Step 1: Understand the Rotor (Open-End) Spinning process. A sliver is fed into the machine, broken down into individual fibers, re-formed into a yarn inside a high-speed rotor, and twisted.
Step 2: Analyze the tasks performed by the machine.
- A. Fibre separation: The sliver is fed to a very fast rotating opening roller (beater) which combs through the sliver and separates it into individual fibers. This is a crucial first step.
- B. Ordering the fibres in the strand: The separated fibers are transported by an air stream into a spinning rotor. Centrifugal force deposits them into a groove in the rotor, where they are collected and ordered into a thin, uniform strand or ribbon of fibers.
- C. Imparting strength by twisting: As the newly formed strand is pulled out of the rotor, the rapid rotation of the rotor itself imparts twist to the yarn (this is called "open-end" twisting). This twist is what gives the yarn its strength.
- D. Removal of neps: The opening roller does have a cleaning effect and can remove some trash and dust. However, rotor spinning is not a primary machine for nep removal. In fact, it is sensitive to neps in the feed sliver. Significant nep removal is the job of the carding machine.
Step 3: Identify the correct tasks. The essential tasks of a rotor spinning machine are fiber separation (A), ordering the fibers in the rotor groove (B), and imparting twist for strength (C). Nep removal is not a primary task.