp sheet from the warp beams with the progress of take-up during weaving.

44. What are the basic weave structures?
Ans. (i) Plain (ii) Twill and (iii) Satin

45. Write down/Classify the types of sett.
Ans. 
  • Warp sett (No. of warp/inch)
  • Weft sett (no. of weft/inch)
46. What is weave?
Ans. Interlacement of the ends and picks with each other produces a coherent structure. The repeating pattern of interlacing is called the weave.

47. What is warp & weft crimp?

Ans. The waviness of the yarns due to interlacing of warp and weft in producing fabric is called crimp.

48. What is face loop?
Ans. The loop where heads are below and hanks are above is called face loop.

49. What is back loop?
Ans. The loop where heads are above and hanks are below is called back loop.

50. What is the basic knitted structure?
Ans. 
  • single jersey or plain
  • 1x1 rib
  • 1x1 inter lock
  • 1x1 purl.
51. Write down the weft knitting elements.
Ans. 
  • Needle
  • Sinker
  • Cam
52. Write down the types of needle.
Ans. 
  • Latch needle
  • Bearded needle
  • Compound needle
53. Write down the types of knit wear.
Ans. 
  • Cut and sew knit wear 
  • Fully fashion knit wear.
54. Write down the basic stitches of knitting structure.
Ans. 
  • Knit stitch
  • Miss/ float stitch
  • Tuck stitch
55. How can you identify single jersey fabric?
Ans. In single jersey fabrics, all face loops are present in one side and all back loops are present in other side of the fabric.

56. How can you identify double jersey fabric?
Ans. In double jersey fabrics, face & back loops are present in every side of the fabric.

57. The size of held loop is always bigger than knit loop (yes/no).
Ans. Yes.

58. Write down the warp knitting elements.
Ans. 
  • Needle
  • Cam
  • Sinker
  • Guide.
59. Needle individually works in which knitting?
Ans. Weft knitting m/c.

60. Needles work unitedly in warp knitting (yes/no). 
Ans. Yes.

61. What is pitch?
Ans. The distance between one needle and another.

62. Technical face and back is of same in rib structure (yes/no).

Ans. Yes.

63. What is a coarse?
Ans. A coarse is a predominantly horizontal row of needle loops.

64. What is a wale?
Ans. A wale is a predominantly vertical column of intermeshed needle loops.

65. What is the first type of needle?
Ans. Bearded needle.

66. What is the problem of bearded needle?
Ans. Presser bar is used as closing elements.

67. What is the function of sinker that performed?
Ans. 
  • loop formation 
  • holding down
  • knocking over.
68. What is cam?
Ans. Cams are the devices which convert the rotary machine drive into a suitable reciprocating action for the needles or other elements.

69. Write down the types of cam.
Ans
  • Engineering cam,
  • Knitting cam.
70. What is needle loop?
Ans. The needle loop is the basic unit of knitted structure.

71. Write down the types of clearing cam.
Ans. 
  • Knit cam,
  • Tuck cam,
  • Miss cam
72. What is the basic knitting action of a needle?
Ans
  • Rest position,
  • Opening,
  • Clearing,
  • Yarn feeding
  • Landing,
  • Knock over.
73. What is held loop?
Ans. A held loop is an old loop that the needle has retained

74. Where the interlock fabrics are used?
Ans. Under garments clothing.

75. Inter lock has the technical face of plain fabric on both side (yes/no).
Ans. Yes.

76. In interlock fabric, reverse or back loop is not seen (yes/no). 
Ans. Yes.

77. Technical face & back is of different in single Jersey fabric (yes/no)
Ans. Yes

78. What do you mean by GSM?
Ans. Gram per square meter.

79. What do you mean by oz/sq. yd?
Ans. Ounce per square yard.

80. Where GSM is used?
Ans. The term GSM is popularly used in knitted industry because buying & selling are done on the basis of weight of the fabrics.

81. What is the GSM range for finer fabrics? 
Ans. Below 150

82. What is the meaning of CVC & PC/TC?
Ans.
  • CVC = Chief value of cotton (i.e. cotton more than 50%)
  • PC/TC=Polyester&Cotton / Tetron & Cotton (i.e.polyester more than 50%)
83. What types of loops produce in knitting?
Ans. Interlocking or Interlooping loops.

