Model Questions and Answers (Yarn Manufacturing )

1. What is fiber?

Ans: Fiber or fibre is classes of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of thread. They are very important in the biology of both plants and animals, for holding tissues together.

2. What is textile fiber?

Ans: Textile fiber has some characteristics which differ between fiber to Textile fiber. Textile fiber can be spun into a yarn or made into a fabric by various methods including weaving, knitting, braiding, felting, and twisting. The essential requirements for fibers to be spun into yarn include a length of at least 5 millimeters, flexibility, cohesiveness, and sufficient strength. Other important properties include elasticity, fineness, uniformity, durability, and luster.

3. What is yarn?

Ans: Yarn is a long continuous length of interlocked fibers, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery, and rope making.

4. Flow chart of carded yarn manufacturing process.

Ans:

Fiber/Bale → Blow Room → Lap/Chute

↓

Lap/Chute → Carding → Sliver (Carded)

↓

Carded Sliver → Draw Frame → Sliver (Drawn)

↓

Drawn Sliver → Simplex → Rove

↓

Rove → Ring Frame → Yarn

↓

Winding

↓

Reeling

↓

Bundling

↓

Bailing

5. Flow chart of combed yarn manufacturing process.

Ans:

Fiber/Bale → Blow Room → Lap/Chute

↓

Lap/Chute → Carding → Sliver (Carded)

↓

Carded Sliver → Pre-Comb Drawing Frame → Sliver (Pre-Drawn)

↓

Sliver → Lap Frame → Lap

↓

Lap → Comber → Sliver

↓

Sliver → Post-Comb Drawing Frame → Sliver (Post-Drawn)

↓

Drawn Sliver → Simplex → Rove

↓

Rove → Ring Frame → Yarn

↓

Winding

↓

Reeling

↓

Bundling

↓

Bailing

6. What is the first process/ machine in yarn production?

Ans. Blow room.

7. What is the second process/ machine in yarn production?

Ans. Carding machine.

8. What process / machine is used after carding?

Ans. Draw frame.

9. What process is used after draw frame?

Ans. Simplex.

10. What process is used after simplex?

Ans. Ring frame.

11. What is the production of blow room?

Ans. Lap.

12. What is the production of carding machine?

Ans. Sliver.

13. What is the production of draw frame?

Ans. Sliver/Drawing sliver

14. What is the production of simplex?

Ans. Roving.

15. What is the production of ring frame?

Ans. Yarn.

16. 1 lb(pound) =?

Ans. 840 yds=1 Hank=0.4536 kg=453.6 gm=16 ounce(oz).

17. What is the input of blow room?

Ans. Bale.

18. What is the input of carding machine?

Ans. Lap/Now chute feed system is being used.

19. What is the input of combing?

Ans. Sliver lap and number of doubling is usually 20-24.

20. What is the input of simplex?

Ans. Drawn sliver, Sliver hank 0.12/0.14/0.16,etc.

21. What is the input of ring frame?

Ans. Roving/Roving hank may be 0.75/0.80,etc.

22. What is fiber fineness?

Ans. Fineness is one of the most important parameter determining the yarn quality (Fine or Coarse).

20. How fineness is specified for cotton?

Ans. Fineness is specified by micronaire value for cotton.

21. The maturity of cotton is defined in terms of the development of cell wall (Yes/no).

Ans. Yes.

22. A fully mature fibre has a well developed thick cell-wall (Yes/no).

Ans. Yes.

23. An immature fibre has a very thin cell-wall (Yes/no).

Ans. Yes.

24. In mature fibre, dye absorption is high (yes/no)

Ans. Yes

25. In immature fibre, dye absorption is low (yes/no).

Ans. Yes

26. What is staple length?

Ans. The average length of spinnable fibre is called staple length.

27. If staple length is increase then yarn quality is also increase (yes/no).

Ans. Yes

28. Toughness of fibre has a direct effect on yarn and fibre strength (yes/no).

Ans. Yes

29. If fibre strength is higher, then yarn and fabric strength is also higher (yes/ no).

Ans. Yes

30. Short fibres deteriorate the yarn strength and uniformity (true/false).

Ans. True.

31. What is the minimum strength for a textile fibre?

Ans. Approximately 6 CN/tex (about 6km breaking length)

32. What do you know about Presley index =?

Ans. Breaking load in Ibs/Bundle weight in mg.

33. What is fibre elongation?

Ans. Elongation is specified as a percentage of the starting length.

34. What is bale management?

Ans. Testing, sorting and mixing bales according to the properties of fibre for producing specific good quality yarn at minimum cost is called bale management.

