RKM / Single Yarn Strength / CSP

RKM :

This can be expressed by the “Length of yarn in km” at which yarn will break of its own weight”. This is equivalent to breaking load in g/tex.

RKM is the short expression for “Reisskilometer” – “Breaking-kilometer”, which is an unit out of date.

E.g.: a Cotton-yarn with 15 RKM means, it would break of its own weight, if you wind off 15 km of the yarn and hang it up in 15km.

Nowadays it is common practice, to use the unit Centi-Newton per Tex (cN/Tex) or gram-force per Tex (gf/Tex). RKM and cN/Tex or gf/Tex are practically the same (a slight difference would be there)

SINGLE YARN STRENGTH (Breaking force) : 

This is the force required to break a strand of single yarn. It is expressing Centi-Newton (cN). 

STRENGTH (Tenacity) :

The Tensile Strength expressed as force per unit linear density is called Tenacity. This is normally expressed as gram force per tex (gf/tex).

CSP (Count Strength Product) :

CSP, the bundle strength, can be predicted using single yarn strength and vice versa. 

Unit of RKM = gms/tex

RKM  = Single yarn strength (Grams force/tex) / Tex count

        = Single yarn strength (Grams force/tex) / (590.5 / Ne count)

        = Single yarn strength (cN) X 1.02 / Tex count

        = Single yarn strength (cN) X 1.02 / (590.5 / Ne Count)

Also Breaking strength in grams of

Tensorapid instrument = 0.87 x Strength in grams from Tensojet

Approximate RKM = 7 X Lea CSP / 1000