84. Weft knitting produce in which form?
Ans. Tubular form.

85. In which/loop, shanks are above and heads are below?
Ans. Face loop.

86. What is sinker loop?
Ans. The loop that joins two adjacent needle loop.

87. What is the basic unit of knitted structure?
Ans. Stitch/loop

88. Legs or shanks are below and heads are above in back loop (Yes/No).
Ans. Yes.

89. In where alternate face and back loops produced by two sets needle?
Ans. Rib structure.

90. In interlock fabric, is back loop invisible?
Ans. Yes.

91. Which is the only movable cam in the cam box?
Ans. Stitch cam.

92. What is the principal element of knitting m/c?
Ans. Needle.

93. What fabric produced by adhesive and punching?
Ans. Non-woven fabric.

94. Write the process sequence of woven fabric production?
Ans. 
(A) Yarn preparation
  • Winding 
  • Drawing in and denting
  • Warping 
  • Leasing
  • Sizing  
  • Tyeing in / Knotting
(B) Weaving
(C) Inspection
(D) Folding
(E) Transfer to DPF (Dyeing, Printing & Finishing)

95. The weave with long floats of threads produce loose structure and short floats produce firm structure (True/False).
Ans. True

96. What are the types of fabric?
Ans. 
  • Woven fabric 
  • Knit fabric 
  • Non woven fabric
97. What is non woven fabric?
Ans. Sheets of fibers are held together by adhesives, stitching or needle punching to give a usable fabric.

98. What do you mean warp & weft yarn?
Ans. 
  • Warp yarn = the lengthwise set of yarn
  • Weft yarn =the widthwise set of yarn.
99. Write down the classification of woven fabric with example.
Ans. 
  • According to raw material e.g. cotton fabric, wool fabric, silk fabric
  • According to processing e.g. solid dyed, yarn dyed
  • According to their weaves or construction e.g. plain fabric, twill fabric, satin fabric
  • According to their structures e.g. single cloth, double cloth, pile fabric
  • According to end uses e.g. Clothing, floor covering, furnishing
100. In weaving process, which is first, sizing or winding?
Ans. Winding (winding → warping → sizing)

101. Why yarn preparation is required for weaving?

Ans.  
  • To wind the yarn uniformly on suitable package
  • To have desired length of yarn on the package
  • To improve weaving efficiency.
102. What are the classifications of winding m/c?
Ans. 
  • Pirn winding m/c
  • Cop winding m/c
  • Spool winding m/c
  • Cheese winding m/c
  • Cone winding m/c
103. What are the types of warping?
Ans. Two types
  • Direct or high speed or beam warping
  • Sectional or pattern or drum warping
104. What types of traversing method?
Ans. 
  • Reciprocating
  • Rotating
105. Ribboning is a winding fault (yes / no) 
Ans. Yes

106. Write down the types of yarn tensioner used in winding.
Ans. 
  • Capstan Tensioner
  • Additive Tensioner
  • Combined Tensioner
  • Gate Tensioner
  • Lever Tensioner or automatic control tensioner.
107. Write down the types of guide.
Ans. 
  • Type A → A yarn end is required for threading
  • Type B→ A yarn end is not required for threading
108. What is the main feature of twill weave?
Ans. A twill weave is characterized by diagonal lines of warp & weft floats on the face of the fabric.

109. What are the derivatives of twill?
Ans. 
  • zigzag / pointed / waved twill 
  • combined twill
  • Herring bone twill 
  • Fancy twill
  • Broken twill 
  • Continuous twill
110. Write down the classification of drafting?
Ans. 
  • Straight draft 
  • Special draft
  • Pointed draft 
  • Skip draft
  • Flat pointed draft 
  • Mixed draft
  • Broken draft
111. What is color & weave effect?
Ans. Simple weaves such as plain, twill and matt may be used in conjunction with two color warp and weft patterns to produce small geometrical designs in two colors that is called color & weave effect.

112. Where double cloth is used?
Ans. Decorative fabrics, such as sofa cover, furnishing cloth.

113. What is denim fabric?
Ans. A strong warp faces cotton cloth used for overalls, jeans, skirts etc. largely made in 3/1 twill weave.

114. Some fabric detail.
Ans. 
  • Jean = 2/1 twill cotton cloth made warp or weft face.
  • Poplin = A plain woven warp rib fabric with fine warp and thick weft.
115. What is winding?
Ans. The transferring of yarn from one package to another is called winding.

