In all types of drafting arrangement, the factors that affect the draft are:
Factors dependent upon the fiber material:
- mass of fiber in the strand cross section;
- degree of order of the fibers (parallel disposition);
- shape of the cross section of the fiber strand;
- compactness of the fiber strand;
- adhesion between the fibers dependent upon
- surface structure,
- crimp,
- spin finish,
- compression of the strand;
- fiber length;
- evenness of distribution of fiber lengths (staple form);
- existing twist in the fiber strand.
Factors dependent upon the drafting arrangement:
- diameter of the rollers;
- hardness of the top rollers;
- pressure exerted by the top rollers;
- surface characteristics of the top rollers;
- fluting of the bottom rollers;
- type and form of fiber guiding devices, such as pressure rods, pin bars, aprons, condenser etc.;
- clamping distances (roller settings);
- level of draft;
- distribution of draft between the various drafting zones.