35. When bale mixing is done?

Ans. Before the blow room/Before the bales going into blow room.

36. What are the basic operations in the blow room?

Ans.

• Opening

• Cleaning

• Mixing & blending

• Even feed of material to the card.

37. What is carding?

Ans. Carding may be defined as the reduction of an entangled mass of fibre to a filmy web by working them between two closely spaced, relatively moving surface clothed with sharp wire points.

38. Objective of carding.

Ans.

• To open up the cotton in to single fibre state.

• To reduce the number of neps, short fibres.

• To produce a thick untwisted rope of fibre called sliver.

39. Carding is called the heart/mother of spinning (true/ false).

Ans. True.

40. What are the main objectives of draw frame?

Ans.

• Straightening & parallelization of fibres by drafting & drawing.

• Minimization of irregularity by doubling.

• Blending & mixing of fibres.

• To produce a more uniform sliver of definite wt/yds.

41. What are the faults of blow room?

Ans.

• Soft lap,

• Conical lap,

• Barrel shaped,

• Split lap,

• Ragged selvedge,

• Lap licking.

42. Find out the hank of the lap when the weight of the lap is 14 oz/yds.

Ans.

14 oz contains = 1 yds,

1 oz contains = 1/14 yds,

16 oz or 1 lb contains = 16/14 yds

=16/14×840 hank=0.00136 hank

So hank of lap = 0.00136.

43. Find out the wt/yds of the lap when hank of the lap is 0.0014? Ans.

Weight of 0.0014×840 yds = 1 lbs or 16 oz

1.176 yds = 16 oz

1 yds = 16/ 1.176 oz = 13.6 oz

So weight of lap = 13. 6 oz/yds

44. For cotton, higher the count, finer the yarn (yes/no). Ans. Yes

45. For jute, lower the count, finer the yarn (yes/ no).

Ans. Yes.

46. What is the name of combing waste?

Ans. Noils.

47. What is the meaning of TPI?

Ans. Turns per Inch/Twist per inch

48. What is the ring frame wastage?

Ans. Pnewmafil, banda, sweep, hard waste.

49. What is roving?

Ans. A roving is a continuous slightly twisted strand of fibres which has not received its final drawing for yarn. Roving hank=0.70 to 0.85, TPI=about 1.15

50. What are the faults of yarn?

Ans.

• Irregular yarn

• Thick & thin places

• Slubs

• Nepped yarn

• Spinners double

• Crackers

• Bad piecing

• Hairiness

• Soft yarn

• Hard & non elastic yarn

• Rough yarn

51. Over twisted yarn become poor in strength (yes/ no).

Ans.Yes

52. What is the meaning of MIC?

Ans. Microgram per inch.

53. In direct system which one is fixed (mass/length)?

Ans. Mass

54. In indirect system which one is fixed (mass/length)?

Ans. Length

55. English count is denoted by Ne (yas/no)?

Ans. Yes.

56. Metric count is denoted by Nm(yes/no)?

Ans. Yes

57. Sliver and roving count is expressed by hank(yes/no)?

Ans. Yes

58. In spinning mill, up to roving the count value is expressed by hank then count (true/false)?

Ans. True

59. The shape of yarn become round due to twist (yas/no)?

Ans. Yas

60. Name the types of fiber?

Ans. Normal fiber, thin walled fiber, Dead fibers .

61. How can you express fiber fineness?

Ans. Weight per unit length.

62. What is stress?

Ans. Stress is the ratio between the applied force and cross sectional area of the specimen,

Stress = applied force/ cross sectional area = F/A.

Unit of stress is N/m2, dyne/cm2, which is also called Pascal (Pa).

63. What is tenacity?

Ans. The tenacity of a fibre is the mass stress at break.

Unit – gm/tex,

Tenacity = breaking load / mass stress or linear density,

Linear density = mass/unit length.

64. What is tensile strength?

Ans. Tensile strength = force required to break the specimen/ cross sectional area

65. What is yield point?

Ans. The point up to which, a material contains its elasticity is called yield point.

66. What are the basic textile materials?

Ans.

Fiber

↓

Yarn

↓

Grey fabric

↓

Finished fabric

↓

End product

67. More fibre drawing produces more short fiber & resulted weak yarn (yes/no).

Ans. Yes

68. What is twist? Ans. Twist is the spirality of bundle of fibres/ filaments.

69. Write down the types of yarn twist.

Ans.

• “z” or clock wise &

• “S” or anti clock wise twist.

