Question

A Poplin sort with 112 ends X 72 picks 40$^s$ produced on a 50" RS auto loom needs

• A. 2/108$^s$ Reed
• B. 2/80$^s$ Reed
• C. 4/52$^s$ Reed
• D. 3/100$^s$ Reed

Hint:

• Poplin is a plain weave fabric, often with a higher warp density than weft density, creating fine ribs.
• EPI (cloth) = (EPI in reed) / (1 - fractional width contraction). Or EPI (reed) = EPI (cloth) $\times$ (1 - fractional width contraction).
• Assume Stockport reed count for Y in "X/Y$^s$": Dents/inch = Y/2.
• Then calculate EPI in reed = (Y/2) $\times$ X.
• Choose the option that gives an EPI in reed reasonably close to (usually slightly less than) the target cloth EPI of 112, considering typical ends/dent patterns for poplin (e.g., 3 or 4).
• 4 ends/dent in a 52s Stockport reed (26 dents/inch) gives 104 EPI in reed. This is a common setup for poplins aiming for around 110-120 EPI in cloth.

Answer 1

The Correct Option is C

When producing a poplin fabric with 112 ends and 72 picks per inch (EPI and PPI), the reed size and type are crucial factors that affect the quality of the fabric. The reed plays a vital role in controlling the warp tension and space between the warp threads during weaving.

Let’s examine each option:

1. 2/108$^s$ Reed

2/108$^s$ Reed is relatively large for poplin fabric. This reed size may cause too much space between the warp yarns, resulting in a looser weave, which is not ideal for a fabric like poplin, which requires tighter and smoother construction.

2. 2/80$^s$ Reed

2/80$^s$ Reed is a fine reed size that works well for many fabric types. However, for poplin, which is a medium-weight fabric, this reed might be too fine, leading to a fabric that is too tightly woven, affecting its texture and performance.

3. 4/52$^s$ Reed

4/52$^s$ Reed is the most suitable choice for poplin fabric. This reed size provides the right balance of tension and space between the warp yarns, ensuring smooth and controlled weaving. It allows for the tight and smooth finish characteristic of poplin fabric. This reed size is ideal for medium-weight fabrics like poplin.

4. 3/100$^s$ Reed

3/100$^s$ Reed is another larger reed size, which may cause excessive space between the warp threads, leading to a looser fabric structure. This is not suitable for poplin, as it requires a finer balance of tension and control over the warp threads.

Why 4/52$^s$ Reed is the Correct Answer

The 4/52$^s$ reed is the ideal choice for poplin fabric. It provides the necessary balance of tension and control over the warp yarns, allowing for a tightly woven fabric with the desired smoothness and quality. This reed size is well-suited for fabrics like poplin, which need a good combination of firmness and flexibility.

Why Not the Other Options?

• 2/108$^s$ Reed: Too large for poplin, leading to a looser weave.
• 2/80$^s$ Reed: Too fine, which may cause the fabric to be too tight and affect its smoothness.
• 3/100$^s$ Reed: Too large and would lead to an inconsistent or looser fabric.

A Simple Way to Remember

For poplin, think of the reed size as balancing tension and smoothness. The 4/52$^s$ reed strikes the right balance for a medium-weight fabric like poplin.

Final Answer

The correct reed for producing a poplin sort with 112 ends X 72 picks on a 50" RS auto loom is 4/52$^s$ Reed.