Question

Drafting force in drawframe, when fibres are sliding, reduces with higher

• A. Draft
• B. Roller setting
• C. Fibre length
• D. Number of fibres in feed sliver

Hint:

Drafting force depends mainly on draft ratio and roller setting. Increasing both improves fiber control and reduces sliding resistance.

Answer 1

The Correct Option is A

The drafting force in a drawframe is the resistance encountered during fiber sliding and stretching. Let us analyze each factor:
Step 1: Draft (A)
With higher draft, fibers are elongated more gradually and aligned better, which reduces the relative sliding resistance between them. Hence, drafting force reduces with higher draft. So, (A) is correct.
Step 2: Roller Setting (B)
When the roller setting (distance between rollers) is increased, fibers are allowed to slide more freely, reducing the drafting force. Thus, (B) is correct.
Step 3: Fibre Length (C)
Longer fibers increase the control zone and reduce slippage, which does not necessarily reduce drafting force in sliding conditions. Therefore, (C) is not correct in this specific context.
Step 4: Number of Fibres (D)
An increase in the number of fibers in the feed sliver generally increases frictional interactions and drafting resistance. Hence, (D) is not correct.
Thus, the correct answers are \fbox{(A) and (B)}.