There are 3 basic index/information when we describe a yarn/thread. First is compositon of the yarn/thread, for example,100% cotton, 100% polyester,T/C(cotton+polyester),etc.The second is the size/thickness. Usually there are two systems to use,English system and Metric system.For example,40s is a English system,we can also write as Ne 40,traditionally we write as 40s,20s,30s,10s,7s in textile industry. The third is spinning method,such as OE(Open-end),OA(Ring spinning),Siro,slub,etc.
Let's see two complet examples:
100% polyester 40s/2 spun thread. 100% polyester is the composition,40s=Ne 40,yarn thickness/size is 40s(English system),Tex 29.5 (Metric system),/2 means the yarn/thread in 2 plies,2 pieces of 40s double and twist as one yarn/thread.
100% cotton OE 10s. 100% cotton---composition, OE---spinning method,10s---yarn size/thickness.
How to convert Ne to Tex? There are formulas to do it!
if the comosition is 100% polyester or other artificial fibles, the formula is: Tex=590.5÷Ne. for example, 100% polyester 40s/2 spun thread---Ne number, 590.5÷40/2=590.5÷40×2=29.5,so Ne 40s/2=Tex 29.5
if the comosition is 100% cotto or other natural fibles, the formula is: Tex=583.1÷Ne.for example, 100% cotton OE 10s---Ne number, 583.1÷10=58.3, so Ne 10=Tex 58.3
if the comosition is blended fibles, the formula is: Tex=588÷Ne. for example, 80% cotton 20% polyester T/C40s/2---Ne number, 588÷40/2=588÷40×2=29.4,so T/C Ne40s/2=Tex 29.5
The proper meaning of Tex 29.5. It means the weight of 1000 meters of a yarn/thread at commercial moisture regain is 29.5g.
Have you got it?