70. Twist increases the strength of yarn (true/ false).

Ans. True

71. Write down the moisture regain of cotton fibre?

Ans. 8.5%

72. What is IPI?

Ans. It indicates yarns thick places, thin places and slubs.

73. What is count?

Ans. Count is a numerical expression which expresses /indicates coarseness or fineness of yarn.

Or, count is a number indicating the mass per unit length or the length per unit mass of yarn.

74. Different types of measurement.

Ans.

1 yard = 0.9144 m

1 m =1.0936 yards=7000 grain

1kg = 2.204 lbs,

1lbs(pound) = 453 .6gm = 7000 grains

1gm =15.43 grains

16 oz = 1 lb(pound)

36 inch = 1 yard

2.54 cm = 1 inch

1 Hank=840 yards=1 pound

75. What is yarn twist? Ans. The spiral disposition of the components of thread which is usually the result of relative rotation of the two ends is called yarn twist.

76. Rotor yarn is “s” twisted (yes/no).

Ans. Yes

77. Ring process yarn is “z” twisted (yes/no).

Ans. Yes

78. What is strain?

Ans. Strain = elongation / initial length

79. What is the unit of Strain?

Ans. No unit.

80. What is the meaning of CSP?

Ans.

Count Strength Product

CSP= Count × Strength

81. If yarn is regular then CSP is higher (yes/no).

Ans. Yes

82. Different relations.

Ans.

• Denier = 9 × Tex

• Ne × Denier = 5315

• Tex × Ne = 590.6

• Tex × Metric = 1000

• Denier × Metric = 9000

83. What are the unusable waste in spinning mill?

Ans: (a)dropping-II, (b)flat strips of coarse count, (c)Floor sweeping-II, (d)dust etc.

84. HVI(high volume instrument) is a very important m/c of Q.C lab in spinning mill.(yes/no)

Ans. Yes

85. What tests are done by HVI m/c?

Ans. (a)fineness, (b)trash, (c)length, (d)strength, (e)Color.

86. How can you determine yarn count in English system?

Ans.

Count (Ne) =length(yds)/length × weight unit/weight in gm

= (120yds/840yds) × (1lbs or 453.6gm/weight in gm)

=64.8/Weight in gm

87. Write down the name of count of direct system?

Ans. Txe,K tex,D tex,Mili tex,Denier,lb/spyndle, Woolen.

88. What do you mean by one lea?

Ans. One lea=120 yds.

89. What do you mean by WIRA?

Ans. Wool International Research Association.

90. Write down the full meaning of some institution?

Ans.

• BSTI = Bangladesh standard and testing institution.

• ISO = International organization for standardization.

• BS = British standard

• AQL = Acceptable quality level.

• BCIRA = British cotton industries research association.

• ITET= Institute of textile engineers and technologist.

• AAMA=American apparel manufacturer association.

• AAQC=American association of quality control.

91. Beater are responsible for removing almost all of the impurity extructed in the blow room (yes/no)?

Ans. Yes

92. Name the last m/c of blow room?

Ans. Scutcher

93. What is the meaning of CV%?

Ans. Coefficient of variation percentage.

94. Where sliver is collected and which form?

Ans. In can and coiler form.

95. In ring frame where yarn is collected?

Ans. Bobbin

96. Name the modern cone winding machine?

Ans. Auto-coner machine/Savio orion

97. Cotton fiber is dissolved with 70% H2SO4 (yes/no)?

Ans. Yes

98.All yarn of ring processing is Z-twist and rotor yarn is S-twist.(yes/no)?

Ans. Yes

99. Where flyer is used in a spinning mill?

Ans. Simplex m/c.

100. What is spinning?

Ans. The process by which yarn is made from fiber.

101. What is the raw material in spinning?

Ans. Fiber

102. What is millionaire value?

Ans. Micro gram per inch.

103. Write down the classification of fiber?

Ans. (i) natural, (II) Man made fiber.

104. Different between cotton and viscose?

Ans.

Cotton = Natural fiber, strength increase in wet condition.

Viscose = Man made fiber, strength decrease in we condition.

105. What is the meaning of AFIS?

Ans. Advanced fiber information system.

106. What is the ratio between length and width of fiber?

Ans. 1000:1

107. Twist and twist direction of yarn affects the fabric structure(True/false)?

Ans. True

108. What is UR?

Ans. UR = uniformity ratio =(50% Spun length/2.5% span length)×100

109. Write down the system of yarn count measurement?

Ans.

• Direct system: Tex,Denier.

• Indirect system: English, metric.

110. When fiber consider short?

Ans. Length shorter than 0.5 inch or 12.8mm.

111. Why yarn preparation is needed?

Ans. To increase weaving efficiency.

