1. Twisting
The process of giving spiral rotation in the drafted material along its axis is called twisting. Twisting helps to bind the fibers together to give a desired strength to the drafted strand just sufficient to enable it to build up in the form of bobbin.

2. Twisting purpose To increase strength. To develop cohesion.
To prevent stretching of roving during winding
To facilitate the subsequent process.
To build a perfect bobbin.

3. Factors consider for selection of twist in roving
Staple length of the fiber:
For higher staple length, twist per inch is lower; because in long fibers lower twist results sufficient strength.
2. Hank of the roving:
For higher hank, TPI increases.
3. Fineness of the material:
Fiber fineness , TPI

4. Factors consider for selection of twist in roving
4. Type of the material:
Depends on fiber strength, different fibers require different twist, eg, cotton fibers require higher twist where polyester requires less twist.

5. Flyer
Flyer is an essential part of a speed frame used to impart twist to roving having a vertical hole at the top, Two flyer leg one of which hollow and a pressure arm.
All the parts of flyer are made of steel or plastic.The legs are carefully balanced for weight to keep the balance while running.

6. Flyer

7. Functions of Flyer
Twisting the roving . It gives one twist per revolution.
Guiding the roving in the proper place on the bobbin during winding.
The pressure arm provide tension in the roving which needs to compact bobbin.
To wind the roving on the bobbin.

8. Types of flyer Spindle mounted flyer ( in conventional machine )
Top mounted flyer ( in modern simplex machine)
Closed typed flyer.