Question

The strength of fiber is usually measured in bundle form because there is better correlation between fiber bundle strength and \(\underline{\hspace{2cm}}\)

• A. Yarn hairiness
• B. Yarn unevenness
• C. Yarn strength
• D. Yarn twist

Hint:

The goal of testing raw material (fiber) is to predict the quality of the final product (yarn). Testing a bundle of fibers is a better simulation of a yarn cross-section than testing a single fiber. Therefore, Fiber Bundle Strength \(\rightarrow\) predicts Yarn Strength.

Answer 1

The Correct Option is C

Step 1: Understand the question. It asks why we test the strength of staple fibers (like cotton) in a bundle (e.g., using a Stelometer or HVI) rather than testing single fibers individually. The reason given is that the bundle strength correlates well with another important property. 
 

Step 2: Analyze the structure of a staple yarn. A staple yarn derives its strength from thousands of individual fibers being twisted together. The strength of the yarn depends not just on the strength of the individual fibers, but also on how they are assembled, their length, fineness, and how they grip each other. 
 

Step 3: Compare single fiber vs. bundle strength tests. Testing single fibers is slow and gives highly variable results. A fiber bundle test, on the other hand, averages out the properties of many fibers at once. This test simulates more closely how the fibers act together within a yarn structure. It has been shown through extensive research and practice that the strength measured from a fiber bundle is a very good predictor of the strength of the yarn that can be spun from those fibers. 

Conclusion: Fiber bundle strength is measured because it provides a strong and reliable correlation with the final yarn strength.