112. What is drafting?

Ans. The process of increasing the length per unit weight of slivers.

113. What is drawing?

Ans. It is the regular and uniform elongation of the sliver to make it light.

114. What is doubling?

Ans. The process of combining several sliver info one.

115. Which one is best ,combed yarn or carded yarn?

Ans. Combed yarn.

116. Roving is wind into the bobbin(yes/no) ?

Ans. Yes.

117. Write down the other name of simplex?

Ans. (I)Speed frame, (II)Fly frame, (III)Roving frame.

118. Some meaning-

Ans.

• DCP=Draft change pinion

• LCP= Lifter change pinion

• PW = poker wheel

• TCP = Twist change pinion

119. Write down the causes of roving breakage?

Ans. (I)Tension variation, (II) irregular roving.

120. Write down the three types of flyer?

Ans. (I) Spindle mounted flyer,(II) top mounted flyer,(III) closed mounted flyer.

121. What is the backbone of the world textile trade?

Ans. Cotton.

122. Silk fiber readily absorbs water (yes/no)?

Ans. Yes

123. Jute plant have high CO2 assimilation rate (yes/no)?

Ans. Yes

124. What is the output of comber machine?

Ans. Combed sliver.

125. What is the output of the ring frame?

Ans. Yarn in bobbin form.

126. What is the first operation in blow room?

Ans. Opening

127. What is yarn?

Ans. It is an assemblage of fibers twisted or laid together to form continuous strand suitable for use In weaving, knitting etc.

128. Manmade fiber are hydrophobic in nature(yes/no)?

Ans. Yes.

129. Finer fiber produce stronger yarn(yes/no)?

Ans. Yes

130. Write down the forms of manmade fiber?

Ans. (I) Filament, (II) Filament tow, (III)staple.

131. What is the manmade cellulose fiber?

Ans. Viscose.

132. Write some name of natural cellulose fiber?

Ans. Cotton, flax, jute, hemp.

133. What is bi-component fiber?

Ans. Bi-component fibers are synthetic fibers which fibers filament contains two types of polymer.

134. What is bi- component yarn?

Ans. A yarn having two different staple fiber.

135. If H-bond present in fiber then fiber gets more strength(yes/no)?

Ans. Yes.

136. What is the length width ratio of cotton?

Ans. 1:350 to 1:6000

137. In staple/spun yarn twist is must(yes/no)?

Ans. Yes

138. Cotton is dissolved into 70% H2SO4(yes/no)?

Ans. Yes

139. Viscose is dissolved into 35% H2SO4(yes/no)?

Ans. Yes

140. Nylon is dissolved into 20% HCL/phenol(yes/no)?

Ans. Yes

141. Polyester is dissolved into 100% nitro benzene at 100 ℃(yes/no)?

Ans. Yes.

142. Burning smell of cotton is like as burning paper(yes/no)?

Ans. Yes.

143. What is lint and linters?

Ans. Then cotton which are get after first time ginning to seeds cotton is called lint and for second time ginning of cotton is called linters.

144. What is blow room?

Ans. The section or line where the compressed bale are converted into uniform lap of particular length or made suitable for carding by opening, blending or mixing.

145. What is MR% of jute?

Ans. 13.75

146. What is MR% of viscose and silk?

Ans. 11.0

147. What is MC % of cotton?

Ans. 7.834

148. What is MR% of wool?

Ans. 16.0

149. What is MR% of nylon?

Ans. 4.0

150. What is MR% of polyester?

Ans. 0.4

151. What are the long staple fiber?

Ans. Jute, wool, flax, hemp.

152. How fiber is form?

Ans.

Elements

↓

Monomer/molecules/macromolecules

↓

Polymer chain

↓

Fibrils/micels

↓

Fiber

153. What are the requirement of fabric construction?

Ans. (I)EPI,(II)PPI, (III)Warp count, (IV)Weft count.

154. What are the factors that determine the yarn properties?

Ans. Fiber properties, fiber arrangement, twist per inch.

155. What is core spun yarn?

Ans. It is a continuous filament polyester core wrapped in cotton fiber.

156. Write down the main part of carding machine?

Ans.(I)Doffer, (II)cylinder, (III)taker-in.

157. What is swelling?

Ans. The change in dimension due to absorbing water or moisture of any textile material is termed as swelling.

Swelling=(Swollen dimension-Dry dimension)/Dry dimension

158. Which countries cotton is the best cotton in the world?

Ans. Mishor.

159. What is the botanical name of cotton?

Ans. Goosypium Herbacum, Goosypium Hirsutum.