116. Write down the classes of winding?
Ans. 
A. On the basis of package hardness/softness-
  • Soft winding 
  • Hard winding
B. On the basis of your coil on the package (traversing)
  • Precision winding and
  • Non-precision winding
117. What are the types of packages?
Ans. Fundamentally three different types of packages
  • The parallel would package.
  • The near-parallel wound packages and
  • The cross wound packages.
118. What are the classes of winding m/c basis on package of yarn produced?
Ans. 
  • Pirn winding m/c
  • Cop winding m/c
  • Spool winding m/c
  • Cheese winding m/c
  • Cone winding m/c
119. What are the ways in which a yarn package may be unwound?
Ans. There are two ways in which a yarn package may be unwound-
  • Side withdrawal and 
  • Over end withdrawal.
120. What are the faults of winding?
Ans. Faults-
  • Too soft or hard package
  • Improper knots.
  • Dirty package
  • Incorrect winding speed
  • Unsatisfactory package shape.
  • Ribboning
  • Balloning
121. Mention the Auxiliary functions of winding machine?
Ans. The Auxiliary functions of a winding machine include-
  • Creeling 
  • Piecing 
  • Doffing.
122. What is warping?
Ans. The parallel winding of a set of warp yarns from many yarn packages (cone/cheese) on a flanged bobbin (warping beam) at uniform spacing, tension and length is called warping.

123. How many types of warping?
Ans. There are mainly two types of warping-
  • Direct or high speed or beam warping
  • Sectional or pattern or drum warping.
124. Write the components of warping machine?
Ans. A warping machine consists of three main parts:
  • Creel 
  • Headstock 
  • Control unit.
125. Classify the sizing method?
Ans. On the basis of size % on the yarn-
  • Light sizing- 10% - 15%
  • Pure sizing - 16% - 25%
  • Medium sizing - 26% - 50%
  • Heavy sizing - 50% - 100%
On the basis of application process-
  • Surface sizing
  • Core sizing
  • Optimal sizing
126. What are the reason of clothing?
Ans.
  • Modesty
  • Protection against adverse climate conditions
  • Adornment
  • Identification
  • Aristocratic reason
127. What the breaks that used to stop the loom?
Ans.
  • Mechanical
  • Pneumatic (used air)
  • Hydraulic (used liquid)
128. Some important terms -
  • * The ratio of RPM of crank shaft and bottom shaft is always 2:1
  • ** RPM of crank shaft = PPM of the loom
129. Can we mount more than two shedding tappet in a loom? 
Ans. No

130. What is dwell?
Ans. The stationary period of heald frames in open shed condition during which time, the shuttle travel from one side of the loom to the other side.

131. How many heald frames can be controlled by Dobby shedding mechanism?
Ans. Theoretically maximum 48 but practically 36 can be controlled. But for cotton yarn weaving 24 controlled.

132. Minimum how many heald frame is controlled by Dobby shedding?

Ans. Minimum 12.

133. Maximum how many heald frame is controlled by Jacquard shedding?
Ans. 1800

134. What is efficiency?
Ans. The weaving efficiency describes how effectively a set of looms work in normal working environment.

135. What is bastard reed?
Ans: A reed in which dent space at each side is slightly greater than in the center.

136. What is flat bed?
Ans: A bed which provides a flat surface in a same pane as the table in which it is mounted.

137. What is Brocade?
Ans: A woven, patterned fabric using multi-colored threads

138. What is Damask?
Ans: It is similar to brocade but is finer, thiner. A woven, patterned fabric, using all one color - think fancy white cloth napkins. Usually silk, linen, cotton, rayon or synthetic blends.

139. What is voile?
Ans: Soft fine sheer fabric.

140. What is worsted?
Ans: Fine closely-woven wool. 
 

Different Types of Dyes with Chemical Structure

Different Types of Dyes with Chemical Structure

Golam Mawla
Daffodil International University
Department of Textile Engineering
Facebook: https://www.facebook.com/golammawlabd
Email: mawla3140@diu.edu.bd



Introduction:
A dye is a coloured compound,normally used in solution,which is capable of being fixed to a fabric. The dye must be ‘fast’or chemically stable so that the colour will not wash with soap and water,fade on exposure to sunlight etc. Dyeing is normally done in a special solution containing dyes and particular chemical material. After dyeing, dye molecules have uncut Chemical bond with fiber molecules. The temperature and time controlling are two key factors in dyeing.

