Question

The maximum yarn tension build up occurs in

• A. Nonlinear cam with 52$^\circ$
• B. Linear cam with 57$^\circ$
• C. Nonlinear cam with 55$^\circ$
• D. linear cam with 45$^\circ$

Hint:

• Yarn tension in knitting is affected by stitch cam design (profile and angle) and settings.
• Stitch cam angle: If defined as angle of descent track with horizontal, a smaller angle means a steeper, more rapid needle pull-down.
• Rapid needle pull-down generally leads to higher peak yarn tension.
• Linear cams provide constant needle velocity (for constant cam rotation), while nonlinear cams are designed for specific acceleration/deceleration profiles (often to reduce peaks).
• A linear cam with a steep angle (smallest angle listed, e.g., 45$^\circ$) is likely to cause the highest tension among the options, as it implies the most abrupt loop formation.

Answer 1

The Correct Option is D

In the context of textile engineering and fiber science, it's critical to understand how yarn tension varies with different types of cam profiles and angles.
The question pertains to the maximum yarn tension buildup. To analyze this, one needs to consider the cam profile (linear or nonlinear) and the cam angle.
Factors Affecting Yarn Tension:

• Cam Type: Linear cams rotate uniformly, leading to consistent acceleration and tension behavior, whereas nonlinear cams can have variable acceleration, impacting yarn tension differently.
• Cam Angle: The angle of the cam impacts the rate of rotational speed and acceleration, thus affecting yarn tension. Smaller angles often increase tension as they can lead to rapid changes in motion.

Analysis of Options:

• Nonlinear cam with 52$^\circ$: Nonlinear nature implies less predictable tension patterns.
• Linear cam with 57$^\circ$: The larger angle typically leads to smoother transitions, reducing tension peaks.
• Nonlinear cam with 55$^\circ$: Similar to the 52$^\circ$ case, the nonlinear profile affects tension differently.
• Linear cam with 45$^\circ$: The linear nature and smaller angle result in sharper tension increases due to faster acceleration.

Conclusion: Since smaller angles with linear cams typically produce higher yarn tension due to their higher acceleration over shorter periods, the correct answer is linear cam with 45$^\circ$.