Question

Assuming no fibre loss in draw frame, if draft is equal to doubling then the delivered sliver, as compared to fed sliver, will exhibit

• A. Decreased mass variation and higher linear density
• B. Increased mass variation and lower linear density
• C. Improved fibre orientation without change in linear density
• D. Poor fibre orientation without change in linear density

Hint:

When draft equals doubling in a draw frame, the result is improved fiber orientation with no change in the linear density of the sliver, which enhances yarn quality.

Answer 1

The Correct Option is C

In the context of the draw frame, the terms "draft" and "doubling" refer to specific processes that affect the characteristics of the delivered sliver compared to the fed sliver.

Step 1: Understanding Draft and Doubling
- Draft refers to the process of stretching the fiber bundle to reduce its size, effectively increasing the fiber length and improving the evenness of the sliver. - Doubling refers to the process of combining two or more fiber slivers to improve the uniformity and consistency of the fiber bundle. When the draft is equal to doubling, the sliver produced will have a certain characteristic that results from the combination of these two processes. The fiber's orientation improves due to the stretching and alignment of the fibers during drafting.

Step 2: What Happens to the Sliver?
- Improved Fibre Orientation: When the draft and doubling are balanced, the fibers become more aligned in the direction of the sliver. This improved fiber orientation results in better quality yarn and greater uniformity in the final product. - No Change in Linear Density: Since the processes of draft and doubling do not affect the total mass of the fiber but rather its distribution and orientation, the linear density (which measures the mass per unit length) remains constant.

Step 3: Analysis of Options
- Option (A) is incorrect because the mass variation does not decrease in this case, and the linear density remains unchanged, making this option untrue. - Option (B) is also incorrect because it suggests increased mass variation, which is not true if the processes are balanced. - Option (D) is incorrect because the fiber orientation improves with the given conditions, not worsens. Thus, the correct answer is (C), where the sliver exhibits improved fiber orientation without a change in linear density.

Final Answer: \[ \boxed{\text{(C) Improved fibre orientation without change in linear density}} \]