Imperfections or IPI indicate the evenness or unevenness in yarn. If the IPI / Imperfection level is high in yarn it indicates that the quality of yarn is not good. If the imperfection or IPI count is less, it reflects the good quality yarn.
A lot of people ask about how to calculate or count the imperfection. counting is very simple after reading our post.
To find the imperfection in yarn you need to have its Uster Testing Report. There you will find several columns like U%, cvb, thin, thick, neps and hairiness Etc.
Usually for ring spun yarn to count the imperfection index we take the total of (Thin-50% + Thick+50% + Neps+200 per kilometer). The total of these three parameters is called imperfection or IPI.
For Open End or Autocoro yarn to count the imperfection index we take the total of (Thin-50% + Thick+50% + Neps+280 per kilometer). The total of these three parameters is called imperfection or IPI.