Question

In needle punching, the DPN, ND and WW will influence

• A. Fibre arrangement of the fabric
• B. Tenacity of the fabric
• C. Width of the fabric
• D. Thickness of the fabric

Hint:

• Needle Punching Parameters
  • DPN (Depth of Penetration) How deep needles go. Affects entanglement and consolidation.
  • ND (Needle Density) Number of needles/area on board, or punches/area on fabric. Affects intensity of needling.
  • (WW - if Working Width of machine, it's a capacity. If Web Weight fed, it's an input material property.)
• These parameters influence many nonwoven fabric properties:
  • Thickness and Density Directly affected. More needling (higher DPN/ND) usually decreases thickness and increases density due to compaction.
  • Strength (Tenacity) Increases with DPN/ND up to an optimum, then may decrease due to fiber damage.
  • Fiber Arrangement Changes from planar to 3D entangled.
• Thickness is a very direct structural property controlled by these parameters.

Answer 1

The Correct Option is D

In the context of needle punching within textile engineering, understanding the influence of different parameters is essential for optimizing fabric characteristics. The parameters mentioned are DPN (Density Per Needle), ND (Needle Density), and WW (Web Width). Let's analyze their influence:

• DPN (Density Per Needle): This refers to the number of needle penetrations per unit area. A higher density can compact the fibers more, resulting in a denser fabric structure.
• ND (Needle Density): Needle density affects how tightly the fibers are interlocked. An increased needle density typically makes the fabric more compact and can influence the fabric's mechanical properties.
• WW (Web Width): This is the width of the fiber web being punched. It can determine the coverage of fibers and indirectly influence fabric properties.

The interaction of these parameters primarily affects the thickness of the fabric. By adjusting DPN, ND, and WW, manufacturers can control how compact or loose the fibers are, impacting the fabric's overall thickness. Therefore, the correct choice based on these considerations is thickness of the fabric.