Textile Engineering: Material Take-off
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Textile Engineering: Material Take-off

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Questions and Answers

What happens during the piecing process involving the detaching roller and the nipper?

  • Nipper moves backward and detaching roller stays still.
  • Both rollers move forward together.
  • Both rollers move backward simultaneously.
  • Detaching roller moves backward while nipper moves forward. (correct)

    • What is the ideal outcome regarding irregularities in the sliver produced?

  • Irregularities should be as low as possible. (correct)
  • Irregularities do not affect the quality.
  • Irregularities should be as high as possible.
  • Irregularities should be moderate.

    • What does the effective take-off (T) of the web depend on?

  • The total speed of both components combined.
  • The difference between forward and backward components. (correct)
  • The speed of the backward component only.
  • Only the forward component speed.

    • How does incorrect machine setting affect the produced sliver?

    <p>It causes faults of thick or thin regions in the sliver.</p> Signup and view all the answers

    What role do calender rollers (K) play in the process of sliver formation?

    <p>They condense the sliver after collection.</p> Signup and view all the answers

    What is indicated by the term 'piecing distance' (PD)?

    <p>The length of the coherent web at detaching rollers.</p> Signup and view all the answers

    What is the significance of eccentric withdrawal of the web from the web plate?

    <p>To ensure uniform sliver thickness.</p> Signup and view all the answers

    What shape is formed by piecing lines when the web is collected toward the center line?

    <p>Curved lines (piecing waves).</p> Signup and view all the answers

    Study Notes

    Take-off of Material

    • Piecing
      • Detaching roller moves backward, and nipper moves forward
      • Detaching roller then moves forward to detach the web, creating a coherent web
      • This process creates a wave-like structure in the sliver with periodic variations
      • The sliver contains periodic irregularities due to the piecing process
    • Combed Web Structure
      • PD = Piecing distance or piecing period
      • FL = Fiber length
      • AL = Detaching length
      • FP = Fiber package length
      • FP is greater than AL + FL
    • Irregularity in the sliver
      • Spectrogram peaks are at about 30-75 cm
      • This irregular pattern should be minimized
    • Eccentric Withdrawal of the Web
      • The web is withdrawn eccentrically from the web plate
      • Machine settings are based on flat parallelograms
      • Parallelograms are laid on each other to minimize unevenness, and any unevenness is partly cancelled out
      • Incorrect setting will cause an increase in unevenness (Thick or Thin fault)
    • Delivery of the Web
      • The forward component (V) is larger than the backward component (R)
      • Effective take-off (T) is calculated as V-R
      • Modern combers have a backward movement that is about 60% of the forward movement
    • Withdrawal of the Web and Formation of a Sliver
      • The web is collected into a sliver by the trumpet (T)
      • The sliver is deposited on the sliver table (B) by the calender rollers (K)
      • There is a web plate (V) for reserve material between the detaching (R) and withdrawing rollers (Z)
      • The web can be collected toward the center line (a) on older web pans, or to one side (b) as on the web plate in modern combers
    • Collection of the Web
      • If the web is collected toward the center line (a), slightly thicker piecing lines form curved piecing waves
      • If the web is collected to one side (b), the piecing lines form diagonals
      • The collection of the web is performed by the sliver trumpet (T)
      • The size of the trumpet (T) is based on the sliver hank
    • Calender Rollers
      • Calender rollers (K) are used to condense the sliver
    • Sliver Take-off
      • Slivers are deflected through 90° by the deflector

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    Description

    Explore the intricate processes involved in the take-off of material in textile engineering. This quiz delves into aspects such as piecing, combed web structure, and managing irregularities in sliver. Test your knowledge on the mechanics of eccentric withdrawal and its importance in minimizing unevenness.

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