Dye:
“It is define as the compound whice containing chromophore and auxochrome groups called dye.Chomophore group is responsible for dye colour due to their nsaturation. Auxochrome group is responsible for dye fibre reaction.”
Different types of dyes
Different types of dyes
Natural dye:
Natural dyes are simply dye substances extracted from natural sources. Although the main source of dyes for early times, they have largely been replaced by synthetic dyes, which are usually more reliable, cheaper and can be supplied more readily. Natural dyes still in use include haematoxylin, carmine, orcein.

Colouring materials have been used for many thousands of years by man. Leather, cloth, food, pottery and housing have all been modified in this way. Some of our most common dyes are still derived from natural sources. These are termed natural dyes. The Colour Index uses this as a classification and naming system.
Each dye is named according to the pattern:

Natural + base colour + number
Natural dyes are often negatively charged. Positively charged natural dyes do exist, but are not common. In other words, the coloured part of the molecule is usually the anion. Although the molecular charge is often shown on a specific atom in structural formulae, it is the whole molecule that is charged. Many, but by no means all, natural dyes require the use of a mordant.

Synthetic dye:
Dyes derived from organic or inorganic compound are known as synthetic dyes. Examples of this class of dyes are Direct, Acid, Basic, Reactive, Mordant, Metal complex, Vat, Sulphure , Disperse dye etc. Synthetic dyes quickly replaced the traditional natural dyes.
They cost less, they offered a vast range of new colors, and they imparted better properties to the dyed materials dyes are now classified according to how they are used in the dyeing process.

Many types of dyes:

Acid dye:
Acid dyes are water-soluble anionic dyes, containing one or more sulfonic acid substituents or other acidic groups. An example of the class is Acid Yellow 36.
Acid yello36
Acid dyes are water-soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers using neutral to acid dye baths. Acid dyes are not substantive to cellulosic fibers. Most synthetic food colors fall in this category. The dyeing process is reversible and may be described as follows:
Basic or Cationic Dye:
This group was the first of the synthetic dyes to be taken out of coal-tar derivatives. As textile dyes, they have been largely replaced by later developments.They are still used in discharge printing, and for preparing leather, paper, wood, and straw. More recently they have been successfully used with some readymade fibers, especially the acrylics. Basic dyes were originally used to color wool, silk, linen, hemp, etc., without the use of a mordant, or using agent. With a mordant like tannic acid they were used on cotton and rayon. Basic dyes give brilliant colors with exceptional fastness to acrylic fibers. They can be used on basic dyeable variants of nylon and polyester.

Basic Brown 1 is an example of a cationic dye that is readily protonated under the pH 2 to 5 conditions of dyeing.
Basic Brown 1
Direct Dye:
These are the dyes which can be applied directly to the fabrics from an aqueous solution. These are most useful for fabrics which can form hydrogen bonds with the Dyeing of Fabrics. The direct dyes mainly the basic dyes and were widely hailed because they made it unnecessary to use a mordant or binder in dyeing cotton. The colors are not as brilliant as those in the basic dyes but they have better fastness to light and washing, and such fastness can be measurably improved by after treatments (diazotized and developed.) Direct dyes can be used on cotton, linen, rayon, wool, silk and nylon. These dyes usually have azo linkage –N=N- and high molecular weight. They are water soluble because of sulfonic acid groups.

Direct orange 26 is a typical direct dye.
Direct orange 26
Azoic Dye:
Azo dyes contain at least one azo group (-N=N-) attached to one or often two aromatic rings. These dyes are used primarily for bright red shades in dyeing and printing since most other classes of fast dyes are lacking in good red dyes. Azoic dyes, called Naphthols in the industry, are actually manufactured in the fabric by applying one half of the dye. The other half is then put on and they combine to form the finished color. Unless they are carefully applied and well washed, they have poor fastness to rubbing or crocking.

The production of bluish red azoic dye from the following two components is an example.
Nitro Dye:
Nitro dyes are polynitro derivatives of phenols containing at least one nitro group ortho or para to the hydroxyl group.It is used to dye wool.It Consist of two or more aromatic rings (benzene, naphthalene).

Example:
Maritus yellow
Disperse Dye:
Disperse dyes were originally developed for dyeing secondary cellulose acetate fibers. These dyes are relatively insoluble in water and are prepared for dyeing by being ground into relatively fine powder in the presence of dispersing agents. In the dye bath, a suspension of the dye particle dispersion produces a very dilute solution of the dyes, which are then absorbed by the fibers. This dye class is used to dye polyester, nylon, acetate and triacetate fibers.

