Rieter

Number of fibers in the yarn cross-section

Index

This determines, among other things, strength, evenness, handle, insulating capacity, thread-breakage rate, and the spinning limit of the raw material. Accordingly, there are lower limits to the number of fibers in the cross-section, as follows (for normal conditions):

 

Cotton yarns
ring-spun yarn:
combed
33 fibers
carded
75 fibers
rotor-spun yarn:
carded
100 fibers
Synthetic fiber yarns
ring-spun yarn:
carded
50 fibers
rotor-spun yarn:
carded
100 fibers

The spinning limit can then be calculated approximately by transposition of the equation:

n_F = \frac {tex_{yarn}}{tex_{fiber}}    

to give    

tex_{yarn} = n_F \times tex_{fiber}

where nF is the number of fibers. However, this formula does not take into account other parameters, such as fiber length, coefficient of friction, etc., which also affect the spinning limit. If it is desired to ascertain the average fiber fineness in a blended yarn, the following formula can be used:

tex_{fiber} = \frac {p_x \times tex_x +p_y \times tex_y}{100}

where p represents the proportion of fibers as a percentage, and the index x represents one component and the index y the other.