The varied and diverse causes of barré can generally be summed up in one word - INCONSISTENCY. An inconsistency that leads to barré can originate in one or more of the following categories:
! fiber quality/raw material management,
! yarn formation/supply management,
! knitting processes, and
! preparation and dyeing techniques
Fiber Quality/Raw Material Management
1. Failure to control fiber diameter (micronaire or denier) from laydown to laydown.
2. Too high a C.V. of micronaire in the laydown for a given mill's opening line blending efficiency.
3. Failure to control the fiber color in the mix (grayness Rd, yellowness +b).
4. Failure to control maturity/fineness in a laydown
5. Most, if not all, fiber barré can be controlled by the above four items; however, under certain unusual circumstances, it may be beneficial to also select mixes using ultraviolet reflectance information for each bale of cotton.
Micronaire
Average micronaire must be controlled within a laydown and from laydown to laydown. Controlling average micronaire in the laydown may not be sufficient to completely eliminate barré. Other micronaire related causes of barré are:
! > 0.2 difference in micronaire.
! > 0.1 change in mix-to-mix average micronaire.
! > 12.0 % CV of micronaire within the laydown.
It may be necessary to change the laydown averages periodically to make use of all the bales in the warehouse. This must be done slowly with no more than a 0.1 change in mix-to-mix averages.