Disperse yellow 3, Disperse Red 4, and Disperse Blue 27 are good examples of disperse dyes.

Example:
Vat Dye:
The vat dyes are insoluble complex polycyclic molecules based on the quinone structure (ketoforms). The term vat comes from the old indigo method dyeing in a vat: indigo had to be reduced to light form. Vat dyes are made from indigo, anthraquinone and carbazole. They are successfully used on cotton, linen, rayon, wool, silk, and sometimes nylon. Vat dyes are also used in the continuous piece of dyeing process sometimes called the pigment application process. The dyeings produced in this way have high wash and light fastness.

An example of a vat dye is Vat Blue 4 (Indanthrene).
Vat Blue 4

Mordant Dye:
These Dyeing of Fabrics do not dye the fabric directly but require a binding agent known as mordant. The mordant acts as a binding agent between the fibre and the dye. Some dyes combine with metal salts (mordanting) to form insoluble colored complexes (lakes). These materials are usually used for the dyeing of cotton, wool or other protein fiber. The metallic precipitate is formed in the fiber producing very fast colors highly resistant to both light and washing.

Example:
Reactive Dye:
These dyes react with the cellulosic fiber to form a covalent bond. This produces dyed fiber with extremely high wash fastness properties. These are the dyeing of fabrics which contain a reactive group which combines directly with the hydroxyl or the amino group of the fibre. Because of the chemical reaction the colour is fast and has a very long life. Cotton, wool or silk can be dyed with this type of dyeing of Fabrics.

Example: This type is the Reactive Blue 5 dye shown below,
Reactive Blue 5
Solvent Dye:
These dyes are water-insoluble but soluble in alcohols, chlorinated hydrocarbons, or liquid ammonia. These colours are applied by dissolving in the target, which is invariably a lipid or non-polar solvent. The Colour Index uses this as a classification and naming system. Each dye is named according to the pattern: – solvent + base colour + number They are used for coloring synthetics, plastics, gasoline, oils and waxes.

Example:
Solvent yellow32
Sulfur Dye:
The sulphur dyes provide very deep shades, which have excellent resistance to washing but poor resistance to sunlight. They will dye cotton, linen, and rayon, but not brightly. A problem with sulphur dyes especially the black colors is that they make the fabric tender, or weaken its structure, so that it breaks easily. Sulfur dyes are applied to cotton from an alkaline reducing bath with sodium sulfide as the reducing agent. They are low cost and have good fastness to light, washings and acids.

Example:
Sulfur red 7
Properties of dyes:
  • These dyes are economical dyes and are generally used to produce dark shades such as dark greens , dark blues and blacks.
  • These dyes have good leveling and color fastness properties.
  • The interaction between fiber and dye is established through very strong ionic bonds , which are formed between the anionic groups of the colorant and ammonium cations on the fiber. Chromium or the metal ion acts as bridge between the dye and fiber , which gives rise to a very strong linkage , resulting into excellent fastness properties.
Some dye application:

Name of Dyes
Application
Man made fiber (Nylon),
Natural fiber (Silk, Wool)
Man made fiber (Viscose),
Natural fiber (Cotton)
Man made fiber (Viscose),
Natural fiber (Cotton, Silk, Wool)
Nylon, Polyester, Acrylic, Tri-acetate, Di-acetate
Jute, Acrylic
Cotton, Wool, Silk, Viscose, Nylon
Cotton, Viscose
Cotton, Wool, Silk
Cotton, Man made fiber
Mineral
Cotton, Wool, Silk
Cotton, Viscose
Aniline Black
Cotton
Rapid and Rapidson dye
Cotton
Onium dye
Cotton, Jute

Conclusion:
At last said that dye is very important for Textile sector.Because the fabric are to make attractive to us by dyeing.Dyes that are used by the Textile industry are now mostly synthetic.These dyes are marketed power sgranules and liquid dispersion.Now the industrial Textile dyes must rise up to meet all these new and specific technical reguirements.


References:
  1. http://en.wikipedia.org/wiki/Dye
  2. http://textilelearner.blogspot.com/2012/03/application-of-dyes-according-to-fiber.html
  3. http://www.iiem.com/em/dyes/chapter3.html
  4. https://textlnfo.wordpress.com/2011/12/04/classification-of-dyes/
  5. http://dyes-pigments.standardcon.com/what-is-dye.html
  6. Industrial Dyes, Chemistry, Properties, Applications by K. Hunger (Editor)