160. What is ginning?

Ans. The procedure by which seeds and cottons are separated from seeds cotton is called Ginning.

161. How much trash% in cotton?

Ans. Generally 1% to 10%.

162. What is blow room waste?

Ans. Dropping-II,Dust,filter waste.

163. What is carding waste?

Ans. Dropping-I, Tacker in waste,Flat strip, motes & flies, sliver waste

164. What is draw frame waste?

Ans. Sliver wastage.

165. What is the simplex wastage?

Ans. Sliver wastage, roving wastage.

166. What is the ring frame wastage?

Ans. Pneumafil, hard waste, bonda waste, etc.

167. What is the comber wastage and waste %?

Ans. Noils,(12-18)%.

168. What is cleaning efficiency in blow room?

Ans. CE% trash cotton - trash in lap/trash in cotton )× 100

169. Step cleaner m/c is placed at 45 degree angle (yes/no)/

Ans. Yes.

170. Production of carding m/c?

Ans. Production = (Doffer speed × Doffer dia × Π)/36 (yds/min)

171. What is model length?

Ans. It is the length of group of fibers where the most number of fibers have equal length.

172. What is spun length?

Ans. It is the term by which we can determined the % of fiber length in case of cotton, wool etc.

173. What is staple length?

Ans. The average length of spinable fiber is called staple length.

** staple length = 0.91 × effective length(U.S.A upland cotton)

174. What is effective length?

Ans. It is the term defined as the length of the main bulk of the longer fiber.

175. How the amount of twist is expressed?

Ans.

• Twist per inch(TPI) = yarn

• Twist per meter (TPM) = roving

• Twist per centimeter (TPCM)

176. What is mass stress?

Ans.

Mass stress = Applied forse/linear density

Unit = CN/tex , gm/tex

177. What is elastic recovery?

Ans. Elastic recovery = Elastic extension/total extension.

178. What is the modern testing equipment for spinning mill?

Ans.

• HVI(High volume instrument)

• AFIS(Advance fiber information system)

• Shirley analyzer = trash%

• Moisture meter = MC%

• Moisture testing oven = MR%

179. If MIC value is increased what should be the fineness?

Ans. Fineness should be decreased.

180. What is pitch?

Ans. The distance between adjustment spindles.

181. What is the maximum count to be produce in rotor m/c and ring m/c in spinning?

Ans.

Rotor m/c = not possible to produce more than 40s count.

Ring m/c = it is possible to produce about 300s count.

182. What is the feed material in ring and rotor m/c?

Ans.

Ring m/c = roving

Rotor m/c = drawing sliver.

183.What is tex?

Ans. Count is the tex system in the weight in grams of 1000m or 1km of yarn.

184. How many types of draw frame ?

Ans. (I)Breaker draw frame, (II)finisher draw frame.

185. What is the output of winding?

Ans. Yarn in cone form.

186. Natural fibres are hydrophilic in nature? (Yes/No)

Ans. Yes.

187.What is the types of waste in a spinning mill?

Ans: (i) useable waste (ii) unusable waste.

188. The flyer is the essential part of speed frame(yes/no)?

Ans. Yes

189.What is neps?

Ans. Entanglement protruding fibres or entangled mass of fibres.

190. Write down the some name of yarn testing machine.

Ans.

• Uster evenness tester

• Uster classimat

• Uster auto sorter.

191. What is the useable waste in spinning mill?

Ans: (a)lap waste,(b) sliver waste,(c)roving waste,(d)bonda waste,(e) pneumafil waste .

192. What is fiber migration?

Ans. It means fiber distribution into the yarn.

193. Number of fibres in the yarn cross-section?

Ans. 60-70

194. What is the standard staple length of cotton fibre?

Ans. Generally 0.5 inch to 2.5 inch.

195. Write some yarn faults which are generally shown?

Ans. (I)Thick place, (II) Thin place, (III) Neps, (IV) slub, (V) Hairiness.

196. How many class or division of yarn preparation?

Ans. (I) Warp yarn preparation, (II) Weft yarn preparation.

197. What are the classes of winding machine for package of yarn?

Ans. (I) pirn winding m/c, (II) cop winding m/c, (III) spol winding m/c, (IV) Cheese winding m/c, (V) cone winding m/c.

198. What are the action of blow room?

Ans.

• Action of opposing spikes

• Action of air current

• Action of beaters,

• Regulating action

199. What is crimp?

Ans. The wavy shape of thread/yarn is called crimp.

200. Total Draft =?

Ans. Total draft = BD×MD×FD

BD=Back draft

MD=Middle draft

FD=Front draft