Question

As compared to cylinder, doffer has

• A. Lower rotational speed and lower wire point density
• B. Lower rotational speed and higher wire point density
• C. Higher rotational speed and lower wire point density
• D. Higher rotational speed and higher wire point density

Hint:

The doffer operates at a lower rotational speed and lower wire point density compared to the cylinder to facilitate the transfer of yarn in the spinning process.

Answer 1

The Correct Option is A

In spinning technology, the cylinder and doffer are two important components in the process of yarn production. The doffer is responsible for transferring the yarn from the cylinder to the next part of the spinning machine. The key differences between the cylinder and the doffer in terms of their operational characteristics include:

Step 1: Understanding Cylinder and Doffer Motion
The cylinder in spinning machines rotates at a higher speed than the doffer. The reason behind this is that the cylinder is primarily involved in the continuous rotation that feeds the yarn to the doffer, while the doffer's function is simply to collect and remove the yarn from the cylinder at a slower rate to prepare for the next stage in production.

Step 2: Wire Point Density
The wire point density refers to the number of wire points (or teeth) on the surface of the drum that come into contact with the fiber. The cylinder, which has a much higher rotational speed, also requires a higher wire point density to achieve the necessary twisting and spinning of the fibers into yarn. In contrast, the doffer, which operates at a slower speed, does not require the same dense arrangement of wire points since its primary job is to gather and transfer the yarn, not twist it.

Step 3: Comparison
Given the above explanation, it can be concluded that the doffer operates with lower rotational speed and lower wire point density compared to the cylinder. This combination of features ensures the effective transfer of the yarn without the need for the high speed and density required by the cylinder.

Final Answer: \[ \boxed{\text{(A) Lower rotational speed and lower wire point density}} \]